Geocentric Heliogyro

Operational Solar-Sail

Technology

GHOST

Nicholas Busbey Mark Dolezal Casey Myers Lauren Persons Emily Proano Megan Scheele Taylor Smith Karynna Tuan

1

Briefing Overview and Content

bull Problem Statement Objectives FBD and CONOPS

bull Baseline Design and Critical Project Elements

bull Testing Procedures

bull Feasibility Analysis and Risk Management

bull Strategies for Future Studies

2

Heliogyro Background

bull Solar-sail blades used as a sustainable form of propulsion without the need of propellant

bull Blades are gyroscopically stiffened in place of structural support - Greatly reduces mass of satellite simple design scales to a much larger conventional solar sail

bull Blades must be very long to provide adequate area

bull Presents a challenge to provide storage and deployment of sails

bull No ground demonstrations of systems capable of packaging and deploying full scale blades currently exists

3

Problem Statement

bull GHOST will design build and test a heliogyro solar sail deployment and pitching mechanism packaged into a CubeSat of up to 12U and capable of deploying and pitching adequately sized solar sail blades to provide a characteristic acceleration of 01 mms2

bull Design a storage system for 4 blades

bull Build and test deployment mechanism for one solar sail

bull Build and test coordinated pitching mechanism for two solar blades using blade-equivalent masses

4

Base Project Components

Heliogyro Sail

bull Deployment through centrifugal tension

bull Lightweight due to reduced structure

bull Sustainable propulsion

CubeSat

bull Small scale low cost

bull Repeatability

bull Rideshare ability provides greater launch opportunities

5

Specific Objectives

bull Blades will deploy using motors aided by centrifugal tension bull Blades will deploy at a controlled rate of 1 ndash 10 cms

bull Verified by deployment test in 1G environment

bull Blade roots demonstrate coordinated pitching motion of 180ordm (

90ordm) bull Vectors a hypothetical solar sail thrust by changing effective area on which

photons would be deflected

bull Entire structure must be stowable within a standard 12U or smaller CubeSat

bull System limited to 10 W of power

bull Must show that structure can survive launch

6

Functional Block Diagram

7

Concept of Operations

(CONOPS)

8

30 Controlled deployment of sails via motors

31 Suspend undeployed blade in 1G

311 Establish electronic connection with

deployment mechanism

32 Initiate deployment mechanism

33 Controlled sail deployment using motors

50 Pitch solar sail roots

51 Establish remote connection with pitching

mechanism

52 Send appropriate pitch command

53 Measure resulting torque from pitching using

an accelerometer

54 Measure resulting pitch angle

541 Record actual pitch angle and compare to

expected pitch angle

542 Ensure both actuators are capable of

generating synchronized - collective frac12 P and

1P cyclic root pitch deflections

Baseline Design

bull Our baseline design includes three systems that must be integrated together bull 8U CubeSat chosen in order to minimize volume and

still accommodate solar sail width

1 Pitching system Encoder motor and axle

bull No gears involved

2 Deployment System Motor without gears bull Motor in-line with deployment axle

3 Interface System Hollow plate bull Houses the deployment system bull Connects to pitching axle

bull The 8U CubeSat and characteristic acceleration requirement create very strict volumetric restrictions which will be addressed in our feasibility analysis

1

2

3

9

Pitching system Encoder Motor

and Axle

bull The encoder and motor are located in the central area of the satellite

with the axle extending from the motor

Encoder Motor

Axle

CubeSat

Vertical

Stabilizer

Space for MCU

Communication and

other instruments

Desired Inner Control

Area

Outer Area for

Deployment and

Interface Systems

bull The motors are stabilized by a vertical pillar attached to the top and bottom of the CubeSat

bull The encoder mitigates the vibrations of the motor

Top-Down View

Command

Power

10

Deployment System Parallel

Axis Motor

bull Rolled sail and motor on same axis centered around the deployment axle

bull Motor is powered by wiring extending from the satellite center and stabilized by connecting to the interface

bull Locking mechanism- the blade tip is held by stabilizers that will prevent bunching upon deployment

Top-Down View

Power and Control

Rolled solar sail

Axle Deployment

Motor

Extra width on end keeps sail ready for deployment

Locking mechanism

Connects to Interface

Side View

Stabilized by

Interface

Stabilized by

Interface

Unrolled solar sail

11

Interface System Hollow Plate

bull Hollow plate interface attaches to pitching axle and houses the deployment system

bull Power and Control wiring spun around or through axle to prevent twisting when pitching

Space for MCU

Communication and

other instruments

Desired Inner Control

Area

Top-Down View (Not to

scale)

bull A thin-set bearing would be used to connect the plate to the CubeSat wall and minimize friction

Locking mechanism

Connects to Interface Plate Sized for thin-set bearing

connected to CubeSat

Power and Control

Wiring for

Deployment Motor

12

Critical Project Elements

bull Blade Deployment bull Earth-based design

bull Successfully deploy one solar sail blade in a 1G environment bull A motor is necessary to deploy one blade at a controlled rate of 1-10 cms bull The blade deployment needs to be tested in a near drag-free environment

bull Space-ready system bull Design a method to initialize the spin of the solar sail bull The blades must stay rigid during deployment

bull Blade Pitching bull Blades must pitch to a deflection angle given an input with a motor

bull Blades must have motor capable to pitch the blades 180

bull Blades must have coordinated deflection response bull Testing needs to confirm blades pitch to desired angle

13

Critical Project Elements

bull Orbit bull Earth-based system

bull While CubeSat is spinning blades must pitch in a periodic motion to direct the thrust bull A spin stand must be used to spin the CubeSat

bull Space-ready design bull Orbit must be designed for altitudes of 1100 ndash 1500 km

bull CubeSat must be launched into an initial orbit

bull Solar sail must have orbit transferring capabilities by pitching blades bull The solar sail blades must be sized to generate an acceleration of 01 mms2 bull Solar sail must be able to enter and exit a transfer orbit

bull Communication bull Earth-based model must be able to receive commands for pitching and deployment

systems bull Space-ready system must be able to communicate with Earth

14

Critical Project Elements

bull Integration bull The CubeSat is restricted by a maximum power available of 10W

bull Motors needed for blade release and pitching

bull The CubeSat is restricted to be no larger than 12U bull Earth-based model will be designed for 2 blades while space design will be for 4 blades

bull The CubeSat needs to hold the blades during a packaged state

bull Plates must be able to pitch without contact and minimum friction

bull The CubeSat must survive launch bull The CubeSat must meet the standards to launch in a Canesterized Satellite Dispenser

bull Extra design must be considered to stabilize the CubeSat for vibrations

bull Launch vibration test to prove survivability

bull Financial bull Earth-based model is restricted by a cost of $5000

15

Blade Deployment Space Model

Centripetal Acceleration

As the spacecraft spins the sail will experience a force

Important because the motor needs to oppose this force

16

Bus

V

r = solar sail length

Blade Deployment Space Model

Centripetal Acceleration

Deployment

Length

(Meters)

Centripetal

Acceleration

(ms2)

Mass

(Kg)

Centripetal

Force (N)

1 0011 0037 000041

15 016 0044 00073

30 033 0052 0017

50 055 0062 0034

100 11 0087 0095

150 16 011 018

200 22 014 03

220 24 015 035

17

Constant Spin Ω = 1 RPM

Gravitational Force

Earth

Orbital Trajectory

Equations

Constants

Blade Deployment

Testing on Earth Relation to Space

CubeSat rotating at 1 RPM rarr centripetal acceleration rarr centrifugal tension

Blade is fully deployed rarr maximum centrifugal tension

Simulate same centrifugal tension the blade would experience in space

Total mass of 36 g used in the deployment test

mTOTAL = mTM + mB = 36 + 110 = 146 g

a = 241 ms2 F = ma = 035 N

F = mg = 035 N g = 981 ms2

mTOTAL = 36 g

The holding torque of the motor used must be able to withstand this force

τ = r

F r = 05 cm F = 035 N

τ = 00018 Nm

Space Application

Motor

CubeSat

rotating at 1

RPM

Blade Tip mass

F

Top View

Tip mass trajectory

mB = 10 g mTM = 26 g

F = mg

Deployment Test

r

Mounted to Table Side View

Tip

mass

Motor

Blade

Front View

MotorBus

Interface

18

Blade Deployment

Earth Test Validation

19

Deployment Test

bull Release one solar sail blade of 15m at a controlled rate of 1-10 cms to demonstrate controlled deployment

bull Will be tested in Professor Frewrsquos lab in Fleming that is 17m high

bull Use video camera to measure rate set markers along wall to track deployment

19

Blade Deployment Space Model

Initial Spin Up

bull Carbon Steel Blade Supports at the end to replace end mass

bull 50 Carbon Steel

bull 01 mm thick

bull Deployment motor will deploy initial blade support structure for initial spin-up

CubeSat

Carbon-Steel

Blade Supports

Solar Blade

20

Blade Deployment Space Model

Initial Spin Up

bull Collective pitch of 35

to produce torque for spin up

bull Mass at end of sail=367g

bull Volume = 47e-6 cubic m

bull Two perpendicular rods rotating about oblate axis bull Both 4 kg

bull I=

bull Known bull Width=01 m

bull Length=047 m

bull Surface Area=00467 squared meters

21

Blade Deployment Space Model

Initial Spin Up

bull

=435

bull α=

bull Time = 24 days

bull Release the rest of sail and centrifugal tension will aid in deployment of sail

bull Solar sail thrust should keep CubeSat at 1 RPM while deploying

CubeSat

∆ω = Ω = 1 RPM

τ = L

F = Iα

L = 057 m

F = 023 μN

22

Orbit Initial Orbit

Final Orbit Selection

bull Sun-Synchronous 1500 km DawnDusk Orbit

bull Assumptions

bull Circular Orbit (e = 0 a = p)

bull No atmospheric drag above 1100 km altitude

bull Only orbital perturbation considered in orbit determination is the oblateness of the earth (second zonal constant J2)

bull All other orbital perturbations are neglected

bull For SS Orbit Node Precession = Solar Precession

bull Gyro rotational axis always oriented towards Sun

23

See Appendix for calculation

24

Orbit Initial Orbit

SS DawnDusk Orbit

Orbit Initial Orbit

Launch

bull Vandenberg AFB CA

bull Atlas V Launch Vehicle

bull Secondary Payload

bull Insertion into near Polar Orbit via Centaur Upper Stage

bull Further transfer necessary to achieve SS orbit

25

Orbit Blade Size

Maximum Solar Radiation Pressure Calculation

bull Assumptions

bull Perfectly reflecting surface

bull α = 0

(incident radiation perpendicular to surface)

26

Preflect2W

cR2cos2 = 908 Pa

where W = 1361 Wm2 c = 30x10 8 ms amp R = 100 AU

Orbit Blade Size

Minimum Solar Blade Surface Area for

Necessary Thrust

bull Assumptions

bull m = 8 kg (based on 8U Volume CubeSat 1 kgU)

27

a ac 01 mms2 requirement

sreflectc APmaFmax Asmac

Preflect8811 m2

bull 4 solar blades

As

42203 m2 per blade

Orbit Transfer

bull Example

bull LV delivers sc into 1100 km circular polar orbit

bull 1) Orbit raising maneuver to 1500 km

bull 2) Inclination change maneuver to i = 10196

bull How long will this take with GHOSTrsquos capabilities

28

29

Orbit Transfer

Orbit Raising Maneuver

Hohmann Transfer

Dual tangential

burn coplanar orbit

transfer

Initial Orbit

Final Orbit

Transfer Orbit

Orbit Transfer

Orbit Raising Maneuver

bull Calculated using Hohmann Transfer Equations

30

initial transfer vi 945 ms

transfer final v f 933 ms

vtotal 1877 ms

torbit raise 123 days

45o Preflect 454 Pa ain plane 177x10 5 ms2

Two blades pitched at

45

producing thrust in along track direction

See appendix for detailed orbit transfer diagrams

Orbit Transfer

Orbit Inclination Change

bull Calculated using inclination change only equations

31

v inc 2v initialcos( fpa)sini

2where vinitial v f fpa 0o amp i 1196o

vinc 148 kms i 00028 oorbit

a ac 01 mms2 P 6959 s Thrust acts over northern hemisphere of orbit (12 of Period)

tinc change 3437 days

Orbit Transfer

Final Destination

bull Δttotal = 4667 days or ~ 155 months bull time it takes to transfer from LV Delivery 1100 km polar orbit to 1500 km SS

orbit

bull this BOTE calculation has huge implications on both

bull mission duration

bull life span of sc components materials etc

bull Validates the high performance orbit transfer capabilities of the heliogyro architecture

32

Integration CubeSat

Pitch Test Validation

Sensor(s) to measure

torque and

Purpose Demonstrate coordinated pitching with equivalent mass and

realistic bus rotation

bull Rotation of 1 RPM

bull Measure torque on bus

bull Measure and compare actual pitching angles

to commanded

pitching angles

Sensors Needed

bull 3 axis Accelerometer (torque measurement)

bull 3 axis Gyroscope (pitch angle measurement)

bull 12 bit resolution (greater than pitching motors)

bull Fit onto or on 8U CubeSat

ADI516xxxIM4

bull 3 axis gyroscope

bull 3 axis magnetometer

bull 3 axis accelerometer

bull 14 bit resolution

bull 1

volume

bull Available free for checkout in ITLL

Sail Equivalent

mass

33

Integration CubeSat

Feasibility of our Baseline Design

bull To achieve characteristic acceleration for an 8U (8kg) CubeSat we needed each sail to be 2203

bull The diameter of the rolled spool inside the CubeSat (pre-deployment) varies with the width of the sail

bull To find the diameter of the rolled spool we calculated the length of one sail for a chosen width Assuming a Mylar thickness of 5 um due to the crinkling effect the spool width was calculated by iterating each rotation with increasing diameter as the blade rolls up

Iterate for rolling up sail until finished

(cm)

(m)

12 1836 247

10 2203 270

8 2754 300

34

Integration CubeSat

Sizing the Blades

bull CubeSat constrained by 20 cm on each side

bull Need to perform 180 degree independent rotation and maximize room inside the satellite for pitching motors controls and communication

Top Down Views of each size ( Scaled to correct dimensions)

12 cm blade width 10 cm blade width 8 cm blade width

bull Not intrusive on inner area

bull Full 180 motion

bull Infringes on space inside

bull Full 180 motion

bull Not intrusive on inner area

bull No Full 180 motion

35

Integration CubeSat

Housing the Rolled Sail

bull The solar sail blades will be controlled by a pitching axle but there must be an interface to connect to the axle

bull Cylindrical plate housing

bull Protects blades

bull Easy to connect to axle

bull No gears

bull Ability to provide counterweight

to deployment motor

bull With the tight volume constraints of our cube the Cylindrical plate must be altered to avoid interference with other sides

36

Integration CubeSat

Fitting the cylindrical Plate

bull Clearance for rolled sail

bull 2 cm clearance on each side

bull 06 cm clearance on behind the motor

bull This leaves overlapping corners

bull To prevent overlap we will make a 45ordm cut around the entire cylinder

2 cm

06 cm

Rolled Sail

Plate Encasing

Overlapping

Corners

45ordm cut to get rid

of corners

37

Integration CubeSat

Fitting the cylindrical Plate

bull The 45ordm cut will give us a 0 cm clearance (with no thickness)

bull If we implement a high-low offset between adjacent plates the distance between the two closest points increases

bull For our 14 cm diameter plates a 2 cm offset from the center for each plate (4 cm total) the effective clearance becomes 251 cm

Two adjacent sides

on same axis

With a High-Low Offset

38

Integration CubeSat

High-Low Offset Plates

The high low offset will give each plate room to rotate a full 180ordm

1 cm clearance between the top of the

blade and the edge of the satellite to fit

the thin-set bearing

A 3mm plate thickness gives adjacent

plates a distance of 19 cm between

their closest points

39

Integration CubeSat

High Low Offset Performance Validation

bull The high-low offset will not effect the performance or stability of the deployment or pitching systems

bull Upon deployment the opposing extension on each side cancels out unwanted torque

View From high side View From low side

bull In a sun-synchronous orbit the high or low setting has no effect as the rotational axis of the satellite is always solar pointing

View From Sun

40

Integration Power

Electronics Feasibility Analysis

bull Project Constraints

bull CubeSat power source Li-Ion batteries (5 and 33 V is common) - Would require thermal protection

bull Communications System - Transceiver (UHF is common) [USART serial port] - Buffer may be needed depending on power constraints

bull Deployment Subsystem - 1 step-motor [output] - 1 encoder [MSSP input] OR direct deployment measurement via external sensor

bull Pitching Subsystem - 2 servomotors [output]

41

Integration Power

PIC18F Series Microchip

bull Inputs 2 USART and 2 MSSP ports available (for basic PICs) - More than 1 device may be connected to each port - 2-3 devices needed

bull Outputs 8 ports - 2 devices needed

bull 16 bit - Though different PICs may be acquired for higher resolution

bull Operating Range 2-55 V - Within provided parameters

42

PIC

Communications

Deployment

Motor

Encoder

Pitching

Motor 1

Pitching

Motor 2 Key

Power Lines

Input Lines

Output Lines

Integration Power

Microchip FBD

5V Battery

Possible Voltage

Buffer

Encoder

43

Integration Power

Motor Power Limitations

bull Power Constraints

Pmax = 100 W

Vmax = 50 V

bull P = IV (Power = CurrentVoltage)

bull Therefore Iave = 20 Amps

bull Blade Pitching (4 motors total needed) - Current limitations for power sources and number of simultaneous blades pitching

Number of Blades 5 V Input 36 V input 31 V input 2 V input

4 040 A 069 A 081 A 125 A

2 080 A 139 A 161 A 250 A

1 160 A 278 A 323 A 500 A

44

Integration Motors

Stepper vs Brushless Servo Motors

45

-Contain many poles (50+) -Contain only 4-12 poles

-Distinct steps cause

vibration during use -Do not suffer from

vibration and resonance

issues smooth movement

-Low maintenance easier to

commission mechanically

simple

-Efficient response to start

stop and reverse commands

-Rely on encoders for

position details in closed

loop response

-Physical sizes

are comparable

-Both available

in various

lengths at same

frame size -Torque can be readily

controlled

-Low cost and high

availability

-Complexity drives cost

upward

Chosen for

deployment motor

Chosen for

pitching motor

Stepper Servo

Integration Blade Deployment

Deployment Motor Feasibility

Required holding torque is calculated to be 18 mNm

Required driving torque is calculated to be 117

10-5 mN∙m

bull Micro Motion Solutions ndash miniature stepper motors bull Physical Properties

bull Diameter = 6-22 mm

bull Length = 93-20 mm

bull Weight = 55-12 g

bull Holding Torque = 24-10 mN∙m = 034-142 oz∙in

bull Resolution bull 1 or 2 phase half-step capability

bull Steps per turn = 20-24 rarr 15˚-18˚ per step

5 of full step accuracy

bull Power Requirements bull Nominal voltage per phase 2-5 V

bull Nominal current per phase 01-1 A

46

Integration Blade Pitching

Blade Pitching Motor Feasibility

Required driving torque is calculated to be 0019 mN∙m

bull Mabuchi Servo Motor bull Physical Size

bull Diameter = 17 mm

bull Length = 25 mm

bull Weight = 16 g

bull Torque

bull Holding Torque = 161 mN∙m = 0228 oz∙in

bull Driving Torque = 0385 mN∙m = 0055 oz∙in

bull Friction Torque = 403

10-3 mN∙m = 571

10-4 oz∙in

bull Power Requirements

bull Nominal voltage per phase 2-5 V

bull Nominal current per phase 006-02 A 47

Integration Launch

Feasibility for Pre-deployment locking mechanism

The tip of the solar sail will be wider than the body with the sail tip set outside the plate

The tip will be held in place vertically by stationary blade stabilizers and kept tight by the holding torque of the deployment motor

Stationary blade

stabilizers

Extra-wide

blade tip

Upon deployment the motor

turns and the blade extends

48

Integration Launch

Canesterized Satellite Dispenser (CSD)

bull Ride in a 12 U CSD

bull Width=239 cm Height=226 cm Length=366 cm

bull Mass=0-24 kg at launch

bull Center of Mass when stowed in

bull x is -40 to 40 mm

bull y is 50 to 125 mm

bull z is 133 to 233 mm

wwwplanetarysytemscorpcom 49

Integration Launch

Test Validation

bull Launch Vibration Test

bull Needs to be space applicable and strong enough to withstand vibration

bull Ball Aerospace can provide a shake table costing $250hr

bull Preparation for Testing using FEM modeling and adding support features

50

Financial

bull Total Budget $5000

bull Components

bull Stepper Motor $100-200

bull Servo Motor (x2) $50-500 each

bull Materials (made in-house) $500-1000

bull Electronics $0-500

bull Testing

bull Deployment amp Pitching Free (Performed on Campus)

bull Launch Survivability Vibration Stand - $250hr Ball Space Systems in Boulder

bull Total Estimation $700-2700 + Vibration Stand Testing

51

Baseline Design All Together

bull The 8u CubeSat and characteristic acceleration requirements create very strict volumetric restrictions

bull The size of the plates and the rolled sail blade must be validated

bull This design will be analyzed and verified in the feasibility requirements

Inner Control Area

bull Motor

bull Encoder

bull Control

bull Communication

bull Power

Possible Load-bearing

corners for deployment

Housed Solar Sail

Top-Down View

Extra room for third

party systems

52

Status Summary

53

SystemMechanism Final Choice Further

Studies

Needed

8U Structure Fit our CubeSat in 12U bus provided by Planetary Services Yes

Adequate Area of Sails to Provide

Orbit Transfer Capabilities

AR = 22001 No

Pitching Mechanism Using a servo motor Yes

Pitching Accuracy Pitching encoder Yes

Plate Integration System Using a two cylinder design with tapered edges so

everything will fit

No

Deployment Motor Using a stepper motor No

Launch Ability Must conform to standards set by Planetary Services Yes

Launch Survivability Verify that GHOST will survive launch Yes

Initial Spin-Up Carbon steel attached to solar blade material Yes 53

Strategy for Conducting

Remaining Studies

bull 8U GHOST inside 12U structure bull Create a SolidWorksCAD model

bull Pitching Mechanism bull Determine adequate motor within size power and cost constraints

bull Pitching Accuracy bull Determine pitching accuracy based on orbital sensitivity

bull Launch Ability bull Because design is symmetrical center of mass is in the center of the satellite during launch bull Further investigations is needed to determine how many counterweights

bull Launch Survivability bull FEM or Vibrations

bull Initial Spin-up bull Determine feasible method to attach carbon steel support structure to solar sail blade material

54

Resources

bull PAYLOAD SPECIFICATION FOR 3U 6U 12U AND 27U Np Planetary Systems Corporation 2013 Print

bull Davis Jason The Planetary Society The Planetary Society Blog Firefly Partners 11 Apr 2012 Web 12 Oct 2013 lthttpwwwplanetaryorgblogsguest-blogsjason-davis3450htmlgt

bull Mao Tengfei 01mm Thickness Measuring Tape Wwwalibabacom Alibabacom nd Web 12 Oct 2013 lthttpwwwalibabacomproduct-gs8359006940_1mm_thickness_measuring_tapehtmlgt

55

Resources

bull ldquoHow servos and steppers stack uprdquo Machine Design 9 February 2012 [httpmachinedesigncomnewshow-servos-and-steppers-stack Accessed 7 October 2013]

bull ldquoMiniature Stepper Motor Drive Systems - Data Sheetrdquo Micro Motion Solutions [httpwwwmicromocomstepper-motors-datasheetsaspx Accessed 11 October 2013]

bull ldquoData Sheet for TS-53 Servorsquos Electric Motorrdquo Mabuchi Motor [httpwwwprincetonedu~mae412TEXTNTRAK2002292-302pdf Accessed 11 October 2013]

56

Briefing Overview and Content

bull Problem Statement Objectives FBD and CONOPS

bull Baseline Design and Critical Project Elements

bull Testing Procedures

bull Feasibility Analysis and Risk Management

bull Strategies for Future Studies

2

Heliogyro Background

bull Solar-sail blades used as a sustainable form of propulsion without the need of propellant

bull Blades are gyroscopically stiffened in place of structural support - Greatly reduces mass of satellite simple design scales to a much larger conventional solar sail

bull Blades must be very long to provide adequate area

bull Presents a challenge to provide storage and deployment of sails

bull No ground demonstrations of systems capable of packaging and deploying full scale blades currently exists

3

Problem Statement

bull GHOST will design build and test a heliogyro solar sail deployment and pitching mechanism packaged into a CubeSat of up to 12U and capable of deploying and pitching adequately sized solar sail blades to provide a characteristic acceleration of 01 mms2

bull Design a storage system for 4 blades

bull Build and test deployment mechanism for one solar sail

bull Build and test coordinated pitching mechanism for two solar blades using blade-equivalent masses

4

Base Project Components

Heliogyro Sail

bull Deployment through centrifugal tension

bull Lightweight due to reduced structure

bull Sustainable propulsion

CubeSat

bull Small scale low cost

bull Repeatability

bull Rideshare ability provides greater launch opportunities

5

Specific Objectives

bull Blades will deploy using motors aided by centrifugal tension bull Blades will deploy at a controlled rate of 1 ndash 10 cms

bull Verified by deployment test in 1G environment

bull Blade roots demonstrate coordinated pitching motion of 180ordm (

90ordm) bull Vectors a hypothetical solar sail thrust by changing effective area on which

photons would be deflected

bull Entire structure must be stowable within a standard 12U or smaller CubeSat

bull System limited to 10 W of power

bull Must show that structure can survive launch

6

Functional Block Diagram

7

Concept of Operations

(CONOPS)

8

30 Controlled deployment of sails via motors

31 Suspend undeployed blade in 1G

311 Establish electronic connection with

deployment mechanism

32 Initiate deployment mechanism

33 Controlled sail deployment using motors

50 Pitch solar sail roots

51 Establish remote connection with pitching

mechanism

52 Send appropriate pitch command

53 Measure resulting torque from pitching using

an accelerometer

54 Measure resulting pitch angle

541 Record actual pitch angle and compare to

expected pitch angle

542 Ensure both actuators are capable of

generating synchronized - collective frac12 P and

1P cyclic root pitch deflections

Baseline Design

bull Our baseline design includes three systems that must be integrated together bull 8U CubeSat chosen in order to minimize volume and

still accommodate solar sail width

1 Pitching system Encoder motor and axle

bull No gears involved

2 Deployment System Motor without gears bull Motor in-line with deployment axle

3 Interface System Hollow plate bull Houses the deployment system bull Connects to pitching axle

bull The 8U CubeSat and characteristic acceleration requirement create very strict volumetric restrictions which will be addressed in our feasibility analysis

1

2

3

9

Pitching system Encoder Motor

and Axle

bull The encoder and motor are located in the central area of the satellite

with the axle extending from the motor

Encoder Motor

Axle

CubeSat

Vertical

Stabilizer

Space for MCU

Communication and

other instruments

Desired Inner Control

Area

Outer Area for

Deployment and

Interface Systems

bull The motors are stabilized by a vertical pillar attached to the top and bottom of the CubeSat

bull The encoder mitigates the vibrations of the motor

Top-Down View

Command

Power

10

Deployment System Parallel

Axis Motor

bull Rolled sail and motor on same axis centered around the deployment axle

bull Motor is powered by wiring extending from the satellite center and stabilized by connecting to the interface

bull Locking mechanism- the blade tip is held by stabilizers that will prevent bunching upon deployment

Top-Down View

Power and Control

Rolled solar sail

Axle Deployment

Motor

Extra width on end keeps sail ready for deployment

Locking mechanism

Connects to Interface

Side View

Stabilized by

Interface

Stabilized by

Interface

Unrolled solar sail

11

Interface System Hollow Plate

bull Hollow plate interface attaches to pitching axle and houses the deployment system

bull Power and Control wiring spun around or through axle to prevent twisting when pitching

Space for MCU

Communication and

other instruments

Desired Inner Control

Area

Top-Down View (Not to

scale)

bull A thin-set bearing would be used to connect the plate to the CubeSat wall and minimize friction

Locking mechanism

Connects to Interface Plate Sized for thin-set bearing

connected to CubeSat

Power and Control

Wiring for

Deployment Motor

12

Critical Project Elements

bull Blade Deployment bull Earth-based design

bull Successfully deploy one solar sail blade in a 1G environment bull A motor is necessary to deploy one blade at a controlled rate of 1-10 cms bull The blade deployment needs to be tested in a near drag-free environment

bull Space-ready system bull Design a method to initialize the spin of the solar sail bull The blades must stay rigid during deployment

bull Blade Pitching bull Blades must pitch to a deflection angle given an input with a motor

bull Blades must have motor capable to pitch the blades 180

bull Blades must have coordinated deflection response bull Testing needs to confirm blades pitch to desired angle

13

Critical Project Elements

bull Orbit bull Earth-based system

bull While CubeSat is spinning blades must pitch in a periodic motion to direct the thrust bull A spin stand must be used to spin the CubeSat

bull Space-ready design bull Orbit must be designed for altitudes of 1100 ndash 1500 km

bull CubeSat must be launched into an initial orbit

bull Solar sail must have orbit transferring capabilities by pitching blades bull The solar sail blades must be sized to generate an acceleration of 01 mms2 bull Solar sail must be able to enter and exit a transfer orbit

bull Communication bull Earth-based model must be able to receive commands for pitching and deployment

systems bull Space-ready system must be able to communicate with Earth

14

Critical Project Elements

bull Integration bull The CubeSat is restricted by a maximum power available of 10W

bull Motors needed for blade release and pitching

bull The CubeSat is restricted to be no larger than 12U bull Earth-based model will be designed for 2 blades while space design will be for 4 blades

bull The CubeSat needs to hold the blades during a packaged state

bull Plates must be able to pitch without contact and minimum friction

bull The CubeSat must survive launch bull The CubeSat must meet the standards to launch in a Canesterized Satellite Dispenser

bull Extra design must be considered to stabilize the CubeSat for vibrations

bull Launch vibration test to prove survivability

bull Financial bull Earth-based model is restricted by a cost of $5000

15

Blade Deployment Space Model

Centripetal Acceleration

As the spacecraft spins the sail will experience a force

Important because the motor needs to oppose this force

16

Bus

V

r = solar sail length

Blade Deployment Space Model

Centripetal Acceleration

Deployment

Length

(Meters)

Centripetal

Acceleration

(ms2)

Mass

(Kg)

Centripetal

Force (N)

1 0011 0037 000041

15 016 0044 00073

30 033 0052 0017

50 055 0062 0034

100 11 0087 0095

150 16 011 018

200 22 014 03

220 24 015 035

17

Constant Spin Ω = 1 RPM

Gravitational Force

Earth

Orbital Trajectory

Equations

Constants

Blade Deployment

Testing on Earth Relation to Space

CubeSat rotating at 1 RPM rarr centripetal acceleration rarr centrifugal tension

Blade is fully deployed rarr maximum centrifugal tension

Simulate same centrifugal tension the blade would experience in space

Total mass of 36 g used in the deployment test

mTOTAL = mTM + mB = 36 + 110 = 146 g

a = 241 ms2 F = ma = 035 N

F = mg = 035 N g = 981 ms2

mTOTAL = 36 g

The holding torque of the motor used must be able to withstand this force

τ = r

F r = 05 cm F = 035 N

τ = 00018 Nm

Space Application

Motor

CubeSat

rotating at 1

RPM

Blade Tip mass

F

Top View

Tip mass trajectory

mB = 10 g mTM = 26 g

F = mg

Deployment Test

r

Mounted to Table Side View

Tip

mass

Motor

Blade

Front View

MotorBus

Interface

18

Blade Deployment

Earth Test Validation

19

Deployment Test

bull Release one solar sail blade of 15m at a controlled rate of 1-10 cms to demonstrate controlled deployment

bull Will be tested in Professor Frewrsquos lab in Fleming that is 17m high

bull Use video camera to measure rate set markers along wall to track deployment

19

Blade Deployment Space Model

Initial Spin Up

bull Carbon Steel Blade Supports at the end to replace end mass

bull 50 Carbon Steel

bull 01 mm thick

bull Deployment motor will deploy initial blade support structure for initial spin-up

CubeSat

Carbon-Steel

Blade Supports

Solar Blade

20

Blade Deployment Space Model

Initial Spin Up

bull Collective pitch of 35

to produce torque for spin up

bull Mass at end of sail=367g

bull Volume = 47e-6 cubic m

bull Two perpendicular rods rotating about oblate axis bull Both 4 kg

bull I=

bull Known bull Width=01 m

bull Length=047 m

bull Surface Area=00467 squared meters

21

Blade Deployment Space Model

Initial Spin Up

bull

=435

bull α=

bull Time = 24 days

bull Release the rest of sail and centrifugal tension will aid in deployment of sail

bull Solar sail thrust should keep CubeSat at 1 RPM while deploying

CubeSat

∆ω = Ω = 1 RPM

τ = L

F = Iα

L = 057 m

F = 023 μN

22

Orbit Initial Orbit

Final Orbit Selection

bull Sun-Synchronous 1500 km DawnDusk Orbit

bull Assumptions

bull Circular Orbit (e = 0 a = p)

bull No atmospheric drag above 1100 km altitude

bull Only orbital perturbation considered in orbit determination is the oblateness of the earth (second zonal constant J2)

bull All other orbital perturbations are neglected

bull For SS Orbit Node Precession = Solar Precession

bull Gyro rotational axis always oriented towards Sun

23

See Appendix for calculation

24

Orbit Initial Orbit

SS DawnDusk Orbit

Orbit Initial Orbit

Launch

bull Vandenberg AFB CA

bull Atlas V Launch Vehicle

bull Secondary Payload

bull Insertion into near Polar Orbit via Centaur Upper Stage

bull Further transfer necessary to achieve SS orbit

25

Orbit Blade Size

Maximum Solar Radiation Pressure Calculation

bull Assumptions

bull Perfectly reflecting surface

bull α = 0

(incident radiation perpendicular to surface)

26

Preflect2W

cR2cos2 = 908 Pa

where W = 1361 Wm2 c = 30x10 8 ms amp R = 100 AU

Orbit Blade Size

Minimum Solar Blade Surface Area for

Necessary Thrust

bull Assumptions

bull m = 8 kg (based on 8U Volume CubeSat 1 kgU)

27

a ac 01 mms2 requirement

sreflectc APmaFmax Asmac

Preflect8811 m2

bull 4 solar blades

As

42203 m2 per blade

Orbit Transfer

bull Example

bull LV delivers sc into 1100 km circular polar orbit

bull 1) Orbit raising maneuver to 1500 km

bull 2) Inclination change maneuver to i = 10196

bull How long will this take with GHOSTrsquos capabilities

28

29

Orbit Transfer

Orbit Raising Maneuver

Hohmann Transfer

Dual tangential

burn coplanar orbit

transfer

Initial Orbit

Final Orbit

Transfer Orbit

Orbit Transfer

Orbit Raising Maneuver

bull Calculated using Hohmann Transfer Equations

30

initial transfer vi 945 ms

transfer final v f 933 ms

vtotal 1877 ms

torbit raise 123 days

45o Preflect 454 Pa ain plane 177x10 5 ms2

Two blades pitched at

45

producing thrust in along track direction

See appendix for detailed orbit transfer diagrams

Orbit Transfer

Orbit Inclination Change

bull Calculated using inclination change only equations

31

v inc 2v initialcos( fpa)sini

2where vinitial v f fpa 0o amp i 1196o

vinc 148 kms i 00028 oorbit

a ac 01 mms2 P 6959 s Thrust acts over northern hemisphere of orbit (12 of Period)

tinc change 3437 days

Orbit Transfer

Final Destination

bull Δttotal = 4667 days or ~ 155 months bull time it takes to transfer from LV Delivery 1100 km polar orbit to 1500 km SS

orbit

bull this BOTE calculation has huge implications on both

bull mission duration

bull life span of sc components materials etc

bull Validates the high performance orbit transfer capabilities of the heliogyro architecture

32

Integration CubeSat

Pitch Test Validation

Sensor(s) to measure

torque and

Purpose Demonstrate coordinated pitching with equivalent mass and

realistic bus rotation

bull Rotation of 1 RPM

bull Measure torque on bus

bull Measure and compare actual pitching angles

to commanded

pitching angles

Sensors Needed

bull 3 axis Accelerometer (torque measurement)

bull 3 axis Gyroscope (pitch angle measurement)

bull 12 bit resolution (greater than pitching motors)

bull Fit onto or on 8U CubeSat

ADI516xxxIM4

bull 3 axis gyroscope

bull 3 axis magnetometer

bull 3 axis accelerometer

bull 14 bit resolution

bull 1

volume

bull Available free for checkout in ITLL

Sail Equivalent

mass

33

Integration CubeSat

Feasibility of our Baseline Design

bull To achieve characteristic acceleration for an 8U (8kg) CubeSat we needed each sail to be 2203

bull The diameter of the rolled spool inside the CubeSat (pre-deployment) varies with the width of the sail

bull To find the diameter of the rolled spool we calculated the length of one sail for a chosen width Assuming a Mylar thickness of 5 um due to the crinkling effect the spool width was calculated by iterating each rotation with increasing diameter as the blade rolls up

Iterate for rolling up sail until finished

(cm)

(m)

12 1836 247

10 2203 270

8 2754 300

34

Integration CubeSat

Sizing the Blades

bull CubeSat constrained by 20 cm on each side

bull Need to perform 180 degree independent rotation and maximize room inside the satellite for pitching motors controls and communication

Top Down Views of each size ( Scaled to correct dimensions)

12 cm blade width 10 cm blade width 8 cm blade width

bull Not intrusive on inner area

bull Full 180 motion

bull Infringes on space inside

bull Full 180 motion

bull Not intrusive on inner area

bull No Full 180 motion

35

Integration CubeSat

Housing the Rolled Sail

bull The solar sail blades will be controlled by a pitching axle but there must be an interface to connect to the axle

bull Cylindrical plate housing

bull Protects blades

bull Easy to connect to axle

bull No gears

bull Ability to provide counterweight

to deployment motor

bull With the tight volume constraints of our cube the Cylindrical plate must be altered to avoid interference with other sides

36

Integration CubeSat

Fitting the cylindrical Plate

bull Clearance for rolled sail

bull 2 cm clearance on each side

bull 06 cm clearance on behind the motor

bull This leaves overlapping corners

bull To prevent overlap we will make a 45ordm cut around the entire cylinder

2 cm

06 cm

Rolled Sail

Plate Encasing

Overlapping

Corners

45ordm cut to get rid

of corners

37

Integration CubeSat

Fitting the cylindrical Plate

bull The 45ordm cut will give us a 0 cm clearance (with no thickness)

bull If we implement a high-low offset between adjacent plates the distance between the two closest points increases

bull For our 14 cm diameter plates a 2 cm offset from the center for each plate (4 cm total) the effective clearance becomes 251 cm

Two adjacent sides

on same axis

With a High-Low Offset

38

Integration CubeSat

High-Low Offset Plates

The high low offset will give each plate room to rotate a full 180ordm

1 cm clearance between the top of the

blade and the edge of the satellite to fit

the thin-set bearing

A 3mm plate thickness gives adjacent

plates a distance of 19 cm between

their closest points

39

Integration CubeSat

High Low Offset Performance Validation

bull The high-low offset will not effect the performance or stability of the deployment or pitching systems

bull Upon deployment the opposing extension on each side cancels out unwanted torque

View From high side View From low side

bull In a sun-synchronous orbit the high or low setting has no effect as the rotational axis of the satellite is always solar pointing

View From Sun

40

Integration Power

Electronics Feasibility Analysis

bull Project Constraints

bull CubeSat power source Li-Ion batteries (5 and 33 V is common) - Would require thermal protection

bull Communications System - Transceiver (UHF is common) [USART serial port] - Buffer may be needed depending on power constraints

bull Deployment Subsystem - 1 step-motor [output] - 1 encoder [MSSP input] OR direct deployment measurement via external sensor

bull Pitching Subsystem - 2 servomotors [output]

41

Integration Power

PIC18F Series Microchip

bull Inputs 2 USART and 2 MSSP ports available (for basic PICs) - More than 1 device may be connected to each port - 2-3 devices needed

bull Outputs 8 ports - 2 devices needed

bull 16 bit - Though different PICs may be acquired for higher resolution

bull Operating Range 2-55 V - Within provided parameters

42

PIC

Communications

Deployment

Motor

Encoder

Pitching

Motor 1

Pitching

Motor 2 Key

Power Lines

Input Lines

Output Lines

Integration Power

Microchip FBD

5V Battery

Possible Voltage

Buffer

Encoder

43

Integration Power

Motor Power Limitations

bull Power Constraints

Pmax = 100 W

Vmax = 50 V

bull P = IV (Power = CurrentVoltage)

bull Therefore Iave = 20 Amps

bull Blade Pitching (4 motors total needed) - Current limitations for power sources and number of simultaneous blades pitching

Number of Blades 5 V Input 36 V input 31 V input 2 V input

4 040 A 069 A 081 A 125 A

2 080 A 139 A 161 A 250 A

1 160 A 278 A 323 A 500 A

44

Integration Motors

Stepper vs Brushless Servo Motors

45

-Contain many poles (50+) -Contain only 4-12 poles

-Distinct steps cause

vibration during use -Do not suffer from

vibration and resonance

issues smooth movement

-Low maintenance easier to

commission mechanically

simple

-Efficient response to start

stop and reverse commands

-Rely on encoders for

position details in closed

loop response

-Physical sizes

are comparable

-Both available

in various

lengths at same

frame size -Torque can be readily

controlled

-Low cost and high

availability

-Complexity drives cost

upward

Chosen for

deployment motor

Chosen for

pitching motor

Stepper Servo

Integration Blade Deployment

Deployment Motor Feasibility

Required holding torque is calculated to be 18 mNm

Required driving torque is calculated to be 117

10-5 mN∙m

bull Micro Motion Solutions ndash miniature stepper motors bull Physical Properties

bull Diameter = 6-22 mm

bull Length = 93-20 mm

bull Weight = 55-12 g

bull Holding Torque = 24-10 mN∙m = 034-142 oz∙in

bull Resolution bull 1 or 2 phase half-step capability

bull Steps per turn = 20-24 rarr 15˚-18˚ per step

5 of full step accuracy

bull Power Requirements bull Nominal voltage per phase 2-5 V

bull Nominal current per phase 01-1 A

46

Integration Blade Pitching

Blade Pitching Motor Feasibility

Required driving torque is calculated to be 0019 mN∙m

bull Mabuchi Servo Motor bull Physical Size

bull Diameter = 17 mm

bull Length = 25 mm

bull Weight = 16 g

bull Torque

bull Holding Torque = 161 mN∙m = 0228 oz∙in

bull Driving Torque = 0385 mN∙m = 0055 oz∙in

bull Friction Torque = 403

10-3 mN∙m = 571

10-4 oz∙in

bull Power Requirements

bull Nominal voltage per phase 2-5 V

bull Nominal current per phase 006-02 A 47

Integration Launch

Feasibility for Pre-deployment locking mechanism

The tip of the solar sail will be wider than the body with the sail tip set outside the plate

The tip will be held in place vertically by stationary blade stabilizers and kept tight by the holding torque of the deployment motor

Stationary blade

stabilizers

Extra-wide

blade tip

Upon deployment the motor

turns and the blade extends

48

Integration Launch

Canesterized Satellite Dispenser (CSD)

bull Ride in a 12 U CSD

bull Width=239 cm Height=226 cm Length=366 cm

bull Mass=0-24 kg at launch

bull Center of Mass when stowed in

bull x is -40 to 40 mm

bull y is 50 to 125 mm

bull z is 133 to 233 mm

wwwplanetarysytemscorpcom 49

Integration Launch

Test Validation

bull Launch Vibration Test

bull Needs to be space applicable and strong enough to withstand vibration

bull Ball Aerospace can provide a shake table costing $250hr

bull Preparation for Testing using FEM modeling and adding support features

50

Financial

bull Total Budget $5000

bull Components

bull Stepper Motor $100-200

bull Servo Motor (x2) $50-500 each

bull Materials (made in-house) $500-1000

bull Electronics $0-500

bull Testing

bull Deployment amp Pitching Free (Performed on Campus)

bull Launch Survivability Vibration Stand - $250hr Ball Space Systems in Boulder

bull Total Estimation $700-2700 + Vibration Stand Testing

51

Baseline Design All Together

bull The 8u CubeSat and characteristic acceleration requirements create very strict volumetric restrictions

bull The size of the plates and the rolled sail blade must be validated

bull This design will be analyzed and verified in the feasibility requirements

Inner Control Area

bull Motor

bull Encoder

bull Control

bull Communication

bull Power

Possible Load-bearing

corners for deployment

Housed Solar Sail

Top-Down View

Extra room for third

party systems

52

Status Summary

53

SystemMechanism Final Choice Further

Studies

Needed

8U Structure Fit our CubeSat in 12U bus provided by Planetary Services Yes

Adequate Area of Sails to Provide

Orbit Transfer Capabilities

AR = 22001 No

Pitching Mechanism Using a servo motor Yes

Pitching Accuracy Pitching encoder Yes

Plate Integration System Using a two cylinder design with tapered edges so

everything will fit

No

Deployment Motor Using a stepper motor No

Launch Ability Must conform to standards set by Planetary Services Yes

Launch Survivability Verify that GHOST will survive launch Yes

Initial Spin-Up Carbon steel attached to solar blade material Yes 53

Strategy for Conducting

Remaining Studies

bull 8U GHOST inside 12U structure bull Create a SolidWorksCAD model

bull Pitching Mechanism bull Determine adequate motor within size power and cost constraints

bull Pitching Accuracy bull Determine pitching accuracy based on orbital sensitivity

bull Launch Ability bull Because design is symmetrical center of mass is in the center of the satellite during launch bull Further investigations is needed to determine how many counterweights

bull Launch Survivability bull FEM or Vibrations

bull Initial Spin-up bull Determine feasible method to attach carbon steel support structure to solar sail blade material

54

Resources

bull PAYLOAD SPECIFICATION FOR 3U 6U 12U AND 27U Np Planetary Systems Corporation 2013 Print

bull Davis Jason The Planetary Society The Planetary Society Blog Firefly Partners 11 Apr 2012 Web 12 Oct 2013 lthttpwwwplanetaryorgblogsguest-blogsjason-davis3450htmlgt

bull Mao Tengfei 01mm Thickness Measuring Tape Wwwalibabacom Alibabacom nd Web 12 Oct 2013 lthttpwwwalibabacomproduct-gs8359006940_1mm_thickness_measuring_tapehtmlgt

55

Resources

bull ldquoHow servos and steppers stack uprdquo Machine Design 9 February 2012 [httpmachinedesigncomnewshow-servos-and-steppers-stack Accessed 7 October 2013]

bull ldquoMiniature Stepper Motor Drive Systems - Data Sheetrdquo Micro Motion Solutions [httpwwwmicromocomstepper-motors-datasheetsaspx Accessed 11 October 2013]

bull ldquoData Sheet for TS-53 Servorsquos Electric Motorrdquo Mabuchi Motor [httpwwwprincetonedu~mae412TEXTNTRAK2002292-302pdf Accessed 11 October 2013]

56

Heliogyro Background

bull Solar-sail blades used as a sustainable form of propulsion without the need of propellant

bull Blades are gyroscopically stiffened in place of structural support - Greatly reduces mass of satellite simple design scales to a much larger conventional solar sail

bull Blades must be very long to provide adequate area

bull Presents a challenge to provide storage and deployment of sails

bull No ground demonstrations of systems capable of packaging and deploying full scale blades currently exists

3

Problem Statement

bull GHOST will design build and test a heliogyro solar sail deployment and pitching mechanism packaged into a CubeSat of up to 12U and capable of deploying and pitching adequately sized solar sail blades to provide a characteristic acceleration of 01 mms2

bull Design a storage system for 4 blades

bull Build and test deployment mechanism for one solar sail

bull Build and test coordinated pitching mechanism for two solar blades using blade-equivalent masses

4

Base Project Components

Heliogyro Sail

bull Deployment through centrifugal tension

bull Lightweight due to reduced structure

bull Sustainable propulsion

CubeSat

bull Small scale low cost

bull Repeatability

bull Rideshare ability provides greater launch opportunities

5

Specific Objectives

bull Blades will deploy using motors aided by centrifugal tension bull Blades will deploy at a controlled rate of 1 ndash 10 cms

bull Verified by deployment test in 1G environment

bull Blade roots demonstrate coordinated pitching motion of 180ordm (

90ordm) bull Vectors a hypothetical solar sail thrust by changing effective area on which

photons would be deflected

bull Entire structure must be stowable within a standard 12U or smaller CubeSat

bull System limited to 10 W of power

bull Must show that structure can survive launch

6

Functional Block Diagram

7

Concept of Operations

(CONOPS)

8

30 Controlled deployment of sails via motors

31 Suspend undeployed blade in 1G

311 Establish electronic connection with

deployment mechanism

32 Initiate deployment mechanism

33 Controlled sail deployment using motors

50 Pitch solar sail roots

51 Establish remote connection with pitching

mechanism

52 Send appropriate pitch command

53 Measure resulting torque from pitching using

an accelerometer

54 Measure resulting pitch angle

541 Record actual pitch angle and compare to

expected pitch angle

542 Ensure both actuators are capable of

generating synchronized - collective frac12 P and

1P cyclic root pitch deflections

Baseline Design

bull Our baseline design includes three systems that must be integrated together bull 8U CubeSat chosen in order to minimize volume and

still accommodate solar sail width

1 Pitching system Encoder motor and axle

bull No gears involved

2 Deployment System Motor without gears bull Motor in-line with deployment axle

3 Interface System Hollow plate bull Houses the deployment system bull Connects to pitching axle

bull The 8U CubeSat and characteristic acceleration requirement create very strict volumetric restrictions which will be addressed in our feasibility analysis

1

2

3

9

Pitching system Encoder Motor

and Axle

bull The encoder and motor are located in the central area of the satellite

with the axle extending from the motor

Encoder Motor

Axle

CubeSat

Vertical

Stabilizer

Space for MCU

Communication and

other instruments

Desired Inner Control

Area

Outer Area for

Deployment and

Interface Systems

bull The motors are stabilized by a vertical pillar attached to the top and bottom of the CubeSat

bull The encoder mitigates the vibrations of the motor

Top-Down View

Command

Power

10

Deployment System Parallel

Axis Motor

bull Rolled sail and motor on same axis centered around the deployment axle

bull Motor is powered by wiring extending from the satellite center and stabilized by connecting to the interface

bull Locking mechanism- the blade tip is held by stabilizers that will prevent bunching upon deployment

Top-Down View

Power and Control

Rolled solar sail

Axle Deployment

Motor

Extra width on end keeps sail ready for deployment

Locking mechanism

Connects to Interface

Side View

Stabilized by

Interface

Stabilized by

Interface

Unrolled solar sail

11

Interface System Hollow Plate

bull Hollow plate interface attaches to pitching axle and houses the deployment system

bull Power and Control wiring spun around or through axle to prevent twisting when pitching

Space for MCU

Communication and

other instruments

Desired Inner Control

Area

Top-Down View (Not to

scale)

bull A thin-set bearing would be used to connect the plate to the CubeSat wall and minimize friction

Locking mechanism

Connects to Interface Plate Sized for thin-set bearing

connected to CubeSat

Power and Control

Wiring for

Deployment Motor

12

Critical Project Elements

bull Blade Deployment bull Earth-based design

bull Successfully deploy one solar sail blade in a 1G environment bull A motor is necessary to deploy one blade at a controlled rate of 1-10 cms bull The blade deployment needs to be tested in a near drag-free environment

bull Space-ready system bull Design a method to initialize the spin of the solar sail bull The blades must stay rigid during deployment

bull Blade Pitching bull Blades must pitch to a deflection angle given an input with a motor

bull Blades must have motor capable to pitch the blades 180

bull Blades must have coordinated deflection response bull Testing needs to confirm blades pitch to desired angle

13

Critical Project Elements

bull Orbit bull Earth-based system

bull While CubeSat is spinning blades must pitch in a periodic motion to direct the thrust bull A spin stand must be used to spin the CubeSat

bull Space-ready design bull Orbit must be designed for altitudes of 1100 ndash 1500 km

bull CubeSat must be launched into an initial orbit

bull Solar sail must have orbit transferring capabilities by pitching blades bull The solar sail blades must be sized to generate an acceleration of 01 mms2 bull Solar sail must be able to enter and exit a transfer orbit

bull Communication bull Earth-based model must be able to receive commands for pitching and deployment

systems bull Space-ready system must be able to communicate with Earth

14

Critical Project Elements

bull Integration bull The CubeSat is restricted by a maximum power available of 10W

bull Motors needed for blade release and pitching

bull The CubeSat is restricted to be no larger than 12U bull Earth-based model will be designed for 2 blades while space design will be for 4 blades

bull The CubeSat needs to hold the blades during a packaged state

bull Plates must be able to pitch without contact and minimum friction

bull The CubeSat must survive launch bull The CubeSat must meet the standards to launch in a Canesterized Satellite Dispenser

bull Extra design must be considered to stabilize the CubeSat for vibrations

bull Launch vibration test to prove survivability

bull Financial bull Earth-based model is restricted by a cost of $5000

15

Blade Deployment Space Model

Centripetal Acceleration

As the spacecraft spins the sail will experience a force

Important because the motor needs to oppose this force

16

Bus

V

r = solar sail length

Blade Deployment Space Model

Centripetal Acceleration

Deployment

Length

(Meters)

Centripetal

Acceleration

(ms2)

Mass

(Kg)

Centripetal

Force (N)

1 0011 0037 000041

15 016 0044 00073

30 033 0052 0017

50 055 0062 0034

100 11 0087 0095

150 16 011 018

200 22 014 03

220 24 015 035

17

Constant Spin Ω = 1 RPM

Gravitational Force

Earth

Orbital Trajectory

Equations

Constants

Blade Deployment

Testing on Earth Relation to Space

CubeSat rotating at 1 RPM rarr centripetal acceleration rarr centrifugal tension

Blade is fully deployed rarr maximum centrifugal tension

Simulate same centrifugal tension the blade would experience in space

Total mass of 36 g used in the deployment test

mTOTAL = mTM + mB = 36 + 110 = 146 g

a = 241 ms2 F = ma = 035 N

F = mg = 035 N g = 981 ms2

mTOTAL = 36 g

The holding torque of the motor used must be able to withstand this force

τ = r

F r = 05 cm F = 035 N

τ = 00018 Nm

Space Application

Motor

CubeSat

rotating at 1

RPM

Blade Tip mass

F

Top View

Tip mass trajectory

mB = 10 g mTM = 26 g

F = mg

Deployment Test

r

Mounted to Table Side View

Tip

mass

Motor

Blade

Front View

MotorBus

Interface

18

Blade Deployment

Earth Test Validation

19

Deployment Test

bull Release one solar sail blade of 15m at a controlled rate of 1-10 cms to demonstrate controlled deployment

bull Will be tested in Professor Frewrsquos lab in Fleming that is 17m high

bull Use video camera to measure rate set markers along wall to track deployment

19

Blade Deployment Space Model

Initial Spin Up

bull Carbon Steel Blade Supports at the end to replace end mass

bull 50 Carbon Steel

bull 01 mm thick

bull Deployment motor will deploy initial blade support structure for initial spin-up

CubeSat

Carbon-Steel

Blade Supports

Solar Blade

20

Blade Deployment Space Model

Initial Spin Up

bull Collective pitch of 35

to produce torque for spin up

bull Mass at end of sail=367g

bull Volume = 47e-6 cubic m

bull Two perpendicular rods rotating about oblate axis bull Both 4 kg

bull I=

bull Known bull Width=01 m

bull Length=047 m

bull Surface Area=00467 squared meters

21

Blade Deployment Space Model

Initial Spin Up

bull

=435

bull α=

bull Time = 24 days

bull Release the rest of sail and centrifugal tension will aid in deployment of sail

bull Solar sail thrust should keep CubeSat at 1 RPM while deploying

CubeSat

∆ω = Ω = 1 RPM

τ = L

F = Iα

L = 057 m

F = 023 μN

22

Orbit Initial Orbit

Final Orbit Selection

bull Sun-Synchronous 1500 km DawnDusk Orbit

bull Assumptions

bull Circular Orbit (e = 0 a = p)

bull No atmospheric drag above 1100 km altitude

bull Only orbital perturbation considered in orbit determination is the oblateness of the earth (second zonal constant J2)

bull All other orbital perturbations are neglected

bull For SS Orbit Node Precession = Solar Precession

bull Gyro rotational axis always oriented towards Sun

23

See Appendix for calculation

24

Orbit Initial Orbit

SS DawnDusk Orbit

Orbit Initial Orbit

Launch

bull Vandenberg AFB CA

bull Atlas V Launch Vehicle

bull Secondary Payload

bull Insertion into near Polar Orbit via Centaur Upper Stage

bull Further transfer necessary to achieve SS orbit

25

Orbit Blade Size

Maximum Solar Radiation Pressure Calculation

bull Assumptions

bull Perfectly reflecting surface

bull α = 0

(incident radiation perpendicular to surface)

26

Preflect2W

cR2cos2 = 908 Pa

where W = 1361 Wm2 c = 30x10 8 ms amp R = 100 AU

Orbit Blade Size

Minimum Solar Blade Surface Area for

Necessary Thrust

bull Assumptions

bull m = 8 kg (based on 8U Volume CubeSat 1 kgU)

27

a ac 01 mms2 requirement

sreflectc APmaFmax Asmac

Preflect8811 m2

bull 4 solar blades

As

42203 m2 per blade

Orbit Transfer

bull Example

bull LV delivers sc into 1100 km circular polar orbit

bull 1) Orbit raising maneuver to 1500 km

bull 2) Inclination change maneuver to i = 10196

bull How long will this take with GHOSTrsquos capabilities

28

29

Orbit Transfer

Orbit Raising Maneuver

Hohmann Transfer

Dual tangential

burn coplanar orbit

transfer

Initial Orbit

Final Orbit

Transfer Orbit

Orbit Transfer

Orbit Raising Maneuver

bull Calculated using Hohmann Transfer Equations

30

initial transfer vi 945 ms

transfer final v f 933 ms

vtotal 1877 ms

torbit raise 123 days

45o Preflect 454 Pa ain plane 177x10 5 ms2

Two blades pitched at

45

producing thrust in along track direction

See appendix for detailed orbit transfer diagrams

Orbit Transfer

Orbit Inclination Change

bull Calculated using inclination change only equations

31

v inc 2v initialcos( fpa)sini

2where vinitial v f fpa 0o amp i 1196o

vinc 148 kms i 00028 oorbit

a ac 01 mms2 P 6959 s Thrust acts over northern hemisphere of orbit (12 of Period)

tinc change 3437 days

Orbit Transfer

Final Destination

bull Δttotal = 4667 days or ~ 155 months bull time it takes to transfer from LV Delivery 1100 km polar orbit to 1500 km SS

orbit

bull this BOTE calculation has huge implications on both

bull mission duration

bull life span of sc components materials etc

bull Validates the high performance orbit transfer capabilities of the heliogyro architecture

32

Integration CubeSat

Pitch Test Validation

Sensor(s) to measure

torque and

Purpose Demonstrate coordinated pitching with equivalent mass and

realistic bus rotation

bull Rotation of 1 RPM

bull Measure torque on bus

bull Measure and compare actual pitching angles

to commanded

pitching angles

Sensors Needed

bull 3 axis Accelerometer (torque measurement)

bull 3 axis Gyroscope (pitch angle measurement)

bull 12 bit resolution (greater than pitching motors)

bull Fit onto or on 8U CubeSat

ADI516xxxIM4

bull 3 axis gyroscope

bull 3 axis magnetometer

bull 3 axis accelerometer

bull 14 bit resolution

bull 1

volume

bull Available free for checkout in ITLL

Sail Equivalent

mass

33

Integration CubeSat

Feasibility of our Baseline Design

bull To achieve characteristic acceleration for an 8U (8kg) CubeSat we needed each sail to be 2203

bull The diameter of the rolled spool inside the CubeSat (pre-deployment) varies with the width of the sail

bull To find the diameter of the rolled spool we calculated the length of one sail for a chosen width Assuming a Mylar thickness of 5 um due to the crinkling effect the spool width was calculated by iterating each rotation with increasing diameter as the blade rolls up

Iterate for rolling up sail until finished

(cm)

(m)

12 1836 247

10 2203 270

8 2754 300

34

Integration CubeSat

Sizing the Blades

bull CubeSat constrained by 20 cm on each side

bull Need to perform 180 degree independent rotation and maximize room inside the satellite for pitching motors controls and communication

Top Down Views of each size ( Scaled to correct dimensions)

12 cm blade width 10 cm blade width 8 cm blade width

bull Not intrusive on inner area

bull Full 180 motion

bull Infringes on space inside

bull Full 180 motion

bull Not intrusive on inner area

bull No Full 180 motion

35

Integration CubeSat

Housing the Rolled Sail

bull The solar sail blades will be controlled by a pitching axle but there must be an interface to connect to the axle

bull Cylindrical plate housing

bull Protects blades

bull Easy to connect to axle

bull No gears

bull Ability to provide counterweight

to deployment motor

bull With the tight volume constraints of our cube the Cylindrical plate must be altered to avoid interference with other sides

36

Integration CubeSat

Fitting the cylindrical Plate

bull Clearance for rolled sail

bull 2 cm clearance on each side

bull 06 cm clearance on behind the motor

bull This leaves overlapping corners

bull To prevent overlap we will make a 45ordm cut around the entire cylinder

2 cm

06 cm

Rolled Sail

Plate Encasing

Overlapping

Corners

45ordm cut to get rid

of corners

37

Integration CubeSat

Fitting the cylindrical Plate

bull The 45ordm cut will give us a 0 cm clearance (with no thickness)

bull If we implement a high-low offset between adjacent plates the distance between the two closest points increases

bull For our 14 cm diameter plates a 2 cm offset from the center for each plate (4 cm total) the effective clearance becomes 251 cm

Two adjacent sides

on same axis

With a High-Low Offset

38

Integration CubeSat

High-Low Offset Plates

The high low offset will give each plate room to rotate a full 180ordm

1 cm clearance between the top of the

blade and the edge of the satellite to fit

the thin-set bearing

A 3mm plate thickness gives adjacent

plates a distance of 19 cm between

their closest points

39

Integration CubeSat

High Low Offset Performance Validation

bull The high-low offset will not effect the performance or stability of the deployment or pitching systems

bull Upon deployment the opposing extension on each side cancels out unwanted torque

View From high side View From low side

bull In a sun-synchronous orbit the high or low setting has no effect as the rotational axis of the satellite is always solar pointing

View From Sun

40

Integration Power

Electronics Feasibility Analysis

bull Project Constraints

bull CubeSat power source Li-Ion batteries (5 and 33 V is common) - Would require thermal protection

bull Communications System - Transceiver (UHF is common) [USART serial port] - Buffer may be needed depending on power constraints

bull Deployment Subsystem - 1 step-motor [output] - 1 encoder [MSSP input] OR direct deployment measurement via external sensor

bull Pitching Subsystem - 2 servomotors [output]

41

Integration Power

PIC18F Series Microchip

bull Inputs 2 USART and 2 MSSP ports available (for basic PICs) - More than 1 device may be connected to each port - 2-3 devices needed

bull Outputs 8 ports - 2 devices needed

bull 16 bit - Though different PICs may be acquired for higher resolution

bull Operating Range 2-55 V - Within provided parameters

42

PIC

Communications

Deployment

Motor

Encoder

Pitching

Motor 1

Pitching

Motor 2 Key

Power Lines

Input Lines

Output Lines

Integration Power

Microchip FBD

5V Battery

Possible Voltage

Buffer

Encoder

43

Integration Power

Motor Power Limitations

bull Power Constraints

Pmax = 100 W

Vmax = 50 V

bull P = IV (Power = CurrentVoltage)

bull Therefore Iave = 20 Amps

bull Blade Pitching (4 motors total needed) - Current limitations for power sources and number of simultaneous blades pitching

Number of Blades 5 V Input 36 V input 31 V input 2 V input

4 040 A 069 A 081 A 125 A

2 080 A 139 A 161 A 250 A

1 160 A 278 A 323 A 500 A

44

Integration Motors

Stepper vs Brushless Servo Motors

45

-Contain many poles (50+) -Contain only 4-12 poles

-Distinct steps cause

vibration during use -Do not suffer from

vibration and resonance

issues smooth movement

-Low maintenance easier to

commission mechanically

simple

-Efficient response to start

stop and reverse commands

-Rely on encoders for

position details in closed

loop response

-Physical sizes

are comparable

-Both available

in various

lengths at same

frame size -Torque can be readily

controlled

-Low cost and high

availability

-Complexity drives cost

upward

Chosen for

deployment motor

Chosen for

pitching motor

Stepper Servo

Integration Blade Deployment

Deployment Motor Feasibility

Required holding torque is calculated to be 18 mNm

Required driving torque is calculated to be 117

10-5 mN∙m

bull Micro Motion Solutions ndash miniature stepper motors bull Physical Properties

bull Diameter = 6-22 mm

bull Length = 93-20 mm

bull Weight = 55-12 g

bull Holding Torque = 24-10 mN∙m = 034-142 oz∙in

bull Resolution bull 1 or 2 phase half-step capability

bull Steps per turn = 20-24 rarr 15˚-18˚ per step

5 of full step accuracy

bull Power Requirements bull Nominal voltage per phase 2-5 V

bull Nominal current per phase 01-1 A

46

Integration Blade Pitching

Blade Pitching Motor Feasibility

Required driving torque is calculated to be 0019 mN∙m

bull Mabuchi Servo Motor bull Physical Size

bull Diameter = 17 mm

bull Length = 25 mm

bull Weight = 16 g

bull Torque

bull Holding Torque = 161 mN∙m = 0228 oz∙in

bull Driving Torque = 0385 mN∙m = 0055 oz∙in

bull Friction Torque = 403

10-3 mN∙m = 571

10-4 oz∙in

bull Power Requirements

bull Nominal voltage per phase 2-5 V

bull Nominal current per phase 006-02 A 47

Integration Launch

Feasibility for Pre-deployment locking mechanism

The tip of the solar sail will be wider than the body with the sail tip set outside the plate

The tip will be held in place vertically by stationary blade stabilizers and kept tight by the holding torque of the deployment motor

Stationary blade

stabilizers

Extra-wide

blade tip

Upon deployment the motor

turns and the blade extends

48

Integration Launch

Canesterized Satellite Dispenser (CSD)

bull Ride in a 12 U CSD

bull Width=239 cm Height=226 cm Length=366 cm

bull Mass=0-24 kg at launch

bull Center of Mass when stowed in

bull x is -40 to 40 mm

bull y is 50 to 125 mm

bull z is 133 to 233 mm

wwwplanetarysytemscorpcom 49

Integration Launch

Test Validation

bull Launch Vibration Test

bull Needs to be space applicable and strong enough to withstand vibration

bull Ball Aerospace can provide a shake table costing $250hr

bull Preparation for Testing using FEM modeling and adding support features

50

Financial

bull Total Budget $5000

bull Components

bull Stepper Motor $100-200

bull Servo Motor (x2) $50-500 each

bull Materials (made in-house) $500-1000

bull Electronics $0-500

bull Testing

bull Deployment amp Pitching Free (Performed on Campus)

bull Launch Survivability Vibration Stand - $250hr Ball Space Systems in Boulder

bull Total Estimation $700-2700 + Vibration Stand Testing

51

Baseline Design All Together

bull The 8u CubeSat and characteristic acceleration requirements create very strict volumetric restrictions

bull The size of the plates and the rolled sail blade must be validated

bull This design will be analyzed and verified in the feasibility requirements

Inner Control Area

bull Motor

bull Encoder

bull Control

bull Communication

bull Power

Possible Load-bearing

corners for deployment

Housed Solar Sail

Top-Down View

Extra room for third

party systems

52

Status Summary

53

SystemMechanism Final Choice Further

Studies

Needed

8U Structure Fit our CubeSat in 12U bus provided by Planetary Services Yes

Adequate Area of Sails to Provide

Orbit Transfer Capabilities

AR = 22001 No

Pitching Mechanism Using a servo motor Yes

Pitching Accuracy Pitching encoder Yes

Plate Integration System Using a two cylinder design with tapered edges so

everything will fit

No

Deployment Motor Using a stepper motor No

Launch Ability Must conform to standards set by Planetary Services Yes

Launch Survivability Verify that GHOST will survive launch Yes

Initial Spin-Up Carbon steel attached to solar blade material Yes 53

Strategy for Conducting

Remaining Studies

bull 8U GHOST inside 12U structure bull Create a SolidWorksCAD model

bull Pitching Mechanism bull Determine adequate motor within size power and cost constraints

bull Pitching Accuracy bull Determine pitching accuracy based on orbital sensitivity

bull Launch Ability bull Because design is symmetrical center of mass is in the center of the satellite during launch bull Further investigations is needed to determine how many counterweights

bull Launch Survivability bull FEM or Vibrations

bull Initial Spin-up bull Determine feasible method to attach carbon steel support structure to solar sail blade material

54

Resources

bull PAYLOAD SPECIFICATION FOR 3U 6U 12U AND 27U Np Planetary Systems Corporation 2013 Print

bull Davis Jason The Planetary Society The Planetary Society Blog Firefly Partners 11 Apr 2012 Web 12 Oct 2013 lthttpwwwplanetaryorgblogsguest-blogsjason-davis3450htmlgt

bull Mao Tengfei 01mm Thickness Measuring Tape Wwwalibabacom Alibabacom nd Web 12 Oct 2013 lthttpwwwalibabacomproduct-gs8359006940_1mm_thickness_measuring_tapehtmlgt

55

Resources

bull ldquoHow servos and steppers stack uprdquo Machine Design 9 February 2012 [httpmachinedesigncomnewshow-servos-and-steppers-stack Accessed 7 October 2013]

bull ldquoMiniature Stepper Motor Drive Systems - Data Sheetrdquo Micro Motion Solutions [httpwwwmicromocomstepper-motors-datasheetsaspx Accessed 11 October 2013]

bull ldquoData Sheet for TS-53 Servorsquos Electric Motorrdquo Mabuchi Motor [httpwwwprincetonedu~mae412TEXTNTRAK2002292-302pdf Accessed 11 October 2013]

56

Problem Statement

bull GHOST will design build and test a heliogyro solar sail deployment and pitching mechanism packaged into a CubeSat of up to 12U and capable of deploying and pitching adequately sized solar sail blades to provide a characteristic acceleration of 01 mms2

bull Design a storage system for 4 blades

bull Build and test deployment mechanism for one solar sail

bull Build and test coordinated pitching mechanism for two solar blades using blade-equivalent masses

4

Base Project Components

Heliogyro Sail

bull Deployment through centrifugal tension

bull Lightweight due to reduced structure

bull Sustainable propulsion

CubeSat

bull Small scale low cost

bull Repeatability

bull Rideshare ability provides greater launch opportunities

5

Specific Objectives

bull Blades will deploy using motors aided by centrifugal tension bull Blades will deploy at a controlled rate of 1 ndash 10 cms

bull Verified by deployment test in 1G environment

bull Blade roots demonstrate coordinated pitching motion of 180ordm (

90ordm) bull Vectors a hypothetical solar sail thrust by changing effective area on which

photons would be deflected

bull Entire structure must be stowable within a standard 12U or smaller CubeSat

bull System limited to 10 W of power

bull Must show that structure can survive launch

6

Functional Block Diagram

7

Concept of Operations

(CONOPS)

8

30 Controlled deployment of sails via motors

31 Suspend undeployed blade in 1G

311 Establish electronic connection with

deployment mechanism

32 Initiate deployment mechanism

33 Controlled sail deployment using motors

50 Pitch solar sail roots

51 Establish remote connection with pitching

mechanism

52 Send appropriate pitch command

53 Measure resulting torque from pitching using

an accelerometer

54 Measure resulting pitch angle

541 Record actual pitch angle and compare to

expected pitch angle

542 Ensure both actuators are capable of

generating synchronized - collective frac12 P and

1P cyclic root pitch deflections

Baseline Design

bull Our baseline design includes three systems that must be integrated together bull 8U CubeSat chosen in order to minimize volume and

still accommodate solar sail width

1 Pitching system Encoder motor and axle

bull No gears involved

2 Deployment System Motor without gears bull Motor in-line with deployment axle

3 Interface System Hollow plate bull Houses the deployment system bull Connects to pitching axle

bull The 8U CubeSat and characteristic acceleration requirement create very strict volumetric restrictions which will be addressed in our feasibility analysis

1

2

3

9

Pitching system Encoder Motor

and Axle

bull The encoder and motor are located in the central area of the satellite

with the axle extending from the motor

Encoder Motor

Axle

CubeSat

Vertical

Stabilizer

Space for MCU

Communication and

other instruments

Desired Inner Control

Area

Outer Area for

Deployment and

Interface Systems

bull The motors are stabilized by a vertical pillar attached to the top and bottom of the CubeSat

bull The encoder mitigates the vibrations of the motor

Top-Down View

Command

Power

10

Deployment System Parallel

Axis Motor

bull Rolled sail and motor on same axis centered around the deployment axle

bull Motor is powered by wiring extending from the satellite center and stabilized by connecting to the interface

bull Locking mechanism- the blade tip is held by stabilizers that will prevent bunching upon deployment

Top-Down View

Power and Control

Rolled solar sail

Axle Deployment

Motor

Extra width on end keeps sail ready for deployment

Locking mechanism

Connects to Interface

Side View

Stabilized by

Interface

Stabilized by

Interface

Unrolled solar sail

11

Interface System Hollow Plate

bull Hollow plate interface attaches to pitching axle and houses the deployment system

bull Power and Control wiring spun around or through axle to prevent twisting when pitching

Space for MCU

Communication and

other instruments

Desired Inner Control

Area

Top-Down View (Not to

scale)

bull A thin-set bearing would be used to connect the plate to the CubeSat wall and minimize friction

Locking mechanism

Connects to Interface Plate Sized for thin-set bearing

connected to CubeSat

Power and Control

Wiring for

Deployment Motor

12

Critical Project Elements

bull Blade Deployment bull Earth-based design

bull Successfully deploy one solar sail blade in a 1G environment bull A motor is necessary to deploy one blade at a controlled rate of 1-10 cms bull The blade deployment needs to be tested in a near drag-free environment

bull Space-ready system bull Design a method to initialize the spin of the solar sail bull The blades must stay rigid during deployment

bull Blade Pitching bull Blades must pitch to a deflection angle given an input with a motor

bull Blades must have motor capable to pitch the blades 180

bull Blades must have coordinated deflection response bull Testing needs to confirm blades pitch to desired angle

13

Critical Project Elements

bull Orbit bull Earth-based system

bull While CubeSat is spinning blades must pitch in a periodic motion to direct the thrust bull A spin stand must be used to spin the CubeSat

bull Space-ready design bull Orbit must be designed for altitudes of 1100 ndash 1500 km

bull CubeSat must be launched into an initial orbit

bull Solar sail must have orbit transferring capabilities by pitching blades bull The solar sail blades must be sized to generate an acceleration of 01 mms2 bull Solar sail must be able to enter and exit a transfer orbit

bull Communication bull Earth-based model must be able to receive commands for pitching and deployment

systems bull Space-ready system must be able to communicate with Earth

14

Critical Project Elements

bull Integration bull The CubeSat is restricted by a maximum power available of 10W

bull Motors needed for blade release and pitching

bull The CubeSat is restricted to be no larger than 12U bull Earth-based model will be designed for 2 blades while space design will be for 4 blades

bull The CubeSat needs to hold the blades during a packaged state

bull Plates must be able to pitch without contact and minimum friction

bull The CubeSat must survive launch bull The CubeSat must meet the standards to launch in a Canesterized Satellite Dispenser

bull Extra design must be considered to stabilize the CubeSat for vibrations

bull Launch vibration test to prove survivability

bull Financial bull Earth-based model is restricted by a cost of $5000

15

Blade Deployment Space Model

Centripetal Acceleration

As the spacecraft spins the sail will experience a force

Important because the motor needs to oppose this force

16

Bus

V

r = solar sail length

Blade Deployment Space Model

Centripetal Acceleration

Deployment

Length

(Meters)

Centripetal

Acceleration

(ms2)

Mass

(Kg)

Centripetal

Force (N)

1 0011 0037 000041

15 016 0044 00073

30 033 0052 0017

50 055 0062 0034

100 11 0087 0095

150 16 011 018

200 22 014 03

220 24 015 035

17

Constant Spin Ω = 1 RPM

Gravitational Force

Earth

Orbital Trajectory

Equations

Constants

Blade Deployment

Testing on Earth Relation to Space

CubeSat rotating at 1 RPM rarr centripetal acceleration rarr centrifugal tension

Blade is fully deployed rarr maximum centrifugal tension

Simulate same centrifugal tension the blade would experience in space

Total mass of 36 g used in the deployment test

mTOTAL = mTM + mB = 36 + 110 = 146 g

a = 241 ms2 F = ma = 035 N

F = mg = 035 N g = 981 ms2

mTOTAL = 36 g

The holding torque of the motor used must be able to withstand this force

τ = r

F r = 05 cm F = 035 N

τ = 00018 Nm

Space Application

Motor

CubeSat

rotating at 1

RPM

Blade Tip mass

F

Top View

Tip mass trajectory

mB = 10 g mTM = 26 g

F = mg

Deployment Test

r

Mounted to Table Side View

Tip

mass

Motor

Blade

Front View

MotorBus

Interface

18

Blade Deployment

Earth Test Validation

19

Deployment Test

bull Release one solar sail blade of 15m at a controlled rate of 1-10 cms to demonstrate controlled deployment

bull Will be tested in Professor Frewrsquos lab in Fleming that is 17m high

bull Use video camera to measure rate set markers along wall to track deployment

19

Blade Deployment Space Model

Initial Spin Up

bull Carbon Steel Blade Supports at the end to replace end mass

bull 50 Carbon Steel

bull 01 mm thick

bull Deployment motor will deploy initial blade support structure for initial spin-up

CubeSat

Carbon-Steel

Blade Supports

Solar Blade

20

Blade Deployment Space Model

Initial Spin Up

bull Collective pitch of 35

to produce torque for spin up

bull Mass at end of sail=367g

bull Volume = 47e-6 cubic m

bull Two perpendicular rods rotating about oblate axis bull Both 4 kg

bull I=

bull Known bull Width=01 m

bull Length=047 m

bull Surface Area=00467 squared meters

21

Blade Deployment Space Model

Initial Spin Up

bull

=435

bull α=

bull Time = 24 days

bull Release the rest of sail and centrifugal tension will aid in deployment of sail

bull Solar sail thrust should keep CubeSat at 1 RPM while deploying

CubeSat

∆ω = Ω = 1 RPM

τ = L

F = Iα

L = 057 m

F = 023 μN

22

Orbit Initial Orbit

Final Orbit Selection

bull Sun-Synchronous 1500 km DawnDusk Orbit

bull Assumptions

bull Circular Orbit (e = 0 a = p)

bull No atmospheric drag above 1100 km altitude

bull Only orbital perturbation considered in orbit determination is the oblateness of the earth (second zonal constant J2)

bull All other orbital perturbations are neglected

bull For SS Orbit Node Precession = Solar Precession

bull Gyro rotational axis always oriented towards Sun

23

See Appendix for calculation

24

Orbit Initial Orbit

SS DawnDusk Orbit

Orbit Initial Orbit

Launch

bull Vandenberg AFB CA

bull Atlas V Launch Vehicle

bull Secondary Payload

bull Insertion into near Polar Orbit via Centaur Upper Stage

bull Further transfer necessary to achieve SS orbit

25

Orbit Blade Size

Maximum Solar Radiation Pressure Calculation

bull Assumptions

bull Perfectly reflecting surface

bull α = 0

(incident radiation perpendicular to surface)

26

Preflect2W

cR2cos2 = 908 Pa

where W = 1361 Wm2 c = 30x10 8 ms amp R = 100 AU

Orbit Blade Size

Minimum Solar Blade Surface Area for

Necessary Thrust

bull Assumptions

bull m = 8 kg (based on 8U Volume CubeSat 1 kgU)

27

a ac 01 mms2 requirement

sreflectc APmaFmax Asmac

Preflect8811 m2

bull 4 solar blades

As

42203 m2 per blade

Orbit Transfer

bull Example

bull LV delivers sc into 1100 km circular polar orbit

bull 1) Orbit raising maneuver to 1500 km

bull 2) Inclination change maneuver to i = 10196

bull How long will this take with GHOSTrsquos capabilities

28

29

Orbit Transfer

Orbit Raising Maneuver

Hohmann Transfer

Dual tangential

burn coplanar orbit

transfer

Initial Orbit

Final Orbit

Transfer Orbit

Orbit Transfer

Orbit Raising Maneuver

bull Calculated using Hohmann Transfer Equations

30

initial transfer vi 945 ms

transfer final v f 933 ms

vtotal 1877 ms

torbit raise 123 days

45o Preflect 454 Pa ain plane 177x10 5 ms2

Two blades pitched at

45

producing thrust in along track direction

See appendix for detailed orbit transfer diagrams

Orbit Transfer

Orbit Inclination Change

bull Calculated using inclination change only equations

31

v inc 2v initialcos( fpa)sini

2where vinitial v f fpa 0o amp i 1196o

vinc 148 kms i 00028 oorbit

a ac 01 mms2 P 6959 s Thrust acts over northern hemisphere of orbit (12 of Period)

tinc change 3437 days

Orbit Transfer

Final Destination

bull Δttotal = 4667 days or ~ 155 months bull time it takes to transfer from LV Delivery 1100 km polar orbit to 1500 km SS

orbit

bull this BOTE calculation has huge implications on both

bull mission duration

bull life span of sc components materials etc

bull Validates the high performance orbit transfer capabilities of the heliogyro architecture

32

Integration CubeSat

Pitch Test Validation

Sensor(s) to measure

torque and

Purpose Demonstrate coordinated pitching with equivalent mass and

realistic bus rotation

bull Rotation of 1 RPM

bull Measure torque on bus

bull Measure and compare actual pitching angles

to commanded

pitching angles

Sensors Needed

bull 3 axis Accelerometer (torque measurement)

bull 3 axis Gyroscope (pitch angle measurement)

bull 12 bit resolution (greater than pitching motors)

bull Fit onto or on 8U CubeSat

ADI516xxxIM4

bull 3 axis gyroscope

bull 3 axis magnetometer

bull 3 axis accelerometer

bull 14 bit resolution

bull 1

volume

bull Available free for checkout in ITLL

Sail Equivalent

mass

33

Integration CubeSat

Feasibility of our Baseline Design

bull To achieve characteristic acceleration for an 8U (8kg) CubeSat we needed each sail to be 2203

bull The diameter of the rolled spool inside the CubeSat (pre-deployment) varies with the width of the sail

bull To find the diameter of the rolled spool we calculated the length of one sail for a chosen width Assuming a Mylar thickness of 5 um due to the crinkling effect the spool width was calculated by iterating each rotation with increasing diameter as the blade rolls up

Iterate for rolling up sail until finished

(cm)

(m)

12 1836 247

10 2203 270

8 2754 300

34

Integration CubeSat

Sizing the Blades

bull CubeSat constrained by 20 cm on each side

bull Need to perform 180 degree independent rotation and maximize room inside the satellite for pitching motors controls and communication

Top Down Views of each size ( Scaled to correct dimensions)

12 cm blade width 10 cm blade width 8 cm blade width

bull Not intrusive on inner area

bull Full 180 motion

bull Infringes on space inside

bull Full 180 motion

bull Not intrusive on inner area

bull No Full 180 motion

35

Integration CubeSat

Housing the Rolled Sail

bull The solar sail blades will be controlled by a pitching axle but there must be an interface to connect to the axle

bull Cylindrical plate housing

bull Protects blades

bull Easy to connect to axle

bull No gears

bull Ability to provide counterweight

to deployment motor

bull With the tight volume constraints of our cube the Cylindrical plate must be altered to avoid interference with other sides

36

Integration CubeSat

Fitting the cylindrical Plate

bull Clearance for rolled sail

bull 2 cm clearance on each side

bull 06 cm clearance on behind the motor

bull This leaves overlapping corners

bull To prevent overlap we will make a 45ordm cut around the entire cylinder

2 cm

06 cm

Rolled Sail

Plate Encasing

Overlapping

Corners

45ordm cut to get rid

of corners

37

Integration CubeSat

Fitting the cylindrical Plate

bull The 45ordm cut will give us a 0 cm clearance (with no thickness)

bull If we implement a high-low offset between adjacent plates the distance between the two closest points increases

bull For our 14 cm diameter plates a 2 cm offset from the center for each plate (4 cm total) the effective clearance becomes 251 cm

Two adjacent sides

on same axis

With a High-Low Offset

38

Integration CubeSat

High-Low Offset Plates

The high low offset will give each plate room to rotate a full 180ordm

1 cm clearance between the top of the

blade and the edge of the satellite to fit

the thin-set bearing

A 3mm plate thickness gives adjacent

plates a distance of 19 cm between

their closest points

39

Integration CubeSat

High Low Offset Performance Validation

bull The high-low offset will not effect the performance or stability of the deployment or pitching systems

bull Upon deployment the opposing extension on each side cancels out unwanted torque

View From high side View From low side

bull In a sun-synchronous orbit the high or low setting has no effect as the rotational axis of the satellite is always solar pointing

View From Sun

40

Integration Power

Electronics Feasibility Analysis

bull Project Constraints

bull CubeSat power source Li-Ion batteries (5 and 33 V is common) - Would require thermal protection

bull Communications System - Transceiver (UHF is common) [USART serial port] - Buffer may be needed depending on power constraints

bull Deployment Subsystem - 1 step-motor [output] - 1 encoder [MSSP input] OR direct deployment measurement via external sensor

bull Pitching Subsystem - 2 servomotors [output]

41

Integration Power

PIC18F Series Microchip

bull Inputs 2 USART and 2 MSSP ports available (for basic PICs) - More than 1 device may be connected to each port - 2-3 devices needed

bull Outputs 8 ports - 2 devices needed

bull 16 bit - Though different PICs may be acquired for higher resolution

bull Operating Range 2-55 V - Within provided parameters

42

PIC

Communications

Deployment

Motor

Encoder

Pitching

Motor 1

Pitching

Motor 2 Key

Power Lines

Input Lines

Output Lines

Integration Power

Microchip FBD

5V Battery

Possible Voltage

Buffer

Encoder

43

Integration Power

Motor Power Limitations

bull Power Constraints

Pmax = 100 W

Vmax = 50 V

bull P = IV (Power = CurrentVoltage)

bull Therefore Iave = 20 Amps

bull Blade Pitching (4 motors total needed) - Current limitations for power sources and number of simultaneous blades pitching

Number of Blades 5 V Input 36 V input 31 V input 2 V input

4 040 A 069 A 081 A 125 A

2 080 A 139 A 161 A 250 A

1 160 A 278 A 323 A 500 A

44

Integration Motors

Stepper vs Brushless Servo Motors

45

-Contain many poles (50+) -Contain only 4-12 poles

-Distinct steps cause

vibration during use -Do not suffer from

vibration and resonance

issues smooth movement

-Low maintenance easier to

commission mechanically

simple

-Efficient response to start

stop and reverse commands

-Rely on encoders for

position details in closed

loop response

-Physical sizes

are comparable

-Both available

in various

lengths at same

frame size -Torque can be readily

controlled

-Low cost and high

availability

-Complexity drives cost

upward

Chosen for

deployment motor

Chosen for

pitching motor

Stepper Servo

Integration Blade Deployment

Deployment Motor Feasibility

Required holding torque is calculated to be 18 mNm

Required driving torque is calculated to be 117

10-5 mN∙m

bull Micro Motion Solutions ndash miniature stepper motors bull Physical Properties

bull Diameter = 6-22 mm

bull Length = 93-20 mm

bull Weight = 55-12 g

bull Holding Torque = 24-10 mN∙m = 034-142 oz∙in

bull Resolution bull 1 or 2 phase half-step capability

bull Steps per turn = 20-24 rarr 15˚-18˚ per step

5 of full step accuracy

bull Power Requirements bull Nominal voltage per phase 2-5 V

bull Nominal current per phase 01-1 A

46

Integration Blade Pitching

Blade Pitching Motor Feasibility

Required driving torque is calculated to be 0019 mN∙m

bull Mabuchi Servo Motor bull Physical Size

bull Diameter = 17 mm

bull Length = 25 mm

bull Weight = 16 g

bull Torque

bull Holding Torque = 161 mN∙m = 0228 oz∙in

bull Driving Torque = 0385 mN∙m = 0055 oz∙in

bull Friction Torque = 403

10-3 mN∙m = 571

10-4 oz∙in

bull Power Requirements

bull Nominal voltage per phase 2-5 V

bull Nominal current per phase 006-02 A 47

Integration Launch

Feasibility for Pre-deployment locking mechanism

The tip of the solar sail will be wider than the body with the sail tip set outside the plate

The tip will be held in place vertically by stationary blade stabilizers and kept tight by the holding torque of the deployment motor

Stationary blade

stabilizers

Extra-wide

blade tip

Upon deployment the motor

turns and the blade extends

48

Integration Launch

Canesterized Satellite Dispenser (CSD)

bull Ride in a 12 U CSD

bull Width=239 cm Height=226 cm Length=366 cm

bull Mass=0-24 kg at launch

bull Center of Mass when stowed in

bull x is -40 to 40 mm

bull y is 50 to 125 mm

bull z is 133 to 233 mm

wwwplanetarysytemscorpcom 49

Integration Launch

Test Validation

bull Launch Vibration Test

bull Needs to be space applicable and strong enough to withstand vibration

bull Ball Aerospace can provide a shake table costing $250hr

bull Preparation for Testing using FEM modeling and adding support features

50

Financial

bull Total Budget $5000

bull Components

bull Stepper Motor $100-200

bull Servo Motor (x2) $50-500 each

bull Materials (made in-house) $500-1000

bull Electronics $0-500

bull Testing

bull Deployment amp Pitching Free (Performed on Campus)

bull Launch Survivability Vibration Stand - $250hr Ball Space Systems in Boulder

bull Total Estimation $700-2700 + Vibration Stand Testing

51

Baseline Design All Together

bull The 8u CubeSat and characteristic acceleration requirements create very strict volumetric restrictions

bull The size of the plates and the rolled sail blade must be validated

bull This design will be analyzed and verified in the feasibility requirements

Inner Control Area

bull Motor

bull Encoder

bull Control

bull Communication

bull Power

Possible Load-bearing

corners for deployment

Housed Solar Sail

Top-Down View

Extra room for third

party systems

52

Status Summary

53

SystemMechanism Final Choice Further

Studies

Needed

8U Structure Fit our CubeSat in 12U bus provided by Planetary Services Yes

Adequate Area of Sails to Provide

Orbit Transfer Capabilities

AR = 22001 No

Pitching Mechanism Using a servo motor Yes

Pitching Accuracy Pitching encoder Yes

Plate Integration System Using a two cylinder design with tapered edges so

everything will fit

No

Deployment Motor Using a stepper motor No

Launch Ability Must conform to standards set by Planetary Services Yes

Launch Survivability Verify that GHOST will survive launch Yes

Initial Spin-Up Carbon steel attached to solar blade material Yes 53

Strategy for Conducting

Remaining Studies

bull 8U GHOST inside 12U structure bull Create a SolidWorksCAD model

bull Pitching Mechanism bull Determine adequate motor within size power and cost constraints

bull Pitching Accuracy bull Determine pitching accuracy based on orbital sensitivity

bull Launch Ability bull Because design is symmetrical center of mass is in the center of the satellite during launch bull Further investigations is needed to determine how many counterweights

bull Launch Survivability bull FEM or Vibrations

bull Initial Spin-up bull Determine feasible method to attach carbon steel support structure to solar sail blade material

54

Resources

bull PAYLOAD SPECIFICATION FOR 3U 6U 12U AND 27U Np Planetary Systems Corporation 2013 Print

bull Davis Jason The Planetary Society The Planetary Society Blog Firefly Partners 11 Apr 2012 Web 12 Oct 2013 lthttpwwwplanetaryorgblogsguest-blogsjason-davis3450htmlgt

bull Mao Tengfei 01mm Thickness Measuring Tape Wwwalibabacom Alibabacom nd Web 12 Oct 2013 lthttpwwwalibabacomproduct-gs8359006940_1mm_thickness_measuring_tapehtmlgt

55

Resources

bull ldquoHow servos and steppers stack uprdquo Machine Design 9 February 2012 [httpmachinedesigncomnewshow-servos-and-steppers-stack Accessed 7 October 2013]

bull ldquoMiniature Stepper Motor Drive Systems - Data Sheetrdquo Micro Motion Solutions [httpwwwmicromocomstepper-motors-datasheetsaspx Accessed 11 October 2013]

bull ldquoData Sheet for TS-53 Servorsquos Electric Motorrdquo Mabuchi Motor [httpwwwprincetonedu~mae412TEXTNTRAK2002292-302pdf Accessed 11 October 2013]

56

Base Project Components

Heliogyro Sail

bull Deployment through centrifugal tension

bull Lightweight due to reduced structure

bull Sustainable propulsion

CubeSat

bull Small scale low cost

bull Repeatability

bull Rideshare ability provides greater launch opportunities

5

Specific Objectives

bull Blades will deploy using motors aided by centrifugal tension bull Blades will deploy at a controlled rate of 1 ndash 10 cms

bull Verified by deployment test in 1G environment

bull Blade roots demonstrate coordinated pitching motion of 180ordm (

90ordm) bull Vectors a hypothetical solar sail thrust by changing effective area on which

photons would be deflected

bull Entire structure must be stowable within a standard 12U or smaller CubeSat

bull System limited to 10 W of power

bull Must show that structure can survive launch

6

Functional Block Diagram

7

Concept of Operations

(CONOPS)

8

30 Controlled deployment of sails via motors

31 Suspend undeployed blade in 1G

311 Establish electronic connection with

deployment mechanism

32 Initiate deployment mechanism

33 Controlled sail deployment using motors

50 Pitch solar sail roots

51 Establish remote connection with pitching

mechanism

52 Send appropriate pitch command

53 Measure resulting torque from pitching using

an accelerometer

54 Measure resulting pitch angle

541 Record actual pitch angle and compare to

expected pitch angle

542 Ensure both actuators are capable of

generating synchronized - collective frac12 P and

1P cyclic root pitch deflections

Baseline Design

bull Our baseline design includes three systems that must be integrated together bull 8U CubeSat chosen in order to minimize volume and

still accommodate solar sail width

1 Pitching system Encoder motor and axle

bull No gears involved

2 Deployment System Motor without gears bull Motor in-line with deployment axle

3 Interface System Hollow plate bull Houses the deployment system bull Connects to pitching axle

bull The 8U CubeSat and characteristic acceleration requirement create very strict volumetric restrictions which will be addressed in our feasibility analysis

1

2

3

9

Pitching system Encoder Motor

and Axle

bull The encoder and motor are located in the central area of the satellite

with the axle extending from the motor

Encoder Motor

Axle

CubeSat

Vertical

Stabilizer

Space for MCU

Communication and

other instruments

Desired Inner Control

Area

Outer Area for

Deployment and

Interface Systems

bull The motors are stabilized by a vertical pillar attached to the top and bottom of the CubeSat

bull The encoder mitigates the vibrations of the motor

Top-Down View

Command

Power

10

Deployment System Parallel

Axis Motor

bull Rolled sail and motor on same axis centered around the deployment axle

bull Motor is powered by wiring extending from the satellite center and stabilized by connecting to the interface

bull Locking mechanism- the blade tip is held by stabilizers that will prevent bunching upon deployment

Top-Down View

Power and Control

Rolled solar sail

Axle Deployment

Motor

Extra width on end keeps sail ready for deployment

Locking mechanism

Connects to Interface

Side View

Stabilized by

Interface

Stabilized by

Interface

Unrolled solar sail

11

Interface System Hollow Plate

bull Hollow plate interface attaches to pitching axle and houses the deployment system

bull Power and Control wiring spun around or through axle to prevent twisting when pitching

Space for MCU

Communication and

other instruments

Desired Inner Control

Area

Top-Down View (Not to

scale)

bull A thin-set bearing would be used to connect the plate to the CubeSat wall and minimize friction

Locking mechanism

Connects to Interface Plate Sized for thin-set bearing

connected to CubeSat

Power and Control

Wiring for

Deployment Motor

12

Critical Project Elements

bull Blade Deployment bull Earth-based design

bull Successfully deploy one solar sail blade in a 1G environment bull A motor is necessary to deploy one blade at a controlled rate of 1-10 cms bull The blade deployment needs to be tested in a near drag-free environment

bull Space-ready system bull Design a method to initialize the spin of the solar sail bull The blades must stay rigid during deployment

bull Blade Pitching bull Blades must pitch to a deflection angle given an input with a motor

bull Blades must have motor capable to pitch the blades 180

bull Blades must have coordinated deflection response bull Testing needs to confirm blades pitch to desired angle

13

Critical Project Elements

bull Orbit bull Earth-based system

bull While CubeSat is spinning blades must pitch in a periodic motion to direct the thrust bull A spin stand must be used to spin the CubeSat

bull Space-ready design bull Orbit must be designed for altitudes of 1100 ndash 1500 km

bull CubeSat must be launched into an initial orbit

bull Solar sail must have orbit transferring capabilities by pitching blades bull The solar sail blades must be sized to generate an acceleration of 01 mms2 bull Solar sail must be able to enter and exit a transfer orbit

bull Communication bull Earth-based model must be able to receive commands for pitching and deployment

systems bull Space-ready system must be able to communicate with Earth

14

Critical Project Elements

bull Integration bull The CubeSat is restricted by a maximum power available of 10W

bull Motors needed for blade release and pitching

bull The CubeSat is restricted to be no larger than 12U bull Earth-based model will be designed for 2 blades while space design will be for 4 blades

bull The CubeSat needs to hold the blades during a packaged state

bull Plates must be able to pitch without contact and minimum friction

bull The CubeSat must survive launch bull The CubeSat must meet the standards to launch in a Canesterized Satellite Dispenser

bull Extra design must be considered to stabilize the CubeSat for vibrations

bull Launch vibration test to prove survivability

bull Financial bull Earth-based model is restricted by a cost of $5000

15

Blade Deployment Space Model

Centripetal Acceleration

As the spacecraft spins the sail will experience a force

Important because the motor needs to oppose this force

16

Bus

V

r = solar sail length

Blade Deployment Space Model

Centripetal Acceleration

Deployment

Length

(Meters)

Centripetal

Acceleration

(ms2)

Mass

(Kg)

Centripetal

Force (N)

1 0011 0037 000041

15 016 0044 00073

30 033 0052 0017

50 055 0062 0034

100 11 0087 0095

150 16 011 018

200 22 014 03

220 24 015 035

17

Constant Spin Ω = 1 RPM

Gravitational Force

Earth

Orbital Trajectory

Equations

Constants

Blade Deployment

Testing on Earth Relation to Space

CubeSat rotating at 1 RPM rarr centripetal acceleration rarr centrifugal tension

Blade is fully deployed rarr maximum centrifugal tension

Simulate same centrifugal tension the blade would experience in space

Total mass of 36 g used in the deployment test

mTOTAL = mTM + mB = 36 + 110 = 146 g

a = 241 ms2 F = ma = 035 N

F = mg = 035 N g = 981 ms2

mTOTAL = 36 g

The holding torque of the motor used must be able to withstand this force

τ = r

F r = 05 cm F = 035 N

τ = 00018 Nm

Space Application

Motor

CubeSat

rotating at 1

RPM

Blade Tip mass

F

Top View

Tip mass trajectory

mB = 10 g mTM = 26 g

F = mg

Deployment Test

r

Mounted to Table Side View

Tip

mass

Motor

Blade

Front View

MotorBus

Interface

18

Blade Deployment

Earth Test Validation

19

Deployment Test

bull Release one solar sail blade of 15m at a controlled rate of 1-10 cms to demonstrate controlled deployment

bull Will be tested in Professor Frewrsquos lab in Fleming that is 17m high

bull Use video camera to measure rate set markers along wall to track deployment

19

Blade Deployment Space Model

Initial Spin Up

bull Carbon Steel Blade Supports at the end to replace end mass

bull 50 Carbon Steel

bull 01 mm thick

bull Deployment motor will deploy initial blade support structure for initial spin-up

CubeSat

Carbon-Steel

Blade Supports

Solar Blade

20

Blade Deployment Space Model

Initial Spin Up

bull Collective pitch of 35

to produce torque for spin up

bull Mass at end of sail=367g

bull Volume = 47e-6 cubic m

bull Two perpendicular rods rotating about oblate axis bull Both 4 kg

bull I=

bull Known bull Width=01 m

bull Length=047 m

bull Surface Area=00467 squared meters

21

Blade Deployment Space Model

Initial Spin Up

bull

=435

bull α=

bull Time = 24 days

bull Release the rest of sail and centrifugal tension will aid in deployment of sail

bull Solar sail thrust should keep CubeSat at 1 RPM while deploying

CubeSat

∆ω = Ω = 1 RPM

τ = L

F = Iα

L = 057 m

F = 023 μN

22

Orbit Initial Orbit

Final Orbit Selection

bull Sun-Synchronous 1500 km DawnDusk Orbit

bull Assumptions

bull Circular Orbit (e = 0 a = p)

bull No atmospheric drag above 1100 km altitude

bull Only orbital perturbation considered in orbit determination is the oblateness of the earth (second zonal constant J2)

bull All other orbital perturbations are neglected

bull For SS Orbit Node Precession = Solar Precession

bull Gyro rotational axis always oriented towards Sun

23

See Appendix for calculation

24

Orbit Initial Orbit

SS DawnDusk Orbit

Orbit Initial Orbit

Launch

bull Vandenberg AFB CA

bull Atlas V Launch Vehicle

bull Secondary Payload

bull Insertion into near Polar Orbit via Centaur Upper Stage

bull Further transfer necessary to achieve SS orbit

25

Orbit Blade Size

Maximum Solar Radiation Pressure Calculation

bull Assumptions

bull Perfectly reflecting surface

bull α = 0

(incident radiation perpendicular to surface)

26

Preflect2W

cR2cos2 = 908 Pa

where W = 1361 Wm2 c = 30x10 8 ms amp R = 100 AU

Orbit Blade Size

Minimum Solar Blade Surface Area for

Necessary Thrust

bull Assumptions

bull m = 8 kg (based on 8U Volume CubeSat 1 kgU)

27

a ac 01 mms2 requirement

sreflectc APmaFmax Asmac

Preflect8811 m2

bull 4 solar blades

As

42203 m2 per blade

Orbit Transfer

bull Example

bull LV delivers sc into 1100 km circular polar orbit

bull 1) Orbit raising maneuver to 1500 km

bull 2) Inclination change maneuver to i = 10196

bull How long will this take with GHOSTrsquos capabilities

28

29

Orbit Transfer

Orbit Raising Maneuver

Hohmann Transfer

Dual tangential

burn coplanar orbit

transfer

Initial Orbit

Final Orbit

Transfer Orbit

Orbit Transfer

Orbit Raising Maneuver

bull Calculated using Hohmann Transfer Equations

30

initial transfer vi 945 ms

transfer final v f 933 ms

vtotal 1877 ms

torbit raise 123 days

45o Preflect 454 Pa ain plane 177x10 5 ms2

Two blades pitched at

45

producing thrust in along track direction

See appendix for detailed orbit transfer diagrams

Orbit Transfer

Orbit Inclination Change

bull Calculated using inclination change only equations

31

v inc 2v initialcos( fpa)sini

2where vinitial v f fpa 0o amp i 1196o

vinc 148 kms i 00028 oorbit

a ac 01 mms2 P 6959 s Thrust acts over northern hemisphere of orbit (12 of Period)

tinc change 3437 days

Orbit Transfer

Final Destination

bull Δttotal = 4667 days or ~ 155 months bull time it takes to transfer from LV Delivery 1100 km polar orbit to 1500 km SS

orbit

bull this BOTE calculation has huge implications on both

bull mission duration

bull life span of sc components materials etc

bull Validates the high performance orbit transfer capabilities of the heliogyro architecture

32

Integration CubeSat

Pitch Test Validation

Sensor(s) to measure

torque and

Purpose Demonstrate coordinated pitching with equivalent mass and

realistic bus rotation

bull Rotation of 1 RPM

bull Measure torque on bus

bull Measure and compare actual pitching angles

to commanded

pitching angles

Sensors Needed

bull 3 axis Accelerometer (torque measurement)

bull 3 axis Gyroscope (pitch angle measurement)

bull 12 bit resolution (greater than pitching motors)

bull Fit onto or on 8U CubeSat

ADI516xxxIM4

bull 3 axis gyroscope

bull 3 axis magnetometer

bull 3 axis accelerometer

bull 14 bit resolution

bull 1

volume

bull Available free for checkout in ITLL

Sail Equivalent

mass

33

Integration CubeSat

Feasibility of our Baseline Design

bull To achieve characteristic acceleration for an 8U (8kg) CubeSat we needed each sail to be 2203

bull The diameter of the rolled spool inside the CubeSat (pre-deployment) varies with the width of the sail

bull To find the diameter of the rolled spool we calculated the length of one sail for a chosen width Assuming a Mylar thickness of 5 um due to the crinkling effect the spool width was calculated by iterating each rotation with increasing diameter as the blade rolls up

Iterate for rolling up sail until finished

(cm)

(m)

12 1836 247

10 2203 270

8 2754 300

34

Integration CubeSat

Sizing the Blades

bull CubeSat constrained by 20 cm on each side

bull Need to perform 180 degree independent rotation and maximize room inside the satellite for pitching motors controls and communication

Top Down Views of each size ( Scaled to correct dimensions)

12 cm blade width 10 cm blade width 8 cm blade width

bull Not intrusive on inner area

bull Full 180 motion

bull Infringes on space inside

bull Full 180 motion

bull Not intrusive on inner area

bull No Full 180 motion

35

Integration CubeSat

Housing the Rolled Sail

bull The solar sail blades will be controlled by a pitching axle but there must be an interface to connect to the axle

bull Cylindrical plate housing

bull Protects blades

bull Easy to connect to axle

bull No gears

bull Ability to provide counterweight

to deployment motor

bull With the tight volume constraints of our cube the Cylindrical plate must be altered to avoid interference with other sides

36

Integration CubeSat

Fitting the cylindrical Plate

bull Clearance for rolled sail

bull 2 cm clearance on each side

bull 06 cm clearance on behind the motor

bull This leaves overlapping corners

bull To prevent overlap we will make a 45ordm cut around the entire cylinder

2 cm

06 cm

Rolled Sail

Plate Encasing

Overlapping

Corners

45ordm cut to get rid

of corners

37

Integration CubeSat

Fitting the cylindrical Plate

bull The 45ordm cut will give us a 0 cm clearance (with no thickness)

bull If we implement a high-low offset between adjacent plates the distance between the two closest points increases

bull For our 14 cm diameter plates a 2 cm offset from the center for each plate (4 cm total) the effective clearance becomes 251 cm

Two adjacent sides

on same axis

With a High-Low Offset

38

Integration CubeSat

High-Low Offset Plates

The high low offset will give each plate room to rotate a full 180ordm

1 cm clearance between the top of the

blade and the edge of the satellite to fit

the thin-set bearing

A 3mm plate thickness gives adjacent

plates a distance of 19 cm between

their closest points

39

Integration CubeSat

High Low Offset Performance Validation

bull The high-low offset will not effect the performance or stability of the deployment or pitching systems

bull Upon deployment the opposing extension on each side cancels out unwanted torque

View From high side View From low side

bull In a sun-synchronous orbit the high or low setting has no effect as the rotational axis of the satellite is always solar pointing

View From Sun

40

Integration Power

Electronics Feasibility Analysis

bull Project Constraints

bull CubeSat power source Li-Ion batteries (5 and 33 V is common) - Would require thermal protection

bull Communications System - Transceiver (UHF is common) [USART serial port] - Buffer may be needed depending on power constraints

bull Deployment Subsystem - 1 step-motor [output] - 1 encoder [MSSP input] OR direct deployment measurement via external sensor

bull Pitching Subsystem - 2 servomotors [output]

41

Integration Power

PIC18F Series Microchip

bull Inputs 2 USART and 2 MSSP ports available (for basic PICs) - More than 1 device may be connected to each port - 2-3 devices needed

bull Outputs 8 ports - 2 devices needed

bull 16 bit - Though different PICs may be acquired for higher resolution

bull Operating Range 2-55 V - Within provided parameters

42

PIC

Communications

Deployment

Motor

Encoder

Pitching

Motor 1

Pitching

Motor 2 Key

Power Lines

Input Lines

Output Lines

Integration Power

Microchip FBD

5V Battery

Possible Voltage

Buffer

Encoder

43

Integration Power

Motor Power Limitations

bull Power Constraints

Pmax = 100 W

Vmax = 50 V

bull P = IV (Power = CurrentVoltage)

bull Therefore Iave = 20 Amps

bull Blade Pitching (4 motors total needed) - Current limitations for power sources and number of simultaneous blades pitching

Number of Blades 5 V Input 36 V input 31 V input 2 V input

4 040 A 069 A 081 A 125 A

2 080 A 139 A 161 A 250 A

1 160 A 278 A 323 A 500 A

44

Integration Motors

Stepper vs Brushless Servo Motors

45

-Contain many poles (50+) -Contain only 4-12 poles

-Distinct steps cause

vibration during use -Do not suffer from

vibration and resonance

issues smooth movement

-Low maintenance easier to

commission mechanically

simple

-Efficient response to start

stop and reverse commands

-Rely on encoders for

position details in closed

loop response

-Physical sizes

are comparable

-Both available

in various

lengths at same

frame size -Torque can be readily

controlled

-Low cost and high

availability

-Complexity drives cost

upward

Chosen for

deployment motor

Chosen for

pitching motor

Stepper Servo

Integration Blade Deployment

Deployment Motor Feasibility

Required holding torque is calculated to be 18 mNm

Required driving torque is calculated to be 117

10-5 mN∙m

bull Micro Motion Solutions ndash miniature stepper motors bull Physical Properties

bull Diameter = 6-22 mm

bull Length = 93-20 mm

bull Weight = 55-12 g

bull Holding Torque = 24-10 mN∙m = 034-142 oz∙in

bull Resolution bull 1 or 2 phase half-step capability

bull Steps per turn = 20-24 rarr 15˚-18˚ per step

5 of full step accuracy

bull Power Requirements bull Nominal voltage per phase 2-5 V

bull Nominal current per phase 01-1 A

46

Integration Blade Pitching

Blade Pitching Motor Feasibility

Required driving torque is calculated to be 0019 mN∙m

bull Mabuchi Servo Motor bull Physical Size

bull Diameter = 17 mm

bull Length = 25 mm

bull Weight = 16 g

bull Torque

bull Holding Torque = 161 mN∙m = 0228 oz∙in

bull Driving Torque = 0385 mN∙m = 0055 oz∙in

bull Friction Torque = 403

10-3 mN∙m = 571

10-4 oz∙in

bull Power Requirements

bull Nominal voltage per phase 2-5 V

bull Nominal current per phase 006-02 A 47

Integration Launch

Feasibility for Pre-deployment locking mechanism

The tip of the solar sail will be wider than the body with the sail tip set outside the plate

The tip will be held in place vertically by stationary blade stabilizers and kept tight by the holding torque of the deployment motor

Stationary blade

stabilizers

Extra-wide

blade tip

Upon deployment the motor

turns and the blade extends

48

Integration Launch

Canesterized Satellite Dispenser (CSD)

bull Ride in a 12 U CSD

bull Width=239 cm Height=226 cm Length=366 cm

bull Mass=0-24 kg at launch

bull Center of Mass when stowed in

bull x is -40 to 40 mm

bull y is 50 to 125 mm

bull z is 133 to 233 mm

wwwplanetarysytemscorpcom 49

Integration Launch

Test Validation

bull Launch Vibration Test

bull Needs to be space applicable and strong enough to withstand vibration

bull Ball Aerospace can provide a shake table costing $250hr

bull Preparation for Testing using FEM modeling and adding support features

50

Financial

bull Total Budget $5000

bull Components

bull Stepper Motor $100-200

bull Servo Motor (x2) $50-500 each

bull Materials (made in-house) $500-1000

bull Electronics $0-500

bull Testing

bull Deployment amp Pitching Free (Performed on Campus)

bull Launch Survivability Vibration Stand - $250hr Ball Space Systems in Boulder

bull Total Estimation $700-2700 + Vibration Stand Testing

51

Baseline Design All Together

bull The 8u CubeSat and characteristic acceleration requirements create very strict volumetric restrictions

bull The size of the plates and the rolled sail blade must be validated

bull This design will be analyzed and verified in the feasibility requirements

Inner Control Area

bull Motor

bull Encoder

bull Control

bull Communication

bull Power

Possible Load-bearing

corners for deployment

Housed Solar Sail

Top-Down View

Extra room for third

party systems

52

Status Summary

53

SystemMechanism Final Choice Further

Studies

Needed

8U Structure Fit our CubeSat in 12U bus provided by Planetary Services Yes

Adequate Area of Sails to Provide

Orbit Transfer Capabilities

AR = 22001 No

Pitching Mechanism Using a servo motor Yes

Pitching Accuracy Pitching encoder Yes

Plate Integration System Using a two cylinder design with tapered edges so

everything will fit

No

Deployment Motor Using a stepper motor No

Launch Ability Must conform to standards set by Planetary Services Yes

Launch Survivability Verify that GHOST will survive launch Yes

Initial Spin-Up Carbon steel attached to solar blade material Yes 53

Strategy for Conducting

Remaining Studies

bull 8U GHOST inside 12U structure bull Create a SolidWorksCAD model

bull Pitching Mechanism bull Determine adequate motor within size power and cost constraints

bull Pitching Accuracy bull Determine pitching accuracy based on orbital sensitivity

bull Launch Ability bull Because design is symmetrical center of mass is in the center of the satellite during launch bull Further investigations is needed to determine how many counterweights

bull Launch Survivability bull FEM or Vibrations

bull Initial Spin-up bull Determine feasible method to attach carbon steel support structure to solar sail blade material

54

Resources

bull PAYLOAD SPECIFICATION FOR 3U 6U 12U AND 27U Np Planetary Systems Corporation 2013 Print

bull Davis Jason The Planetary Society The Planetary Society Blog Firefly Partners 11 Apr 2012 Web 12 Oct 2013 lthttpwwwplanetaryorgblogsguest-blogsjason-davis3450htmlgt

bull Mao Tengfei 01mm Thickness Measuring Tape Wwwalibabacom Alibabacom nd Web 12 Oct 2013 lthttpwwwalibabacomproduct-gs8359006940_1mm_thickness_measuring_tapehtmlgt

55

Resources

bull ldquoHow servos and steppers stack uprdquo Machine Design 9 February 2012 [httpmachinedesigncomnewshow-servos-and-steppers-stack Accessed 7 October 2013]

bull ldquoMiniature Stepper Motor Drive Systems - Data Sheetrdquo Micro Motion Solutions [httpwwwmicromocomstepper-motors-datasheetsaspx Accessed 11 October 2013]

bull ldquoData Sheet for TS-53 Servorsquos Electric Motorrdquo Mabuchi Motor [httpwwwprincetonedu~mae412TEXTNTRAK2002292-302pdf Accessed 11 October 2013]

56

Specific Objectives

bull Blades will deploy using motors aided by centrifugal tension bull Blades will deploy at a controlled rate of 1 ndash 10 cms

bull Verified by deployment test in 1G environment

bull Blade roots demonstrate coordinated pitching motion of 180ordm (

90ordm) bull Vectors a hypothetical solar sail thrust by changing effective area on which

photons would be deflected

bull Entire structure must be stowable within a standard 12U or smaller CubeSat

bull System limited to 10 W of power

bull Must show that structure can survive launch

6

Functional Block Diagram

7

Concept of Operations

(CONOPS)

8

30 Controlled deployment of sails via motors

31 Suspend undeployed blade in 1G

311 Establish electronic connection with

deployment mechanism

32 Initiate deployment mechanism

33 Controlled sail deployment using motors

50 Pitch solar sail roots

51 Establish remote connection with pitching

mechanism

52 Send appropriate pitch command

53 Measure resulting torque from pitching using

an accelerometer

54 Measure resulting pitch angle

541 Record actual pitch angle and compare to

expected pitch angle

542 Ensure both actuators are capable of

generating synchronized - collective frac12 P and

1P cyclic root pitch deflections

Baseline Design

bull Our baseline design includes three systems that must be integrated together bull 8U CubeSat chosen in order to minimize volume and

still accommodate solar sail width

1 Pitching system Encoder motor and axle

bull No gears involved

2 Deployment System Motor without gears bull Motor in-line with deployment axle

3 Interface System Hollow plate bull Houses the deployment system bull Connects to pitching axle

bull The 8U CubeSat and characteristic acceleration requirement create very strict volumetric restrictions which will be addressed in our feasibility analysis

1

2

3

9

Pitching system Encoder Motor

and Axle

bull The encoder and motor are located in the central area of the satellite

with the axle extending from the motor

Encoder Motor

Axle

CubeSat

Vertical

Stabilizer

Space for MCU

Communication and

other instruments

Desired Inner Control

Area

Outer Area for

Deployment and

Interface Systems

bull The motors are stabilized by a vertical pillar attached to the top and bottom of the CubeSat

bull The encoder mitigates the vibrations of the motor

Top-Down View

Command

Power

10

Deployment System Parallel

Axis Motor

bull Rolled sail and motor on same axis centered around the deployment axle

bull Motor is powered by wiring extending from the satellite center and stabilized by connecting to the interface

bull Locking mechanism- the blade tip is held by stabilizers that will prevent bunching upon deployment

Top-Down View

Power and Control

Rolled solar sail

Axle Deployment

Motor

Extra width on end keeps sail ready for deployment

Locking mechanism

Connects to Interface

Side View

Stabilized by

Interface

Stabilized by

Interface

Unrolled solar sail

11

Interface System Hollow Plate

bull Hollow plate interface attaches to pitching axle and houses the deployment system

bull Power and Control wiring spun around or through axle to prevent twisting when pitching

Space for MCU

Communication and

other instruments

Desired Inner Control

Area

Top-Down View (Not to

scale)

bull A thin-set bearing would be used to connect the plate to the CubeSat wall and minimize friction

Locking mechanism

Connects to Interface Plate Sized for thin-set bearing

connected to CubeSat

Power and Control

Wiring for

Deployment Motor

12

Critical Project Elements

bull Blade Deployment bull Earth-based design

bull Successfully deploy one solar sail blade in a 1G environment bull A motor is necessary to deploy one blade at a controlled rate of 1-10 cms bull The blade deployment needs to be tested in a near drag-free environment

bull Space-ready system bull Design a method to initialize the spin of the solar sail bull The blades must stay rigid during deployment

bull Blade Pitching bull Blades must pitch to a deflection angle given an input with a motor

bull Blades must have motor capable to pitch the blades 180

bull Blades must have coordinated deflection response bull Testing needs to confirm blades pitch to desired angle

13

Critical Project Elements

bull Orbit bull Earth-based system

bull While CubeSat is spinning blades must pitch in a periodic motion to direct the thrust bull A spin stand must be used to spin the CubeSat

bull Space-ready design bull Orbit must be designed for altitudes of 1100 ndash 1500 km

bull CubeSat must be launched into an initial orbit

bull Solar sail must have orbit transferring capabilities by pitching blades bull The solar sail blades must be sized to generate an acceleration of 01 mms2 bull Solar sail must be able to enter and exit a transfer orbit

bull Communication bull Earth-based model must be able to receive commands for pitching and deployment

systems bull Space-ready system must be able to communicate with Earth

14

Critical Project Elements

bull Integration bull The CubeSat is restricted by a maximum power available of 10W

bull Motors needed for blade release and pitching

bull The CubeSat is restricted to be no larger than 12U bull Earth-based model will be designed for 2 blades while space design will be for 4 blades

bull The CubeSat needs to hold the blades during a packaged state

bull Plates must be able to pitch without contact and minimum friction

bull The CubeSat must survive launch bull The CubeSat must meet the standards to launch in a Canesterized Satellite Dispenser

bull Extra design must be considered to stabilize the CubeSat for vibrations

bull Launch vibration test to prove survivability

bull Financial bull Earth-based model is restricted by a cost of $5000

15

Blade Deployment Space Model

Centripetal Acceleration

As the spacecraft spins the sail will experience a force

Important because the motor needs to oppose this force

16

Bus

V

r = solar sail length

Blade Deployment Space Model

Centripetal Acceleration

Deployment

Length

(Meters)

Centripetal

Acceleration

(ms2)

Mass

(Kg)

Centripetal

Force (N)

1 0011 0037 000041

15 016 0044 00073

30 033 0052 0017

50 055 0062 0034

100 11 0087 0095

150 16 011 018

200 22 014 03

220 24 015 035

17

Constant Spin Ω = 1 RPM

Gravitational Force

Earth

Orbital Trajectory

Equations

Constants

Blade Deployment

Testing on Earth Relation to Space

CubeSat rotating at 1 RPM rarr centripetal acceleration rarr centrifugal tension

Blade is fully deployed rarr maximum centrifugal tension

Simulate same centrifugal tension the blade would experience in space

Total mass of 36 g used in the deployment test

mTOTAL = mTM + mB = 36 + 110 = 146 g

a = 241 ms2 F = ma = 035 N

F = mg = 035 N g = 981 ms2

mTOTAL = 36 g

The holding torque of the motor used must be able to withstand this force

τ = r

F r = 05 cm F = 035 N

τ = 00018 Nm

Space Application

Motor

CubeSat

rotating at 1

RPM

Blade Tip mass

F

Top View

Tip mass trajectory

mB = 10 g mTM = 26 g

F = mg

Deployment Test

r

Mounted to Table Side View

Tip

mass

Motor

Blade

Front View

MotorBus

Interface

18

Blade Deployment

Earth Test Validation

19

Deployment Test

bull Release one solar sail blade of 15m at a controlled rate of 1-10 cms to demonstrate controlled deployment

bull Will be tested in Professor Frewrsquos lab in Fleming that is 17m high

bull Use video camera to measure rate set markers along wall to track deployment

19

Blade Deployment Space Model

Initial Spin Up

bull Carbon Steel Blade Supports at the end to replace end mass

bull 50 Carbon Steel

bull 01 mm thick

bull Deployment motor will deploy initial blade support structure for initial spin-up

CubeSat

Carbon-Steel

Blade Supports

Solar Blade

20

Blade Deployment Space Model

Initial Spin Up

bull Collective pitch of 35

to produce torque for spin up

bull Mass at end of sail=367g

bull Volume = 47e-6 cubic m

bull Two perpendicular rods rotating about oblate axis bull Both 4 kg

bull I=

bull Known bull Width=01 m

bull Length=047 m

bull Surface Area=00467 squared meters

21

Blade Deployment Space Model

Initial Spin Up

bull

=435

bull α=

bull Time = 24 days

bull Release the rest of sail and centrifugal tension will aid in deployment of sail

bull Solar sail thrust should keep CubeSat at 1 RPM while deploying

CubeSat

∆ω = Ω = 1 RPM

τ = L

F = Iα

L = 057 m

F = 023 μN

22

Orbit Initial Orbit

Final Orbit Selection

bull Sun-Synchronous 1500 km DawnDusk Orbit

bull Assumptions

bull Circular Orbit (e = 0 a = p)

bull No atmospheric drag above 1100 km altitude

bull Only orbital perturbation considered in orbit determination is the oblateness of the earth (second zonal constant J2)

bull All other orbital perturbations are neglected

bull For SS Orbit Node Precession = Solar Precession

bull Gyro rotational axis always oriented towards Sun

23

See Appendix for calculation

24

Orbit Initial Orbit

SS DawnDusk Orbit

Orbit Initial Orbit

Launch

bull Vandenberg AFB CA

bull Atlas V Launch Vehicle

bull Secondary Payload

bull Insertion into near Polar Orbit via Centaur Upper Stage

bull Further transfer necessary to achieve SS orbit

25

Orbit Blade Size

Maximum Solar Radiation Pressure Calculation

bull Assumptions

bull Perfectly reflecting surface

bull α = 0

(incident radiation perpendicular to surface)

26

Preflect2W

cR2cos2 = 908 Pa

where W = 1361 Wm2 c = 30x10 8 ms amp R = 100 AU

Orbit Blade Size

Minimum Solar Blade Surface Area for

Necessary Thrust

bull Assumptions

bull m = 8 kg (based on 8U Volume CubeSat 1 kgU)

27

a ac 01 mms2 requirement

sreflectc APmaFmax Asmac

Preflect8811 m2

bull 4 solar blades

As

42203 m2 per blade

Orbit Transfer

bull Example

bull LV delivers sc into 1100 km circular polar orbit

bull 1) Orbit raising maneuver to 1500 km

bull 2) Inclination change maneuver to i = 10196

bull How long will this take with GHOSTrsquos capabilities

28

29

Orbit Transfer

Orbit Raising Maneuver

Hohmann Transfer

Dual tangential

burn coplanar orbit

transfer

Initial Orbit

Final Orbit

Transfer Orbit

Orbit Transfer

Orbit Raising Maneuver

bull Calculated using Hohmann Transfer Equations

30

initial transfer vi 945 ms

transfer final v f 933 ms

vtotal 1877 ms

torbit raise 123 days

45o Preflect 454 Pa ain plane 177x10 5 ms2

Two blades pitched at

45

producing thrust in along track direction

See appendix for detailed orbit transfer diagrams

Orbit Transfer

Orbit Inclination Change

bull Calculated using inclination change only equations

31

v inc 2v initialcos( fpa)sini

2where vinitial v f fpa 0o amp i 1196o

vinc 148 kms i 00028 oorbit

a ac 01 mms2 P 6959 s Thrust acts over northern hemisphere of orbit (12 of Period)

tinc change 3437 days

Orbit Transfer

Final Destination

bull Δttotal = 4667 days or ~ 155 months bull time it takes to transfer from LV Delivery 1100 km polar orbit to 1500 km SS

orbit

bull this BOTE calculation has huge implications on both

bull mission duration

bull life span of sc components materials etc

bull Validates the high performance orbit transfer capabilities of the heliogyro architecture

32

Integration CubeSat

Pitch Test Validation

Sensor(s) to measure

torque and

Purpose Demonstrate coordinated pitching with equivalent mass and

realistic bus rotation

bull Rotation of 1 RPM

bull Measure torque on bus

bull Measure and compare actual pitching angles

to commanded

pitching angles

Sensors Needed

bull 3 axis Accelerometer (torque measurement)

bull 3 axis Gyroscope (pitch angle measurement)

bull 12 bit resolution (greater than pitching motors)

bull Fit onto or on 8U CubeSat

ADI516xxxIM4

bull 3 axis gyroscope

bull 3 axis magnetometer

bull 3 axis accelerometer

bull 14 bit resolution

bull 1

volume

bull Available free for checkout in ITLL

Sail Equivalent

mass

33

Integration CubeSat

Feasibility of our Baseline Design

bull To achieve characteristic acceleration for an 8U (8kg) CubeSat we needed each sail to be 2203

bull The diameter of the rolled spool inside the CubeSat (pre-deployment) varies with the width of the sail

bull To find the diameter of the rolled spool we calculated the length of one sail for a chosen width Assuming a Mylar thickness of 5 um due to the crinkling effect the spool width was calculated by iterating each rotation with increasing diameter as the blade rolls up

Iterate for rolling up sail until finished

(cm)

(m)

12 1836 247

10 2203 270

8 2754 300

34

Integration CubeSat

Sizing the Blades

bull CubeSat constrained by 20 cm on each side

bull Need to perform 180 degree independent rotation and maximize room inside the satellite for pitching motors controls and communication

Top Down Views of each size ( Scaled to correct dimensions)

12 cm blade width 10 cm blade width 8 cm blade width

bull Not intrusive on inner area

bull Full 180 motion

bull Infringes on space inside

bull Full 180 motion

bull Not intrusive on inner area

bull No Full 180 motion

35

Integration CubeSat

Housing the Rolled Sail

bull The solar sail blades will be controlled by a pitching axle but there must be an interface to connect to the axle

bull Cylindrical plate housing

bull Protects blades

bull Easy to connect to axle

bull No gears

bull Ability to provide counterweight

to deployment motor

bull With the tight volume constraints of our cube the Cylindrical plate must be altered to avoid interference with other sides

36

Integration CubeSat

Fitting the cylindrical Plate

bull Clearance for rolled sail

bull 2 cm clearance on each side

bull 06 cm clearance on behind the motor

bull This leaves overlapping corners

bull To prevent overlap we will make a 45ordm cut around the entire cylinder

2 cm

06 cm

Rolled Sail

Plate Encasing

Overlapping

Corners

45ordm cut to get rid

of corners

37

Integration CubeSat

Fitting the cylindrical Plate

bull The 45ordm cut will give us a 0 cm clearance (with no thickness)

bull If we implement a high-low offset between adjacent plates the distance between the two closest points increases

bull For our 14 cm diameter plates a 2 cm offset from the center for each plate (4 cm total) the effective clearance becomes 251 cm

Two adjacent sides

on same axis

With a High-Low Offset

38

Integration CubeSat

High-Low Offset Plates

The high low offset will give each plate room to rotate a full 180ordm

1 cm clearance between the top of the

blade and the edge of the satellite to fit

the thin-set bearing

A 3mm plate thickness gives adjacent

plates a distance of 19 cm between

their closest points

39

Integration CubeSat

High Low Offset Performance Validation

bull The high-low offset will not effect the performance or stability of the deployment or pitching systems

bull Upon deployment the opposing extension on each side cancels out unwanted torque

View From high side View From low side

bull In a sun-synchronous orbit the high or low setting has no effect as the rotational axis of the satellite is always solar pointing

View From Sun

40

Integration Power

Electronics Feasibility Analysis

bull Project Constraints

bull CubeSat power source Li-Ion batteries (5 and 33 V is common) - Would require thermal protection

bull Communications System - Transceiver (UHF is common) [USART serial port] - Buffer may be needed depending on power constraints

bull Deployment Subsystem - 1 step-motor [output] - 1 encoder [MSSP input] OR direct deployment measurement via external sensor

bull Pitching Subsystem - 2 servomotors [output]

41

Integration Power

PIC18F Series Microchip

bull Inputs 2 USART and 2 MSSP ports available (for basic PICs) - More than 1 device may be connected to each port - 2-3 devices needed

bull Outputs 8 ports - 2 devices needed

bull 16 bit - Though different PICs may be acquired for higher resolution

bull Operating Range 2-55 V - Within provided parameters

42

PIC

Communications

Deployment

Motor

Encoder

Pitching

Motor 1

Pitching

Motor 2 Key

Power Lines

Input Lines

Output Lines

Integration Power

Microchip FBD

5V Battery

Possible Voltage

Buffer

Encoder

43

Integration Power

Motor Power Limitations

bull Power Constraints

Pmax = 100 W

Vmax = 50 V

bull P = IV (Power = CurrentVoltage)

bull Therefore Iave = 20 Amps

bull Blade Pitching (4 motors total needed) - Current limitations for power sources and number of simultaneous blades pitching

Number of Blades 5 V Input 36 V input 31 V input 2 V input

4 040 A 069 A 081 A 125 A

2 080 A 139 A 161 A 250 A

1 160 A 278 A 323 A 500 A

44

Integration Motors

Stepper vs Brushless Servo Motors

45

-Contain many poles (50+) -Contain only 4-12 poles

-Distinct steps cause

vibration during use -Do not suffer from

vibration and resonance

issues smooth movement

-Low maintenance easier to

commission mechanically

simple

-Efficient response to start

stop and reverse commands

-Rely on encoders for

position details in closed

loop response

-Physical sizes

are comparable

-Both available

in various

lengths at same

frame size -Torque can be readily

controlled

-Low cost and high

availability

-Complexity drives cost

upward

Chosen for

deployment motor

Chosen for

pitching motor

Stepper Servo

Integration Blade Deployment

Deployment Motor Feasibility

Required holding torque is calculated to be 18 mNm

Required driving torque is calculated to be 117

10-5 mN∙m

bull Micro Motion Solutions ndash miniature stepper motors bull Physical Properties

bull Diameter = 6-22 mm

bull Length = 93-20 mm

bull Weight = 55-12 g

bull Holding Torque = 24-10 mN∙m = 034-142 oz∙in

bull Resolution bull 1 or 2 phase half-step capability

bull Steps per turn = 20-24 rarr 15˚-18˚ per step

5 of full step accuracy

bull Power Requirements bull Nominal voltage per phase 2-5 V

bull Nominal current per phase 01-1 A

46

Integration Blade Pitching

Blade Pitching Motor Feasibility

Required driving torque is calculated to be 0019 mN∙m

bull Mabuchi Servo Motor bull Physical Size

bull Diameter = 17 mm

bull Length = 25 mm

bull Weight = 16 g

bull Torque

bull Holding Torque = 161 mN∙m = 0228 oz∙in

bull Driving Torque = 0385 mN∙m = 0055 oz∙in

bull Friction Torque = 403

10-3 mN∙m = 571

10-4 oz∙in

bull Power Requirements

bull Nominal voltage per phase 2-5 V

bull Nominal current per phase 006-02 A 47

Integration Launch

Feasibility for Pre-deployment locking mechanism

The tip of the solar sail will be wider than the body with the sail tip set outside the plate

The tip will be held in place vertically by stationary blade stabilizers and kept tight by the holding torque of the deployment motor

Stationary blade

stabilizers

Extra-wide

blade tip

Upon deployment the motor

turns and the blade extends

48

Integration Launch

Canesterized Satellite Dispenser (CSD)

bull Ride in a 12 U CSD

bull Width=239 cm Height=226 cm Length=366 cm

bull Mass=0-24 kg at launch

bull Center of Mass when stowed in

bull x is -40 to 40 mm

bull y is 50 to 125 mm

bull z is 133 to 233 mm

wwwplanetarysytemscorpcom 49

Integration Launch

Test Validation

bull Launch Vibration Test

bull Needs to be space applicable and strong enough to withstand vibration

bull Ball Aerospace can provide a shake table costing $250hr

bull Preparation for Testing using FEM modeling and adding support features

50

Financial

bull Total Budget $5000

bull Components

bull Stepper Motor $100-200

bull Servo Motor (x2) $50-500 each

bull Materials (made in-house) $500-1000

bull Electronics $0-500

bull Testing

bull Deployment amp Pitching Free (Performed on Campus)

bull Launch Survivability Vibration Stand - $250hr Ball Space Systems in Boulder

bull Total Estimation $700-2700 + Vibration Stand Testing

51

Baseline Design All Together

bull The 8u CubeSat and characteristic acceleration requirements create very strict volumetric restrictions

bull The size of the plates and the rolled sail blade must be validated

bull This design will be analyzed and verified in the feasibility requirements

Inner Control Area

bull Motor

bull Encoder

bull Control

bull Communication

bull Power

Possible Load-bearing

corners for deployment

Housed Solar Sail

Top-Down View

Extra room for third

party systems

52

Status Summary

53

SystemMechanism Final Choice Further

Studies

Needed

8U Structure Fit our CubeSat in 12U bus provided by Planetary Services Yes

Adequate Area of Sails to Provide

Orbit Transfer Capabilities

AR = 22001 No

Pitching Mechanism Using a servo motor Yes

Pitching Accuracy Pitching encoder Yes

Plate Integration System Using a two cylinder design with tapered edges so

everything will fit

No

Deployment Motor Using a stepper motor No

Launch Ability Must conform to standards set by Planetary Services Yes

Launch Survivability Verify that GHOST will survive launch Yes

Initial Spin-Up Carbon steel attached to solar blade material Yes 53

Strategy for Conducting

Remaining Studies

bull 8U GHOST inside 12U structure bull Create a SolidWorksCAD model

bull Pitching Mechanism bull Determine adequate motor within size power and cost constraints

bull Pitching Accuracy bull Determine pitching accuracy based on orbital sensitivity

bull Launch Ability bull Because design is symmetrical center of mass is in the center of the satellite during launch bull Further investigations is needed to determine how many counterweights

bull Launch Survivability bull FEM or Vibrations

bull Initial Spin-up bull Determine feasible method to attach carbon steel support structure to solar sail blade material

54

Resources

bull PAYLOAD SPECIFICATION FOR 3U 6U 12U AND 27U Np Planetary Systems Corporation 2013 Print

bull Davis Jason The Planetary Society The Planetary Society Blog Firefly Partners 11 Apr 2012 Web 12 Oct 2013 lthttpwwwplanetaryorgblogsguest-blogsjason-davis3450htmlgt

bull Mao Tengfei 01mm Thickness Measuring Tape Wwwalibabacom Alibabacom nd Web 12 Oct 2013 lthttpwwwalibabacomproduct-gs8359006940_1mm_thickness_measuring_tapehtmlgt

55

Resources

bull ldquoHow servos and steppers stack uprdquo Machine Design 9 February 2012 [httpmachinedesigncomnewshow-servos-and-steppers-stack Accessed 7 October 2013]

bull ldquoMiniature Stepper Motor Drive Systems - Data Sheetrdquo Micro Motion Solutions [httpwwwmicromocomstepper-motors-datasheetsaspx Accessed 11 October 2013]

bull ldquoData Sheet for TS-53 Servorsquos Electric Motorrdquo Mabuchi Motor [httpwwwprincetonedu~mae412TEXTNTRAK2002292-302pdf Accessed 11 October 2013]

56

Functional Block Diagram

7

Concept of Operations

(CONOPS)

8

30 Controlled deployment of sails via motors

31 Suspend undeployed blade in 1G

311 Establish electronic connection with

deployment mechanism

32 Initiate deployment mechanism

33 Controlled sail deployment using motors

50 Pitch solar sail roots

51 Establish remote connection with pitching

mechanism

52 Send appropriate pitch command

53 Measure resulting torque from pitching using

an accelerometer

54 Measure resulting pitch angle

541 Record actual pitch angle and compare to

expected pitch angle

542 Ensure both actuators are capable of

generating synchronized - collective frac12 P and

1P cyclic root pitch deflections

Baseline Design

bull Our baseline design includes three systems that must be integrated together bull 8U CubeSat chosen in order to minimize volume and

still accommodate solar sail width

1 Pitching system Encoder motor and axle

bull No gears involved

2 Deployment System Motor without gears bull Motor in-line with deployment axle

3 Interface System Hollow plate bull Houses the deployment system bull Connects to pitching axle

bull The 8U CubeSat and characteristic acceleration requirement create very strict volumetric restrictions which will be addressed in our feasibility analysis

1

2

3

9

Pitching system Encoder Motor

and Axle

bull The encoder and motor are located in the central area of the satellite

with the axle extending from the motor

Encoder Motor

Axle

CubeSat

Vertical

Stabilizer

Space for MCU

Communication and

other instruments

Desired Inner Control

Area

Outer Area for

Deployment and

Interface Systems

bull The motors are stabilized by a vertical pillar attached to the top and bottom of the CubeSat

bull The encoder mitigates the vibrations of the motor

Top-Down View

Command

Power

10

Deployment System Parallel

Axis Motor

bull Rolled sail and motor on same axis centered around the deployment axle

bull Motor is powered by wiring extending from the satellite center and stabilized by connecting to the interface

bull Locking mechanism- the blade tip is held by stabilizers that will prevent bunching upon deployment

Top-Down View

Power and Control

Rolled solar sail

Axle Deployment

Motor

Extra width on end keeps sail ready for deployment

Locking mechanism

Connects to Interface

Side View

Stabilized by

Interface

Stabilized by

Interface

Unrolled solar sail

11

Interface System Hollow Plate

bull Hollow plate interface attaches to pitching axle and houses the deployment system

bull Power and Control wiring spun around or through axle to prevent twisting when pitching

Space for MCU

Communication and

other instruments

Desired Inner Control

Area

Top-Down View (Not to

scale)

bull A thin-set bearing would be used to connect the plate to the CubeSat wall and minimize friction

Locking mechanism

Connects to Interface Plate Sized for thin-set bearing

connected to CubeSat

Power and Control

Wiring for

Deployment Motor

12

Critical Project Elements

bull Blade Deployment bull Earth-based design

bull Successfully deploy one solar sail blade in a 1G environment bull A motor is necessary to deploy one blade at a controlled rate of 1-10 cms bull The blade deployment needs to be tested in a near drag-free environment

bull Space-ready system bull Design a method to initialize the spin of the solar sail bull The blades must stay rigid during deployment

bull Blade Pitching bull Blades must pitch to a deflection angle given an input with a motor

bull Blades must have motor capable to pitch the blades 180

bull Blades must have coordinated deflection response bull Testing needs to confirm blades pitch to desired angle

13

Critical Project Elements

bull Orbit bull Earth-based system

bull While CubeSat is spinning blades must pitch in a periodic motion to direct the thrust bull A spin stand must be used to spin the CubeSat

bull Space-ready design bull Orbit must be designed for altitudes of 1100 ndash 1500 km

bull CubeSat must be launched into an initial orbit

bull Solar sail must have orbit transferring capabilities by pitching blades bull The solar sail blades must be sized to generate an acceleration of 01 mms2 bull Solar sail must be able to enter and exit a transfer orbit

bull Communication bull Earth-based model must be able to receive commands for pitching and deployment

systems bull Space-ready system must be able to communicate with Earth

14

Critical Project Elements

bull Integration bull The CubeSat is restricted by a maximum power available of 10W

bull Motors needed for blade release and pitching

bull The CubeSat is restricted to be no larger than 12U bull Earth-based model will be designed for 2 blades while space design will be for 4 blades

bull The CubeSat needs to hold the blades during a packaged state

bull Plates must be able to pitch without contact and minimum friction

bull The CubeSat must survive launch bull The CubeSat must meet the standards to launch in a Canesterized Satellite Dispenser

bull Extra design must be considered to stabilize the CubeSat for vibrations

bull Launch vibration test to prove survivability

bull Financial bull Earth-based model is restricted by a cost of $5000

15

Blade Deployment Space Model

Centripetal Acceleration

As the spacecraft spins the sail will experience a force

Important because the motor needs to oppose this force

16

Bus

V

r = solar sail length

Blade Deployment Space Model

Centripetal Acceleration

Deployment

Length

(Meters)

Centripetal

Acceleration

(ms2)

Mass

(Kg)

Centripetal

Force (N)

1 0011 0037 000041

15 016 0044 00073

30 033 0052 0017

50 055 0062 0034

100 11 0087 0095

150 16 011 018

200 22 014 03

220 24 015 035

17

Constant Spin Ω = 1 RPM

Gravitational Force

Earth

Orbital Trajectory

Equations

Constants

Blade Deployment

Testing on Earth Relation to Space

CubeSat rotating at 1 RPM rarr centripetal acceleration rarr centrifugal tension

Blade is fully deployed rarr maximum centrifugal tension

Simulate same centrifugal tension the blade would experience in space

Total mass of 36 g used in the deployment test

mTOTAL = mTM + mB = 36 + 110 = 146 g

a = 241 ms2 F = ma = 035 N

F = mg = 035 N g = 981 ms2

mTOTAL = 36 g

The holding torque of the motor used must be able to withstand this force

τ = r

F r = 05 cm F = 035 N

τ = 00018 Nm

Space Application

Motor

CubeSat

rotating at 1

RPM

Blade Tip mass

F

Top View

Tip mass trajectory

mB = 10 g mTM = 26 g

F = mg

Deployment Test

r

Mounted to Table Side View

Tip

mass

Motor

Blade

Front View

MotorBus

Interface

18

Blade Deployment

Earth Test Validation

19

Deployment Test

bull Release one solar sail blade of 15m at a controlled rate of 1-10 cms to demonstrate controlled deployment

bull Will be tested in Professor Frewrsquos lab in Fleming that is 17m high

bull Use video camera to measure rate set markers along wall to track deployment

19

Blade Deployment Space Model

Initial Spin Up

bull Carbon Steel Blade Supports at the end to replace end mass

bull 50 Carbon Steel

bull 01 mm thick

bull Deployment motor will deploy initial blade support structure for initial spin-up

CubeSat

Carbon-Steel

Blade Supports

Solar Blade

20

Blade Deployment Space Model

Initial Spin Up

bull Collective pitch of 35

to produce torque for spin up

bull Mass at end of sail=367g

bull Volume = 47e-6 cubic m

bull Two perpendicular rods rotating about oblate axis bull Both 4 kg

bull I=

bull Known bull Width=01 m

bull Length=047 m

bull Surface Area=00467 squared meters

21

Blade Deployment Space Model

Initial Spin Up

bull

=435

bull α=

bull Time = 24 days

bull Release the rest of sail and centrifugal tension will aid in deployment of sail

bull Solar sail thrust should keep CubeSat at 1 RPM while deploying

CubeSat

∆ω = Ω = 1 RPM

τ = L

F = Iα

L = 057 m

F = 023 μN

22

Orbit Initial Orbit

Final Orbit Selection

bull Sun-Synchronous 1500 km DawnDusk Orbit

bull Assumptions

bull Circular Orbit (e = 0 a = p)

bull No atmospheric drag above 1100 km altitude

bull Only orbital perturbation considered in orbit determination is the oblateness of the earth (second zonal constant J2)

bull All other orbital perturbations are neglected

bull For SS Orbit Node Precession = Solar Precession

bull Gyro rotational axis always oriented towards Sun

23

See Appendix for calculation

24

Orbit Initial Orbit

SS DawnDusk Orbit

Orbit Initial Orbit

Launch

bull Vandenberg AFB CA

bull Atlas V Launch Vehicle

bull Secondary Payload

bull Insertion into near Polar Orbit via Centaur Upper Stage

bull Further transfer necessary to achieve SS orbit

25

Orbit Blade Size

Maximum Solar Radiation Pressure Calculation

bull Assumptions

bull Perfectly reflecting surface

bull α = 0

(incident radiation perpendicular to surface)

26

Preflect2W

cR2cos2 = 908 Pa

where W = 1361 Wm2 c = 30x10 8 ms amp R = 100 AU

Orbit Blade Size

Minimum Solar Blade Surface Area for

Necessary Thrust

bull Assumptions

bull m = 8 kg (based on 8U Volume CubeSat 1 kgU)

27

a ac 01 mms2 requirement

sreflectc APmaFmax Asmac

Preflect8811 m2

bull 4 solar blades

As

42203 m2 per blade

Orbit Transfer

bull Example

bull LV delivers sc into 1100 km circular polar orbit

bull 1) Orbit raising maneuver to 1500 km

bull 2) Inclination change maneuver to i = 10196

bull How long will this take with GHOSTrsquos capabilities

28

29

Orbit Transfer

Orbit Raising Maneuver

Hohmann Transfer

Dual tangential

burn coplanar orbit

transfer

Initial Orbit

Final Orbit

Transfer Orbit

Orbit Transfer

Orbit Raising Maneuver

bull Calculated using Hohmann Transfer Equations

30

initial transfer vi 945 ms

transfer final v f 933 ms

vtotal 1877 ms

torbit raise 123 days

45o Preflect 454 Pa ain plane 177x10 5 ms2

Two blades pitched at

45

producing thrust in along track direction

See appendix for detailed orbit transfer diagrams

Orbit Transfer

Orbit Inclination Change

bull Calculated using inclination change only equations

31

v inc 2v initialcos( fpa)sini

2where vinitial v f fpa 0o amp i 1196o

vinc 148 kms i 00028 oorbit

a ac 01 mms2 P 6959 s Thrust acts over northern hemisphere of orbit (12 of Period)

tinc change 3437 days

Orbit Transfer

Final Destination

bull Δttotal = 4667 days or ~ 155 months bull time it takes to transfer from LV Delivery 1100 km polar orbit to 1500 km SS

orbit

bull this BOTE calculation has huge implications on both

bull mission duration

bull life span of sc components materials etc

bull Validates the high performance orbit transfer capabilities of the heliogyro architecture

32

Integration CubeSat

Pitch Test Validation

Sensor(s) to measure

torque and

Purpose Demonstrate coordinated pitching with equivalent mass and

realistic bus rotation

bull Rotation of 1 RPM

bull Measure torque on bus

bull Measure and compare actual pitching angles

to commanded

pitching angles

Sensors Needed

bull 3 axis Accelerometer (torque measurement)

bull 3 axis Gyroscope (pitch angle measurement)

bull 12 bit resolution (greater than pitching motors)

bull Fit onto or on 8U CubeSat

ADI516xxxIM4

bull 3 axis gyroscope

bull 3 axis magnetometer

bull 3 axis accelerometer

bull 14 bit resolution

bull 1

volume

bull Available free for checkout in ITLL

Sail Equivalent

mass

33

Integration CubeSat

Feasibility of our Baseline Design

bull To achieve characteristic acceleration for an 8U (8kg) CubeSat we needed each sail to be 2203

bull The diameter of the rolled spool inside the CubeSat (pre-deployment) varies with the width of the sail

bull To find the diameter of the rolled spool we calculated the length of one sail for a chosen width Assuming a Mylar thickness of 5 um due to the crinkling effect the spool width was calculated by iterating each rotation with increasing diameter as the blade rolls up

Iterate for rolling up sail until finished

(cm)

(m)

12 1836 247

10 2203 270

8 2754 300

34

Integration CubeSat

Sizing the Blades

bull CubeSat constrained by 20 cm on each side

bull Need to perform 180 degree independent rotation and maximize room inside the satellite for pitching motors controls and communication

Top Down Views of each size ( Scaled to correct dimensions)

12 cm blade width 10 cm blade width 8 cm blade width

bull Not intrusive on inner area

bull Full 180 motion

bull Infringes on space inside

bull Full 180 motion

bull Not intrusive on inner area

bull No Full 180 motion

35

Integration CubeSat

Housing the Rolled Sail

bull The solar sail blades will be controlled by a pitching axle but there must be an interface to connect to the axle

bull Cylindrical plate housing

bull Protects blades

bull Easy to connect to axle

bull No gears

bull Ability to provide counterweight

to deployment motor

bull With the tight volume constraints of our cube the Cylindrical plate must be altered to avoid interference with other sides

36

Integration CubeSat

Fitting the cylindrical Plate

bull Clearance for rolled sail

bull 2 cm clearance on each side

bull 06 cm clearance on behind the motor

bull This leaves overlapping corners

bull To prevent overlap we will make a 45ordm cut around the entire cylinder

2 cm

06 cm

Rolled Sail

Plate Encasing

Overlapping

Corners

45ordm cut to get rid

of corners

37

Integration CubeSat

Fitting the cylindrical Plate

bull The 45ordm cut will give us a 0 cm clearance (with no thickness)

bull If we implement a high-low offset between adjacent plates the distance between the two closest points increases

bull For our 14 cm diameter plates a 2 cm offset from the center for each plate (4 cm total) the effective clearance becomes 251 cm

Two adjacent sides

on same axis

With a High-Low Offset

38

Integration CubeSat

High-Low Offset Plates

The high low offset will give each plate room to rotate a full 180ordm

1 cm clearance between the top of the

blade and the edge of the satellite to fit

the thin-set bearing

A 3mm plate thickness gives adjacent

plates a distance of 19 cm between

their closest points

39

Integration CubeSat

High Low Offset Performance Validation

bull The high-low offset will not effect the performance or stability of the deployment or pitching systems

bull Upon deployment the opposing extension on each side cancels out unwanted torque

View From high side View From low side

bull In a sun-synchronous orbit the high or low setting has no effect as the rotational axis of the satellite is always solar pointing

View From Sun

40

Integration Power

Electronics Feasibility Analysis

bull Project Constraints

bull CubeSat power source Li-Ion batteries (5 and 33 V is common) - Would require thermal protection

bull Communications System - Transceiver (UHF is common) [USART serial port] - Buffer may be needed depending on power constraints

bull Deployment Subsystem - 1 step-motor [output] - 1 encoder [MSSP input] OR direct deployment measurement via external sensor

bull Pitching Subsystem - 2 servomotors [output]

41

Integration Power

PIC18F Series Microchip

bull Inputs 2 USART and 2 MSSP ports available (for basic PICs) - More than 1 device may be connected to each port - 2-3 devices needed

bull Outputs 8 ports - 2 devices needed

bull 16 bit - Though different PICs may be acquired for higher resolution

bull Operating Range 2-55 V - Within provided parameters

42

PIC

Communications

Deployment

Motor

Encoder

Pitching

Motor 1

Pitching

Motor 2 Key

Power Lines

Input Lines

Output Lines

Integration Power

Microchip FBD

5V Battery

Possible Voltage

Buffer

Encoder

43

Integration Power

Motor Power Limitations

bull Power Constraints

Pmax = 100 W

Vmax = 50 V

bull P = IV (Power = CurrentVoltage)

bull Therefore Iave = 20 Amps

bull Blade Pitching (4 motors total needed) - Current limitations for power sources and number of simultaneous blades pitching

Number of Blades 5 V Input 36 V input 31 V input 2 V input

4 040 A 069 A 081 A 125 A

2 080 A 139 A 161 A 250 A

1 160 A 278 A 323 A 500 A

44

Integration Motors

Stepper vs Brushless Servo Motors

45

-Contain many poles (50+) -Contain only 4-12 poles

-Distinct steps cause

vibration during use -Do not suffer from

vibration and resonance

issues smooth movement

-Low maintenance easier to

commission mechanically

simple

-Efficient response to start

stop and reverse commands

-Rely on encoders for

position details in closed

loop response

-Physical sizes

are comparable

-Both available

in various

lengths at same

frame size -Torque can be readily

controlled

-Low cost and high

availability

-Complexity drives cost

upward

Chosen for

deployment motor

Chosen for

pitching motor

Stepper Servo

Integration Blade Deployment

Deployment Motor Feasibility

Required holding torque is calculated to be 18 mNm

Required driving torque is calculated to be 117

10-5 mN∙m

bull Micro Motion Solutions ndash miniature stepper motors bull Physical Properties

bull Diameter = 6-22 mm

bull Length = 93-20 mm

bull Weight = 55-12 g

bull Holding Torque = 24-10 mN∙m = 034-142 oz∙in

bull Resolution bull 1 or 2 phase half-step capability

bull Steps per turn = 20-24 rarr 15˚-18˚ per step

5 of full step accuracy

bull Power Requirements bull Nominal voltage per phase 2-5 V

bull Nominal current per phase 01-1 A

46

Integration Blade Pitching

Blade Pitching Motor Feasibility

Required driving torque is calculated to be 0019 mN∙m

bull Mabuchi Servo Motor bull Physical Size

bull Diameter = 17 mm

bull Length = 25 mm

bull Weight = 16 g

bull Torque

bull Holding Torque = 161 mN∙m = 0228 oz∙in

bull Driving Torque = 0385 mN∙m = 0055 oz∙in

bull Friction Torque = 403

10-3 mN∙m = 571

10-4 oz∙in

bull Power Requirements

bull Nominal voltage per phase 2-5 V

bull Nominal current per phase 006-02 A 47

Integration Launch

Feasibility for Pre-deployment locking mechanism

The tip of the solar sail will be wider than the body with the sail tip set outside the plate

The tip will be held in place vertically by stationary blade stabilizers and kept tight by the holding torque of the deployment motor

Stationary blade

stabilizers

Extra-wide

blade tip

Upon deployment the motor

turns and the blade extends

48

Integration Launch

Canesterized Satellite Dispenser (CSD)

bull Ride in a 12 U CSD

bull Width=239 cm Height=226 cm Length=366 cm

bull Mass=0-24 kg at launch

bull Center of Mass when stowed in

bull x is -40 to 40 mm

bull y is 50 to 125 mm

bull z is 133 to 233 mm

wwwplanetarysytemscorpcom 49

Integration Launch

Test Validation

bull Launch Vibration Test

bull Needs to be space applicable and strong enough to withstand vibration

bull Ball Aerospace can provide a shake table costing $250hr

bull Preparation for Testing using FEM modeling and adding support features

50

Financial

bull Total Budget $5000

bull Components

bull Stepper Motor $100-200

bull Servo Motor (x2) $50-500 each

bull Materials (made in-house) $500-1000

bull Electronics $0-500

bull Testing

bull Deployment amp Pitching Free (Performed on Campus)

bull Launch Survivability Vibration Stand - $250hr Ball Space Systems in Boulder

bull Total Estimation $700-2700 + Vibration Stand Testing

51

Baseline Design All Together

bull The 8u CubeSat and characteristic acceleration requirements create very strict volumetric restrictions

bull The size of the plates and the rolled sail blade must be validated

bull This design will be analyzed and verified in the feasibility requirements

Inner Control Area

bull Motor

bull Encoder

bull Control

bull Communication

bull Power

Possible Load-bearing

corners for deployment

Housed Solar Sail

Top-Down View

Extra room for third

party systems

52

Status Summary

53

SystemMechanism Final Choice Further

Studies

Needed

8U Structure Fit our CubeSat in 12U bus provided by Planetary Services Yes

Adequate Area of Sails to Provide

Orbit Transfer Capabilities

AR = 22001 No

Pitching Mechanism Using a servo motor Yes

Pitching Accuracy Pitching encoder Yes

Plate Integration System Using a two cylinder design with tapered edges so

everything will fit

No

Deployment Motor Using a stepper motor No

Launch Ability Must conform to standards set by Planetary Services Yes

Launch Survivability Verify that GHOST will survive launch Yes

Initial Spin-Up Carbon steel attached to solar blade material Yes 53

Strategy for Conducting

Remaining Studies

bull 8U GHOST inside 12U structure bull Create a SolidWorksCAD model

bull Pitching Mechanism bull Determine adequate motor within size power and cost constraints

bull Pitching Accuracy bull Determine pitching accuracy based on orbital sensitivity

bull Launch Ability bull Because design is symmetrical center of mass is in the center of the satellite during launch bull Further investigations is needed to determine how many counterweights

bull Launch Survivability bull FEM or Vibrations

bull Initial Spin-up bull Determine feasible method to attach carbon steel support structure to solar sail blade material

54

Resources

bull PAYLOAD SPECIFICATION FOR 3U 6U 12U AND 27U Np Planetary Systems Corporation 2013 Print

bull Davis Jason The Planetary Society The Planetary Society Blog Firefly Partners 11 Apr 2012 Web 12 Oct 2013 lthttpwwwplanetaryorgblogsguest-blogsjason-davis3450htmlgt

bull Mao Tengfei 01mm Thickness Measuring Tape Wwwalibabacom Alibabacom nd Web 12 Oct 2013 lthttpwwwalibabacomproduct-gs8359006940_1mm_thickness_measuring_tapehtmlgt

55

Resources

bull ldquoHow servos and steppers stack uprdquo Machine Design 9 February 2012 [httpmachinedesigncomnewshow-servos-and-steppers-stack Accessed 7 October 2013]

bull ldquoMiniature Stepper Motor Drive Systems - Data Sheetrdquo Micro Motion Solutions [httpwwwmicromocomstepper-motors-datasheetsaspx Accessed 11 October 2013]

bull ldquoData Sheet for TS-53 Servorsquos Electric Motorrdquo Mabuchi Motor [httpwwwprincetonedu~mae412TEXTNTRAK2002292-302pdf Accessed 11 October 2013]

56

Concept of Operations

(CONOPS)

8

30 Controlled deployment of sails via motors

31 Suspend undeployed blade in 1G

311 Establish electronic connection with

deployment mechanism

32 Initiate deployment mechanism

33 Controlled sail deployment using motors

50 Pitch solar sail roots

51 Establish remote connection with pitching

mechanism

52 Send appropriate pitch command

53 Measure resulting torque from pitching using

an accelerometer

54 Measure resulting pitch angle

541 Record actual pitch angle and compare to

expected pitch angle

542 Ensure both actuators are capable of

generating synchronized - collective frac12 P and

1P cyclic root pitch deflections

Baseline Design

bull Our baseline design includes three systems that must be integrated together bull 8U CubeSat chosen in order to minimize volume and

still accommodate solar sail width

1 Pitching system Encoder motor and axle

bull No gears involved

2 Deployment System Motor without gears bull Motor in-line with deployment axle

3 Interface System Hollow plate bull Houses the deployment system bull Connects to pitching axle

bull The 8U CubeSat and characteristic acceleration requirement create very strict volumetric restrictions which will be addressed in our feasibility analysis

1

2

3

9

Pitching system Encoder Motor

and Axle

bull The encoder and motor are located in the central area of the satellite

with the axle extending from the motor

Encoder Motor

Axle

CubeSat

Vertical

Stabilizer

Space for MCU

Communication and

other instruments

Desired Inner Control

Area

Outer Area for

Deployment and

Interface Systems

bull The motors are stabilized by a vertical pillar attached to the top and bottom of the CubeSat

bull The encoder mitigates the vibrations of the motor

Top-Down View

Command

Power

10

Deployment System Parallel

Axis Motor

bull Rolled sail and motor on same axis centered around the deployment axle

bull Motor is powered by wiring extending from the satellite center and stabilized by connecting to the interface

bull Locking mechanism- the blade tip is held by stabilizers that will prevent bunching upon deployment

Top-Down View

Power and Control

Rolled solar sail

Axle Deployment

Motor

Extra width on end keeps sail ready for deployment

Locking mechanism

Connects to Interface

Side View

Stabilized by

Interface

Stabilized by

Interface

Unrolled solar sail

11

Interface System Hollow Plate

bull Hollow plate interface attaches to pitching axle and houses the deployment system

bull Power and Control wiring spun around or through axle to prevent twisting when pitching

Space for MCU

Communication and

other instruments

Desired Inner Control

Area

Top-Down View (Not to

scale)

bull A thin-set bearing would be used to connect the plate to the CubeSat wall and minimize friction

Locking mechanism

Connects to Interface Plate Sized for thin-set bearing

connected to CubeSat

Power and Control

Wiring for

Deployment Motor

12

Critical Project Elements

bull Blade Deployment bull Earth-based design

bull Successfully deploy one solar sail blade in a 1G environment bull A motor is necessary to deploy one blade at a controlled rate of 1-10 cms bull The blade deployment needs to be tested in a near drag-free environment

bull Space-ready system bull Design a method to initialize the spin of the solar sail bull The blades must stay rigid during deployment

bull Blade Pitching bull Blades must pitch to a deflection angle given an input with a motor

bull Blades must have motor capable to pitch the blades 180

bull Blades must have coordinated deflection response bull Testing needs to confirm blades pitch to desired angle

13

Critical Project Elements

bull Orbit bull Earth-based system

bull While CubeSat is spinning blades must pitch in a periodic motion to direct the thrust bull A spin stand must be used to spin the CubeSat

bull Space-ready design bull Orbit must be designed for altitudes of 1100 ndash 1500 km

bull CubeSat must be launched into an initial orbit

bull Solar sail must have orbit transferring capabilities by pitching blades bull The solar sail blades must be sized to generate an acceleration of 01 mms2 bull Solar sail must be able to enter and exit a transfer orbit

bull Communication bull Earth-based model must be able to receive commands for pitching and deployment

systems bull Space-ready system must be able to communicate with Earth

14

Critical Project Elements

bull Integration bull The CubeSat is restricted by a maximum power available of 10W

bull Motors needed for blade release and pitching

bull The CubeSat is restricted to be no larger than 12U bull Earth-based model will be designed for 2 blades while space design will be for 4 blades

bull The CubeSat needs to hold the blades during a packaged state

bull Plates must be able to pitch without contact and minimum friction

bull The CubeSat must survive launch bull The CubeSat must meet the standards to launch in a Canesterized Satellite Dispenser

bull Extra design must be considered to stabilize the CubeSat for vibrations

bull Launch vibration test to prove survivability

bull Financial bull Earth-based model is restricted by a cost of $5000

15

Blade Deployment Space Model

Centripetal Acceleration

As the spacecraft spins the sail will experience a force

Important because the motor needs to oppose this force

16

Bus

V

r = solar sail length

Blade Deployment Space Model

Centripetal Acceleration

Deployment

Length

(Meters)

Centripetal

Acceleration

(ms2)

Mass

(Kg)

Centripetal

Force (N)

1 0011 0037 000041

15 016 0044 00073

30 033 0052 0017

50 055 0062 0034

100 11 0087 0095

150 16 011 018

200 22 014 03

220 24 015 035

17

Constant Spin Ω = 1 RPM

Gravitational Force

Earth

Orbital Trajectory

Equations

Constants

Blade Deployment

Testing on Earth Relation to Space

CubeSat rotating at 1 RPM rarr centripetal acceleration rarr centrifugal tension

Blade is fully deployed rarr maximum centrifugal tension

Simulate same centrifugal tension the blade would experience in space

Total mass of 36 g used in the deployment test

mTOTAL = mTM + mB = 36 + 110 = 146 g

a = 241 ms2 F = ma = 035 N

F = mg = 035 N g = 981 ms2

mTOTAL = 36 g

The holding torque of the motor used must be able to withstand this force

τ = r

F r = 05 cm F = 035 N

τ = 00018 Nm

Space Application

Motor

CubeSat

rotating at 1

RPM

Blade Tip mass

F

Top View

Tip mass trajectory

mB = 10 g mTM = 26 g

F = mg

Deployment Test

r

Mounted to Table Side View

Tip

mass

Motor

Blade

Front View

MotorBus

Interface

18

Blade Deployment

Earth Test Validation

19

Deployment Test

bull Release one solar sail blade of 15m at a controlled rate of 1-10 cms to demonstrate controlled deployment

bull Will be tested in Professor Frewrsquos lab in Fleming that is 17m high

bull Use video camera to measure rate set markers along wall to track deployment

19

Blade Deployment Space Model

Initial Spin Up

bull Carbon Steel Blade Supports at the end to replace end mass

bull 50 Carbon Steel

bull 01 mm thick

bull Deployment motor will deploy initial blade support structure for initial spin-up

CubeSat

Carbon-Steel

Blade Supports

Solar Blade

20

Blade Deployment Space Model

Initial Spin Up

bull Collective pitch of 35

to produce torque for spin up

bull Mass at end of sail=367g

bull Volume = 47e-6 cubic m

bull Two perpendicular rods rotating about oblate axis bull Both 4 kg

bull I=

bull Known bull Width=01 m

bull Length=047 m

bull Surface Area=00467 squared meters

21

Blade Deployment Space Model

Initial Spin Up

bull

=435

bull α=

bull Time = 24 days

bull Release the rest of sail and centrifugal tension will aid in deployment of sail

bull Solar sail thrust should keep CubeSat at 1 RPM while deploying

CubeSat

∆ω = Ω = 1 RPM

τ = L

F = Iα

L = 057 m

F = 023 μN

22

Orbit Initial Orbit

Final Orbit Selection

bull Sun-Synchronous 1500 km DawnDusk Orbit

bull Assumptions

bull Circular Orbit (e = 0 a = p)

bull No atmospheric drag above 1100 km altitude

bull Only orbital perturbation considered in orbit determination is the oblateness of the earth (second zonal constant J2)

bull All other orbital perturbations are neglected

bull For SS Orbit Node Precession = Solar Precession

bull Gyro rotational axis always oriented towards Sun

23

See Appendix for calculation

24

Orbit Initial Orbit

SS DawnDusk Orbit

Orbit Initial Orbit

Launch

bull Vandenberg AFB CA

bull Atlas V Launch Vehicle

bull Secondary Payload

bull Insertion into near Polar Orbit via Centaur Upper Stage

bull Further transfer necessary to achieve SS orbit

25

Orbit Blade Size

Maximum Solar Radiation Pressure Calculation

bull Assumptions

bull Perfectly reflecting surface

bull α = 0

(incident radiation perpendicular to surface)

26

Preflect2W

cR2cos2 = 908 Pa

where W = 1361 Wm2 c = 30x10 8 ms amp R = 100 AU

Orbit Blade Size

Minimum Solar Blade Surface Area for

Necessary Thrust

bull Assumptions

bull m = 8 kg (based on 8U Volume CubeSat 1 kgU)

27

a ac 01 mms2 requirement

sreflectc APmaFmax Asmac

Preflect8811 m2

bull 4 solar blades

As

42203 m2 per blade

Orbit Transfer

bull Example

bull LV delivers sc into 1100 km circular polar orbit

bull 1) Orbit raising maneuver to 1500 km

bull 2) Inclination change maneuver to i = 10196

bull How long will this take with GHOSTrsquos capabilities

28

29

Orbit Transfer

Orbit Raising Maneuver

Hohmann Transfer

Dual tangential

burn coplanar orbit

transfer

Initial Orbit

Final Orbit

Transfer Orbit

Orbit Transfer

Orbit Raising Maneuver

bull Calculated using Hohmann Transfer Equations

30

initial transfer vi 945 ms

transfer final v f 933 ms

vtotal 1877 ms

torbit raise 123 days

45o Preflect 454 Pa ain plane 177x10 5 ms2

Two blades pitched at

45

producing thrust in along track direction

See appendix for detailed orbit transfer diagrams

Orbit Transfer

Orbit Inclination Change

bull Calculated using inclination change only equations

31

v inc 2v initialcos( fpa)sini

2where vinitial v f fpa 0o amp i 1196o

vinc 148 kms i 00028 oorbit

a ac 01 mms2 P 6959 s Thrust acts over northern hemisphere of orbit (12 of Period)

tinc change 3437 days

Orbit Transfer

Final Destination

bull Δttotal = 4667 days or ~ 155 months bull time it takes to transfer from LV Delivery 1100 km polar orbit to 1500 km SS

orbit

bull this BOTE calculation has huge implications on both

bull mission duration

bull life span of sc components materials etc

bull Validates the high performance orbit transfer capabilities of the heliogyro architecture

32

Integration CubeSat

Pitch Test Validation

Sensor(s) to measure

torque and

Purpose Demonstrate coordinated pitching with equivalent mass and

realistic bus rotation

bull Rotation of 1 RPM

bull Measure torque on bus

bull Measure and compare actual pitching angles

to commanded

pitching angles

Sensors Needed

bull 3 axis Accelerometer (torque measurement)

bull 3 axis Gyroscope (pitch angle measurement)

bull 12 bit resolution (greater than pitching motors)

bull Fit onto or on 8U CubeSat

ADI516xxxIM4

bull 3 axis gyroscope

bull 3 axis magnetometer

bull 3 axis accelerometer

bull 14 bit resolution

bull 1

volume

bull Available free for checkout in ITLL

Sail Equivalent

mass

33

Integration CubeSat

Feasibility of our Baseline Design

bull To achieve characteristic acceleration for an 8U (8kg) CubeSat we needed each sail to be 2203

bull The diameter of the rolled spool inside the CubeSat (pre-deployment) varies with the width of the sail

bull To find the diameter of the rolled spool we calculated the length of one sail for a chosen width Assuming a Mylar thickness of 5 um due to the crinkling effect the spool width was calculated by iterating each rotation with increasing diameter as the blade rolls up

Iterate for rolling up sail until finished

(cm)

(m)

12 1836 247

10 2203 270

8 2754 300

34

Integration CubeSat

Sizing the Blades

bull CubeSat constrained by 20 cm on each side

bull Need to perform 180 degree independent rotation and maximize room inside the satellite for pitching motors controls and communication

Top Down Views of each size ( Scaled to correct dimensions)

12 cm blade width 10 cm blade width 8 cm blade width

bull Not intrusive on inner area

bull Full 180 motion

bull Infringes on space inside

bull Full 180 motion

bull Not intrusive on inner area

bull No Full 180 motion

35

Integration CubeSat

Housing the Rolled Sail

bull The solar sail blades will be controlled by a pitching axle but there must be an interface to connect to the axle

bull Cylindrical plate housing

bull Protects blades

bull Easy to connect to axle

bull No gears

bull Ability to provide counterweight

to deployment motor

bull With the tight volume constraints of our cube the Cylindrical plate must be altered to avoid interference with other sides

36

Integration CubeSat

Fitting the cylindrical Plate

bull Clearance for rolled sail

bull 2 cm clearance on each side

bull 06 cm clearance on behind the motor

bull This leaves overlapping corners

bull To prevent overlap we will make a 45ordm cut around the entire cylinder

2 cm

06 cm

Rolled Sail

Plate Encasing

Overlapping

Corners

45ordm cut to get rid

of corners

37

Integration CubeSat

Fitting the cylindrical Plate

bull The 45ordm cut will give us a 0 cm clearance (with no thickness)

bull If we implement a high-low offset between adjacent plates the distance between the two closest points increases

bull For our 14 cm diameter plates a 2 cm offset from the center for each plate (4 cm total) the effective clearance becomes 251 cm

Two adjacent sides

on same axis

With a High-Low Offset

38

Integration CubeSat

High-Low Offset Plates

The high low offset will give each plate room to rotate a full 180ordm

1 cm clearance between the top of the

blade and the edge of the satellite to fit

the thin-set bearing

A 3mm plate thickness gives adjacent

plates a distance of 19 cm between

their closest points

39

Integration CubeSat

High Low Offset Performance Validation

bull The high-low offset will not effect the performance or stability of the deployment or pitching systems

bull Upon deployment the opposing extension on each side cancels out unwanted torque

View From high side View From low side

bull In a sun-synchronous orbit the high or low setting has no effect as the rotational axis of the satellite is always solar pointing

View From Sun

40

Integration Power

Electronics Feasibility Analysis

bull Project Constraints

bull CubeSat power source Li-Ion batteries (5 and 33 V is common) - Would require thermal protection

bull Communications System - Transceiver (UHF is common) [USART serial port] - Buffer may be needed depending on power constraints

bull Deployment Subsystem - 1 step-motor [output] - 1 encoder [MSSP input] OR direct deployment measurement via external sensor

bull Pitching Subsystem - 2 servomotors [output]

41

Integration Power

PIC18F Series Microchip

bull Inputs 2 USART and 2 MSSP ports available (for basic PICs) - More than 1 device may be connected to each port - 2-3 devices needed

bull Outputs 8 ports - 2 devices needed

bull 16 bit - Though different PICs may be acquired for higher resolution

bull Operating Range 2-55 V - Within provided parameters

42

PIC

Communications

Deployment

Motor

Encoder

Pitching

Motor 1

Pitching

Motor 2 Key

Power Lines

Input Lines

Output Lines

Integration Power

Microchip FBD

5V Battery

Possible Voltage

Buffer

Encoder

43

Integration Power

Motor Power Limitations

bull Power Constraints

Pmax = 100 W

Vmax = 50 V

bull P = IV (Power = CurrentVoltage)

bull Therefore Iave = 20 Amps

bull Blade Pitching (4 motors total needed) - Current limitations for power sources and number of simultaneous blades pitching

Number of Blades 5 V Input 36 V input 31 V input 2 V input

4 040 A 069 A 081 A 125 A

2 080 A 139 A 161 A 250 A

1 160 A 278 A 323 A 500 A

44

Integration Motors

Stepper vs Brushless Servo Motors

45

-Contain many poles (50+) -Contain only 4-12 poles

-Distinct steps cause

vibration during use -Do not suffer from

vibration and resonance

issues smooth movement

-Low maintenance easier to

commission mechanically

simple

-Efficient response to start

stop and reverse commands

-Rely on encoders for

position details in closed

loop response

-Physical sizes

are comparable

-Both available

in various

lengths at same

frame size -Torque can be readily

controlled

-Low cost and high

availability

-Complexity drives cost

upward

Chosen for

deployment motor

Chosen for

pitching motor

Stepper Servo

Integration Blade Deployment

Deployment Motor Feasibility

Required holding torque is calculated to be 18 mNm

Required driving torque is calculated to be 117

10-5 mN∙m

bull Micro Motion Solutions ndash miniature stepper motors bull Physical Properties

bull Diameter = 6-22 mm

bull Length = 93-20 mm

bull Weight = 55-12 g

bull Holding Torque = 24-10 mN∙m = 034-142 oz∙in

bull Resolution bull 1 or 2 phase half-step capability

bull Steps per turn = 20-24 rarr 15˚-18˚ per step

5 of full step accuracy

bull Power Requirements bull Nominal voltage per phase 2-5 V

bull Nominal current per phase 01-1 A

46

Integration Blade Pitching

Blade Pitching Motor Feasibility

Required driving torque is calculated to be 0019 mN∙m

bull Mabuchi Servo Motor bull Physical Size

bull Diameter = 17 mm

bull Length = 25 mm

bull Weight = 16 g

bull Torque

bull Holding Torque = 161 mN∙m = 0228 oz∙in

bull Driving Torque = 0385 mN∙m = 0055 oz∙in

bull Friction Torque = 403

10-3 mN∙m = 571

10-4 oz∙in

bull Power Requirements

bull Nominal voltage per phase 2-5 V

bull Nominal current per phase 006-02 A 47

Integration Launch

Feasibility for Pre-deployment locking mechanism

The tip of the solar sail will be wider than the body with the sail tip set outside the plate

The tip will be held in place vertically by stationary blade stabilizers and kept tight by the holding torque of the deployment motor

Stationary blade

stabilizers

Extra-wide

blade tip

Upon deployment the motor

turns and the blade extends

48

Integration Launch

Canesterized Satellite Dispenser (CSD)

bull Ride in a 12 U CSD

bull Width=239 cm Height=226 cm Length=366 cm

bull Mass=0-24 kg at launch

bull Center of Mass when stowed in

bull x is -40 to 40 mm

bull y is 50 to 125 mm

bull z is 133 to 233 mm

wwwplanetarysytemscorpcom 49

Integration Launch

Test Validation

bull Launch Vibration Test

bull Needs to be space applicable and strong enough to withstand vibration

bull Ball Aerospace can provide a shake table costing $250hr

bull Preparation for Testing using FEM modeling and adding support features

50

Financial

bull Total Budget $5000

bull Components

bull Stepper Motor $100-200

bull Servo Motor (x2) $50-500 each

bull Materials (made in-house) $500-1000

bull Electronics $0-500

bull Testing

bull Deployment amp Pitching Free (Performed on Campus)

bull Launch Survivability Vibration Stand - $250hr Ball Space Systems in Boulder

bull Total Estimation $700-2700 + Vibration Stand Testing

51

Baseline Design All Together

bull The 8u CubeSat and characteristic acceleration requirements create very strict volumetric restrictions

bull The size of the plates and the rolled sail blade must be validated

bull This design will be analyzed and verified in the feasibility requirements

Inner Control Area

bull Motor

bull Encoder

bull Control

bull Communication

bull Power

Possible Load-bearing

corners for deployment

Housed Solar Sail

Top-Down View

Extra room for third

party systems

52

Status Summary

53

SystemMechanism Final Choice Further

Studies

Needed

8U Structure Fit our CubeSat in 12U bus provided by Planetary Services Yes

Adequate Area of Sails to Provide

Orbit Transfer Capabilities

AR = 22001 No

Pitching Mechanism Using a servo motor Yes

Pitching Accuracy Pitching encoder Yes

Plate Integration System Using a two cylinder design with tapered edges so

everything will fit

No

Deployment Motor Using a stepper motor No

Launch Ability Must conform to standards set by Planetary Services Yes

Launch Survivability Verify that GHOST will survive launch Yes

Initial Spin-Up Carbon steel attached to solar blade material Yes 53

Strategy for Conducting

Remaining Studies

bull 8U GHOST inside 12U structure bull Create a SolidWorksCAD model

bull Pitching Mechanism bull Determine adequate motor within size power and cost constraints

bull Pitching Accuracy bull Determine pitching accuracy based on orbital sensitivity

bull Launch Ability bull Because design is symmetrical center of mass is in the center of the satellite during launch bull Further investigations is needed to determine how many counterweights

bull Launch Survivability bull FEM or Vibrations

bull Initial Spin-up bull Determine feasible method to attach carbon steel support structure to solar sail blade material

54

Resources

bull PAYLOAD SPECIFICATION FOR 3U 6U 12U AND 27U Np Planetary Systems Corporation 2013 Print

bull Davis Jason The Planetary Society The Planetary Society Blog Firefly Partners 11 Apr 2012 Web 12 Oct 2013 lthttpwwwplanetaryorgblogsguest-blogsjason-davis3450htmlgt

bull Mao Tengfei 01mm Thickness Measuring Tape Wwwalibabacom Alibabacom nd Web 12 Oct 2013 lthttpwwwalibabacomproduct-gs8359006940_1mm_thickness_measuring_tapehtmlgt

55

Resources

bull ldquoHow servos and steppers stack uprdquo Machine Design 9 February 2012 [httpmachinedesigncomnewshow-servos-and-steppers-stack Accessed 7 October 2013]

bull ldquoMiniature Stepper Motor Drive Systems - Data Sheetrdquo Micro Motion Solutions [httpwwwmicromocomstepper-motors-datasheetsaspx Accessed 11 October 2013]

bull ldquoData Sheet for TS-53 Servorsquos Electric Motorrdquo Mabuchi Motor [httpwwwprincetonedu~mae412TEXTNTRAK2002292-302pdf Accessed 11 October 2013]

56

Baseline Design

bull Our baseline design includes three systems that must be integrated together bull 8U CubeSat chosen in order to minimize volume and

still accommodate solar sail width

1 Pitching system Encoder motor and axle

bull No gears involved

2 Deployment System Motor without gears bull Motor in-line with deployment axle

3 Interface System Hollow plate bull Houses the deployment system bull Connects to pitching axle

bull The 8U CubeSat and characteristic acceleration requirement create very strict volumetric restrictions which will be addressed in our feasibility analysis

1

2

3

9

Pitching system Encoder Motor

and Axle

bull The encoder and motor are located in the central area of the satellite

with the axle extending from the motor

Encoder Motor

Axle

CubeSat

Vertical

Stabilizer

Space for MCU

Communication and

other instruments

Desired Inner Control

Area

Outer Area for

Deployment and

Interface Systems

bull The motors are stabilized by a vertical pillar attached to the top and bottom of the CubeSat

bull The encoder mitigates the vibrations of the motor

Top-Down View

Command

Power

10

Deployment System Parallel

Axis Motor

bull Rolled sail and motor on same axis centered around the deployment axle

bull Motor is powered by wiring extending from the satellite center and stabilized by connecting to the interface

bull Locking mechanism- the blade tip is held by stabilizers that will prevent bunching upon deployment

Top-Down View

Power and Control

Rolled solar sail

Axle Deployment

Motor

Extra width on end keeps sail ready for deployment

Locking mechanism

Connects to Interface

Side View

Stabilized by

Interface

Stabilized by

Interface

Unrolled solar sail

11

Interface System Hollow Plate

bull Hollow plate interface attaches to pitching axle and houses the deployment system

bull Power and Control wiring spun around or through axle to prevent twisting when pitching

Space for MCU

Communication and

other instruments

Desired Inner Control

Area

Top-Down View (Not to

scale)

bull A thin-set bearing would be used to connect the plate to the CubeSat wall and minimize friction

Locking mechanism

Connects to Interface Plate Sized for thin-set bearing

connected to CubeSat

Power and Control

Wiring for

Deployment Motor

12

Critical Project Elements

bull Blade Deployment bull Earth-based design

bull Successfully deploy one solar sail blade in a 1G environment bull A motor is necessary to deploy one blade at a controlled rate of 1-10 cms bull The blade deployment needs to be tested in a near drag-free environment

bull Space-ready system bull Design a method to initialize the spin of the solar sail bull The blades must stay rigid during deployment

bull Blade Pitching bull Blades must pitch to a deflection angle given an input with a motor

bull Blades must have motor capable to pitch the blades 180

bull Blades must have coordinated deflection response bull Testing needs to confirm blades pitch to desired angle

13

Critical Project Elements

bull Orbit bull Earth-based system

bull While CubeSat is spinning blades must pitch in a periodic motion to direct the thrust bull A spin stand must be used to spin the CubeSat

bull Space-ready design bull Orbit must be designed for altitudes of 1100 ndash 1500 km

bull CubeSat must be launched into an initial orbit

bull Solar sail must have orbit transferring capabilities by pitching blades bull The solar sail blades must be sized to generate an acceleration of 01 mms2 bull Solar sail must be able to enter and exit a transfer orbit

bull Communication bull Earth-based model must be able to receive commands for pitching and deployment

systems bull Space-ready system must be able to communicate with Earth

14

Critical Project Elements

bull Integration bull The CubeSat is restricted by a maximum power available of 10W

bull Motors needed for blade release and pitching

bull The CubeSat is restricted to be no larger than 12U bull Earth-based model will be designed for 2 blades while space design will be for 4 blades

bull The CubeSat needs to hold the blades during a packaged state

bull Plates must be able to pitch without contact and minimum friction

bull The CubeSat must survive launch bull The CubeSat must meet the standards to launch in a Canesterized Satellite Dispenser

bull Extra design must be considered to stabilize the CubeSat for vibrations

bull Launch vibration test to prove survivability

bull Financial bull Earth-based model is restricted by a cost of $5000

15

Blade Deployment Space Model

Centripetal Acceleration

As the spacecraft spins the sail will experience a force

Important because the motor needs to oppose this force

16

Bus

V

r = solar sail length

Blade Deployment Space Model

Centripetal Acceleration

Deployment

Length

(Meters)

Centripetal

Acceleration

(ms2)

Mass

(Kg)

Centripetal

Force (N)

1 0011 0037 000041

15 016 0044 00073

30 033 0052 0017

50 055 0062 0034

100 11 0087 0095

150 16 011 018

200 22 014 03

220 24 015 035

17

Constant Spin Ω = 1 RPM

Gravitational Force

Earth

Orbital Trajectory

Equations

Constants

Blade Deployment

Testing on Earth Relation to Space

CubeSat rotating at 1 RPM rarr centripetal acceleration rarr centrifugal tension

Blade is fully deployed rarr maximum centrifugal tension

Simulate same centrifugal tension the blade would experience in space

Total mass of 36 g used in the deployment test

mTOTAL = mTM + mB = 36 + 110 = 146 g

a = 241 ms2 F = ma = 035 N

F = mg = 035 N g = 981 ms2

mTOTAL = 36 g

The holding torque of the motor used must be able to withstand this force

τ = r

F r = 05 cm F = 035 N

τ = 00018 Nm

Space Application

Motor

CubeSat

rotating at 1

RPM

Blade Tip mass

F

Top View

Tip mass trajectory

mB = 10 g mTM = 26 g

F = mg

Deployment Test

r

Mounted to Table Side View

Tip

mass

Motor

Blade

Front View

MotorBus

Interface

18

Blade Deployment

Earth Test Validation

19

Deployment Test

bull Release one solar sail blade of 15m at a controlled rate of 1-10 cms to demonstrate controlled deployment

bull Will be tested in Professor Frewrsquos lab in Fleming that is 17m high

bull Use video camera to measure rate set markers along wall to track deployment

19

Blade Deployment Space Model

Initial Spin Up

bull Carbon Steel Blade Supports at the end to replace end mass

bull 50 Carbon Steel

bull 01 mm thick

bull Deployment motor will deploy initial blade support structure for initial spin-up

CubeSat

Carbon-Steel

Blade Supports

Solar Blade

20

Blade Deployment Space Model

Initial Spin Up

bull Collective pitch of 35

to produce torque for spin up

bull Mass at end of sail=367g

bull Volume = 47e-6 cubic m

bull Two perpendicular rods rotating about oblate axis bull Both 4 kg

bull I=

bull Known bull Width=01 m

bull Length=047 m

bull Surface Area=00467 squared meters

21

Blade Deployment Space Model

Initial Spin Up

bull

=435

bull α=

bull Time = 24 days

bull Release the rest of sail and centrifugal tension will aid in deployment of sail

bull Solar sail thrust should keep CubeSat at 1 RPM while deploying

CubeSat

∆ω = Ω = 1 RPM

τ = L

F = Iα

L = 057 m

F = 023 μN

22

Orbit Initial Orbit

Final Orbit Selection

bull Sun-Synchronous 1500 km DawnDusk Orbit

bull Assumptions

bull Circular Orbit (e = 0 a = p)

bull No atmospheric drag above 1100 km altitude

bull Only orbital perturbation considered in orbit determination is the oblateness of the earth (second zonal constant J2)

bull All other orbital perturbations are neglected

bull For SS Orbit Node Precession = Solar Precession

bull Gyro rotational axis always oriented towards Sun

23

See Appendix for calculation

24

Orbit Initial Orbit

SS DawnDusk Orbit

Orbit Initial Orbit

Launch

bull Vandenberg AFB CA

bull Atlas V Launch Vehicle

bull Secondary Payload

bull Insertion into near Polar Orbit via Centaur Upper Stage

bull Further transfer necessary to achieve SS orbit

25

Orbit Blade Size

Maximum Solar Radiation Pressure Calculation

bull Assumptions

bull Perfectly reflecting surface

bull α = 0

(incident radiation perpendicular to surface)

26

Preflect2W

cR2cos2 = 908 Pa

where W = 1361 Wm2 c = 30x10 8 ms amp R = 100 AU

Orbit Blade Size

Minimum Solar Blade Surface Area for

Necessary Thrust

bull Assumptions

bull m = 8 kg (based on 8U Volume CubeSat 1 kgU)

27

a ac 01 mms2 requirement

sreflectc APmaFmax Asmac

Preflect8811 m2

bull 4 solar blades

As

42203 m2 per blade

Orbit Transfer

bull Example

bull LV delivers sc into 1100 km circular polar orbit

bull 1) Orbit raising maneuver to 1500 km

bull 2) Inclination change maneuver to i = 10196

bull How long will this take with GHOSTrsquos capabilities

28

29

Orbit Transfer

Orbit Raising Maneuver

Hohmann Transfer

Dual tangential

burn coplanar orbit

transfer

Initial Orbit

Final Orbit

Transfer Orbit

Orbit Transfer

Orbit Raising Maneuver

bull Calculated using Hohmann Transfer Equations

30

initial transfer vi 945 ms

transfer final v f 933 ms

vtotal 1877 ms

torbit raise 123 days

45o Preflect 454 Pa ain plane 177x10 5 ms2

Two blades pitched at

45

producing thrust in along track direction

See appendix for detailed orbit transfer diagrams

Orbit Transfer

Orbit Inclination Change

bull Calculated using inclination change only equations

31

v inc 2v initialcos( fpa)sini

2where vinitial v f fpa 0o amp i 1196o

vinc 148 kms i 00028 oorbit

a ac 01 mms2 P 6959 s Thrust acts over northern hemisphere of orbit (12 of Period)

tinc change 3437 days

Orbit Transfer

Final Destination

bull Δttotal = 4667 days or ~ 155 months bull time it takes to transfer from LV Delivery 1100 km polar orbit to 1500 km SS

orbit

bull this BOTE calculation has huge implications on both

bull mission duration

bull life span of sc components materials etc

bull Validates the high performance orbit transfer capabilities of the heliogyro architecture

32

Integration CubeSat

Pitch Test Validation

Sensor(s) to measure

torque and

Purpose Demonstrate coordinated pitching with equivalent mass and

realistic bus rotation

bull Rotation of 1 RPM

bull Measure torque on bus

bull Measure and compare actual pitching angles

to commanded

pitching angles

Sensors Needed

bull 3 axis Accelerometer (torque measurement)

bull 3 axis Gyroscope (pitch angle measurement)

bull 12 bit resolution (greater than pitching motors)

bull Fit onto or on 8U CubeSat

ADI516xxxIM4

bull 3 axis gyroscope

bull 3 axis magnetometer

bull 3 axis accelerometer

bull 14 bit resolution

bull 1

volume

bull Available free for checkout in ITLL

Sail Equivalent

mass

33

Integration CubeSat

Feasibility of our Baseline Design

bull To achieve characteristic acceleration for an 8U (8kg) CubeSat we needed each sail to be 2203

bull The diameter of the rolled spool inside the CubeSat (pre-deployment) varies with the width of the sail

bull To find the diameter of the rolled spool we calculated the length of one sail for a chosen width Assuming a Mylar thickness of 5 um due to the crinkling effect the spool width was calculated by iterating each rotation with increasing diameter as the blade rolls up

Iterate for rolling up sail until finished

(cm)

(m)

12 1836 247

10 2203 270

8 2754 300

34

Integration CubeSat

Sizing the Blades

bull CubeSat constrained by 20 cm on each side

bull Need to perform 180 degree independent rotation and maximize room inside the satellite for pitching motors controls and communication

Top Down Views of each size ( Scaled to correct dimensions)

12 cm blade width 10 cm blade width 8 cm blade width

bull Not intrusive on inner area

bull Full 180 motion

bull Infringes on space inside

bull Full 180 motion

bull Not intrusive on inner area

bull No Full 180 motion

35

Integration CubeSat

Housing the Rolled Sail

bull The solar sail blades will be controlled by a pitching axle but there must be an interface to connect to the axle

bull Cylindrical plate housing

bull Protects blades

bull Easy to connect to axle

bull No gears

bull Ability to provide counterweight

to deployment motor

bull With the tight volume constraints of our cube the Cylindrical plate must be altered to avoid interference with other sides

36

Integration CubeSat

Fitting the cylindrical Plate

bull Clearance for rolled sail

bull 2 cm clearance on each side

bull 06 cm clearance on behind the motor

bull This leaves overlapping corners

bull To prevent overlap we will make a 45ordm cut around the entire cylinder

2 cm

06 cm

Rolled Sail

Plate Encasing

Overlapping

Corners

45ordm cut to get rid

of corners

37

Integration CubeSat

Fitting the cylindrical Plate

bull The 45ordm cut will give us a 0 cm clearance (with no thickness)

bull If we implement a high-low offset between adjacent plates the distance between the two closest points increases

bull For our 14 cm diameter plates a 2 cm offset from the center for each plate (4 cm total) the effective clearance becomes 251 cm

Two adjacent sides

on same axis

With a High-Low Offset

38

Integration CubeSat

High-Low Offset Plates

The high low offset will give each plate room to rotate a full 180ordm

1 cm clearance between the top of the

blade and the edge of the satellite to fit

the thin-set bearing

A 3mm plate thickness gives adjacent

plates a distance of 19 cm between

their closest points

39

Integration CubeSat

High Low Offset Performance Validation

bull The high-low offset will not effect the performance or stability of the deployment or pitching systems

bull Upon deployment the opposing extension on each side cancels out unwanted torque

View From high side View From low side

bull In a sun-synchronous orbit the high or low setting has no effect as the rotational axis of the satellite is always solar pointing

View From Sun

40

Integration Power

Electronics Feasibility Analysis

bull Project Constraints

bull CubeSat power source Li-Ion batteries (5 and 33 V is common) - Would require thermal protection

bull Communications System - Transceiver (UHF is common) [USART serial port] - Buffer may be needed depending on power constraints

bull Deployment Subsystem - 1 step-motor [output] - 1 encoder [MSSP input] OR direct deployment measurement via external sensor

bull Pitching Subsystem - 2 servomotors [output]

41

Integration Power

PIC18F Series Microchip

bull Inputs 2 USART and 2 MSSP ports available (for basic PICs) - More than 1 device may be connected to each port - 2-3 devices needed

bull Outputs 8 ports - 2 devices needed

bull 16 bit - Though different PICs may be acquired for higher resolution

bull Operating Range 2-55 V - Within provided parameters

42

PIC

Communications

Deployment

Motor

Encoder

Pitching

Motor 1

Pitching

Motor 2 Key

Power Lines

Input Lines

Output Lines

Integration Power

Microchip FBD

5V Battery

Possible Voltage

Buffer

Encoder

43

Integration Power

Motor Power Limitations

bull Power Constraints

Pmax = 100 W

Vmax = 50 V

bull P = IV (Power = CurrentVoltage)

bull Therefore Iave = 20 Amps

bull Blade Pitching (4 motors total needed) - Current limitations for power sources and number of simultaneous blades pitching

Number of Blades 5 V Input 36 V input 31 V input 2 V input

4 040 A 069 A 081 A 125 A

2 080 A 139 A 161 A 250 A

1 160 A 278 A 323 A 500 A

44

Integration Motors

Stepper vs Brushless Servo Motors

45

-Contain many poles (50+) -Contain only 4-12 poles

-Distinct steps cause

vibration during use -Do not suffer from

vibration and resonance

issues smooth movement

-Low maintenance easier to

commission mechanically

simple

-Efficient response to start

stop and reverse commands

-Rely on encoders for

position details in closed

loop response

-Physical sizes

are comparable

-Both available

in various

lengths at same

frame size -Torque can be readily

controlled

-Low cost and high

availability

-Complexity drives cost

upward

Chosen for

deployment motor

Chosen for

pitching motor

Stepper Servo

Integration Blade Deployment

Deployment Motor Feasibility

Required holding torque is calculated to be 18 mNm

Required driving torque is calculated to be 117

10-5 mN∙m

bull Micro Motion Solutions ndash miniature stepper motors bull Physical Properties

bull Diameter = 6-22 mm

bull Length = 93-20 mm

bull Weight = 55-12 g

bull Holding Torque = 24-10 mN∙m = 034-142 oz∙in

bull Resolution bull 1 or 2 phase half-step capability

bull Steps per turn = 20-24 rarr 15˚-18˚ per step

5 of full step accuracy

bull Power Requirements bull Nominal voltage per phase 2-5 V

bull Nominal current per phase 01-1 A

46

Integration Blade Pitching

Blade Pitching Motor Feasibility

Required driving torque is calculated to be 0019 mN∙m

bull Mabuchi Servo Motor bull Physical Size

bull Diameter = 17 mm

bull Length = 25 mm

bull Weight = 16 g

bull Torque

bull Holding Torque = 161 mN∙m = 0228 oz∙in

bull Driving Torque = 0385 mN∙m = 0055 oz∙in

bull Friction Torque = 403

10-3 mN∙m = 571

10-4 oz∙in

bull Power Requirements

bull Nominal voltage per phase 2-5 V

bull Nominal current per phase 006-02 A 47

Integration Launch

Feasibility for Pre-deployment locking mechanism

The tip of the solar sail will be wider than the body with the sail tip set outside the plate

The tip will be held in place vertically by stationary blade stabilizers and kept tight by the holding torque of the deployment motor

Stationary blade

stabilizers

Extra-wide

blade tip

Upon deployment the motor

turns and the blade extends

48

Integration Launch

Canesterized Satellite Dispenser (CSD)

bull Ride in a 12 U CSD

bull Width=239 cm Height=226 cm Length=366 cm

bull Mass=0-24 kg at launch

bull Center of Mass when stowed in

bull x is -40 to 40 mm

bull y is 50 to 125 mm

bull z is 133 to 233 mm

wwwplanetarysytemscorpcom 49

Integration Launch

Test Validation

bull Launch Vibration Test

bull Needs to be space applicable and strong enough to withstand vibration

bull Ball Aerospace can provide a shake table costing $250hr

bull Preparation for Testing using FEM modeling and adding support features

50

Financial

bull Total Budget $5000

bull Components

bull Stepper Motor $100-200

bull Servo Motor (x2) $50-500 each

bull Materials (made in-house) $500-1000

bull Electronics $0-500

bull Testing

bull Deployment amp Pitching Free (Performed on Campus)

bull Launch Survivability Vibration Stand - $250hr Ball Space Systems in Boulder

bull Total Estimation $700-2700 + Vibration Stand Testing

51

Baseline Design All Together

bull The 8u CubeSat and characteristic acceleration requirements create very strict volumetric restrictions

bull The size of the plates and the rolled sail blade must be validated

bull This design will be analyzed and verified in the feasibility requirements

Inner Control Area

bull Motor

bull Encoder

bull Control

bull Communication

bull Power

Possible Load-bearing

corners for deployment

Housed Solar Sail

Top-Down View

Extra room for third

party systems

52

Status Summary

53

SystemMechanism Final Choice Further

Studies

Needed

8U Structure Fit our CubeSat in 12U bus provided by Planetary Services Yes

Adequate Area of Sails to Provide

Orbit Transfer Capabilities

AR = 22001 No

Pitching Mechanism Using a servo motor Yes

Pitching Accuracy Pitching encoder Yes

Plate Integration System Using a two cylinder design with tapered edges so

everything will fit

No

Deployment Motor Using a stepper motor No

Launch Ability Must conform to standards set by Planetary Services Yes

Launch Survivability Verify that GHOST will survive launch Yes

Initial Spin-Up Carbon steel attached to solar blade material Yes 53

Strategy for Conducting

Remaining Studies

bull 8U GHOST inside 12U structure bull Create a SolidWorksCAD model

bull Pitching Mechanism bull Determine adequate motor within size power and cost constraints

bull Pitching Accuracy bull Determine pitching accuracy based on orbital sensitivity

bull Launch Ability bull Because design is symmetrical center of mass is in the center of the satellite during launch bull Further investigations is needed to determine how many counterweights

bull Launch Survivability bull FEM or Vibrations

bull Initial Spin-up bull Determine feasible method to attach carbon steel support structure to solar sail blade material

54

Resources

bull PAYLOAD SPECIFICATION FOR 3U 6U 12U AND 27U Np Planetary Systems Corporation 2013 Print

bull Davis Jason The Planetary Society The Planetary Society Blog Firefly Partners 11 Apr 2012 Web 12 Oct 2013 lthttpwwwplanetaryorgblogsguest-blogsjason-davis3450htmlgt

bull Mao Tengfei 01mm Thickness Measuring Tape Wwwalibabacom Alibabacom nd Web 12 Oct 2013 lthttpwwwalibabacomproduct-gs8359006940_1mm_thickness_measuring_tapehtmlgt

55

Resources

bull ldquoHow servos and steppers stack uprdquo Machine Design 9 February 2012 [httpmachinedesigncomnewshow-servos-and-steppers-stack Accessed 7 October 2013]

bull ldquoMiniature Stepper Motor Drive Systems - Data Sheetrdquo Micro Motion Solutions [httpwwwmicromocomstepper-motors-datasheetsaspx Accessed 11 October 2013]

bull ldquoData Sheet for TS-53 Servorsquos Electric Motorrdquo Mabuchi Motor [httpwwwprincetonedu~mae412TEXTNTRAK2002292-302pdf Accessed 11 October 2013]

56

Pitching system Encoder Motor

and Axle

bull The encoder and motor are located in the central area of the satellite

with the axle extending from the motor

Encoder Motor

Axle

CubeSat

Vertical

Stabilizer

Space for MCU

Communication and

other instruments

Desired Inner Control

Area

Outer Area for

Deployment and

Interface Systems

bull The motors are stabilized by a vertical pillar attached to the top and bottom of the CubeSat

bull The encoder mitigates the vibrations of the motor

Top-Down View

Command

Power

10

Deployment System Parallel

Axis Motor

bull Rolled sail and motor on same axis centered around the deployment axle

bull Motor is powered by wiring extending from the satellite center and stabilized by connecting to the interface

bull Locking mechanism- the blade tip is held by stabilizers that will prevent bunching upon deployment

Top-Down View

Power and Control

Rolled solar sail

Axle Deployment

Motor

Extra width on end keeps sail ready for deployment

Locking mechanism

Connects to Interface

Side View

Stabilized by

Interface

Stabilized by

Interface

Unrolled solar sail

11

Interface System Hollow Plate

bull Hollow plate interface attaches to pitching axle and houses the deployment system

bull Power and Control wiring spun around or through axle to prevent twisting when pitching

Space for MCU

Communication and

other instruments

Desired Inner Control

Area

Top-Down View (Not to

scale)

bull A thin-set bearing would be used to connect the plate to the CubeSat wall and minimize friction

Locking mechanism

Connects to Interface Plate Sized for thin-set bearing

connected to CubeSat

Power and Control

Wiring for

Deployment Motor

12

Critical Project Elements

bull Blade Deployment bull Earth-based design

bull Successfully deploy one solar sail blade in a 1G environment bull A motor is necessary to deploy one blade at a controlled rate of 1-10 cms bull The blade deployment needs to be tested in a near drag-free environment

bull Space-ready system bull Design a method to initialize the spin of the solar sail bull The blades must stay rigid during deployment

bull Blade Pitching bull Blades must pitch to a deflection angle given an input with a motor

bull Blades must have motor capable to pitch the blades 180

bull Blades must have coordinated deflection response bull Testing needs to confirm blades pitch to desired angle

13

Critical Project Elements

bull Orbit bull Earth-based system

bull While CubeSat is spinning blades must pitch in a periodic motion to direct the thrust bull A spin stand must be used to spin the CubeSat

bull Space-ready design bull Orbit must be designed for altitudes of 1100 ndash 1500 km

bull CubeSat must be launched into an initial orbit

bull Solar sail must have orbit transferring capabilities by pitching blades bull The solar sail blades must be sized to generate an acceleration of 01 mms2 bull Solar sail must be able to enter and exit a transfer orbit

bull Communication bull Earth-based model must be able to receive commands for pitching and deployment

systems bull Space-ready system must be able to communicate with Earth

14

Critical Project Elements

bull Integration bull The CubeSat is restricted by a maximum power available of 10W

bull Motors needed for blade release and pitching

bull The CubeSat is restricted to be no larger than 12U bull Earth-based model will be designed for 2 blades while space design will be for 4 blades

bull The CubeSat needs to hold the blades during a packaged state

bull Plates must be able to pitch without contact and minimum friction

bull The CubeSat must survive launch bull The CubeSat must meet the standards to launch in a Canesterized Satellite Dispenser

bull Extra design must be considered to stabilize the CubeSat for vibrations

bull Launch vibration test to prove survivability

bull Financial bull Earth-based model is restricted by a cost of $5000

15

Blade Deployment Space Model

Centripetal Acceleration

As the spacecraft spins the sail will experience a force

Important because the motor needs to oppose this force

16

Bus

V

r = solar sail length

Blade Deployment Space Model

Centripetal Acceleration

Deployment

Length

(Meters)

Centripetal

Acceleration

(ms2)

Mass

(Kg)

Centripetal

Force (N)

1 0011 0037 000041

15 016 0044 00073

30 033 0052 0017

50 055 0062 0034

100 11 0087 0095

150 16 011 018

200 22 014 03

220 24 015 035

17

Constant Spin Ω = 1 RPM

Gravitational Force

Earth

Orbital Trajectory

Equations

Constants

Blade Deployment

Testing on Earth Relation to Space

CubeSat rotating at 1 RPM rarr centripetal acceleration rarr centrifugal tension

Blade is fully deployed rarr maximum centrifugal tension

Simulate same centrifugal tension the blade would experience in space

Total mass of 36 g used in the deployment test

mTOTAL = mTM + mB = 36 + 110 = 146 g

a = 241 ms2 F = ma = 035 N

F = mg = 035 N g = 981 ms2

mTOTAL = 36 g

The holding torque of the motor used must be able to withstand this force

τ = r

F r = 05 cm F = 035 N

τ = 00018 Nm

Space Application

Motor

CubeSat

rotating at 1

RPM

Blade Tip mass

F

Top View

Tip mass trajectory

mB = 10 g mTM = 26 g

F = mg

Deployment Test

r

Mounted to Table Side View

Tip

mass

Motor

Blade

Front View

MotorBus

Interface

18

Blade Deployment

Earth Test Validation

19

Deployment Test

bull Release one solar sail blade of 15m at a controlled rate of 1-10 cms to demonstrate controlled deployment

bull Will be tested in Professor Frewrsquos lab in Fleming that is 17m high

bull Use video camera to measure rate set markers along wall to track deployment

19

Blade Deployment Space Model

Initial Spin Up

bull Carbon Steel Blade Supports at the end to replace end mass

bull 50 Carbon Steel

bull 01 mm thick

bull Deployment motor will deploy initial blade support structure for initial spin-up

CubeSat

Carbon-Steel

Blade Supports

Solar Blade

20

Blade Deployment Space Model

Initial Spin Up

bull Collective pitch of 35

to produce torque for spin up

bull Mass at end of sail=367g

bull Volume = 47e-6 cubic m

bull Two perpendicular rods rotating about oblate axis bull Both 4 kg

bull I=

bull Known bull Width=01 m

bull Length=047 m

bull Surface Area=00467 squared meters

21

Blade Deployment Space Model

Initial Spin Up

bull

=435

bull α=

bull Time = 24 days

bull Release the rest of sail and centrifugal tension will aid in deployment of sail

bull Solar sail thrust should keep CubeSat at 1 RPM while deploying

CubeSat

∆ω = Ω = 1 RPM

τ = L

F = Iα

L = 057 m

F = 023 μN

22

Orbit Initial Orbit

Final Orbit Selection

bull Sun-Synchronous 1500 km DawnDusk Orbit

bull Assumptions

bull Circular Orbit (e = 0 a = p)

bull No atmospheric drag above 1100 km altitude

bull Only orbital perturbation considered in orbit determination is the oblateness of the earth (second zonal constant J2)

bull All other orbital perturbations are neglected

bull For SS Orbit Node Precession = Solar Precession

bull Gyro rotational axis always oriented towards Sun

23

See Appendix for calculation

24

Orbit Initial Orbit

SS DawnDusk Orbit

Orbit Initial Orbit

Launch

bull Vandenberg AFB CA

bull Atlas V Launch Vehicle

bull Secondary Payload

bull Insertion into near Polar Orbit via Centaur Upper Stage

bull Further transfer necessary to achieve SS orbit

25

Orbit Blade Size

Maximum Solar Radiation Pressure Calculation

bull Assumptions

bull Perfectly reflecting surface

bull α = 0

(incident radiation perpendicular to surface)

26

Preflect2W

cR2cos2 = 908 Pa

where W = 1361 Wm2 c = 30x10 8 ms amp R = 100 AU

Orbit Blade Size

Minimum Solar Blade Surface Area for

Necessary Thrust

bull Assumptions

bull m = 8 kg (based on 8U Volume CubeSat 1 kgU)

27

a ac 01 mms2 requirement

sreflectc APmaFmax Asmac

Preflect8811 m2

bull 4 solar blades

As

42203 m2 per blade

Orbit Transfer

bull Example

bull LV delivers sc into 1100 km circular polar orbit

bull 1) Orbit raising maneuver to 1500 km

bull 2) Inclination change maneuver to i = 10196

bull How long will this take with GHOSTrsquos capabilities

28

29

Orbit Transfer

Orbit Raising Maneuver

Hohmann Transfer

Dual tangential

burn coplanar orbit

transfer

Initial Orbit

Final Orbit

Transfer Orbit

Orbit Transfer

Orbit Raising Maneuver

bull Calculated using Hohmann Transfer Equations

30

initial transfer vi 945 ms

transfer final v f 933 ms

vtotal 1877 ms

torbit raise 123 days

45o Preflect 454 Pa ain plane 177x10 5 ms2

Two blades pitched at

45

producing thrust in along track direction

See appendix for detailed orbit transfer diagrams

Orbit Transfer

Orbit Inclination Change

bull Calculated using inclination change only equations

31

v inc 2v initialcos( fpa)sini

2where vinitial v f fpa 0o amp i 1196o

vinc 148 kms i 00028 oorbit

a ac 01 mms2 P 6959 s Thrust acts over northern hemisphere of orbit (12 of Period)

tinc change 3437 days

Orbit Transfer

Final Destination

bull Δttotal = 4667 days or ~ 155 months bull time it takes to transfer from LV Delivery 1100 km polar orbit to 1500 km SS

orbit

bull this BOTE calculation has huge implications on both

bull mission duration

bull life span of sc components materials etc

bull Validates the high performance orbit transfer capabilities of the heliogyro architecture

32

Integration CubeSat

Pitch Test Validation

Sensor(s) to measure

torque and

Purpose Demonstrate coordinated pitching with equivalent mass and

realistic bus rotation

bull Rotation of 1 RPM

bull Measure torque on bus

bull Measure and compare actual pitching angles

to commanded

pitching angles

Sensors Needed

bull 3 axis Accelerometer (torque measurement)

bull 3 axis Gyroscope (pitch angle measurement)

bull 12 bit resolution (greater than pitching motors)

bull Fit onto or on 8U CubeSat

ADI516xxxIM4

bull 3 axis gyroscope

bull 3 axis magnetometer

bull 3 axis accelerometer

bull 14 bit resolution

bull 1

volume

bull Available free for checkout in ITLL

Sail Equivalent

mass

33

Integration CubeSat

Feasibility of our Baseline Design

bull To achieve characteristic acceleration for an 8U (8kg) CubeSat we needed each sail to be 2203

bull The diameter of the rolled spool inside the CubeSat (pre-deployment) varies with the width of the sail

bull To find the diameter of the rolled spool we calculated the length of one sail for a chosen width Assuming a Mylar thickness of 5 um due to the crinkling effect the spool width was calculated by iterating each rotation with increasing diameter as the blade rolls up

Iterate for rolling up sail until finished

(cm)

(m)

12 1836 247

10 2203 270

8 2754 300

34

Integration CubeSat

Sizing the Blades

bull CubeSat constrained by 20 cm on each side

bull Need to perform 180 degree independent rotation and maximize room inside the satellite for pitching motors controls and communication

Top Down Views of each size ( Scaled to correct dimensions)

12 cm blade width 10 cm blade width 8 cm blade width

bull Not intrusive on inner area

bull Full 180 motion

bull Infringes on space inside

bull Full 180 motion

bull Not intrusive on inner area

bull No Full 180 motion

35

Integration CubeSat

Housing the Rolled Sail

bull The solar sail blades will be controlled by a pitching axle but there must be an interface to connect to the axle

bull Cylindrical plate housing

bull Protects blades

bull Easy to connect to axle

bull No gears

bull Ability to provide counterweight

to deployment motor

bull With the tight volume constraints of our cube the Cylindrical plate must be altered to avoid interference with other sides

36

Integration CubeSat

Fitting the cylindrical Plate

bull Clearance for rolled sail

bull 2 cm clearance on each side

bull 06 cm clearance on behind the motor

bull This leaves overlapping corners

bull To prevent overlap we will make a 45ordm cut around the entire cylinder

2 cm

06 cm

Rolled Sail

Plate Encasing

Overlapping

Corners

45ordm cut to get rid

of corners

37

Integration CubeSat

Fitting the cylindrical Plate

bull The 45ordm cut will give us a 0 cm clearance (with no thickness)

bull If we implement a high-low offset between adjacent plates the distance between the two closest points increases

bull For our 14 cm diameter plates a 2 cm offset from the center for each plate (4 cm total) the effective clearance becomes 251 cm

Two adjacent sides

on same axis

With a High-Low Offset

38

Integration CubeSat

High-Low Offset Plates

The high low offset will give each plate room to rotate a full 180ordm

1 cm clearance between the top of the

blade and the edge of the satellite to fit

the thin-set bearing

A 3mm plate thickness gives adjacent

plates a distance of 19 cm between

their closest points

39

Integration CubeSat

High Low Offset Performance Validation

bull The high-low offset will not effect the performance or stability of the deployment or pitching systems

bull Upon deployment the opposing extension on each side cancels out unwanted torque

View From high side View From low side

bull In a sun-synchronous orbit the high or low setting has no effect as the rotational axis of the satellite is always solar pointing

View From Sun

40

Integration Power

Electronics Feasibility Analysis

bull Project Constraints

bull CubeSat power source Li-Ion batteries (5 and 33 V is common) - Would require thermal protection

bull Communications System - Transceiver (UHF is common) [USART serial port] - Buffer may be needed depending on power constraints

bull Deployment Subsystem - 1 step-motor [output] - 1 encoder [MSSP input] OR direct deployment measurement via external sensor

bull Pitching Subsystem - 2 servomotors [output]

41

Integration Power

PIC18F Series Microchip

bull Inputs 2 USART and 2 MSSP ports available (for basic PICs) - More than 1 device may be connected to each port - 2-3 devices needed

bull Outputs 8 ports - 2 devices needed

bull 16 bit - Though different PICs may be acquired for higher resolution

bull Operating Range 2-55 V - Within provided parameters

42

PIC

Communications

Deployment

Motor

Encoder

Pitching

Motor 1

Pitching

Motor 2 Key

Power Lines

Input Lines

Output Lines

Integration Power

Microchip FBD

5V Battery

Possible Voltage

Buffer

Encoder

43

Integration Power

Motor Power Limitations

bull Power Constraints

Pmax = 100 W

Vmax = 50 V

bull P = IV (Power = CurrentVoltage)

bull Therefore Iave = 20 Amps

bull Blade Pitching (4 motors total needed) - Current limitations for power sources and number of simultaneous blades pitching

Number of Blades 5 V Input 36 V input 31 V input 2 V input

4 040 A 069 A 081 A 125 A

2 080 A 139 A 161 A 250 A

1 160 A 278 A 323 A 500 A

44

Integration Motors

Stepper vs Brushless Servo Motors

45

-Contain many poles (50+) -Contain only 4-12 poles

-Distinct steps cause

vibration during use -Do not suffer from

vibration and resonance

issues smooth movement

-Low maintenance easier to

commission mechanically

simple

-Efficient response to start

stop and reverse commands

-Rely on encoders for

position details in closed

loop response

-Physical sizes

are comparable

-Both available

in various

lengths at same

frame size -Torque can be readily

controlled

-Low cost and high

availability

-Complexity drives cost

upward

Chosen for

deployment motor

Chosen for

pitching motor

Stepper Servo

Integration Blade Deployment

Deployment Motor Feasibility

Required holding torque is calculated to be 18 mNm

Required driving torque is calculated to be 117

10-5 mN∙m

bull Micro Motion Solutions ndash miniature stepper motors bull Physical Properties

bull Diameter = 6-22 mm

bull Length = 93-20 mm

bull Weight = 55-12 g

bull Holding Torque = 24-10 mN∙m = 034-142 oz∙in

bull Resolution bull 1 or 2 phase half-step capability

bull Steps per turn = 20-24 rarr 15˚-18˚ per step

5 of full step accuracy

bull Power Requirements bull Nominal voltage per phase 2-5 V

bull Nominal current per phase 01-1 A

46

Integration Blade Pitching

Blade Pitching Motor Feasibility

Required driving torque is calculated to be 0019 mN∙m

bull Mabuchi Servo Motor bull Physical Size

bull Diameter = 17 mm

bull Length = 25 mm

bull Weight = 16 g

bull Torque

bull Holding Torque = 161 mN∙m = 0228 oz∙in

bull Driving Torque = 0385 mN∙m = 0055 oz∙in

bull Friction Torque = 403

10-3 mN∙m = 571

10-4 oz∙in

bull Power Requirements

bull Nominal voltage per phase 2-5 V

bull Nominal current per phase 006-02 A 47

Integration Launch

Feasibility for Pre-deployment locking mechanism

The tip of the solar sail will be wider than the body with the sail tip set outside the plate

The tip will be held in place vertically by stationary blade stabilizers and kept tight by the holding torque of the deployment motor

Stationary blade

stabilizers

Extra-wide

blade tip

Upon deployment the motor

turns and the blade extends

48

Integration Launch

Canesterized Satellite Dispenser (CSD)

bull Ride in a 12 U CSD

bull Width=239 cm Height=226 cm Length=366 cm

bull Mass=0-24 kg at launch

bull Center of Mass when stowed in

bull x is -40 to 40 mm

bull y is 50 to 125 mm

bull z is 133 to 233 mm

wwwplanetarysytemscorpcom 49

Integration Launch

Test Validation

bull Launch Vibration Test

bull Needs to be space applicable and strong enough to withstand vibration

bull Ball Aerospace can provide a shake table costing $250hr

bull Preparation for Testing using FEM modeling and adding support features

50

Financial

bull Total Budget $5000

bull Components

bull Stepper Motor $100-200

bull Servo Motor (x2) $50-500 each

bull Materials (made in-house) $500-1000

bull Electronics $0-500

bull Testing

bull Deployment amp Pitching Free (Performed on Campus)

bull Launch Survivability Vibration Stand - $250hr Ball Space Systems in Boulder

bull Total Estimation $700-2700 + Vibration Stand Testing

51

Baseline Design All Together

bull The 8u CubeSat and characteristic acceleration requirements create very strict volumetric restrictions

bull The size of the plates and the rolled sail blade must be validated

bull This design will be analyzed and verified in the feasibility requirements

Inner Control Area

bull Motor

bull Encoder

bull Control

bull Communication

bull Power

Possible Load-bearing

corners for deployment

Housed Solar Sail

Top-Down View

Extra room for third

party systems

52

Status Summary

53

SystemMechanism Final Choice Further

Studies

Needed

8U Structure Fit our CubeSat in 12U bus provided by Planetary Services Yes

Adequate Area of Sails to Provide

Orbit Transfer Capabilities

AR = 22001 No

Pitching Mechanism Using a servo motor Yes

Pitching Accuracy Pitching encoder Yes

Plate Integration System Using a two cylinder design with tapered edges so

everything will fit

No

Deployment Motor Using a stepper motor No

Launch Ability Must conform to standards set by Planetary Services Yes

Launch Survivability Verify that GHOST will survive launch Yes

Initial Spin-Up Carbon steel attached to solar blade material Yes 53

Strategy for Conducting

Remaining Studies

bull 8U GHOST inside 12U structure bull Create a SolidWorksCAD model

bull Pitching Mechanism bull Determine adequate motor within size power and cost constraints

bull Pitching Accuracy bull Determine pitching accuracy based on orbital sensitivity

bull Launch Ability bull Because design is symmetrical center of mass is in the center of the satellite during launch bull Further investigations is needed to determine how many counterweights

bull Launch Survivability bull FEM or Vibrations

bull Initial Spin-up bull Determine feasible method to attach carbon steel support structure to solar sail blade material

54

Resources

bull PAYLOAD SPECIFICATION FOR 3U 6U 12U AND 27U Np Planetary Systems Corporation 2013 Print

bull Davis Jason The Planetary Society The Planetary Society Blog Firefly Partners 11 Apr 2012 Web 12 Oct 2013 lthttpwwwplanetaryorgblogsguest-blogsjason-davis3450htmlgt

bull Mao Tengfei 01mm Thickness Measuring Tape Wwwalibabacom Alibabacom nd Web 12 Oct 2013 lthttpwwwalibabacomproduct-gs8359006940_1mm_thickness_measuring_tapehtmlgt

55

Resources

bull ldquoHow servos and steppers stack uprdquo Machine Design 9 February 2012 [httpmachinedesigncomnewshow-servos-and-steppers-stack Accessed 7 October 2013]

bull ldquoMiniature Stepper Motor Drive Systems - Data Sheetrdquo Micro Motion Solutions [httpwwwmicromocomstepper-motors-datasheetsaspx Accessed 11 October 2013]

bull ldquoData Sheet for TS-53 Servorsquos Electric Motorrdquo Mabuchi Motor [httpwwwprincetonedu~mae412TEXTNTRAK2002292-302pdf Accessed 11 October 2013]

56

Deployment System Parallel

Axis Motor

bull Rolled sail and motor on same axis centered around the deployment axle

bull Motor is powered by wiring extending from the satellite center and stabilized by connecting to the interface

bull Locking mechanism- the blade tip is held by stabilizers that will prevent bunching upon deployment

Top-Down View

Power and Control

Rolled solar sail

Axle Deployment

Motor

Extra width on end keeps sail ready for deployment

Locking mechanism

Connects to Interface

Side View

Stabilized by

Interface

Stabilized by

Interface

Unrolled solar sail

11

Interface System Hollow Plate

bull Hollow plate interface attaches to pitching axle and houses the deployment system

bull Power and Control wiring spun around or through axle to prevent twisting when pitching

Space for MCU

Communication and

other instruments

Desired Inner Control

Area

Top-Down View (Not to

scale)

bull A thin-set bearing would be used to connect the plate to the CubeSat wall and minimize friction

Locking mechanism

Connects to Interface Plate Sized for thin-set bearing

connected to CubeSat

Power and Control

Wiring for

Deployment Motor

12

Critical Project Elements

bull Blade Deployment bull Earth-based design

bull Successfully deploy one solar sail blade in a 1G environment bull A motor is necessary to deploy one blade at a controlled rate of 1-10 cms bull The blade deployment needs to be tested in a near drag-free environment

bull Space-ready system bull Design a method to initialize the spin of the solar sail bull The blades must stay rigid during deployment

bull Blade Pitching bull Blades must pitch to a deflection angle given an input with a motor

bull Blades must have motor capable to pitch the blades 180

bull Blades must have coordinated deflection response bull Testing needs to confirm blades pitch to desired angle

13

Critical Project Elements

bull Orbit bull Earth-based system

bull While CubeSat is spinning blades must pitch in a periodic motion to direct the thrust bull A spin stand must be used to spin the CubeSat

bull Space-ready design bull Orbit must be designed for altitudes of 1100 ndash 1500 km

bull CubeSat must be launched into an initial orbit

bull Solar sail must have orbit transferring capabilities by pitching blades bull The solar sail blades must be sized to generate an acceleration of 01 mms2 bull Solar sail must be able to enter and exit a transfer orbit

bull Communication bull Earth-based model must be able to receive commands for pitching and deployment

systems bull Space-ready system must be able to communicate with Earth

14

Critical Project Elements

bull Integration bull The CubeSat is restricted by a maximum power available of 10W

bull Motors needed for blade release and pitching

bull The CubeSat is restricted to be no larger than 12U bull Earth-based model will be designed for 2 blades while space design will be for 4 blades

bull The CubeSat needs to hold the blades during a packaged state

bull Plates must be able to pitch without contact and minimum friction

bull The CubeSat must survive launch bull The CubeSat must meet the standards to launch in a Canesterized Satellite Dispenser

bull Extra design must be considered to stabilize the CubeSat for vibrations

bull Launch vibration test to prove survivability

bull Financial bull Earth-based model is restricted by a cost of $5000

15

Blade Deployment Space Model

Centripetal Acceleration

As the spacecraft spins the sail will experience a force

Important because the motor needs to oppose this force

16

Bus

V

r = solar sail length

Blade Deployment Space Model

Centripetal Acceleration

Deployment

Length

(Meters)

Centripetal

Acceleration

(ms2)

Mass

(Kg)

Centripetal

Force (N)

1 0011 0037 000041

15 016 0044 00073

30 033 0052 0017

50 055 0062 0034

100 11 0087 0095

150 16 011 018

200 22 014 03

220 24 015 035

17

Constant Spin Ω = 1 RPM

Gravitational Force

Earth

Orbital Trajectory

Equations

Constants

Blade Deployment

Testing on Earth Relation to Space

CubeSat rotating at 1 RPM rarr centripetal acceleration rarr centrifugal tension

Blade is fully deployed rarr maximum centrifugal tension

Simulate same centrifugal tension the blade would experience in space

Total mass of 36 g used in the deployment test

mTOTAL = mTM + mB = 36 + 110 = 146 g

a = 241 ms2 F = ma = 035 N

F = mg = 035 N g = 981 ms2

mTOTAL = 36 g

The holding torque of the motor used must be able to withstand this force

τ = r

F r = 05 cm F = 035 N

τ = 00018 Nm

Space Application

Motor

CubeSat

rotating at 1

RPM

Blade Tip mass

F

Top View

Tip mass trajectory

mB = 10 g mTM = 26 g

F = mg

Deployment Test

r

Mounted to Table Side View

Tip

mass

Motor

Blade

Front View

MotorBus

Interface

18

Blade Deployment

Earth Test Validation

19

Deployment Test

bull Release one solar sail blade of 15m at a controlled rate of 1-10 cms to demonstrate controlled deployment

bull Will be tested in Professor Frewrsquos lab in Fleming that is 17m high

bull Use video camera to measure rate set markers along wall to track deployment

19

Blade Deployment Space Model

Initial Spin Up

bull Carbon Steel Blade Supports at the end to replace end mass

bull 50 Carbon Steel

bull 01 mm thick

bull Deployment motor will deploy initial blade support structure for initial spin-up

CubeSat

Carbon-Steel

Blade Supports

Solar Blade

20

Blade Deployment Space Model

Initial Spin Up

bull Collective pitch of 35

to produce torque for spin up

bull Mass at end of sail=367g

bull Volume = 47e-6 cubic m

bull Two perpendicular rods rotating about oblate axis bull Both 4 kg

bull I=

bull Known bull Width=01 m

bull Length=047 m

bull Surface Area=00467 squared meters

21

Blade Deployment Space Model

Initial Spin Up

bull

=435

bull α=

bull Time = 24 days

bull Release the rest of sail and centrifugal tension will aid in deployment of sail

bull Solar sail thrust should keep CubeSat at 1 RPM while deploying

CubeSat

∆ω = Ω = 1 RPM

τ = L

F = Iα

L = 057 m

F = 023 μN

22

Orbit Initial Orbit

Final Orbit Selection

bull Sun-Synchronous 1500 km DawnDusk Orbit

bull Assumptions

bull Circular Orbit (e = 0 a = p)

bull No atmospheric drag above 1100 km altitude

bull Only orbital perturbation considered in orbit determination is the oblateness of the earth (second zonal constant J2)

bull All other orbital perturbations are neglected

bull For SS Orbit Node Precession = Solar Precession

bull Gyro rotational axis always oriented towards Sun

23

See Appendix for calculation

24

Orbit Initial Orbit

SS DawnDusk Orbit

Orbit Initial Orbit

Launch

bull Vandenberg AFB CA

bull Atlas V Launch Vehicle

bull Secondary Payload

bull Insertion into near Polar Orbit via Centaur Upper Stage

bull Further transfer necessary to achieve SS orbit

25

Orbit Blade Size

Maximum Solar Radiation Pressure Calculation

bull Assumptions

bull Perfectly reflecting surface

bull α = 0

(incident radiation perpendicular to surface)

26

Preflect2W

cR2cos2 = 908 Pa

where W = 1361 Wm2 c = 30x10 8 ms amp R = 100 AU

Orbit Blade Size

Minimum Solar Blade Surface Area for

Necessary Thrust

bull Assumptions

bull m = 8 kg (based on 8U Volume CubeSat 1 kgU)

27

a ac 01 mms2 requirement

sreflectc APmaFmax Asmac

Preflect8811 m2

bull 4 solar blades

As

42203 m2 per blade

Orbit Transfer

bull Example

bull LV delivers sc into 1100 km circular polar orbit

bull 1) Orbit raising maneuver to 1500 km

bull 2) Inclination change maneuver to i = 10196

bull How long will this take with GHOSTrsquos capabilities

28

29

Orbit Transfer

Orbit Raising Maneuver

Hohmann Transfer

Dual tangential

burn coplanar orbit

transfer

Initial Orbit

Final Orbit

Transfer Orbit

Orbit Transfer

Orbit Raising Maneuver

bull Calculated using Hohmann Transfer Equations

30

initial transfer vi 945 ms

transfer final v f 933 ms

vtotal 1877 ms

torbit raise 123 days

45o Preflect 454 Pa ain plane 177x10 5 ms2

Two blades pitched at

45

producing thrust in along track direction

See appendix for detailed orbit transfer diagrams

Orbit Transfer

Orbit Inclination Change

bull Calculated using inclination change only equations

31

v inc 2v initialcos( fpa)sini

2where vinitial v f fpa 0o amp i 1196o

vinc 148 kms i 00028 oorbit

a ac 01 mms2 P 6959 s Thrust acts over northern hemisphere of orbit (12 of Period)

tinc change 3437 days

Orbit Transfer

Final Destination

bull Δttotal = 4667 days or ~ 155 months bull time it takes to transfer from LV Delivery 1100 km polar orbit to 1500 km SS

orbit

bull this BOTE calculation has huge implications on both

bull mission duration

bull life span of sc components materials etc

bull Validates the high performance orbit transfer capabilities of the heliogyro architecture

32

Integration CubeSat

Pitch Test Validation

Sensor(s) to measure

torque and

Purpose Demonstrate coordinated pitching with equivalent mass and

realistic bus rotation

bull Rotation of 1 RPM

bull Measure torque on bus

bull Measure and compare actual pitching angles

to commanded

pitching angles

Sensors Needed

bull 3 axis Accelerometer (torque measurement)

bull 3 axis Gyroscope (pitch angle measurement)

bull 12 bit resolution (greater than pitching motors)

bull Fit onto or on 8U CubeSat

ADI516xxxIM4

bull 3 axis gyroscope

bull 3 axis magnetometer

bull 3 axis accelerometer

bull 14 bit resolution

bull 1

volume

bull Available free for checkout in ITLL

Sail Equivalent

mass

33

Integration CubeSat

Feasibility of our Baseline Design

bull To achieve characteristic acceleration for an 8U (8kg) CubeSat we needed each sail to be 2203

bull The diameter of the rolled spool inside the CubeSat (pre-deployment) varies with the width of the sail

bull To find the diameter of the rolled spool we calculated the length of one sail for a chosen width Assuming a Mylar thickness of 5 um due to the crinkling effect the spool width was calculated by iterating each rotation with increasing diameter as the blade rolls up

Iterate for rolling up sail until finished

(cm)

(m)

12 1836 247

10 2203 270

8 2754 300

34

Integration CubeSat

Sizing the Blades

bull CubeSat constrained by 20 cm on each side

bull Need to perform 180 degree independent rotation and maximize room inside the satellite for pitching motors controls and communication

Top Down Views of each size ( Scaled to correct dimensions)

12 cm blade width 10 cm blade width 8 cm blade width

bull Not intrusive on inner area

bull Full 180 motion

bull Infringes on space inside

bull Full 180 motion

bull Not intrusive on inner area

bull No Full 180 motion

35

Integration CubeSat

Housing the Rolled Sail

bull The solar sail blades will be controlled by a pitching axle but there must be an interface to connect to the axle

bull Cylindrical plate housing

bull Protects blades

bull Easy to connect to axle

bull No gears

bull Ability to provide counterweight

to deployment motor

bull With the tight volume constraints of our cube the Cylindrical plate must be altered to avoid interference with other sides

36

Integration CubeSat

Fitting the cylindrical Plate

bull Clearance for rolled sail

bull 2 cm clearance on each side

bull 06 cm clearance on behind the motor

bull This leaves overlapping corners

bull To prevent overlap we will make a 45ordm cut around the entire cylinder

2 cm

06 cm

Rolled Sail

Plate Encasing

Overlapping

Corners

45ordm cut to get rid

of corners

37

Integration CubeSat

Fitting the cylindrical Plate

bull The 45ordm cut will give us a 0 cm clearance (with no thickness)

bull If we implement a high-low offset between adjacent plates the distance between the two closest points increases

bull For our 14 cm diameter plates a 2 cm offset from the center for each plate (4 cm total) the effective clearance becomes 251 cm

Two adjacent sides

on same axis

With a High-Low Offset

38

Integration CubeSat

High-Low Offset Plates

The high low offset will give each plate room to rotate a full 180ordm

1 cm clearance between the top of the

blade and the edge of the satellite to fit

the thin-set bearing

A 3mm plate thickness gives adjacent

plates a distance of 19 cm between

their closest points

39

Integration CubeSat

High Low Offset Performance Validation

bull The high-low offset will not effect the performance or stability of the deployment or pitching systems

bull Upon deployment the opposing extension on each side cancels out unwanted torque

View From high side View From low side

bull In a sun-synchronous orbit the high or low setting has no effect as the rotational axis of the satellite is always solar pointing

View From Sun

40

Integration Power

Electronics Feasibility Analysis

bull Project Constraints

bull CubeSat power source Li-Ion batteries (5 and 33 V is common) - Would require thermal protection

bull Communications System - Transceiver (UHF is common) [USART serial port] - Buffer may be needed depending on power constraints

bull Deployment Subsystem - 1 step-motor [output] - 1 encoder [MSSP input] OR direct deployment measurement via external sensor

bull Pitching Subsystem - 2 servomotors [output]

41

Integration Power

PIC18F Series Microchip

bull Inputs 2 USART and 2 MSSP ports available (for basic PICs) - More than 1 device may be connected to each port - 2-3 devices needed

bull Outputs 8 ports - 2 devices needed

bull 16 bit - Though different PICs may be acquired for higher resolution

bull Operating Range 2-55 V - Within provided parameters

42

PIC

Communications

Deployment

Motor

Encoder

Pitching

Motor 1

Pitching

Motor 2 Key

Power Lines

Input Lines

Output Lines

Integration Power

Microchip FBD

5V Battery

Possible Voltage

Buffer

Encoder

43

Integration Power

Motor Power Limitations

bull Power Constraints

Pmax = 100 W

Vmax = 50 V

bull P = IV (Power = CurrentVoltage)

bull Therefore Iave = 20 Amps

bull Blade Pitching (4 motors total needed) - Current limitations for power sources and number of simultaneous blades pitching

Number of Blades 5 V Input 36 V input 31 V input 2 V input

4 040 A 069 A 081 A 125 A

2 080 A 139 A 161 A 250 A

1 160 A 278 A 323 A 500 A

44

Integration Motors

Stepper vs Brushless Servo Motors

45

-Contain many poles (50+) -Contain only 4-12 poles

-Distinct steps cause

vibration during use -Do not suffer from

vibration and resonance

issues smooth movement

-Low maintenance easier to

commission mechanically

simple

-Efficient response to start

stop and reverse commands

-Rely on encoders for

position details in closed

loop response

-Physical sizes

are comparable

-Both available

in various

lengths at same

frame size -Torque can be readily

controlled

-Low cost and high

availability

-Complexity drives cost

upward

Chosen for

deployment motor

Chosen for

pitching motor

Stepper Servo

Integration Blade Deployment

Deployment Motor Feasibility

Required holding torque is calculated to be 18 mNm

Required driving torque is calculated to be 117

10-5 mN∙m

bull Micro Motion Solutions ndash miniature stepper motors bull Physical Properties

bull Diameter = 6-22 mm

bull Length = 93-20 mm

bull Weight = 55-12 g

bull Holding Torque = 24-10 mN∙m = 034-142 oz∙in

bull Resolution bull 1 or 2 phase half-step capability

bull Steps per turn = 20-24 rarr 15˚-18˚ per step

5 of full step accuracy

bull Power Requirements bull Nominal voltage per phase 2-5 V

bull Nominal current per phase 01-1 A

46

Integration Blade Pitching

Blade Pitching Motor Feasibility

Required driving torque is calculated to be 0019 mN∙m

bull Mabuchi Servo Motor bull Physical Size

bull Diameter = 17 mm

bull Length = 25 mm

bull Weight = 16 g

bull Torque

bull Holding Torque = 161 mN∙m = 0228 oz∙in

bull Driving Torque = 0385 mN∙m = 0055 oz∙in

bull Friction Torque = 403

10-3 mN∙m = 571

10-4 oz∙in

bull Power Requirements

bull Nominal voltage per phase 2-5 V

bull Nominal current per phase 006-02 A 47

Integration Launch

Feasibility for Pre-deployment locking mechanism

The tip of the solar sail will be wider than the body with the sail tip set outside the plate

The tip will be held in place vertically by stationary blade stabilizers and kept tight by the holding torque of the deployment motor

Stationary blade

stabilizers

Extra-wide

blade tip

Upon deployment the motor

turns and the blade extends

48

Integration Launch

Canesterized Satellite Dispenser (CSD)

bull Ride in a 12 U CSD

bull Width=239 cm Height=226 cm Length=366 cm

bull Mass=0-24 kg at launch

bull Center of Mass when stowed in

bull x is -40 to 40 mm

bull y is 50 to 125 mm

bull z is 133 to 233 mm

wwwplanetarysytemscorpcom 49

Integration Launch

Test Validation

bull Launch Vibration Test

bull Needs to be space applicable and strong enough to withstand vibration

bull Ball Aerospace can provide a shake table costing $250hr

bull Preparation for Testing using FEM modeling and adding support features

50

Financial

bull Total Budget $5000

bull Components

bull Stepper Motor $100-200

bull Servo Motor (x2) $50-500 each

bull Materials (made in-house) $500-1000

bull Electronics $0-500

bull Testing

bull Deployment amp Pitching Free (Performed on Campus)

bull Launch Survivability Vibration Stand - $250hr Ball Space Systems in Boulder

bull Total Estimation $700-2700 + Vibration Stand Testing

51

Baseline Design All Together

bull The 8u CubeSat and characteristic acceleration requirements create very strict volumetric restrictions

bull The size of the plates and the rolled sail blade must be validated

bull This design will be analyzed and verified in the feasibility requirements

Inner Control Area

bull Motor

bull Encoder

bull Control

bull Communication

bull Power

Possible Load-bearing

corners for deployment

Housed Solar Sail

Top-Down View

Extra room for third

party systems

52

Status Summary

53

SystemMechanism Final Choice Further

Studies

Needed

8U Structure Fit our CubeSat in 12U bus provided by Planetary Services Yes

Adequate Area of Sails to Provide

Orbit Transfer Capabilities

AR = 22001 No

Pitching Mechanism Using a servo motor Yes

Pitching Accuracy Pitching encoder Yes

Plate Integration System Using a two cylinder design with tapered edges so

everything will fit

No

Deployment Motor Using a stepper motor No

Launch Ability Must conform to standards set by Planetary Services Yes

Launch Survivability Verify that GHOST will survive launch Yes

Initial Spin-Up Carbon steel attached to solar blade material Yes 53

Strategy for Conducting

Remaining Studies

bull 8U GHOST inside 12U structure bull Create a SolidWorksCAD model

bull Pitching Mechanism bull Determine adequate motor within size power and cost constraints

bull Pitching Accuracy bull Determine pitching accuracy based on orbital sensitivity

bull Launch Ability bull Because design is symmetrical center of mass is in the center of the satellite during launch bull Further investigations is needed to determine how many counterweights

bull Launch Survivability bull FEM or Vibrations

bull Initial Spin-up bull Determine feasible method to attach carbon steel support structure to solar sail blade material

54

Resources

bull PAYLOAD SPECIFICATION FOR 3U 6U 12U AND 27U Np Planetary Systems Corporation 2013 Print

bull Davis Jason The Planetary Society The Planetary Society Blog Firefly Partners 11 Apr 2012 Web 12 Oct 2013 lthttpwwwplanetaryorgblogsguest-blogsjason-davis3450htmlgt

bull Mao Tengfei 01mm Thickness Measuring Tape Wwwalibabacom Alibabacom nd Web 12 Oct 2013 lthttpwwwalibabacomproduct-gs8359006940_1mm_thickness_measuring_tapehtmlgt

55

Resources

bull ldquoHow servos and steppers stack uprdquo Machine Design 9 February 2012 [httpmachinedesigncomnewshow-servos-and-steppers-stack Accessed 7 October 2013]

bull ldquoMiniature Stepper Motor Drive Systems - Data Sheetrdquo Micro Motion Solutions [httpwwwmicromocomstepper-motors-datasheetsaspx Accessed 11 October 2013]

bull ldquoData Sheet for TS-53 Servorsquos Electric Motorrdquo Mabuchi Motor [httpwwwprincetonedu~mae412TEXTNTRAK2002292-302pdf Accessed 11 October 2013]

56

Interface System Hollow Plate

bull Hollow plate interface attaches to pitching axle and houses the deployment system

bull Power and Control wiring spun around or through axle to prevent twisting when pitching

Space for MCU

Communication and

other instruments

Desired Inner Control

Area

Top-Down View (Not to

scale)

bull A thin-set bearing would be used to connect the plate to the CubeSat wall and minimize friction

Locking mechanism

Connects to Interface Plate Sized for thin-set bearing

connected to CubeSat

Power and Control

Wiring for

Deployment Motor

12

Critical Project Elements

bull Blade Deployment bull Earth-based design

bull Successfully deploy one solar sail blade in a 1G environment bull A motor is necessary to deploy one blade at a controlled rate of 1-10 cms bull The blade deployment needs to be tested in a near drag-free environment

bull Space-ready system bull Design a method to initialize the spin of the solar sail bull The blades must stay rigid during deployment

bull Blade Pitching bull Blades must pitch to a deflection angle given an input with a motor

bull Blades must have motor capable to pitch the blades 180

bull Blades must have coordinated deflection response bull Testing needs to confirm blades pitch to desired angle

13

Critical Project Elements

bull Orbit bull Earth-based system

bull While CubeSat is spinning blades must pitch in a periodic motion to direct the thrust bull A spin stand must be used to spin the CubeSat

bull Space-ready design bull Orbit must be designed for altitudes of 1100 ndash 1500 km

bull CubeSat must be launched into an initial orbit

bull Solar sail must have orbit transferring capabilities by pitching blades bull The solar sail blades must be sized to generate an acceleration of 01 mms2 bull Solar sail must be able to enter and exit a transfer orbit

bull Communication bull Earth-based model must be able to receive commands for pitching and deployment

systems bull Space-ready system must be able to communicate with Earth

14

Critical Project Elements

bull Integration bull The CubeSat is restricted by a maximum power available of 10W

bull Motors needed for blade release and pitching

bull The CubeSat is restricted to be no larger than 12U bull Earth-based model will be designed for 2 blades while space design will be for 4 blades

bull The CubeSat needs to hold the blades during a packaged state

bull Plates must be able to pitch without contact and minimum friction

bull The CubeSat must survive launch bull The CubeSat must meet the standards to launch in a Canesterized Satellite Dispenser

bull Extra design must be considered to stabilize the CubeSat for vibrations

bull Launch vibration test to prove survivability

bull Financial bull Earth-based model is restricted by a cost of $5000

15

Blade Deployment Space Model

Centripetal Acceleration

As the spacecraft spins the sail will experience a force

Important because the motor needs to oppose this force

16

Bus

V

r = solar sail length

Blade Deployment Space Model

Centripetal Acceleration

Deployment

Length

(Meters)

Centripetal

Acceleration

(ms2)

Mass

(Kg)

Centripetal

Force (N)

1 0011 0037 000041

15 016 0044 00073

30 033 0052 0017

50 055 0062 0034

100 11 0087 0095

150 16 011 018

200 22 014 03

220 24 015 035

17

Constant Spin Ω = 1 RPM

Gravitational Force

Earth

Orbital Trajectory

Equations

Constants

Blade Deployment

Testing on Earth Relation to Space

CubeSat rotating at 1 RPM rarr centripetal acceleration rarr centrifugal tension

Blade is fully deployed rarr maximum centrifugal tension

Simulate same centrifugal tension the blade would experience in space

Total mass of 36 g used in the deployment test

mTOTAL = mTM + mB = 36 + 110 = 146 g

a = 241 ms2 F = ma = 035 N

F = mg = 035 N g = 981 ms2

mTOTAL = 36 g

The holding torque of the motor used must be able to withstand this force

τ = r

F r = 05 cm F = 035 N

τ = 00018 Nm

Space Application

Motor

CubeSat

rotating at 1

RPM

Blade Tip mass

F

Top View

Tip mass trajectory

mB = 10 g mTM = 26 g

F = mg

Deployment Test

r

Mounted to Table Side View

Tip

mass

Motor

Blade

Front View

MotorBus

Interface

18

Blade Deployment

Earth Test Validation

19

Deployment Test

bull Release one solar sail blade of 15m at a controlled rate of 1-10 cms to demonstrate controlled deployment

bull Will be tested in Professor Frewrsquos lab in Fleming that is 17m high

bull Use video camera to measure rate set markers along wall to track deployment

19

Blade Deployment Space Model

Initial Spin Up

bull Carbon Steel Blade Supports at the end to replace end mass

bull 50 Carbon Steel

bull 01 mm thick

bull Deployment motor will deploy initial blade support structure for initial spin-up

CubeSat

Carbon-Steel

Blade Supports

Solar Blade

20

Blade Deployment Space Model

Initial Spin Up

bull Collective pitch of 35

to produce torque for spin up

bull Mass at end of sail=367g

bull Volume = 47e-6 cubic m

bull Two perpendicular rods rotating about oblate axis bull Both 4 kg

bull I=

bull Known bull Width=01 m

bull Length=047 m

bull Surface Area=00467 squared meters

21

Blade Deployment Space Model

Initial Spin Up

bull

=435

bull α=

bull Time = 24 days

bull Release the rest of sail and centrifugal tension will aid in deployment of sail

bull Solar sail thrust should keep CubeSat at 1 RPM while deploying

CubeSat

∆ω = Ω = 1 RPM

τ = L

F = Iα

L = 057 m

F = 023 μN

22

Orbit Initial Orbit

Final Orbit Selection

bull Sun-Synchronous 1500 km DawnDusk Orbit

bull Assumptions

bull Circular Orbit (e = 0 a = p)

bull No atmospheric drag above 1100 km altitude

bull Only orbital perturbation considered in orbit determination is the oblateness of the earth (second zonal constant J2)

bull All other orbital perturbations are neglected

bull For SS Orbit Node Precession = Solar Precession

bull Gyro rotational axis always oriented towards Sun

23

See Appendix for calculation

24

Orbit Initial Orbit

SS DawnDusk Orbit

Orbit Initial Orbit

Launch

bull Vandenberg AFB CA

bull Atlas V Launch Vehicle

bull Secondary Payload

bull Insertion into near Polar Orbit via Centaur Upper Stage

bull Further transfer necessary to achieve SS orbit

25

Orbit Blade Size

Maximum Solar Radiation Pressure Calculation

bull Assumptions

bull Perfectly reflecting surface

bull α = 0

(incident radiation perpendicular to surface)

26

Preflect2W

cR2cos2 = 908 Pa

where W = 1361 Wm2 c = 30x10 8 ms amp R = 100 AU

Orbit Blade Size

Minimum Solar Blade Surface Area for

Necessary Thrust

bull Assumptions

bull m = 8 kg (based on 8U Volume CubeSat 1 kgU)

27

a ac 01 mms2 requirement

sreflectc APmaFmax Asmac

Preflect8811 m2

bull 4 solar blades

As

42203 m2 per blade

Orbit Transfer

bull Example

bull LV delivers sc into 1100 km circular polar orbit

bull 1) Orbit raising maneuver to 1500 km

bull 2) Inclination change maneuver to i = 10196

bull How long will this take with GHOSTrsquos capabilities

28

29

Orbit Transfer

Orbit Raising Maneuver

Hohmann Transfer

Dual tangential

burn coplanar orbit

transfer

Initial Orbit

Final Orbit

Transfer Orbit

Orbit Transfer

Orbit Raising Maneuver

bull Calculated using Hohmann Transfer Equations

30

initial transfer vi 945 ms

transfer final v f 933 ms

vtotal 1877 ms

torbit raise 123 days

45o Preflect 454 Pa ain plane 177x10 5 ms2

Two blades pitched at

45

producing thrust in along track direction

See appendix for detailed orbit transfer diagrams

Orbit Transfer

Orbit Inclination Change

bull Calculated using inclination change only equations

31

v inc 2v initialcos( fpa)sini

2where vinitial v f fpa 0o amp i 1196o

vinc 148 kms i 00028 oorbit

a ac 01 mms2 P 6959 s Thrust acts over northern hemisphere of orbit (12 of Period)

tinc change 3437 days

Orbit Transfer

Final Destination

bull Δttotal = 4667 days or ~ 155 months bull time it takes to transfer from LV Delivery 1100 km polar orbit to 1500 km SS

orbit

bull this BOTE calculation has huge implications on both

bull mission duration

bull life span of sc components materials etc

bull Validates the high performance orbit transfer capabilities of the heliogyro architecture

32

Integration CubeSat

Pitch Test Validation

Sensor(s) to measure

torque and

Purpose Demonstrate coordinated pitching with equivalent mass and

realistic bus rotation

bull Rotation of 1 RPM

bull Measure torque on bus

bull Measure and compare actual pitching angles

to commanded

pitching angles

Sensors Needed

bull 3 axis Accelerometer (torque measurement)

bull 3 axis Gyroscope (pitch angle measurement)

bull 12 bit resolution (greater than pitching motors)

bull Fit onto or on 8U CubeSat

ADI516xxxIM4

bull 3 axis gyroscope

bull 3 axis magnetometer

bull 3 axis accelerometer

bull 14 bit resolution

bull 1

volume

bull Available free for checkout in ITLL

Sail Equivalent

mass

33

Integration CubeSat

Feasibility of our Baseline Design

bull To achieve characteristic acceleration for an 8U (8kg) CubeSat we needed each sail to be 2203

bull The diameter of the rolled spool inside the CubeSat (pre-deployment) varies with the width of the sail

bull To find the diameter of the rolled spool we calculated the length of one sail for a chosen width Assuming a Mylar thickness of 5 um due to the crinkling effect the spool width was calculated by iterating each rotation with increasing diameter as the blade rolls up

Iterate for rolling up sail until finished

(cm)

(m)

12 1836 247

10 2203 270

8 2754 300

34

Integration CubeSat

Sizing the Blades

bull CubeSat constrained by 20 cm on each side

bull Need to perform 180 degree independent rotation and maximize room inside the satellite for pitching motors controls and communication

Top Down Views of each size ( Scaled to correct dimensions)

12 cm blade width 10 cm blade width 8 cm blade width

bull Not intrusive on inner area

bull Full 180 motion

bull Infringes on space inside

bull Full 180 motion

bull Not intrusive on inner area

bull No Full 180 motion

35

Integration CubeSat

Housing the Rolled Sail

bull The solar sail blades will be controlled by a pitching axle but there must be an interface to connect to the axle

bull Cylindrical plate housing

bull Protects blades

bull Easy to connect to axle

bull No gears

bull Ability to provide counterweight

to deployment motor

bull With the tight volume constraints of our cube the Cylindrical plate must be altered to avoid interference with other sides

36

Integration CubeSat

Fitting the cylindrical Plate

bull Clearance for rolled sail

bull 2 cm clearance on each side

bull 06 cm clearance on behind the motor

bull This leaves overlapping corners

bull To prevent overlap we will make a 45ordm cut around the entire cylinder

2 cm

06 cm

Rolled Sail

Plate Encasing

Overlapping

Corners

45ordm cut to get rid

of corners

37

Integration CubeSat

Fitting the cylindrical Plate

bull The 45ordm cut will give us a 0 cm clearance (with no thickness)

bull If we implement a high-low offset between adjacent plates the distance between the two closest points increases

bull For our 14 cm diameter plates a 2 cm offset from the center for each plate (4 cm total) the effective clearance becomes 251 cm

Two adjacent sides

on same axis

With a High-Low Offset

38

Integration CubeSat

High-Low Offset Plates

The high low offset will give each plate room to rotate a full 180ordm

1 cm clearance between the top of the

blade and the edge of the satellite to fit

the thin-set bearing

A 3mm plate thickness gives adjacent

plates a distance of 19 cm between

their closest points

39

Integration CubeSat

High Low Offset Performance Validation

bull The high-low offset will not effect the performance or stability of the deployment or pitching systems

bull Upon deployment the opposing extension on each side cancels out unwanted torque

View From high side View From low side

bull In a sun-synchronous orbit the high or low setting has no effect as the rotational axis of the satellite is always solar pointing

View From Sun

40

Integration Power

Electronics Feasibility Analysis

bull Project Constraints

bull CubeSat power source Li-Ion batteries (5 and 33 V is common) - Would require thermal protection

bull Communications System - Transceiver (UHF is common) [USART serial port] - Buffer may be needed depending on power constraints

bull Deployment Subsystem - 1 step-motor [output] - 1 encoder [MSSP input] OR direct deployment measurement via external sensor

bull Pitching Subsystem - 2 servomotors [output]

41

Integration Power

PIC18F Series Microchip

bull Inputs 2 USART and 2 MSSP ports available (for basic PICs) - More than 1 device may be connected to each port - 2-3 devices needed

bull Outputs 8 ports - 2 devices needed

bull 16 bit - Though different PICs may be acquired for higher resolution

bull Operating Range 2-55 V - Within provided parameters

42

PIC

Communications

Deployment

Motor

Encoder

Pitching

Motor 1

Pitching

Motor 2 Key

Power Lines

Input Lines

Output Lines

Integration Power

Microchip FBD

5V Battery

Possible Voltage

Buffer

Encoder

43

Integration Power

Motor Power Limitations

bull Power Constraints

Pmax = 100 W

Vmax = 50 V

bull P = IV (Power = CurrentVoltage)

bull Therefore Iave = 20 Amps

bull Blade Pitching (4 motors total needed) - Current limitations for power sources and number of simultaneous blades pitching

Number of Blades 5 V Input 36 V input 31 V input 2 V input

4 040 A 069 A 081 A 125 A

2 080 A 139 A 161 A 250 A

1 160 A 278 A 323 A 500 A

44

Integration Motors

Stepper vs Brushless Servo Motors

45

-Contain many poles (50+) -Contain only 4-12 poles

-Distinct steps cause

vibration during use -Do not suffer from

vibration and resonance

issues smooth movement

-Low maintenance easier to

commission mechanically

simple

-Efficient response to start

stop and reverse commands

-Rely on encoders for

position details in closed

loop response

-Physical sizes

are comparable

-Both available

in various

lengths at same

frame size -Torque can be readily

controlled

-Low cost and high

availability

-Complexity drives cost

upward

Chosen for

deployment motor

Chosen for

pitching motor

Stepper Servo

Integration Blade Deployment

Deployment Motor Feasibility

Required holding torque is calculated to be 18 mNm

Required driving torque is calculated to be 117

10-5 mN∙m

bull Micro Motion Solutions ndash miniature stepper motors bull Physical Properties

bull Diameter = 6-22 mm

bull Length = 93-20 mm

bull Weight = 55-12 g

bull Holding Torque = 24-10 mN∙m = 034-142 oz∙in

bull Resolution bull 1 or 2 phase half-step capability

bull Steps per turn = 20-24 rarr 15˚-18˚ per step

5 of full step accuracy

bull Power Requirements bull Nominal voltage per phase 2-5 V

bull Nominal current per phase 01-1 A

46

Integration Blade Pitching

Blade Pitching Motor Feasibility

Required driving torque is calculated to be 0019 mN∙m

bull Mabuchi Servo Motor bull Physical Size

bull Diameter = 17 mm

bull Length = 25 mm

bull Weight = 16 g

bull Torque

bull Holding Torque = 161 mN∙m = 0228 oz∙in

bull Driving Torque = 0385 mN∙m = 0055 oz∙in

bull Friction Torque = 403

10-3 mN∙m = 571

10-4 oz∙in

bull Power Requirements

bull Nominal voltage per phase 2-5 V

bull Nominal current per phase 006-02 A 47

Integration Launch

Feasibility for Pre-deployment locking mechanism

The tip of the solar sail will be wider than the body with the sail tip set outside the plate

The tip will be held in place vertically by stationary blade stabilizers and kept tight by the holding torque of the deployment motor

Stationary blade

stabilizers

Extra-wide

blade tip

Upon deployment the motor

turns and the blade extends

48

Integration Launch

Canesterized Satellite Dispenser (CSD)

bull Ride in a 12 U CSD

bull Width=239 cm Height=226 cm Length=366 cm

bull Mass=0-24 kg at launch

bull Center of Mass when stowed in

bull x is -40 to 40 mm

bull y is 50 to 125 mm

bull z is 133 to 233 mm

wwwplanetarysytemscorpcom 49

Integration Launch

Test Validation

bull Launch Vibration Test

bull Needs to be space applicable and strong enough to withstand vibration

bull Ball Aerospace can provide a shake table costing $250hr

bull Preparation for Testing using FEM modeling and adding support features

50

Financial

bull Total Budget $5000

bull Components

bull Stepper Motor $100-200

bull Servo Motor (x2) $50-500 each

bull Materials (made in-house) $500-1000

bull Electronics $0-500

bull Testing

bull Deployment amp Pitching Free (Performed on Campus)

bull Launch Survivability Vibration Stand - $250hr Ball Space Systems in Boulder

bull Total Estimation $700-2700 + Vibration Stand Testing

51

Baseline Design All Together

bull The 8u CubeSat and characteristic acceleration requirements create very strict volumetric restrictions

bull The size of the plates and the rolled sail blade must be validated

bull This design will be analyzed and verified in the feasibility requirements

Inner Control Area

bull Motor

bull Encoder

bull Control

bull Communication

bull Power

Possible Load-bearing

corners for deployment

Housed Solar Sail

Top-Down View

Extra room for third

party systems

52

Status Summary

53

SystemMechanism Final Choice Further

Studies

Needed

8U Structure Fit our CubeSat in 12U bus provided by Planetary Services Yes

Adequate Area of Sails to Provide

Orbit Transfer Capabilities

AR = 22001 No

Pitching Mechanism Using a servo motor Yes

Pitching Accuracy Pitching encoder Yes

Plate Integration System Using a two cylinder design with tapered edges so

everything will fit

No

Deployment Motor Using a stepper motor No

Launch Ability Must conform to standards set by Planetary Services Yes

Launch Survivability Verify that GHOST will survive launch Yes

Initial Spin-Up Carbon steel attached to solar blade material Yes 53

Strategy for Conducting

Remaining Studies

bull 8U GHOST inside 12U structure bull Create a SolidWorksCAD model

bull Pitching Mechanism bull Determine adequate motor within size power and cost constraints

bull Pitching Accuracy bull Determine pitching accuracy based on orbital sensitivity

bull Launch Ability bull Because design is symmetrical center of mass is in the center of the satellite during launch bull Further investigations is needed to determine how many counterweights

bull Launch Survivability bull FEM or Vibrations

bull Initial Spin-up bull Determine feasible method to attach carbon steel support structure to solar sail blade material

54

Resources

bull PAYLOAD SPECIFICATION FOR 3U 6U 12U AND 27U Np Planetary Systems Corporation 2013 Print

bull Davis Jason The Planetary Society The Planetary Society Blog Firefly Partners 11 Apr 2012 Web 12 Oct 2013 lthttpwwwplanetaryorgblogsguest-blogsjason-davis3450htmlgt

bull Mao Tengfei 01mm Thickness Measuring Tape Wwwalibabacom Alibabacom nd Web 12 Oct 2013 lthttpwwwalibabacomproduct-gs8359006940_1mm_thickness_measuring_tapehtmlgt

55

Resources

bull ldquoHow servos and steppers stack uprdquo Machine Design 9 February 2012 [httpmachinedesigncomnewshow-servos-and-steppers-stack Accessed 7 October 2013]

bull ldquoMiniature Stepper Motor Drive Systems - Data Sheetrdquo Micro Motion Solutions [httpwwwmicromocomstepper-motors-datasheetsaspx Accessed 11 October 2013]

bull ldquoData Sheet for TS-53 Servorsquos Electric Motorrdquo Mabuchi Motor [httpwwwprincetonedu~mae412TEXTNTRAK2002292-302pdf Accessed 11 October 2013]

56

Critical Project Elements

bull Blade Deployment bull Earth-based design

bull Successfully deploy one solar sail blade in a 1G environment bull A motor is necessary to deploy one blade at a controlled rate of 1-10 cms bull The blade deployment needs to be tested in a near drag-free environment

bull Space-ready system bull Design a method to initialize the spin of the solar sail bull The blades must stay rigid during deployment

bull Blade Pitching bull Blades must pitch to a deflection angle given an input with a motor

bull Blades must have motor capable to pitch the blades 180

bull Blades must have coordinated deflection response bull Testing needs to confirm blades pitch to desired angle

13

Critical Project Elements

bull Orbit bull Earth-based system

bull While CubeSat is spinning blades must pitch in a periodic motion to direct the thrust bull A spin stand must be used to spin the CubeSat

bull Space-ready design bull Orbit must be designed for altitudes of 1100 ndash 1500 km

bull CubeSat must be launched into an initial orbit

bull Solar sail must have orbit transferring capabilities by pitching blades bull The solar sail blades must be sized to generate an acceleration of 01 mms2 bull Solar sail must be able to enter and exit a transfer orbit

bull Communication bull Earth-based model must be able to receive commands for pitching and deployment

systems bull Space-ready system must be able to communicate with Earth

14

Critical Project Elements

bull Integration bull The CubeSat is restricted by a maximum power available of 10W

bull Motors needed for blade release and pitching

bull The CubeSat is restricted to be no larger than 12U bull Earth-based model will be designed for 2 blades while space design will be for 4 blades

bull The CubeSat needs to hold the blades during a packaged state

bull Plates must be able to pitch without contact and minimum friction

bull The CubeSat must survive launch bull The CubeSat must meet the standards to launch in a Canesterized Satellite Dispenser

bull Extra design must be considered to stabilize the CubeSat for vibrations

bull Launch vibration test to prove survivability

bull Financial bull Earth-based model is restricted by a cost of $5000

15

Blade Deployment Space Model

Centripetal Acceleration

As the spacecraft spins the sail will experience a force

Important because the motor needs to oppose this force

16

Bus

V

r = solar sail length

Blade Deployment Space Model

Centripetal Acceleration

Deployment

Length

(Meters)

Centripetal

Acceleration

(ms2)

Mass

(Kg)

Centripetal

Force (N)

1 0011 0037 000041

15 016 0044 00073

30 033 0052 0017

50 055 0062 0034

100 11 0087 0095

150 16 011 018

200 22 014 03

220 24 015 035

17

Constant Spin Ω = 1 RPM

Gravitational Force

Earth

Orbital Trajectory

Equations

Constants

Blade Deployment

Testing on Earth Relation to Space

CubeSat rotating at 1 RPM rarr centripetal acceleration rarr centrifugal tension

Blade is fully deployed rarr maximum centrifugal tension

Simulate same centrifugal tension the blade would experience in space

Total mass of 36 g used in the deployment test

mTOTAL = mTM + mB = 36 + 110 = 146 g

a = 241 ms2 F = ma = 035 N

F = mg = 035 N g = 981 ms2

mTOTAL = 36 g

The holding torque of the motor used must be able to withstand this force

τ = r

F r = 05 cm F = 035 N

τ = 00018 Nm

Space Application

Motor

CubeSat

rotating at 1

RPM

Blade Tip mass

F

Top View

Tip mass trajectory

mB = 10 g mTM = 26 g

F = mg

Deployment Test

r

Mounted to Table Side View

Tip

mass

Motor

Blade

Front View

MotorBus

Interface

18

Blade Deployment

Earth Test Validation

19

Deployment Test

bull Release one solar sail blade of 15m at a controlled rate of 1-10 cms to demonstrate controlled deployment

bull Will be tested in Professor Frewrsquos lab in Fleming that is 17m high

bull Use video camera to measure rate set markers along wall to track deployment

19

Blade Deployment Space Model

Initial Spin Up

bull Carbon Steel Blade Supports at the end to replace end mass

bull 50 Carbon Steel

bull 01 mm thick

bull Deployment motor will deploy initial blade support structure for initial spin-up

CubeSat

Carbon-Steel

Blade Supports

Solar Blade

20

Blade Deployment Space Model

Initial Spin Up

bull Collective pitch of 35

to produce torque for spin up

bull Mass at end of sail=367g

bull Volume = 47e-6 cubic m

bull Two perpendicular rods rotating about oblate axis bull Both 4 kg

bull I=

bull Known bull Width=01 m

bull Length=047 m

bull Surface Area=00467 squared meters

21

Blade Deployment Space Model

Initial Spin Up

bull

=435

bull α=

bull Time = 24 days

bull Release the rest of sail and centrifugal tension will aid in deployment of sail

bull Solar sail thrust should keep CubeSat at 1 RPM while deploying

CubeSat

∆ω = Ω = 1 RPM

τ = L

F = Iα

L = 057 m

F = 023 μN

22

Orbit Initial Orbit

Final Orbit Selection

bull Sun-Synchronous 1500 km DawnDusk Orbit

bull Assumptions

bull Circular Orbit (e = 0 a = p)

bull No atmospheric drag above 1100 km altitude

bull Only orbital perturbation considered in orbit determination is the oblateness of the earth (second zonal constant J2)

bull All other orbital perturbations are neglected

bull For SS Orbit Node Precession = Solar Precession

bull Gyro rotational axis always oriented towards Sun

23

See Appendix for calculation

24

Orbit Initial Orbit

SS DawnDusk Orbit

Orbit Initial Orbit

Launch

bull Vandenberg AFB CA

bull Atlas V Launch Vehicle

bull Secondary Payload

bull Insertion into near Polar Orbit via Centaur Upper Stage

bull Further transfer necessary to achieve SS orbit

25

Orbit Blade Size

Maximum Solar Radiation Pressure Calculation

bull Assumptions

bull Perfectly reflecting surface

bull α = 0

(incident radiation perpendicular to surface)

26

Preflect2W

cR2cos2 = 908 Pa

where W = 1361 Wm2 c = 30x10 8 ms amp R = 100 AU

Orbit Blade Size

Minimum Solar Blade Surface Area for

Necessary Thrust

bull Assumptions

bull m = 8 kg (based on 8U Volume CubeSat 1 kgU)

27

a ac 01 mms2 requirement

sreflectc APmaFmax Asmac

Preflect8811 m2

bull 4 solar blades

As

42203 m2 per blade

Orbit Transfer

bull Example

bull LV delivers sc into 1100 km circular polar orbit

bull 1) Orbit raising maneuver to 1500 km

bull 2) Inclination change maneuver to i = 10196

bull How long will this take with GHOSTrsquos capabilities

28

29

Orbit Transfer

Orbit Raising Maneuver

Hohmann Transfer

Dual tangential

burn coplanar orbit

transfer

Initial Orbit

Final Orbit

Transfer Orbit

Orbit Transfer

Orbit Raising Maneuver

bull Calculated using Hohmann Transfer Equations

30

initial transfer vi 945 ms

transfer final v f 933 ms

vtotal 1877 ms

torbit raise 123 days

45o Preflect 454 Pa ain plane 177x10 5 ms2

Two blades pitched at

45

producing thrust in along track direction

See appendix for detailed orbit transfer diagrams

Orbit Transfer

Orbit Inclination Change

bull Calculated using inclination change only equations

31

v inc 2v initialcos( fpa)sini

2where vinitial v f fpa 0o amp i 1196o

vinc 148 kms i 00028 oorbit

a ac 01 mms2 P 6959 s Thrust acts over northern hemisphere of orbit (12 of Period)

tinc change 3437 days

Orbit Transfer

Final Destination

bull Δttotal = 4667 days or ~ 155 months bull time it takes to transfer from LV Delivery 1100 km polar orbit to 1500 km SS

orbit

bull this BOTE calculation has huge implications on both

bull mission duration

bull life span of sc components materials etc

bull Validates the high performance orbit transfer capabilities of the heliogyro architecture

32

Integration CubeSat

Pitch Test Validation

Sensor(s) to measure

torque and

Purpose Demonstrate coordinated pitching with equivalent mass and

realistic bus rotation

bull Rotation of 1 RPM

bull Measure torque on bus

bull Measure and compare actual pitching angles

to commanded

pitching angles

Sensors Needed

bull 3 axis Accelerometer (torque measurement)

bull 3 axis Gyroscope (pitch angle measurement)

bull 12 bit resolution (greater than pitching motors)

bull Fit onto or on 8U CubeSat

ADI516xxxIM4

bull 3 axis gyroscope

bull 3 axis magnetometer

bull 3 axis accelerometer

bull 14 bit resolution

bull 1

volume

bull Available free for checkout in ITLL

Sail Equivalent

mass

33

Integration CubeSat

Feasibility of our Baseline Design

bull To achieve characteristic acceleration for an 8U (8kg) CubeSat we needed each sail to be 2203

bull The diameter of the rolled spool inside the CubeSat (pre-deployment) varies with the width of the sail

bull To find the diameter of the rolled spool we calculated the length of one sail for a chosen width Assuming a Mylar thickness of 5 um due to the crinkling effect the spool width was calculated by iterating each rotation with increasing diameter as the blade rolls up

Iterate for rolling up sail until finished

(cm)

(m)

12 1836 247

10 2203 270

8 2754 300

34

Integration CubeSat

Sizing the Blades

bull CubeSat constrained by 20 cm on each side

bull Need to perform 180 degree independent rotation and maximize room inside the satellite for pitching motors controls and communication

Top Down Views of each size ( Scaled to correct dimensions)

12 cm blade width 10 cm blade width 8 cm blade width

bull Not intrusive on inner area

bull Full 180 motion

bull Infringes on space inside

bull Full 180 motion

bull Not intrusive on inner area

bull No Full 180 motion

35

Integration CubeSat

Housing the Rolled Sail

bull The solar sail blades will be controlled by a pitching axle but there must be an interface to connect to the axle

bull Cylindrical plate housing

bull Protects blades

bull Easy to connect to axle

bull No gears

bull Ability to provide counterweight

to deployment motor

bull With the tight volume constraints of our cube the Cylindrical plate must be altered to avoid interference with other sides

36

Integration CubeSat

Fitting the cylindrical Plate

bull Clearance for rolled sail

bull 2 cm clearance on each side

bull 06 cm clearance on behind the motor

bull This leaves overlapping corners

bull To prevent overlap we will make a 45ordm cut around the entire cylinder

2 cm

06 cm

Rolled Sail

Plate Encasing

Overlapping

Corners

45ordm cut to get rid

of corners

37

Integration CubeSat

Fitting the cylindrical Plate

bull The 45ordm cut will give us a 0 cm clearance (with no thickness)

bull If we implement a high-low offset between adjacent plates the distance between the two closest points increases

bull For our 14 cm diameter plates a 2 cm offset from the center for each plate (4 cm total) the effective clearance becomes 251 cm

Two adjacent sides

on same axis

With a High-Low Offset

38

Integration CubeSat

High-Low Offset Plates

The high low offset will give each plate room to rotate a full 180ordm

1 cm clearance between the top of the

blade and the edge of the satellite to fit

the thin-set bearing

A 3mm plate thickness gives adjacent

plates a distance of 19 cm between

their closest points

39

Integration CubeSat

High Low Offset Performance Validation

bull The high-low offset will not effect the performance or stability of the deployment or pitching systems

bull Upon deployment the opposing extension on each side cancels out unwanted torque

View From high side View From low side

bull In a sun-synchronous orbit the high or low setting has no effect as the rotational axis of the satellite is always solar pointing

View From Sun

40

Integration Power

Electronics Feasibility Analysis

bull Project Constraints

bull CubeSat power source Li-Ion batteries (5 and 33 V is common) - Would require thermal protection

bull Communications System - Transceiver (UHF is common) [USART serial port] - Buffer may be needed depending on power constraints

bull Deployment Subsystem - 1 step-motor [output] - 1 encoder [MSSP input] OR direct deployment measurement via external sensor

bull Pitching Subsystem - 2 servomotors [output]

41

Integration Power

PIC18F Series Microchip

bull Inputs 2 USART and 2 MSSP ports available (for basic PICs) - More than 1 device may be connected to each port - 2-3 devices needed

bull Outputs 8 ports - 2 devices needed

bull 16 bit - Though different PICs may be acquired for higher resolution

bull Operating Range 2-55 V - Within provided parameters

42

PIC

Communications

Deployment

Motor

Encoder

Pitching

Motor 1

Pitching

Motor 2 Key

Power Lines

Input Lines

Output Lines

Integration Power

Microchip FBD

5V Battery

Possible Voltage

Buffer

Encoder

43

Integration Power

Motor Power Limitations

bull Power Constraints

Pmax = 100 W

Vmax = 50 V

bull P = IV (Power = CurrentVoltage)

bull Therefore Iave = 20 Amps

bull Blade Pitching (4 motors total needed) - Current limitations for power sources and number of simultaneous blades pitching

Number of Blades 5 V Input 36 V input 31 V input 2 V input

4 040 A 069 A 081 A 125 A

2 080 A 139 A 161 A 250 A

1 160 A 278 A 323 A 500 A

44

Integration Motors

Stepper vs Brushless Servo Motors

45

-Contain many poles (50+) -Contain only 4-12 poles

-Distinct steps cause

vibration during use -Do not suffer from

vibration and resonance

issues smooth movement

-Low maintenance easier to

commission mechanically

simple

-Efficient response to start

stop and reverse commands

-Rely on encoders for

position details in closed

loop response

-Physical sizes

are comparable

-Both available

in various

lengths at same

frame size -Torque can be readily

controlled

-Low cost and high

availability

-Complexity drives cost

upward

Chosen for

deployment motor

Chosen for

pitching motor

Stepper Servo

Integration Blade Deployment

Deployment Motor Feasibility

Required holding torque is calculated to be 18 mNm

Required driving torque is calculated to be 117

10-5 mN∙m

bull Micro Motion Solutions ndash miniature stepper motors bull Physical Properties

bull Diameter = 6-22 mm

bull Length = 93-20 mm

bull Weight = 55-12 g

bull Holding Torque = 24-10 mN∙m = 034-142 oz∙in

bull Resolution bull 1 or 2 phase half-step capability

bull Steps per turn = 20-24 rarr 15˚-18˚ per step

5 of full step accuracy

bull Power Requirements bull Nominal voltage per phase 2-5 V

bull Nominal current per phase 01-1 A

46

Integration Blade Pitching

Blade Pitching Motor Feasibility

Required driving torque is calculated to be 0019 mN∙m

bull Mabuchi Servo Motor bull Physical Size

bull Diameter = 17 mm

bull Length = 25 mm

bull Weight = 16 g

bull Torque

bull Holding Torque = 161 mN∙m = 0228 oz∙in

bull Driving Torque = 0385 mN∙m = 0055 oz∙in

bull Friction Torque = 403

10-3 mN∙m = 571

10-4 oz∙in

bull Power Requirements

bull Nominal voltage per phase 2-5 V

bull Nominal current per phase 006-02 A 47

Integration Launch

Feasibility for Pre-deployment locking mechanism

The tip of the solar sail will be wider than the body with the sail tip set outside the plate

The tip will be held in place vertically by stationary blade stabilizers and kept tight by the holding torque of the deployment motor

Stationary blade

stabilizers

Extra-wide

blade tip

Upon deployment the motor

turns and the blade extends

48

Integration Launch

Canesterized Satellite Dispenser (CSD)

bull Ride in a 12 U CSD

bull Width=239 cm Height=226 cm Length=366 cm

bull Mass=0-24 kg at launch

bull Center of Mass when stowed in

bull x is -40 to 40 mm

bull y is 50 to 125 mm

bull z is 133 to 233 mm

wwwplanetarysytemscorpcom 49

Integration Launch

Test Validation

bull Launch Vibration Test

bull Needs to be space applicable and strong enough to withstand vibration

bull Ball Aerospace can provide a shake table costing $250hr

bull Preparation for Testing using FEM modeling and adding support features

50

Financial

bull Total Budget $5000

bull Components

bull Stepper Motor $100-200

bull Servo Motor (x2) $50-500 each

bull Materials (made in-house) $500-1000

bull Electronics $0-500

bull Testing

bull Deployment amp Pitching Free (Performed on Campus)

bull Launch Survivability Vibration Stand - $250hr Ball Space Systems in Boulder

bull Total Estimation $700-2700 + Vibration Stand Testing

51

Baseline Design All Together

bull The 8u CubeSat and characteristic acceleration requirements create very strict volumetric restrictions

bull The size of the plates and the rolled sail blade must be validated

bull This design will be analyzed and verified in the feasibility requirements

Inner Control Area

bull Motor

bull Encoder

bull Control

bull Communication

bull Power

Possible Load-bearing

corners for deployment

Housed Solar Sail

Top-Down View

Extra room for third

party systems

52

Status Summary

53

SystemMechanism Final Choice Further

Studies

Needed

8U Structure Fit our CubeSat in 12U bus provided by Planetary Services Yes

Adequate Area of Sails to Provide

Orbit Transfer Capabilities

AR = 22001 No

Pitching Mechanism Using a servo motor Yes

Pitching Accuracy Pitching encoder Yes

Plate Integration System Using a two cylinder design with tapered edges so

everything will fit

No

Deployment Motor Using a stepper motor No

Launch Ability Must conform to standards set by Planetary Services Yes

Launch Survivability Verify that GHOST will survive launch Yes

Initial Spin-Up Carbon steel attached to solar blade material Yes 53

Strategy for Conducting

Remaining Studies

bull 8U GHOST inside 12U structure bull Create a SolidWorksCAD model

bull Pitching Mechanism bull Determine adequate motor within size power and cost constraints

bull Pitching Accuracy bull Determine pitching accuracy based on orbital sensitivity

bull Launch Ability bull Because design is symmetrical center of mass is in the center of the satellite during launch bull Further investigations is needed to determine how many counterweights

bull Launch Survivability bull FEM or Vibrations

bull Initial Spin-up bull Determine feasible method to attach carbon steel support structure to solar sail blade material

54

Resources

bull PAYLOAD SPECIFICATION FOR 3U 6U 12U AND 27U Np Planetary Systems Corporation 2013 Print

bull Davis Jason The Planetary Society The Planetary Society Blog Firefly Partners 11 Apr 2012 Web 12 Oct 2013 lthttpwwwplanetaryorgblogsguest-blogsjason-davis3450htmlgt

bull Mao Tengfei 01mm Thickness Measuring Tape Wwwalibabacom Alibabacom nd Web 12 Oct 2013 lthttpwwwalibabacomproduct-gs8359006940_1mm_thickness_measuring_tapehtmlgt

55

Resources

bull ldquoHow servos and steppers stack uprdquo Machine Design 9 February 2012 [httpmachinedesigncomnewshow-servos-and-steppers-stack Accessed 7 October 2013]

bull ldquoMiniature Stepper Motor Drive Systems - Data Sheetrdquo Micro Motion Solutions [httpwwwmicromocomstepper-motors-datasheetsaspx Accessed 11 October 2013]

bull ldquoData Sheet for TS-53 Servorsquos Electric Motorrdquo Mabuchi Motor [httpwwwprincetonedu~mae412TEXTNTRAK2002292-302pdf Accessed 11 October 2013]

56

Critical Project Elements

bull Orbit bull Earth-based system

bull While CubeSat is spinning blades must pitch in a periodic motion to direct the thrust bull A spin stand must be used to spin the CubeSat

bull Space-ready design bull Orbit must be designed for altitudes of 1100 ndash 1500 km

bull CubeSat must be launched into an initial orbit

bull Solar sail must have orbit transferring capabilities by pitching blades bull The solar sail blades must be sized to generate an acceleration of 01 mms2 bull Solar sail must be able to enter and exit a transfer orbit

bull Communication bull Earth-based model must be able to receive commands for pitching and deployment

systems bull Space-ready system must be able to communicate with Earth

14

Critical Project Elements

bull Integration bull The CubeSat is restricted by a maximum power available of 10W

bull Motors needed for blade release and pitching

bull The CubeSat is restricted to be no larger than 12U bull Earth-based model will be designed for 2 blades while space design will be for 4 blades

bull The CubeSat needs to hold the blades during a packaged state

bull Plates must be able to pitch without contact and minimum friction

bull The CubeSat must survive launch bull The CubeSat must meet the standards to launch in a Canesterized Satellite Dispenser

bull Extra design must be considered to stabilize the CubeSat for vibrations

bull Launch vibration test to prove survivability

bull Financial bull Earth-based model is restricted by a cost of $5000

15

Blade Deployment Space Model

Centripetal Acceleration

As the spacecraft spins the sail will experience a force

Important because the motor needs to oppose this force

16

Bus

V

r = solar sail length

Blade Deployment Space Model

Centripetal Acceleration

Deployment

Length

(Meters)

Centripetal

Acceleration

(ms2)

Mass

(Kg)

Centripetal

Force (N)

1 0011 0037 000041

15 016 0044 00073

30 033 0052 0017

50 055 0062 0034

100 11 0087 0095

150 16 011 018

200 22 014 03

220 24 015 035

17

Constant Spin Ω = 1 RPM

Gravitational Force

Earth

Orbital Trajectory

Equations

Constants

Blade Deployment

Testing on Earth Relation to Space

CubeSat rotating at 1 RPM rarr centripetal acceleration rarr centrifugal tension

Blade is fully deployed rarr maximum centrifugal tension

Simulate same centrifugal tension the blade would experience in space

Total mass of 36 g used in the deployment test

mTOTAL = mTM + mB = 36 + 110 = 146 g

a = 241 ms2 F = ma = 035 N

F = mg = 035 N g = 981 ms2

mTOTAL = 36 g

The holding torque of the motor used must be able to withstand this force

τ = r

F r = 05 cm F = 035 N

τ = 00018 Nm

Space Application

Motor

CubeSat

rotating at 1

RPM

Blade Tip mass

F

Top View

Tip mass trajectory

mB = 10 g mTM = 26 g

F = mg

Deployment Test

r

Mounted to Table Side View

Tip

mass

Motor

Blade

Front View

MotorBus

Interface

18

Blade Deployment

Earth Test Validation

19

Deployment Test

bull Release one solar sail blade of 15m at a controlled rate of 1-10 cms to demonstrate controlled deployment

bull Will be tested in Professor Frewrsquos lab in Fleming that is 17m high

bull Use video camera to measure rate set markers along wall to track deployment

19

Blade Deployment Space Model

Initial Spin Up

bull Carbon Steel Blade Supports at the end to replace end mass

bull 50 Carbon Steel

bull 01 mm thick

bull Deployment motor will deploy initial blade support structure for initial spin-up

CubeSat

Carbon-Steel

Blade Supports

Solar Blade

20

Blade Deployment Space Model

Initial Spin Up

bull Collective pitch of 35

to produce torque for spin up

bull Mass at end of sail=367g

bull Volume = 47e-6 cubic m

bull Two perpendicular rods rotating about oblate axis bull Both 4 kg

bull I=

bull Known bull Width=01 m

bull Length=047 m

bull Surface Area=00467 squared meters

21

Blade Deployment Space Model

Initial Spin Up

bull

=435

bull α=

bull Time = 24 days

bull Release the rest of sail and centrifugal tension will aid in deployment of sail

bull Solar sail thrust should keep CubeSat at 1 RPM while deploying

CubeSat

∆ω = Ω = 1 RPM

τ = L

F = Iα

L = 057 m

F = 023 μN

22

Orbit Initial Orbit

Final Orbit Selection

bull Sun-Synchronous 1500 km DawnDusk Orbit

bull Assumptions

bull Circular Orbit (e = 0 a = p)

bull No atmospheric drag above 1100 km altitude

bull Only orbital perturbation considered in orbit determination is the oblateness of the earth (second zonal constant J2)

bull All other orbital perturbations are neglected

bull For SS Orbit Node Precession = Solar Precession

bull Gyro rotational axis always oriented towards Sun

23

See Appendix for calculation

24

Orbit Initial Orbit

SS DawnDusk Orbit

Orbit Initial Orbit

Launch

bull Vandenberg AFB CA

bull Atlas V Launch Vehicle

bull Secondary Payload

bull Insertion into near Polar Orbit via Centaur Upper Stage

bull Further transfer necessary to achieve SS orbit

25

Orbit Blade Size

Maximum Solar Radiation Pressure Calculation

bull Assumptions

bull Perfectly reflecting surface

bull α = 0

(incident radiation perpendicular to surface)

26

Preflect2W

cR2cos2 = 908 Pa

where W = 1361 Wm2 c = 30x10 8 ms amp R = 100 AU

Orbit Blade Size

Minimum Solar Blade Surface Area for

Necessary Thrust

bull Assumptions

bull m = 8 kg (based on 8U Volume CubeSat 1 kgU)

27

a ac 01 mms2 requirement

sreflectc APmaFmax Asmac

Preflect8811 m2

bull 4 solar blades

As

42203 m2 per blade

Orbit Transfer

bull Example

bull LV delivers sc into 1100 km circular polar orbit

bull 1) Orbit raising maneuver to 1500 km

bull 2) Inclination change maneuver to i = 10196

bull How long will this take with GHOSTrsquos capabilities

28

29

Orbit Transfer

Orbit Raising Maneuver

Hohmann Transfer

Dual tangential

burn coplanar orbit

transfer

Initial Orbit

Final Orbit

Transfer Orbit

Orbit Transfer

Orbit Raising Maneuver

bull Calculated using Hohmann Transfer Equations

30

initial transfer vi 945 ms

transfer final v f 933 ms

vtotal 1877 ms

torbit raise 123 days

45o Preflect 454 Pa ain plane 177x10 5 ms2

Two blades pitched at

45

producing thrust in along track direction

See appendix for detailed orbit transfer diagrams

Orbit Transfer

Orbit Inclination Change

bull Calculated using inclination change only equations

31

v inc 2v initialcos( fpa)sini

2where vinitial v f fpa 0o amp i 1196o

vinc 148 kms i 00028 oorbit

a ac 01 mms2 P 6959 s Thrust acts over northern hemisphere of orbit (12 of Period)

tinc change 3437 days

Orbit Transfer

Final Destination

bull Δttotal = 4667 days or ~ 155 months bull time it takes to transfer from LV Delivery 1100 km polar orbit to 1500 km SS

orbit

bull this BOTE calculation has huge implications on both

bull mission duration

bull life span of sc components materials etc

bull Validates the high performance orbit transfer capabilities of the heliogyro architecture

32

Integration CubeSat

Pitch Test Validation

Sensor(s) to measure

torque and

Purpose Demonstrate coordinated pitching with equivalent mass and

realistic bus rotation

bull Rotation of 1 RPM

bull Measure torque on bus

bull Measure and compare actual pitching angles

to commanded

pitching angles

Sensors Needed

bull 3 axis Accelerometer (torque measurement)

bull 3 axis Gyroscope (pitch angle measurement)

bull 12 bit resolution (greater than pitching motors)

bull Fit onto or on 8U CubeSat

ADI516xxxIM4

bull 3 axis gyroscope

bull 3 axis magnetometer

bull 3 axis accelerometer

bull 14 bit resolution

bull 1

volume

bull Available free for checkout in ITLL

Sail Equivalent

mass

33

Integration CubeSat

Feasibility of our Baseline Design

bull To achieve characteristic acceleration for an 8U (8kg) CubeSat we needed each sail to be 2203

bull The diameter of the rolled spool inside the CubeSat (pre-deployment) varies with the width of the sail

bull To find the diameter of the rolled spool we calculated the length of one sail for a chosen width Assuming a Mylar thickness of 5 um due to the crinkling effect the spool width was calculated by iterating each rotation with increasing diameter as the blade rolls up

Iterate for rolling up sail until finished

(cm)

(m)

12 1836 247

10 2203 270

8 2754 300

34

Integration CubeSat

Sizing the Blades

bull CubeSat constrained by 20 cm on each side

bull Need to perform 180 degree independent rotation and maximize room inside the satellite for pitching motors controls and communication

Top Down Views of each size ( Scaled to correct dimensions)

12 cm blade width 10 cm blade width 8 cm blade width

bull Not intrusive on inner area

bull Full 180 motion

bull Infringes on space inside

bull Full 180 motion

bull Not intrusive on inner area

bull No Full 180 motion

35

Integration CubeSat

Housing the Rolled Sail

bull The solar sail blades will be controlled by a pitching axle but there must be an interface to connect to the axle

bull Cylindrical plate housing

bull Protects blades

bull Easy to connect to axle

bull No gears

bull Ability to provide counterweight

to deployment motor

bull With the tight volume constraints of our cube the Cylindrical plate must be altered to avoid interference with other sides

36

Integration CubeSat

Fitting the cylindrical Plate

bull Clearance for rolled sail

bull 2 cm clearance on each side

bull 06 cm clearance on behind the motor

bull This leaves overlapping corners

bull To prevent overlap we will make a 45ordm cut around the entire cylinder

2 cm

06 cm

Rolled Sail

Plate Encasing

Overlapping

Corners

45ordm cut to get rid

of corners

37

Integration CubeSat

Fitting the cylindrical Plate

bull The 45ordm cut will give us a 0 cm clearance (with no thickness)

bull If we implement a high-low offset between adjacent plates the distance between the two closest points increases

bull For our 14 cm diameter plates a 2 cm offset from the center for each plate (4 cm total) the effective clearance becomes 251 cm

Two adjacent sides

on same axis

With a High-Low Offset

38

Integration CubeSat

High-Low Offset Plates

The high low offset will give each plate room to rotate a full 180ordm

1 cm clearance between the top of the

blade and the edge of the satellite to fit

the thin-set bearing

A 3mm plate thickness gives adjacent

plates a distance of 19 cm between

their closest points

39

Integration CubeSat

High Low Offset Performance Validation

bull The high-low offset will not effect the performance or stability of the deployment or pitching systems

bull Upon deployment the opposing extension on each side cancels out unwanted torque

View From high side View From low side

bull In a sun-synchronous orbit the high or low setting has no effect as the rotational axis of the satellite is always solar pointing

View From Sun

40

Integration Power

Electronics Feasibility Analysis

bull Project Constraints

bull CubeSat power source Li-Ion batteries (5 and 33 V is common) - Would require thermal protection

bull Communications System - Transceiver (UHF is common) [USART serial port] - Buffer may be needed depending on power constraints

bull Deployment Subsystem - 1 step-motor [output] - 1 encoder [MSSP input] OR direct deployment measurement via external sensor

bull Pitching Subsystem - 2 servomotors [output]

41

Integration Power

PIC18F Series Microchip

bull Inputs 2 USART and 2 MSSP ports available (for basic PICs) - More than 1 device may be connected to each port - 2-3 devices needed

bull Outputs 8 ports - 2 devices needed

bull 16 bit - Though different PICs may be acquired for higher resolution

bull Operating Range 2-55 V - Within provided parameters

42

PIC

Communications

Deployment

Motor

Encoder

Pitching

Motor 1

Pitching

Motor 2 Key

Power Lines

Input Lines

Output Lines

Integration Power

Microchip FBD

5V Battery

Possible Voltage

Buffer

Encoder

43

Integration Power

Motor Power Limitations

bull Power Constraints

Pmax = 100 W

Vmax = 50 V

bull P = IV (Power = CurrentVoltage)

bull Therefore Iave = 20 Amps

bull Blade Pitching (4 motors total needed) - Current limitations for power sources and number of simultaneous blades pitching

Number of Blades 5 V Input 36 V input 31 V input 2 V input

4 040 A 069 A 081 A 125 A

2 080 A 139 A 161 A 250 A

1 160 A 278 A 323 A 500 A

44

Integration Motors

Stepper vs Brushless Servo Motors

45

-Contain many poles (50+) -Contain only 4-12 poles

-Distinct steps cause

vibration during use -Do not suffer from

vibration and resonance

issues smooth movement

-Low maintenance easier to

commission mechanically

simple

-Efficient response to start

stop and reverse commands

-Rely on encoders for

position details in closed

loop response

-Physical sizes

are comparable

-Both available

in various

lengths at same

frame size -Torque can be readily

controlled

-Low cost and high

availability

-Complexity drives cost

upward

Chosen for

deployment motor

Chosen for

pitching motor

Stepper Servo

Integration Blade Deployment

Deployment Motor Feasibility

Required holding torque is calculated to be 18 mNm

Required driving torque is calculated to be 117

10-5 mN∙m

bull Micro Motion Solutions ndash miniature stepper motors bull Physical Properties

bull Diameter = 6-22 mm

bull Length = 93-20 mm

bull Weight = 55-12 g

bull Holding Torque = 24-10 mN∙m = 034-142 oz∙in

bull Resolution bull 1 or 2 phase half-step capability

bull Steps per turn = 20-24 rarr 15˚-18˚ per step

5 of full step accuracy

bull Power Requirements bull Nominal voltage per phase 2-5 V

bull Nominal current per phase 01-1 A

46

Integration Blade Pitching

Blade Pitching Motor Feasibility

Required driving torque is calculated to be 0019 mN∙m

bull Mabuchi Servo Motor bull Physical Size

bull Diameter = 17 mm

bull Length = 25 mm

bull Weight = 16 g

bull Torque

bull Holding Torque = 161 mN∙m = 0228 oz∙in

bull Driving Torque = 0385 mN∙m = 0055 oz∙in

bull Friction Torque = 403

10-3 mN∙m = 571

10-4 oz∙in

bull Power Requirements

bull Nominal voltage per phase 2-5 V

bull Nominal current per phase 006-02 A 47

Integration Launch

Feasibility for Pre-deployment locking mechanism

The tip of the solar sail will be wider than the body with the sail tip set outside the plate

The tip will be held in place vertically by stationary blade stabilizers and kept tight by the holding torque of the deployment motor

Stationary blade

stabilizers

Extra-wide

blade tip

Upon deployment the motor

turns and the blade extends

48

Integration Launch

Canesterized Satellite Dispenser (CSD)

bull Ride in a 12 U CSD

bull Width=239 cm Height=226 cm Length=366 cm

bull Mass=0-24 kg at launch

bull Center of Mass when stowed in

bull x is -40 to 40 mm

bull y is 50 to 125 mm

bull z is 133 to 233 mm

wwwplanetarysytemscorpcom 49

Integration Launch

Test Validation

bull Launch Vibration Test

bull Needs to be space applicable and strong enough to withstand vibration

bull Ball Aerospace can provide a shake table costing $250hr

bull Preparation for Testing using FEM modeling and adding support features

50

Financial

bull Total Budget $5000

bull Components

bull Stepper Motor $100-200

bull Servo Motor (x2) $50-500 each

bull Materials (made in-house) $500-1000

bull Electronics $0-500

bull Testing

bull Deployment amp Pitching Free (Performed on Campus)

bull Launch Survivability Vibration Stand - $250hr Ball Space Systems in Boulder

bull Total Estimation $700-2700 + Vibration Stand Testing

51

Baseline Design All Together

bull The 8u CubeSat and characteristic acceleration requirements create very strict volumetric restrictions

bull The size of the plates and the rolled sail blade must be validated

bull This design will be analyzed and verified in the feasibility requirements

Inner Control Area

bull Motor

bull Encoder

bull Control

bull Communication

bull Power

Possible Load-bearing

corners for deployment

Housed Solar Sail

Top-Down View

Extra room for third

party systems

52

Status Summary

53

SystemMechanism Final Choice Further

Studies

Needed

8U Structure Fit our CubeSat in 12U bus provided by Planetary Services Yes

Adequate Area of Sails to Provide

Orbit Transfer Capabilities

AR = 22001 No

Pitching Mechanism Using a servo motor Yes

Pitching Accuracy Pitching encoder Yes

Plate Integration System Using a two cylinder design with tapered edges so

everything will fit

No

Deployment Motor Using a stepper motor No

Launch Ability Must conform to standards set by Planetary Services Yes

Launch Survivability Verify that GHOST will survive launch Yes

Initial Spin-Up Carbon steel attached to solar blade material Yes 53

Strategy for Conducting

Remaining Studies

bull 8U GHOST inside 12U structure bull Create a SolidWorksCAD model

bull Pitching Mechanism bull Determine adequate motor within size power and cost constraints

bull Pitching Accuracy bull Determine pitching accuracy based on orbital sensitivity

bull Launch Ability bull Because design is symmetrical center of mass is in the center of the satellite during launch bull Further investigations is needed to determine how many counterweights

bull Launch Survivability bull FEM or Vibrations

bull Initial Spin-up bull Determine feasible method to attach carbon steel support structure to solar sail blade material

54

Resources

bull PAYLOAD SPECIFICATION FOR 3U 6U 12U AND 27U Np Planetary Systems Corporation 2013 Print

bull Davis Jason The Planetary Society The Planetary Society Blog Firefly Partners 11 Apr 2012 Web 12 Oct 2013 lthttpwwwplanetaryorgblogsguest-blogsjason-davis3450htmlgt

bull Mao Tengfei 01mm Thickness Measuring Tape Wwwalibabacom Alibabacom nd Web 12 Oct 2013 lthttpwwwalibabacomproduct-gs8359006940_1mm_thickness_measuring_tapehtmlgt

55

Resources

bull ldquoHow servos and steppers stack uprdquo Machine Design 9 February 2012 [httpmachinedesigncomnewshow-servos-and-steppers-stack Accessed 7 October 2013]

bull ldquoMiniature Stepper Motor Drive Systems - Data Sheetrdquo Micro Motion Solutions [httpwwwmicromocomstepper-motors-datasheetsaspx Accessed 11 October 2013]

bull ldquoData Sheet for TS-53 Servorsquos Electric Motorrdquo Mabuchi Motor [httpwwwprincetonedu~mae412TEXTNTRAK2002292-302pdf Accessed 11 October 2013]

56

Critical Project Elements

bull Integration bull The CubeSat is restricted by a maximum power available of 10W

bull Motors needed for blade release and pitching

bull The CubeSat is restricted to be no larger than 12U bull Earth-based model will be designed for 2 blades while space design will be for 4 blades

bull The CubeSat needs to hold the blades during a packaged state

bull Plates must be able to pitch without contact and minimum friction

bull The CubeSat must survive launch bull The CubeSat must meet the standards to launch in a Canesterized Satellite Dispenser

bull Extra design must be considered to stabilize the CubeSat for vibrations

bull Launch vibration test to prove survivability

bull Financial bull Earth-based model is restricted by a cost of $5000

15

Blade Deployment Space Model

Centripetal Acceleration

As the spacecraft spins the sail will experience a force

Important because the motor needs to oppose this force

16

Bus

V

r = solar sail length

Blade Deployment Space Model

Centripetal Acceleration

Deployment

Length

(Meters)

Centripetal

Acceleration

(ms2)

Mass

(Kg)

Centripetal

Force (N)

1 0011 0037 000041

15 016 0044 00073

30 033 0052 0017

50 055 0062 0034

100 11 0087 0095

150 16 011 018

200 22 014 03

220 24 015 035

17

Constant Spin Ω = 1 RPM

Gravitational Force

Earth

Orbital Trajectory

Equations

Constants

Blade Deployment

Testing on Earth Relation to Space

CubeSat rotating at 1 RPM rarr centripetal acceleration rarr centrifugal tension

Blade is fully deployed rarr maximum centrifugal tension

Simulate same centrifugal tension the blade would experience in space

Total mass of 36 g used in the deployment test

mTOTAL = mTM + mB = 36 + 110 = 146 g

a = 241 ms2 F = ma = 035 N

F = mg = 035 N g = 981 ms2

mTOTAL = 36 g

The holding torque of the motor used must be able to withstand this force

τ = r

F r = 05 cm F = 035 N

τ = 00018 Nm

Space Application

Motor

CubeSat

rotating at 1

RPM

Blade Tip mass

F

Top View

Tip mass trajectory

mB = 10 g mTM = 26 g

F = mg

Deployment Test

r

Mounted to Table Side View

Tip

mass

Motor

Blade

Front View

MotorBus

Interface

18

Blade Deployment

Earth Test Validation

19

Deployment Test

bull Release one solar sail blade of 15m at a controlled rate of 1-10 cms to demonstrate controlled deployment

bull Will be tested in Professor Frewrsquos lab in Fleming that is 17m high

bull Use video camera to measure rate set markers along wall to track deployment

19

Blade Deployment Space Model

Initial Spin Up

bull Carbon Steel Blade Supports at the end to replace end mass

bull 50 Carbon Steel

bull 01 mm thick

bull Deployment motor will deploy initial blade support structure for initial spin-up

CubeSat

Carbon-Steel

Blade Supports

Solar Blade

20

Blade Deployment Space Model

Initial Spin Up

bull Collective pitch of 35

to produce torque for spin up

bull Mass at end of sail=367g

bull Volume = 47e-6 cubic m

bull Two perpendicular rods rotating about oblate axis bull Both 4 kg

bull I=

bull Known bull Width=01 m

bull Length=047 m

bull Surface Area=00467 squared meters

21

Blade Deployment Space Model

Initial Spin Up

bull

=435

bull α=

bull Time = 24 days

bull Release the rest of sail and centrifugal tension will aid in deployment of sail

bull Solar sail thrust should keep CubeSat at 1 RPM while deploying

CubeSat

∆ω = Ω = 1 RPM

τ = L

F = Iα

L = 057 m

F = 023 μN

22

Orbit Initial Orbit

Final Orbit Selection

bull Sun-Synchronous 1500 km DawnDusk Orbit

bull Assumptions

bull Circular Orbit (e = 0 a = p)

bull No atmospheric drag above 1100 km altitude

bull Only orbital perturbation considered in orbit determination is the oblateness of the earth (second zonal constant J2)

bull All other orbital perturbations are neglected

bull For SS Orbit Node Precession = Solar Precession

bull Gyro rotational axis always oriented towards Sun

23

See Appendix for calculation

24

Orbit Initial Orbit

SS DawnDusk Orbit

Orbit Initial Orbit

Launch

bull Vandenberg AFB CA

bull Atlas V Launch Vehicle

bull Secondary Payload

bull Insertion into near Polar Orbit via Centaur Upper Stage

bull Further transfer necessary to achieve SS orbit

25

Orbit Blade Size

Maximum Solar Radiation Pressure Calculation

bull Assumptions

bull Perfectly reflecting surface

bull α = 0

(incident radiation perpendicular to surface)

26

Preflect2W

cR2cos2 = 908 Pa

where W = 1361 Wm2 c = 30x10 8 ms amp R = 100 AU

Orbit Blade Size

Minimum Solar Blade Surface Area for

Necessary Thrust

bull Assumptions

bull m = 8 kg (based on 8U Volume CubeSat 1 kgU)

27

a ac 01 mms2 requirement

sreflectc APmaFmax Asmac

Preflect8811 m2

bull 4 solar blades

As

42203 m2 per blade

Orbit Transfer

bull Example

bull LV delivers sc into 1100 km circular polar orbit

bull 1) Orbit raising maneuver to 1500 km

bull 2) Inclination change maneuver to i = 10196

bull How long will this take with GHOSTrsquos capabilities

28

29

Orbit Transfer

Orbit Raising Maneuver

Hohmann Transfer

Dual tangential

burn coplanar orbit

transfer

Initial Orbit

Final Orbit

Transfer Orbit

Orbit Transfer

Orbit Raising Maneuver

bull Calculated using Hohmann Transfer Equations

30

initial transfer vi 945 ms

transfer final v f 933 ms

vtotal 1877 ms

torbit raise 123 days

45o Preflect 454 Pa ain plane 177x10 5 ms2

Two blades pitched at

45

producing thrust in along track direction

See appendix for detailed orbit transfer diagrams

Orbit Transfer

Orbit Inclination Change

bull Calculated using inclination change only equations

31

v inc 2v initialcos( fpa)sini

2where vinitial v f fpa 0o amp i 1196o

vinc 148 kms i 00028 oorbit

a ac 01 mms2 P 6959 s Thrust acts over northern hemisphere of orbit (12 of Period)

tinc change 3437 days

Orbit Transfer

Final Destination

bull Δttotal = 4667 days or ~ 155 months bull time it takes to transfer from LV Delivery 1100 km polar orbit to 1500 km SS

orbit

bull this BOTE calculation has huge implications on both

bull mission duration

bull life span of sc components materials etc

bull Validates the high performance orbit transfer capabilities of the heliogyro architecture

32

Integration CubeSat

Pitch Test Validation

Sensor(s) to measure

torque and

Purpose Demonstrate coordinated pitching with equivalent mass and

realistic bus rotation

bull Rotation of 1 RPM

bull Measure torque on bus

bull Measure and compare actual pitching angles

to commanded

pitching angles

Sensors Needed

bull 3 axis Accelerometer (torque measurement)

bull 3 axis Gyroscope (pitch angle measurement)

bull 12 bit resolution (greater than pitching motors)

bull Fit onto or on 8U CubeSat

ADI516xxxIM4

bull 3 axis gyroscope

bull 3 axis magnetometer

bull 3 axis accelerometer

bull 14 bit resolution

bull 1

volume

bull Available free for checkout in ITLL

Sail Equivalent

mass

33

Integration CubeSat

Feasibility of our Baseline Design

bull To achieve characteristic acceleration for an 8U (8kg) CubeSat we needed each sail to be 2203

bull The diameter of the rolled spool inside the CubeSat (pre-deployment) varies with the width of the sail

bull To find the diameter of the rolled spool we calculated the length of one sail for a chosen width Assuming a Mylar thickness of 5 um due to the crinkling effect the spool width was calculated by iterating each rotation with increasing diameter as the blade rolls up

Iterate for rolling up sail until finished

(cm)

(m)

12 1836 247

10 2203 270

8 2754 300

34

Integration CubeSat

Sizing the Blades

bull CubeSat constrained by 20 cm on each side

bull Need to perform 180 degree independent rotation and maximize room inside the satellite for pitching motors controls and communication

Top Down Views of each size ( Scaled to correct dimensions)

12 cm blade width 10 cm blade width 8 cm blade width

bull Not intrusive on inner area

bull Full 180 motion

bull Infringes on space inside

bull Full 180 motion

bull Not intrusive on inner area

bull No Full 180 motion

35

Integration CubeSat

Housing the Rolled Sail

bull The solar sail blades will be controlled by a pitching axle but there must be an interface to connect to the axle

bull Cylindrical plate housing

bull Protects blades

bull Easy to connect to axle

bull No gears

bull Ability to provide counterweight

to deployment motor

bull With the tight volume constraints of our cube the Cylindrical plate must be altered to avoid interference with other sides

36

Integration CubeSat

Fitting the cylindrical Plate

bull Clearance for rolled sail

bull 2 cm clearance on each side

bull 06 cm clearance on behind the motor

bull This leaves overlapping corners

bull To prevent overlap we will make a 45ordm cut around the entire cylinder

2 cm

06 cm

Rolled Sail

Plate Encasing

Overlapping

Corners

45ordm cut to get rid

of corners

37

Integration CubeSat

Fitting the cylindrical Plate

bull The 45ordm cut will give us a 0 cm clearance (with no thickness)

bull If we implement a high-low offset between adjacent plates the distance between the two closest points increases

bull For our 14 cm diameter plates a 2 cm offset from the center for each plate (4 cm total) the effective clearance becomes 251 cm

Two adjacent sides

on same axis

With a High-Low Offset

38

Integration CubeSat

High-Low Offset Plates

The high low offset will give each plate room to rotate a full 180ordm

1 cm clearance between the top of the

blade and the edge of the satellite to fit

the thin-set bearing

A 3mm plate thickness gives adjacent

plates a distance of 19 cm between

their closest points

39

Integration CubeSat

High Low Offset Performance Validation

bull The high-low offset will not effect the performance or stability of the deployment or pitching systems

bull Upon deployment the opposing extension on each side cancels out unwanted torque

View From high side View From low side

bull In a sun-synchronous orbit the high or low setting has no effect as the rotational axis of the satellite is always solar pointing

View From Sun

40

Integration Power

Electronics Feasibility Analysis

bull Project Constraints

bull CubeSat power source Li-Ion batteries (5 and 33 V is common) - Would require thermal protection

bull Communications System - Transceiver (UHF is common) [USART serial port] - Buffer may be needed depending on power constraints

bull Deployment Subsystem - 1 step-motor [output] - 1 encoder [MSSP input] OR direct deployment measurement via external sensor

bull Pitching Subsystem - 2 servomotors [output]

41

Integration Power

PIC18F Series Microchip

bull Inputs 2 USART and 2 MSSP ports available (for basic PICs) - More than 1 device may be connected to each port - 2-3 devices needed

bull Outputs 8 ports - 2 devices needed

bull 16 bit - Though different PICs may be acquired for higher resolution

bull Operating Range 2-55 V - Within provided parameters

42

PIC

Communications

Deployment

Motor

Encoder

Pitching

Motor 1

Pitching

Motor 2 Key

Power Lines

Input Lines

Output Lines

Integration Power

Microchip FBD

5V Battery

Possible Voltage

Buffer

Encoder

43

Integration Power

Motor Power Limitations

bull Power Constraints

Pmax = 100 W

Vmax = 50 V

bull P = IV (Power = CurrentVoltage)

bull Therefore Iave = 20 Amps

bull Blade Pitching (4 motors total needed) - Current limitations for power sources and number of simultaneous blades pitching

Number of Blades 5 V Input 36 V input 31 V input 2 V input

4 040 A 069 A 081 A 125 A

2 080 A 139 A 161 A 250 A

1 160 A 278 A 323 A 500 A

44

Integration Motors

Stepper vs Brushless Servo Motors

45

-Contain many poles (50+) -Contain only 4-12 poles

-Distinct steps cause

vibration during use -Do not suffer from

vibration and resonance

issues smooth movement

-Low maintenance easier to

commission mechanically

simple

-Efficient response to start

stop and reverse commands

-Rely on encoders for

position details in closed

loop response

-Physical sizes

are comparable

-Both available

in various

lengths at same

frame size -Torque can be readily

controlled

-Low cost and high

availability

-Complexity drives cost

upward

Chosen for

deployment motor

Chosen for

pitching motor

Stepper Servo

Integration Blade Deployment

Deployment Motor Feasibility

Required holding torque is calculated to be 18 mNm

Required driving torque is calculated to be 117

10-5 mN∙m

bull Micro Motion Solutions ndash miniature stepper motors bull Physical Properties

bull Diameter = 6-22 mm

bull Length = 93-20 mm

bull Weight = 55-12 g

bull Holding Torque = 24-10 mN∙m = 034-142 oz∙in

bull Resolution bull 1 or 2 phase half-step capability

bull Steps per turn = 20-24 rarr 15˚-18˚ per step

5 of full step accuracy

bull Power Requirements bull Nominal voltage per phase 2-5 V

bull Nominal current per phase 01-1 A

46

Integration Blade Pitching

Blade Pitching Motor Feasibility

Required driving torque is calculated to be 0019 mN∙m

bull Mabuchi Servo Motor bull Physical Size

bull Diameter = 17 mm

bull Length = 25 mm

bull Weight = 16 g

bull Torque

bull Holding Torque = 161 mN∙m = 0228 oz∙in

bull Driving Torque = 0385 mN∙m = 0055 oz∙in

bull Friction Torque = 403

10-3 mN∙m = 571

10-4 oz∙in

bull Power Requirements

bull Nominal voltage per phase 2-5 V

bull Nominal current per phase 006-02 A 47

Integration Launch

Feasibility for Pre-deployment locking mechanism

The tip of the solar sail will be wider than the body with the sail tip set outside the plate

The tip will be held in place vertically by stationary blade stabilizers and kept tight by the holding torque of the deployment motor

Stationary blade

stabilizers

Extra-wide

blade tip

Upon deployment the motor

turns and the blade extends

48

Integration Launch

Canesterized Satellite Dispenser (CSD)

bull Ride in a 12 U CSD

bull Width=239 cm Height=226 cm Length=366 cm

bull Mass=0-24 kg at launch

bull Center of Mass when stowed in

bull x is -40 to 40 mm

bull y is 50 to 125 mm

bull z is 133 to 233 mm

wwwplanetarysytemscorpcom 49

Integration Launch

Test Validation

bull Launch Vibration Test

bull Needs to be space applicable and strong enough to withstand vibration

bull Ball Aerospace can provide a shake table costing $250hr

bull Preparation for Testing using FEM modeling and adding support features

50

Financial

bull Total Budget $5000

bull Components

bull Stepper Motor $100-200

bull Servo Motor (x2) $50-500 each

bull Materials (made in-house) $500-1000

bull Electronics $0-500

bull Testing

bull Deployment amp Pitching Free (Performed on Campus)

bull Launch Survivability Vibration Stand - $250hr Ball Space Systems in Boulder

bull Total Estimation $700-2700 + Vibration Stand Testing

51

Baseline Design All Together

bull The 8u CubeSat and characteristic acceleration requirements create very strict volumetric restrictions

bull The size of the plates and the rolled sail blade must be validated

bull This design will be analyzed and verified in the feasibility requirements

Inner Control Area

bull Motor

bull Encoder

bull Control

bull Communication

bull Power

Possible Load-bearing

corners for deployment

Housed Solar Sail

Top-Down View

Extra room for third

party systems

52

Status Summary

53

SystemMechanism Final Choice Further

Studies

Needed

8U Structure Fit our CubeSat in 12U bus provided by Planetary Services Yes

Adequate Area of Sails to Provide

Orbit Transfer Capabilities

AR = 22001 No

Pitching Mechanism Using a servo motor Yes

Pitching Accuracy Pitching encoder Yes

Plate Integration System Using a two cylinder design with tapered edges so

everything will fit

No

Deployment Motor Using a stepper motor No

Launch Ability Must conform to standards set by Planetary Services Yes

Launch Survivability Verify that GHOST will survive launch Yes

Initial Spin-Up Carbon steel attached to solar blade material Yes 53

Strategy for Conducting

Remaining Studies

bull 8U GHOST inside 12U structure bull Create a SolidWorksCAD model

bull Pitching Mechanism bull Determine adequate motor within size power and cost constraints

bull Pitching Accuracy bull Determine pitching accuracy based on orbital sensitivity

bull Launch Ability bull Because design is symmetrical center of mass is in the center of the satellite during launch bull Further investigations is needed to determine how many counterweights

bull Launch Survivability bull FEM or Vibrations

bull Initial Spin-up bull Determine feasible method to attach carbon steel support structure to solar sail blade material

54

Resources

bull PAYLOAD SPECIFICATION FOR 3U 6U 12U AND 27U Np Planetary Systems Corporation 2013 Print

bull Davis Jason The Planetary Society The Planetary Society Blog Firefly Partners 11 Apr 2012 Web 12 Oct 2013 lthttpwwwplanetaryorgblogsguest-blogsjason-davis3450htmlgt

bull Mao Tengfei 01mm Thickness Measuring Tape Wwwalibabacom Alibabacom nd Web 12 Oct 2013 lthttpwwwalibabacomproduct-gs8359006940_1mm_thickness_measuring_tapehtmlgt

55

Resources

bull ldquoHow servos and steppers stack uprdquo Machine Design 9 February 2012 [httpmachinedesigncomnewshow-servos-and-steppers-stack Accessed 7 October 2013]

bull ldquoMiniature Stepper Motor Drive Systems - Data Sheetrdquo Micro Motion Solutions [httpwwwmicromocomstepper-motors-datasheetsaspx Accessed 11 October 2013]

bull ldquoData Sheet for TS-53 Servorsquos Electric Motorrdquo Mabuchi Motor [httpwwwprincetonedu~mae412TEXTNTRAK2002292-302pdf Accessed 11 October 2013]

56

Blade Deployment Space Model

Centripetal Acceleration

As the spacecraft spins the sail will experience a force

Important because the motor needs to oppose this force

16

Bus

V

r = solar sail length

Blade Deployment Space Model

Centripetal Acceleration

Deployment

Length

(Meters)

Centripetal

Acceleration

(ms2)

Mass

(Kg)

Centripetal

Force (N)

1 0011 0037 000041

15 016 0044 00073

30 033 0052 0017

50 055 0062 0034

100 11 0087 0095

150 16 011 018

200 22 014 03

220 24 015 035

17

Constant Spin Ω = 1 RPM

Gravitational Force

Earth

Orbital Trajectory

Equations

Constants

Blade Deployment

Testing on Earth Relation to Space

CubeSat rotating at 1 RPM rarr centripetal acceleration rarr centrifugal tension

Blade is fully deployed rarr maximum centrifugal tension

Simulate same centrifugal tension the blade would experience in space

Total mass of 36 g used in the deployment test

mTOTAL = mTM + mB = 36 + 110 = 146 g

a = 241 ms2 F = ma = 035 N

F = mg = 035 N g = 981 ms2

mTOTAL = 36 g

The holding torque of the motor used must be able to withstand this force

τ = r

F r = 05 cm F = 035 N

τ = 00018 Nm

Space Application

Motor

CubeSat

rotating at 1

RPM

Blade Tip mass

F

Top View

Tip mass trajectory

mB = 10 g mTM = 26 g

F = mg

Deployment Test

r

Mounted to Table Side View

Tip

mass

Motor

Blade

Front View

MotorBus

Interface

18

Blade Deployment

Earth Test Validation

19

Deployment Test

bull Release one solar sail blade of 15m at a controlled rate of 1-10 cms to demonstrate controlled deployment

bull Will be tested in Professor Frewrsquos lab in Fleming that is 17m high

bull Use video camera to measure rate set markers along wall to track deployment

19

Blade Deployment Space Model

Initial Spin Up

bull Carbon Steel Blade Supports at the end to replace end mass

bull 50 Carbon Steel

bull 01 mm thick

bull Deployment motor will deploy initial blade support structure for initial spin-up

CubeSat

Carbon-Steel

Blade Supports

Solar Blade

20

Blade Deployment Space Model

Initial Spin Up

bull Collective pitch of 35

to produce torque for spin up

bull Mass at end of sail=367g

bull Volume = 47e-6 cubic m

bull Two perpendicular rods rotating about oblate axis bull Both 4 kg

bull I=

bull Known bull Width=01 m

bull Length=047 m

bull Surface Area=00467 squared meters

21

Blade Deployment Space Model

Initial Spin Up

bull

=435

bull α=

bull Time = 24 days

bull Release the rest of sail and centrifugal tension will aid in deployment of sail

bull Solar sail thrust should keep CubeSat at 1 RPM while deploying

CubeSat

∆ω = Ω = 1 RPM

τ = L

F = Iα

L = 057 m

F = 023 μN

22

Orbit Initial Orbit

Final Orbit Selection

bull Sun-Synchronous 1500 km DawnDusk Orbit

bull Assumptions

bull Circular Orbit (e = 0 a = p)

bull No atmospheric drag above 1100 km altitude

bull Only orbital perturbation considered in orbit determination is the oblateness of the earth (second zonal constant J2)

bull All other orbital perturbations are neglected

bull For SS Orbit Node Precession = Solar Precession

bull Gyro rotational axis always oriented towards Sun

23

See Appendix for calculation

24

Orbit Initial Orbit

SS DawnDusk Orbit

Orbit Initial Orbit

Launch

bull Vandenberg AFB CA

bull Atlas V Launch Vehicle

bull Secondary Payload

bull Insertion into near Polar Orbit via Centaur Upper Stage

bull Further transfer necessary to achieve SS orbit

25

Orbit Blade Size

Maximum Solar Radiation Pressure Calculation

bull Assumptions

bull Perfectly reflecting surface

bull α = 0

(incident radiation perpendicular to surface)

26

Preflect2W

cR2cos2 = 908 Pa

where W = 1361 Wm2 c = 30x10 8 ms amp R = 100 AU

Orbit Blade Size

Minimum Solar Blade Surface Area for

Necessary Thrust

bull Assumptions

bull m = 8 kg (based on 8U Volume CubeSat 1 kgU)

27

a ac 01 mms2 requirement

sreflectc APmaFmax Asmac

Preflect8811 m2

bull 4 solar blades

As

42203 m2 per blade

Orbit Transfer

bull Example

bull LV delivers sc into 1100 km circular polar orbit

bull 1) Orbit raising maneuver to 1500 km

bull 2) Inclination change maneuver to i = 10196

bull How long will this take with GHOSTrsquos capabilities

28

29

Orbit Transfer

Orbit Raising Maneuver

Hohmann Transfer

Dual tangential

burn coplanar orbit

transfer

Initial Orbit

Final Orbit

Transfer Orbit

Orbit Transfer

Orbit Raising Maneuver

bull Calculated using Hohmann Transfer Equations

30

initial transfer vi 945 ms

transfer final v f 933 ms

vtotal 1877 ms

torbit raise 123 days

45o Preflect 454 Pa ain plane 177x10 5 ms2

Two blades pitched at

45

producing thrust in along track direction

See appendix for detailed orbit transfer diagrams

Orbit Transfer

Orbit Inclination Change

bull Calculated using inclination change only equations

31

v inc 2v initialcos( fpa)sini

2where vinitial v f fpa 0o amp i 1196o

vinc 148 kms i 00028 oorbit

a ac 01 mms2 P 6959 s Thrust acts over northern hemisphere of orbit (12 of Period)

tinc change 3437 days

Orbit Transfer

Final Destination

bull Δttotal = 4667 days or ~ 155 months bull time it takes to transfer from LV Delivery 1100 km polar orbit to 1500 km SS

orbit

bull this BOTE calculation has huge implications on both

bull mission duration

bull life span of sc components materials etc

bull Validates the high performance orbit transfer capabilities of the heliogyro architecture

32

Integration CubeSat

Pitch Test Validation

Sensor(s) to measure

torque and

Purpose Demonstrate coordinated pitching with equivalent mass and

realistic bus rotation

bull Rotation of 1 RPM

bull Measure torque on bus

bull Measure and compare actual pitching angles

to commanded

pitching angles

Sensors Needed

bull 3 axis Accelerometer (torque measurement)

bull 3 axis Gyroscope (pitch angle measurement)

bull 12 bit resolution (greater than pitching motors)

bull Fit onto or on 8U CubeSat

ADI516xxxIM4

bull 3 axis gyroscope

bull 3 axis magnetometer

bull 3 axis accelerometer

bull 14 bit resolution

bull 1

volume

bull Available free for checkout in ITLL

Sail Equivalent

mass

33

Integration CubeSat

Feasibility of our Baseline Design

bull To achieve characteristic acceleration for an 8U (8kg) CubeSat we needed each sail to be 2203

bull The diameter of the rolled spool inside the CubeSat (pre-deployment) varies with the width of the sail

bull To find the diameter of the rolled spool we calculated the length of one sail for a chosen width Assuming a Mylar thickness of 5 um due to the crinkling effect the spool width was calculated by iterating each rotation with increasing diameter as the blade rolls up

Iterate for rolling up sail until finished

(cm)

(m)

12 1836 247

10 2203 270

8 2754 300

34

Integration CubeSat

Sizing the Blades

bull CubeSat constrained by 20 cm on each side

bull Need to perform 180 degree independent rotation and maximize room inside the satellite for pitching motors controls and communication

Top Down Views of each size ( Scaled to correct dimensions)

12 cm blade width 10 cm blade width 8 cm blade width

bull Not intrusive on inner area

bull Full 180 motion

bull Infringes on space inside

bull Full 180 motion

bull Not intrusive on inner area

bull No Full 180 motion

35

Integration CubeSat

Housing the Rolled Sail

bull The solar sail blades will be controlled by a pitching axle but there must be an interface to connect to the axle

bull Cylindrical plate housing

bull Protects blades

bull Easy to connect to axle

bull No gears

bull Ability to provide counterweight

to deployment motor

bull With the tight volume constraints of our cube the Cylindrical plate must be altered to avoid interference with other sides

36

Integration CubeSat

Fitting the cylindrical Plate

bull Clearance for rolled sail

bull 2 cm clearance on each side

bull 06 cm clearance on behind the motor

bull This leaves overlapping corners

bull To prevent overlap we will make a 45ordm cut around the entire cylinder

2 cm

06 cm

Rolled Sail

Plate Encasing

Overlapping

Corners

45ordm cut to get rid

of corners

37

Integration CubeSat

Fitting the cylindrical Plate

bull The 45ordm cut will give us a 0 cm clearance (with no thickness)

bull If we implement a high-low offset between adjacent plates the distance between the two closest points increases

bull For our 14 cm diameter plates a 2 cm offset from the center for each plate (4 cm total) the effective clearance becomes 251 cm

Two adjacent sides

on same axis

With a High-Low Offset

38

Integration CubeSat

High-Low Offset Plates

The high low offset will give each plate room to rotate a full 180ordm

1 cm clearance between the top of the

blade and the edge of the satellite to fit

the thin-set bearing

A 3mm plate thickness gives adjacent

plates a distance of 19 cm between

their closest points

39

Integration CubeSat

High Low Offset Performance Validation

bull The high-low offset will not effect the performance or stability of the deployment or pitching systems

bull Upon deployment the opposing extension on each side cancels out unwanted torque

View From high side View From low side

bull In a sun-synchronous orbit the high or low setting has no effect as the rotational axis of the satellite is always solar pointing

View From Sun

40

Integration Power

Electronics Feasibility Analysis

bull Project Constraints

bull CubeSat power source Li-Ion batteries (5 and 33 V is common) - Would require thermal protection

bull Communications System - Transceiver (UHF is common) [USART serial port] - Buffer may be needed depending on power constraints

bull Deployment Subsystem - 1 step-motor [output] - 1 encoder [MSSP input] OR direct deployment measurement via external sensor

bull Pitching Subsystem - 2 servomotors [output]

41

Integration Power

PIC18F Series Microchip

bull Inputs 2 USART and 2 MSSP ports available (for basic PICs) - More than 1 device may be connected to each port - 2-3 devices needed

bull Outputs 8 ports - 2 devices needed

bull 16 bit - Though different PICs may be acquired for higher resolution

bull Operating Range 2-55 V - Within provided parameters

42

PIC

Communications

Deployment

Motor

Encoder

Pitching

Motor 1

Pitching

Motor 2 Key

Power Lines

Input Lines

Output Lines

Integration Power

Microchip FBD

5V Battery

Possible Voltage

Buffer

Encoder

43

Integration Power

Motor Power Limitations

bull Power Constraints

Pmax = 100 W

Vmax = 50 V

bull P = IV (Power = CurrentVoltage)

bull Therefore Iave = 20 Amps

bull Blade Pitching (4 motors total needed) - Current limitations for power sources and number of simultaneous blades pitching

Number of Blades 5 V Input 36 V input 31 V input 2 V input

4 040 A 069 A 081 A 125 A

2 080 A 139 A 161 A 250 A

1 160 A 278 A 323 A 500 A

44

Integration Motors

Stepper vs Brushless Servo Motors

45

-Contain many poles (50+) -Contain only 4-12 poles

-Distinct steps cause

vibration during use -Do not suffer from

vibration and resonance

issues smooth movement

-Low maintenance easier to

commission mechanically

simple

-Efficient response to start

stop and reverse commands

-Rely on encoders for

position details in closed

loop response

-Physical sizes

are comparable

-Both available

in various

lengths at same

frame size -Torque can be readily

controlled

-Low cost and high

availability

-Complexity drives cost

upward

Chosen for

deployment motor

Chosen for

pitching motor

Stepper Servo

Integration Blade Deployment

Deployment Motor Feasibility

Required holding torque is calculated to be 18 mNm

Required driving torque is calculated to be 117

10-5 mN∙m

bull Micro Motion Solutions ndash miniature stepper motors bull Physical Properties

bull Diameter = 6-22 mm

bull Length = 93-20 mm

bull Weight = 55-12 g

bull Holding Torque = 24-10 mN∙m = 034-142 oz∙in

bull Resolution bull 1 or 2 phase half-step capability

bull Steps per turn = 20-24 rarr 15˚-18˚ per step

5 of full step accuracy

bull Power Requirements bull Nominal voltage per phase 2-5 V

bull Nominal current per phase 01-1 A

46

Integration Blade Pitching

Blade Pitching Motor Feasibility

Required driving torque is calculated to be 0019 mN∙m

bull Mabuchi Servo Motor bull Physical Size

bull Diameter = 17 mm

bull Length = 25 mm

bull Weight = 16 g

bull Torque

bull Holding Torque = 161 mN∙m = 0228 oz∙in

bull Driving Torque = 0385 mN∙m = 0055 oz∙in

bull Friction Torque = 403

10-3 mN∙m = 571

10-4 oz∙in

bull Power Requirements

bull Nominal voltage per phase 2-5 V

bull Nominal current per phase 006-02 A 47

Integration Launch

Feasibility for Pre-deployment locking mechanism

The tip of the solar sail will be wider than the body with the sail tip set outside the plate

The tip will be held in place vertically by stationary blade stabilizers and kept tight by the holding torque of the deployment motor

Stationary blade

stabilizers

Extra-wide

blade tip

Upon deployment the motor

turns and the blade extends

48

Integration Launch

Canesterized Satellite Dispenser (CSD)

bull Ride in a 12 U CSD

bull Width=239 cm Height=226 cm Length=366 cm

bull Mass=0-24 kg at launch

bull Center of Mass when stowed in

bull x is -40 to 40 mm

bull y is 50 to 125 mm

bull z is 133 to 233 mm

wwwplanetarysytemscorpcom 49

Integration Launch

Test Validation

bull Launch Vibration Test

bull Needs to be space applicable and strong enough to withstand vibration

bull Ball Aerospace can provide a shake table costing $250hr

bull Preparation for Testing using FEM modeling and adding support features

50

Financial

bull Total Budget $5000

bull Components

bull Stepper Motor $100-200

bull Servo Motor (x2) $50-500 each

bull Materials (made in-house) $500-1000

bull Electronics $0-500

bull Testing

bull Deployment amp Pitching Free (Performed on Campus)

bull Launch Survivability Vibration Stand - $250hr Ball Space Systems in Boulder

bull Total Estimation $700-2700 + Vibration Stand Testing

51

Baseline Design All Together

bull The 8u CubeSat and characteristic acceleration requirements create very strict volumetric restrictions

bull The size of the plates and the rolled sail blade must be validated

bull This design will be analyzed and verified in the feasibility requirements

Inner Control Area

bull Motor

bull Encoder

bull Control

bull Communication

bull Power

Possible Load-bearing

corners for deployment

Housed Solar Sail

Top-Down View

Extra room for third

party systems

52

Status Summary

53

SystemMechanism Final Choice Further

Studies

Needed

8U Structure Fit our CubeSat in 12U bus provided by Planetary Services Yes

Adequate Area of Sails to Provide

Orbit Transfer Capabilities

AR = 22001 No

Pitching Mechanism Using a servo motor Yes

Pitching Accuracy Pitching encoder Yes

Plate Integration System Using a two cylinder design with tapered edges so

everything will fit

No

Deployment Motor Using a stepper motor No

Launch Ability Must conform to standards set by Planetary Services Yes

Launch Survivability Verify that GHOST will survive launch Yes

Initial Spin-Up Carbon steel attached to solar blade material Yes 53

Strategy for Conducting

Remaining Studies

bull 8U GHOST inside 12U structure bull Create a SolidWorksCAD model

bull Pitching Mechanism bull Determine adequate motor within size power and cost constraints

bull Pitching Accuracy bull Determine pitching accuracy based on orbital sensitivity

bull Launch Ability bull Because design is symmetrical center of mass is in the center of the satellite during launch bull Further investigations is needed to determine how many counterweights

bull Launch Survivability bull FEM or Vibrations

bull Initial Spin-up bull Determine feasible method to attach carbon steel support structure to solar sail blade material

54

Resources

bull PAYLOAD SPECIFICATION FOR 3U 6U 12U AND 27U Np Planetary Systems Corporation 2013 Print

bull Davis Jason The Planetary Society The Planetary Society Blog Firefly Partners 11 Apr 2012 Web 12 Oct 2013 lthttpwwwplanetaryorgblogsguest-blogsjason-davis3450htmlgt

bull Mao Tengfei 01mm Thickness Measuring Tape Wwwalibabacom Alibabacom nd Web 12 Oct 2013 lthttpwwwalibabacomproduct-gs8359006940_1mm_thickness_measuring_tapehtmlgt

55

Resources

bull ldquoHow servos and steppers stack uprdquo Machine Design 9 February 2012 [httpmachinedesigncomnewshow-servos-and-steppers-stack Accessed 7 October 2013]

bull ldquoMiniature Stepper Motor Drive Systems - Data Sheetrdquo Micro Motion Solutions [httpwwwmicromocomstepper-motors-datasheetsaspx Accessed 11 October 2013]

bull ldquoData Sheet for TS-53 Servorsquos Electric Motorrdquo Mabuchi Motor [httpwwwprincetonedu~mae412TEXTNTRAK2002292-302pdf Accessed 11 October 2013]

56

Blade Deployment Space Model

Centripetal Acceleration

Deployment

Length

(Meters)

Centripetal

Acceleration

(ms2)

Mass

(Kg)

Centripetal

Force (N)

1 0011 0037 000041

15 016 0044 00073

30 033 0052 0017

50 055 0062 0034

100 11 0087 0095

150 16 011 018

200 22 014 03

220 24 015 035

17

Constant Spin Ω = 1 RPM

Gravitational Force

Earth

Orbital Trajectory

Equations

Constants

Blade Deployment

Testing on Earth Relation to Space

CubeSat rotating at 1 RPM rarr centripetal acceleration rarr centrifugal tension

Blade is fully deployed rarr maximum centrifugal tension

Simulate same centrifugal tension the blade would experience in space

Total mass of 36 g used in the deployment test

mTOTAL = mTM + mB = 36 + 110 = 146 g

a = 241 ms2 F = ma = 035 N

F = mg = 035 N g = 981 ms2

mTOTAL = 36 g

The holding torque of the motor used must be able to withstand this force

τ = r

F r = 05 cm F = 035 N

τ = 00018 Nm

Space Application

Motor

CubeSat

rotating at 1

RPM

Blade Tip mass

F

Top View

Tip mass trajectory

mB = 10 g mTM = 26 g

F = mg

Deployment Test

r

Mounted to Table Side View

Tip

mass

Motor

Blade

Front View

MotorBus

Interface

18

Blade Deployment

Earth Test Validation

19

Deployment Test

bull Release one solar sail blade of 15m at a controlled rate of 1-10 cms to demonstrate controlled deployment

bull Will be tested in Professor Frewrsquos lab in Fleming that is 17m high

bull Use video camera to measure rate set markers along wall to track deployment

19

Blade Deployment Space Model

Initial Spin Up

bull Carbon Steel Blade Supports at the end to replace end mass

bull 50 Carbon Steel

bull 01 mm thick

bull Deployment motor will deploy initial blade support structure for initial spin-up

CubeSat

Carbon-Steel

Blade Supports

Solar Blade

20

Blade Deployment Space Model

Initial Spin Up

bull Collective pitch of 35

to produce torque for spin up

bull Mass at end of sail=367g

bull Volume = 47e-6 cubic m

bull Two perpendicular rods rotating about oblate axis bull Both 4 kg

bull I=

bull Known bull Width=01 m

bull Length=047 m

bull Surface Area=00467 squared meters

21

Blade Deployment Space Model

Initial Spin Up

bull

=435

bull α=

bull Time = 24 days

bull Release the rest of sail and centrifugal tension will aid in deployment of sail

bull Solar sail thrust should keep CubeSat at 1 RPM while deploying

CubeSat

∆ω = Ω = 1 RPM

τ = L

F = Iα

L = 057 m

F = 023 μN

22

Orbit Initial Orbit

Final Orbit Selection

bull Sun-Synchronous 1500 km DawnDusk Orbit

bull Assumptions

bull Circular Orbit (e = 0 a = p)

bull No atmospheric drag above 1100 km altitude

bull Only orbital perturbation considered in orbit determination is the oblateness of the earth (second zonal constant J2)

bull All other orbital perturbations are neglected

bull For SS Orbit Node Precession = Solar Precession

bull Gyro rotational axis always oriented towards Sun

23

See Appendix for calculation

24

Orbit Initial Orbit

SS DawnDusk Orbit

Orbit Initial Orbit

Launch

bull Vandenberg AFB CA

bull Atlas V Launch Vehicle

bull Secondary Payload

bull Insertion into near Polar Orbit via Centaur Upper Stage

bull Further transfer necessary to achieve SS orbit

25

Orbit Blade Size

Maximum Solar Radiation Pressure Calculation

bull Assumptions

bull Perfectly reflecting surface

bull α = 0

(incident radiation perpendicular to surface)

26

Preflect2W

cR2cos2 = 908 Pa

where W = 1361 Wm2 c = 30x10 8 ms amp R = 100 AU

Orbit Blade Size

Minimum Solar Blade Surface Area for

Necessary Thrust

bull Assumptions

bull m = 8 kg (based on 8U Volume CubeSat 1 kgU)

27

a ac 01 mms2 requirement

sreflectc APmaFmax Asmac

Preflect8811 m2

bull 4 solar blades

As

42203 m2 per blade

Orbit Transfer

bull Example

bull LV delivers sc into 1100 km circular polar orbit

bull 1) Orbit raising maneuver to 1500 km

bull 2) Inclination change maneuver to i = 10196

bull How long will this take with GHOSTrsquos capabilities

28

29

Orbit Transfer

Orbit Raising Maneuver

Hohmann Transfer

Dual tangential

burn coplanar orbit

transfer

Initial Orbit

Final Orbit

Transfer Orbit

Orbit Transfer

Orbit Raising Maneuver

bull Calculated using Hohmann Transfer Equations

30

initial transfer vi 945 ms

transfer final v f 933 ms

vtotal 1877 ms

torbit raise 123 days

45o Preflect 454 Pa ain plane 177x10 5 ms2

Two blades pitched at

45

producing thrust in along track direction

See appendix for detailed orbit transfer diagrams

Orbit Transfer

Orbit Inclination Change

bull Calculated using inclination change only equations

31

v inc 2v initialcos( fpa)sini

2where vinitial v f fpa 0o amp i 1196o

vinc 148 kms i 00028 oorbit

a ac 01 mms2 P 6959 s Thrust acts over northern hemisphere of orbit (12 of Period)

tinc change 3437 days

Orbit Transfer

Final Destination

bull Δttotal = 4667 days or ~ 155 months bull time it takes to transfer from LV Delivery 1100 km polar orbit to 1500 km SS

orbit

bull this BOTE calculation has huge implications on both

bull mission duration

bull life span of sc components materials etc

bull Validates the high performance orbit transfer capabilities of the heliogyro architecture

32

Integration CubeSat

Pitch Test Validation

Sensor(s) to measure

torque and

Purpose Demonstrate coordinated pitching with equivalent mass and

realistic bus rotation

bull Rotation of 1 RPM

bull Measure torque on bus

bull Measure and compare actual pitching angles

to commanded

pitching angles

Sensors Needed

bull 3 axis Accelerometer (torque measurement)

bull 3 axis Gyroscope (pitch angle measurement)

bull 12 bit resolution (greater than pitching motors)

bull Fit onto or on 8U CubeSat

ADI516xxxIM4

bull 3 axis gyroscope

bull 3 axis magnetometer

bull 3 axis accelerometer

bull 14 bit resolution

bull 1

volume

bull Available free for checkout in ITLL

Sail Equivalent

mass

33

Integration CubeSat

Feasibility of our Baseline Design

bull To achieve characteristic acceleration for an 8U (8kg) CubeSat we needed each sail to be 2203

bull The diameter of the rolled spool inside the CubeSat (pre-deployment) varies with the width of the sail

bull To find the diameter of the rolled spool we calculated the length of one sail for a chosen width Assuming a Mylar thickness of 5 um due to the crinkling effect the spool width was calculated by iterating each rotation with increasing diameter as the blade rolls up

Iterate for rolling up sail until finished

(cm)

(m)

12 1836 247

10 2203 270

8 2754 300

34

Integration CubeSat

Sizing the Blades

bull CubeSat constrained by 20 cm on each side

bull Need to perform 180 degree independent rotation and maximize room inside the satellite for pitching motors controls and communication

Top Down Views of each size ( Scaled to correct dimensions)

12 cm blade width 10 cm blade width 8 cm blade width

bull Not intrusive on inner area

bull Full 180 motion

bull Infringes on space inside

bull Full 180 motion

bull Not intrusive on inner area

bull No Full 180 motion

35

Integration CubeSat

Housing the Rolled Sail

bull The solar sail blades will be controlled by a pitching axle but there must be an interface to connect to the axle

bull Cylindrical plate housing

bull Protects blades

bull Easy to connect to axle

bull No gears

bull Ability to provide counterweight

to deployment motor

bull With the tight volume constraints of our cube the Cylindrical plate must be altered to avoid interference with other sides

36

Integration CubeSat

Fitting the cylindrical Plate

bull Clearance for rolled sail

bull 2 cm clearance on each side

bull 06 cm clearance on behind the motor

bull This leaves overlapping corners

bull To prevent overlap we will make a 45ordm cut around the entire cylinder

2 cm

06 cm

Rolled Sail

Plate Encasing

Overlapping

Corners

45ordm cut to get rid

of corners

37

Integration CubeSat

Fitting the cylindrical Plate

bull The 45ordm cut will give us a 0 cm clearance (with no thickness)

bull If we implement a high-low offset between adjacent plates the distance between the two closest points increases

bull For our 14 cm diameter plates a 2 cm offset from the center for each plate (4 cm total) the effective clearance becomes 251 cm

Two adjacent sides

on same axis

With a High-Low Offset

38

Integration CubeSat

High-Low Offset Plates

The high low offset will give each plate room to rotate a full 180ordm

1 cm clearance between the top of the

blade and the edge of the satellite to fit

the thin-set bearing

A 3mm plate thickness gives adjacent

plates a distance of 19 cm between

their closest points

39

Integration CubeSat

High Low Offset Performance Validation

bull The high-low offset will not effect the performance or stability of the deployment or pitching systems

bull Upon deployment the opposing extension on each side cancels out unwanted torque

View From high side View From low side

bull In a sun-synchronous orbit the high or low setting has no effect as the rotational axis of the satellite is always solar pointing

View From Sun

40

Integration Power

Electronics Feasibility Analysis

bull Project Constraints

bull CubeSat power source Li-Ion batteries (5 and 33 V is common) - Would require thermal protection

bull Communications System - Transceiver (UHF is common) [USART serial port] - Buffer may be needed depending on power constraints

bull Deployment Subsystem - 1 step-motor [output] - 1 encoder [MSSP input] OR direct deployment measurement via external sensor

bull Pitching Subsystem - 2 servomotors [output]

41

Integration Power

PIC18F Series Microchip

bull Inputs 2 USART and 2 MSSP ports available (for basic PICs) - More than 1 device may be connected to each port - 2-3 devices needed

bull Outputs 8 ports - 2 devices needed

bull 16 bit - Though different PICs may be acquired for higher resolution

bull Operating Range 2-55 V - Within provided parameters

42

PIC

Communications

Deployment

Motor

Encoder

Pitching

Motor 1

Pitching

Motor 2 Key

Power Lines

Input Lines

Output Lines

Integration Power

Microchip FBD

5V Battery

Possible Voltage

Buffer

Encoder

43

Integration Power

Motor Power Limitations

bull Power Constraints

Pmax = 100 W

Vmax = 50 V

bull P = IV (Power = CurrentVoltage)

bull Therefore Iave = 20 Amps

bull Blade Pitching (4 motors total needed) - Current limitations for power sources and number of simultaneous blades pitching

Number of Blades 5 V Input 36 V input 31 V input 2 V input

4 040 A 069 A 081 A 125 A

2 080 A 139 A 161 A 250 A

1 160 A 278 A 323 A 500 A

44

Integration Motors

Stepper vs Brushless Servo Motors

45

-Contain many poles (50+) -Contain only 4-12 poles

-Distinct steps cause

vibration during use -Do not suffer from

vibration and resonance

issues smooth movement

-Low maintenance easier to

commission mechanically

simple

-Efficient response to start

stop and reverse commands

-Rely on encoders for

position details in closed

loop response

-Physical sizes

are comparable

-Both available

in various

lengths at same

frame size -Torque can be readily

controlled

-Low cost and high

availability

-Complexity drives cost

upward

Chosen for

deployment motor

Chosen for

pitching motor

Stepper Servo

Integration Blade Deployment

Deployment Motor Feasibility

Required holding torque is calculated to be 18 mNm

Required driving torque is calculated to be 117

10-5 mN∙m

bull Micro Motion Solutions ndash miniature stepper motors bull Physical Properties

bull Diameter = 6-22 mm

bull Length = 93-20 mm

bull Weight = 55-12 g

bull Holding Torque = 24-10 mN∙m = 034-142 oz∙in

bull Resolution bull 1 or 2 phase half-step capability

bull Steps per turn = 20-24 rarr 15˚-18˚ per step

5 of full step accuracy

bull Power Requirements bull Nominal voltage per phase 2-5 V

bull Nominal current per phase 01-1 A

46

Integration Blade Pitching

Blade Pitching Motor Feasibility

Required driving torque is calculated to be 0019 mN∙m

bull Mabuchi Servo Motor bull Physical Size

bull Diameter = 17 mm

bull Length = 25 mm

bull Weight = 16 g

bull Torque

bull Holding Torque = 161 mN∙m = 0228 oz∙in

bull Driving Torque = 0385 mN∙m = 0055 oz∙in

bull Friction Torque = 403

10-3 mN∙m = 571

10-4 oz∙in

bull Power Requirements

bull Nominal voltage per phase 2-5 V

bull Nominal current per phase 006-02 A 47

Integration Launch

Feasibility for Pre-deployment locking mechanism

The tip of the solar sail will be wider than the body with the sail tip set outside the plate

The tip will be held in place vertically by stationary blade stabilizers and kept tight by the holding torque of the deployment motor

Stationary blade

stabilizers

Extra-wide

blade tip

Upon deployment the motor

turns and the blade extends

48

Integration Launch

Canesterized Satellite Dispenser (CSD)

bull Ride in a 12 U CSD

bull Width=239 cm Height=226 cm Length=366 cm

bull Mass=0-24 kg at launch

bull Center of Mass when stowed in

bull x is -40 to 40 mm

bull y is 50 to 125 mm

bull z is 133 to 233 mm

wwwplanetarysytemscorpcom 49

Integration Launch

Test Validation

bull Launch Vibration Test

bull Needs to be space applicable and strong enough to withstand vibration

bull Ball Aerospace can provide a shake table costing $250hr

bull Preparation for Testing using FEM modeling and adding support features

50

Financial

bull Total Budget $5000

bull Components

bull Stepper Motor $100-200

bull Servo Motor (x2) $50-500 each

bull Materials (made in-house) $500-1000

bull Electronics $0-500

bull Testing

bull Deployment amp Pitching Free (Performed on Campus)

bull Launch Survivability Vibration Stand - $250hr Ball Space Systems in Boulder

bull Total Estimation $700-2700 + Vibration Stand Testing

51

Baseline Design All Together

bull The 8u CubeSat and characteristic acceleration requirements create very strict volumetric restrictions

bull The size of the plates and the rolled sail blade must be validated

bull This design will be analyzed and verified in the feasibility requirements

Inner Control Area

bull Motor

bull Encoder

bull Control

bull Communication

bull Power

Possible Load-bearing

corners for deployment

Housed Solar Sail

Top-Down View

Extra room for third

party systems

52

Status Summary

53

SystemMechanism Final Choice Further

Studies

Needed

8U Structure Fit our CubeSat in 12U bus provided by Planetary Services Yes

Adequate Area of Sails to Provide

Orbit Transfer Capabilities

AR = 22001 No

Pitching Mechanism Using a servo motor Yes

Pitching Accuracy Pitching encoder Yes

Plate Integration System Using a two cylinder design with tapered edges so

everything will fit

No

Deployment Motor Using a stepper motor No

Launch Ability Must conform to standards set by Planetary Services Yes

Launch Survivability Verify that GHOST will survive launch Yes

Initial Spin-Up Carbon steel attached to solar blade material Yes 53

Strategy for Conducting

Remaining Studies

bull 8U GHOST inside 12U structure bull Create a SolidWorksCAD model

bull Pitching Mechanism bull Determine adequate motor within size power and cost constraints

bull Pitching Accuracy bull Determine pitching accuracy based on orbital sensitivity

bull Launch Ability bull Because design is symmetrical center of mass is in the center of the satellite during launch bull Further investigations is needed to determine how many counterweights

bull Launch Survivability bull FEM or Vibrations

bull Initial Spin-up bull Determine feasible method to attach carbon steel support structure to solar sail blade material

54

Resources

bull PAYLOAD SPECIFICATION FOR 3U 6U 12U AND 27U Np Planetary Systems Corporation 2013 Print

bull Davis Jason The Planetary Society The Planetary Society Blog Firefly Partners 11 Apr 2012 Web 12 Oct 2013 lthttpwwwplanetaryorgblogsguest-blogsjason-davis3450htmlgt

bull Mao Tengfei 01mm Thickness Measuring Tape Wwwalibabacom Alibabacom nd Web 12 Oct 2013 lthttpwwwalibabacomproduct-gs8359006940_1mm_thickness_measuring_tapehtmlgt

55

Resources

bull ldquoHow servos and steppers stack uprdquo Machine Design 9 February 2012 [httpmachinedesigncomnewshow-servos-and-steppers-stack Accessed 7 October 2013]

bull ldquoMiniature Stepper Motor Drive Systems - Data Sheetrdquo Micro Motion Solutions [httpwwwmicromocomstepper-motors-datasheetsaspx Accessed 11 October 2013]

bull ldquoData Sheet for TS-53 Servorsquos Electric Motorrdquo Mabuchi Motor [httpwwwprincetonedu~mae412TEXTNTRAK2002292-302pdf Accessed 11 October 2013]

56

Blade Deployment

Testing on Earth Relation to Space

CubeSat rotating at 1 RPM rarr centripetal acceleration rarr centrifugal tension

Blade is fully deployed rarr maximum centrifugal tension

Simulate same centrifugal tension the blade would experience in space

Total mass of 36 g used in the deployment test

mTOTAL = mTM + mB = 36 + 110 = 146 g

a = 241 ms2 F = ma = 035 N

F = mg = 035 N g = 981 ms2

mTOTAL = 36 g

The holding torque of the motor used must be able to withstand this force

τ = r

F r = 05 cm F = 035 N

τ = 00018 Nm

Space Application

Motor

CubeSat

rotating at 1

RPM

Blade Tip mass

F

Top View

Tip mass trajectory

mB = 10 g mTM = 26 g

F = mg

Deployment Test

r

Mounted to Table Side View

Tip

mass

Motor

Blade

Front View

MotorBus

Interface

18

Blade Deployment

Earth Test Validation

19

Deployment Test

bull Release one solar sail blade of 15m at a controlled rate of 1-10 cms to demonstrate controlled deployment

bull Will be tested in Professor Frewrsquos lab in Fleming that is 17m high

bull Use video camera to measure rate set markers along wall to track deployment

19

Blade Deployment Space Model

Initial Spin Up

bull Carbon Steel Blade Supports at the end to replace end mass

bull 50 Carbon Steel

bull 01 mm thick

bull Deployment motor will deploy initial blade support structure for initial spin-up

CubeSat

Carbon-Steel

Blade Supports

Solar Blade

20

Blade Deployment Space Model

Initial Spin Up

bull Collective pitch of 35

to produce torque for spin up

bull Mass at end of sail=367g

bull Volume = 47e-6 cubic m

bull Two perpendicular rods rotating about oblate axis bull Both 4 kg

bull I=

bull Known bull Width=01 m

bull Length=047 m

bull Surface Area=00467 squared meters

21

Blade Deployment Space Model

Initial Spin Up

bull

=435

bull α=

bull Time = 24 days

bull Release the rest of sail and centrifugal tension will aid in deployment of sail

bull Solar sail thrust should keep CubeSat at 1 RPM while deploying

CubeSat

∆ω = Ω = 1 RPM

τ = L

F = Iα

L = 057 m

F = 023 μN

22

Orbit Initial Orbit

Final Orbit Selection

bull Sun-Synchronous 1500 km DawnDusk Orbit

bull Assumptions

bull Circular Orbit (e = 0 a = p)

bull No atmospheric drag above 1100 km altitude

bull Only orbital perturbation considered in orbit determination is the oblateness of the earth (second zonal constant J2)

bull All other orbital perturbations are neglected

bull For SS Orbit Node Precession = Solar Precession

bull Gyro rotational axis always oriented towards Sun

23

See Appendix for calculation

24

Orbit Initial Orbit

SS DawnDusk Orbit

Orbit Initial Orbit

Launch

bull Vandenberg AFB CA

bull Atlas V Launch Vehicle

bull Secondary Payload

bull Insertion into near Polar Orbit via Centaur Upper Stage

bull Further transfer necessary to achieve SS orbit

25

Orbit Blade Size

Maximum Solar Radiation Pressure Calculation

bull Assumptions

bull Perfectly reflecting surface

bull α = 0

(incident radiation perpendicular to surface)

26

Preflect2W

cR2cos2 = 908 Pa

where W = 1361 Wm2 c = 30x10 8 ms amp R = 100 AU

Orbit Blade Size

Minimum Solar Blade Surface Area for

Necessary Thrust

bull Assumptions

bull m = 8 kg (based on 8U Volume CubeSat 1 kgU)

27

a ac 01 mms2 requirement

sreflectc APmaFmax Asmac

Preflect8811 m2

bull 4 solar blades

As

42203 m2 per blade

Orbit Transfer

bull Example

bull LV delivers sc into 1100 km circular polar orbit

bull 1) Orbit raising maneuver to 1500 km

bull 2) Inclination change maneuver to i = 10196

bull How long will this take with GHOSTrsquos capabilities

28

29

Orbit Transfer

Orbit Raising Maneuver

Hohmann Transfer

Dual tangential

burn coplanar orbit

transfer

Initial Orbit

Final Orbit

Transfer Orbit

Orbit Transfer

Orbit Raising Maneuver

bull Calculated using Hohmann Transfer Equations

30

initial transfer vi 945 ms

transfer final v f 933 ms

vtotal 1877 ms

torbit raise 123 days

45o Preflect 454 Pa ain plane 177x10 5 ms2

Two blades pitched at

45

producing thrust in along track direction

See appendix for detailed orbit transfer diagrams

Orbit Transfer

Orbit Inclination Change

bull Calculated using inclination change only equations

31

v inc 2v initialcos( fpa)sini

2where vinitial v f fpa 0o amp i 1196o

vinc 148 kms i 00028 oorbit

a ac 01 mms2 P 6959 s Thrust acts over northern hemisphere of orbit (12 of Period)

tinc change 3437 days

Orbit Transfer

Final Destination

bull Δttotal = 4667 days or ~ 155 months bull time it takes to transfer from LV Delivery 1100 km polar orbit to 1500 km SS

orbit

bull this BOTE calculation has huge implications on both

bull mission duration

bull life span of sc components materials etc

bull Validates the high performance orbit transfer capabilities of the heliogyro architecture

32

Integration CubeSat

Pitch Test Validation

Sensor(s) to measure

torque and

Purpose Demonstrate coordinated pitching with equivalent mass and

realistic bus rotation

bull Rotation of 1 RPM

bull Measure torque on bus

bull Measure and compare actual pitching angles

to commanded

pitching angles

Sensors Needed

bull 3 axis Accelerometer (torque measurement)

bull 3 axis Gyroscope (pitch angle measurement)

bull 12 bit resolution (greater than pitching motors)

bull Fit onto or on 8U CubeSat

ADI516xxxIM4

bull 3 axis gyroscope

bull 3 axis magnetometer

bull 3 axis accelerometer

bull 14 bit resolution

bull 1

volume

bull Available free for checkout in ITLL

Sail Equivalent

mass

33

Integration CubeSat

Feasibility of our Baseline Design

bull To achieve characteristic acceleration for an 8U (8kg) CubeSat we needed each sail to be 2203

bull The diameter of the rolled spool inside the CubeSat (pre-deployment) varies with the width of the sail

bull To find the diameter of the rolled spool we calculated the length of one sail for a chosen width Assuming a Mylar thickness of 5 um due to the crinkling effect the spool width was calculated by iterating each rotation with increasing diameter as the blade rolls up

Iterate for rolling up sail until finished

(cm)

(m)

12 1836 247

10 2203 270

8 2754 300

34

Integration CubeSat

Sizing the Blades

bull CubeSat constrained by 20 cm on each side

bull Need to perform 180 degree independent rotation and maximize room inside the satellite for pitching motors controls and communication

Top Down Views of each size ( Scaled to correct dimensions)

12 cm blade width 10 cm blade width 8 cm blade width

bull Not intrusive on inner area

bull Full 180 motion

bull Infringes on space inside

bull Full 180 motion

bull Not intrusive on inner area

bull No Full 180 motion

35

Integration CubeSat

Housing the Rolled Sail

bull The solar sail blades will be controlled by a pitching axle but there must be an interface to connect to the axle

bull Cylindrical plate housing

bull Protects blades

bull Easy to connect to axle

bull No gears

bull Ability to provide counterweight

to deployment motor

bull With the tight volume constraints of our cube the Cylindrical plate must be altered to avoid interference with other sides

36

Integration CubeSat

Fitting the cylindrical Plate

bull Clearance for rolled sail

bull 2 cm clearance on each side

bull 06 cm clearance on behind the motor

bull This leaves overlapping corners

bull To prevent overlap we will make a 45ordm cut around the entire cylinder

2 cm

06 cm

Rolled Sail

Plate Encasing

Overlapping

Corners

45ordm cut to get rid

of corners

37

Integration CubeSat

Fitting the cylindrical Plate

bull The 45ordm cut will give us a 0 cm clearance (with no thickness)

bull If we implement a high-low offset between adjacent plates the distance between the two closest points increases

bull For our 14 cm diameter plates a 2 cm offset from the center for each plate (4 cm total) the effective clearance becomes 251 cm

Two adjacent sides

on same axis

With a High-Low Offset

38

Integration CubeSat

High-Low Offset Plates

The high low offset will give each plate room to rotate a full 180ordm

1 cm clearance between the top of the

blade and the edge of the satellite to fit

the thin-set bearing

A 3mm plate thickness gives adjacent

plates a distance of 19 cm between

their closest points

39

Integration CubeSat

High Low Offset Performance Validation

bull The high-low offset will not effect the performance or stability of the deployment or pitching systems

bull Upon deployment the opposing extension on each side cancels out unwanted torque

View From high side View From low side

bull In a sun-synchronous orbit the high or low setting has no effect as the rotational axis of the satellite is always solar pointing

View From Sun

40

Integration Power

Electronics Feasibility Analysis

bull Project Constraints

bull CubeSat power source Li-Ion batteries (5 and 33 V is common) - Would require thermal protection

bull Communications System - Transceiver (UHF is common) [USART serial port] - Buffer may be needed depending on power constraints

bull Deployment Subsystem - 1 step-motor [output] - 1 encoder [MSSP input] OR direct deployment measurement via external sensor

bull Pitching Subsystem - 2 servomotors [output]

41

Integration Power

PIC18F Series Microchip

bull Inputs 2 USART and 2 MSSP ports available (for basic PICs) - More than 1 device may be connected to each port - 2-3 devices needed

bull Outputs 8 ports - 2 devices needed

bull 16 bit - Though different PICs may be acquired for higher resolution

bull Operating Range 2-55 V - Within provided parameters

42

PIC

Communications

Deployment

Motor

Encoder

Pitching

Motor 1

Pitching

Motor 2 Key

Power Lines

Input Lines

Output Lines

Integration Power

Microchip FBD

5V Battery

Possible Voltage

Buffer

Encoder

43

Integration Power

Motor Power Limitations

bull Power Constraints

Pmax = 100 W

Vmax = 50 V

bull P = IV (Power = CurrentVoltage)

bull Therefore Iave = 20 Amps

bull Blade Pitching (4 motors total needed) - Current limitations for power sources and number of simultaneous blades pitching

Number of Blades 5 V Input 36 V input 31 V input 2 V input

4 040 A 069 A 081 A 125 A

2 080 A 139 A 161 A 250 A

1 160 A 278 A 323 A 500 A

44

Integration Motors

Stepper vs Brushless Servo Motors

45

-Contain many poles (50+) -Contain only 4-12 poles

-Distinct steps cause

vibration during use -Do not suffer from

vibration and resonance

issues smooth movement

-Low maintenance easier to

commission mechanically

simple

-Efficient response to start

stop and reverse commands

-Rely on encoders for

position details in closed

loop response

-Physical sizes

are comparable

-Both available

in various

lengths at same

frame size -Torque can be readily

controlled

-Low cost and high

availability

-Complexity drives cost

upward

Chosen for

deployment motor

Chosen for

pitching motor

Stepper Servo

Integration Blade Deployment

Deployment Motor Feasibility

Required holding torque is calculated to be 18 mNm

Required driving torque is calculated to be 117

10-5 mN∙m

bull Micro Motion Solutions ndash miniature stepper motors bull Physical Properties

bull Diameter = 6-22 mm

bull Length = 93-20 mm

bull Weight = 55-12 g

bull Holding Torque = 24-10 mN∙m = 034-142 oz∙in

bull Resolution bull 1 or 2 phase half-step capability

bull Steps per turn = 20-24 rarr 15˚-18˚ per step

5 of full step accuracy

bull Power Requirements bull Nominal voltage per phase 2-5 V

bull Nominal current per phase 01-1 A

46

Integration Blade Pitching

Blade Pitching Motor Feasibility

Required driving torque is calculated to be 0019 mN∙m

bull Mabuchi Servo Motor bull Physical Size

bull Diameter = 17 mm

bull Length = 25 mm

bull Weight = 16 g

bull Torque

bull Holding Torque = 161 mN∙m = 0228 oz∙in

bull Driving Torque = 0385 mN∙m = 0055 oz∙in

bull Friction Torque = 403

10-3 mN∙m = 571

10-4 oz∙in

bull Power Requirements

bull Nominal voltage per phase 2-5 V

bull Nominal current per phase 006-02 A 47

Integration Launch

Feasibility for Pre-deployment locking mechanism

The tip of the solar sail will be wider than the body with the sail tip set outside the plate

The tip will be held in place vertically by stationary blade stabilizers and kept tight by the holding torque of the deployment motor

Stationary blade

stabilizers

Extra-wide

blade tip

Upon deployment the motor

turns and the blade extends

48

Integration Launch

Canesterized Satellite Dispenser (CSD)

bull Ride in a 12 U CSD

bull Width=239 cm Height=226 cm Length=366 cm

bull Mass=0-24 kg at launch

bull Center of Mass when stowed in

bull x is -40 to 40 mm

bull y is 50 to 125 mm

bull z is 133 to 233 mm

wwwplanetarysytemscorpcom 49

Integration Launch

Test Validation

bull Launch Vibration Test

bull Needs to be space applicable and strong enough to withstand vibration

bull Ball Aerospace can provide a shake table costing $250hr

bull Preparation for Testing using FEM modeling and adding support features

50

Financial

bull Total Budget $5000

bull Components

bull Stepper Motor $100-200

bull Servo Motor (x2) $50-500 each

bull Materials (made in-house) $500-1000

bull Electronics $0-500

bull Testing

bull Deployment amp Pitching Free (Performed on Campus)

bull Launch Survivability Vibration Stand - $250hr Ball Space Systems in Boulder

bull Total Estimation $700-2700 + Vibration Stand Testing

51

Baseline Design All Together

bull The 8u CubeSat and characteristic acceleration requirements create very strict volumetric restrictions

bull The size of the plates and the rolled sail blade must be validated

bull This design will be analyzed and verified in the feasibility requirements

Inner Control Area

bull Motor

bull Encoder

bull Control

bull Communication

bull Power

Possible Load-bearing

corners for deployment

Housed Solar Sail

Top-Down View

Extra room for third

party systems

52

Status Summary

53

SystemMechanism Final Choice Further

Studies

Needed

8U Structure Fit our CubeSat in 12U bus provided by Planetary Services Yes

Adequate Area of Sails to Provide

Orbit Transfer Capabilities

AR = 22001 No

Pitching Mechanism Using a servo motor Yes

Pitching Accuracy Pitching encoder Yes

Plate Integration System Using a two cylinder design with tapered edges so

everything will fit

No

Deployment Motor Using a stepper motor No

Launch Ability Must conform to standards set by Planetary Services Yes

Launch Survivability Verify that GHOST will survive launch Yes

Initial Spin-Up Carbon steel attached to solar blade material Yes 53

Strategy for Conducting

Remaining Studies

bull 8U GHOST inside 12U structure bull Create a SolidWorksCAD model

bull Pitching Mechanism bull Determine adequate motor within size power and cost constraints

bull Pitching Accuracy bull Determine pitching accuracy based on orbital sensitivity

bull Launch Ability bull Because design is symmetrical center of mass is in the center of the satellite during launch bull Further investigations is needed to determine how many counterweights

bull Launch Survivability bull FEM or Vibrations

bull Initial Spin-up bull Determine feasible method to attach carbon steel support structure to solar sail blade material

54

Resources

bull PAYLOAD SPECIFICATION FOR 3U 6U 12U AND 27U Np Planetary Systems Corporation 2013 Print

bull Davis Jason The Planetary Society The Planetary Society Blog Firefly Partners 11 Apr 2012 Web 12 Oct 2013 lthttpwwwplanetaryorgblogsguest-blogsjason-davis3450htmlgt

bull Mao Tengfei 01mm Thickness Measuring Tape Wwwalibabacom Alibabacom nd Web 12 Oct 2013 lthttpwwwalibabacomproduct-gs8359006940_1mm_thickness_measuring_tapehtmlgt

55

Resources

bull ldquoHow servos and steppers stack uprdquo Machine Design 9 February 2012 [httpmachinedesigncomnewshow-servos-and-steppers-stack Accessed 7 October 2013]

bull ldquoMiniature Stepper Motor Drive Systems - Data Sheetrdquo Micro Motion Solutions [httpwwwmicromocomstepper-motors-datasheetsaspx Accessed 11 October 2013]

bull ldquoData Sheet for TS-53 Servorsquos Electric Motorrdquo Mabuchi Motor [httpwwwprincetonedu~mae412TEXTNTRAK2002292-302pdf Accessed 11 October 2013]

56

Blade Deployment

Earth Test Validation

19

Deployment Test

bull Release one solar sail blade of 15m at a controlled rate of 1-10 cms to demonstrate controlled deployment

bull Will be tested in Professor Frewrsquos lab in Fleming that is 17m high

bull Use video camera to measure rate set markers along wall to track deployment

19

Blade Deployment Space Model

Initial Spin Up

bull Carbon Steel Blade Supports at the end to replace end mass

bull 50 Carbon Steel

bull 01 mm thick

bull Deployment motor will deploy initial blade support structure for initial spin-up

CubeSat

Carbon-Steel

Blade Supports

Solar Blade

20

Blade Deployment Space Model

Initial Spin Up

bull Collective pitch of 35

to produce torque for spin up

bull Mass at end of sail=367g

bull Volume = 47e-6 cubic m

bull Two perpendicular rods rotating about oblate axis bull Both 4 kg

bull I=

bull Known bull Width=01 m

bull Length=047 m

bull Surface Area=00467 squared meters

21

Blade Deployment Space Model

Initial Spin Up

bull

=435

bull α=

bull Time = 24 days

bull Release the rest of sail and centrifugal tension will aid in deployment of sail

bull Solar sail thrust should keep CubeSat at 1 RPM while deploying

CubeSat

∆ω = Ω = 1 RPM

τ = L

F = Iα

L = 057 m

F = 023 μN

22

Orbit Initial Orbit

Final Orbit Selection

bull Sun-Synchronous 1500 km DawnDusk Orbit

bull Assumptions

bull Circular Orbit (e = 0 a = p)

bull No atmospheric drag above 1100 km altitude

bull Only orbital perturbation considered in orbit determination is the oblateness of the earth (second zonal constant J2)

bull All other orbital perturbations are neglected

bull For SS Orbit Node Precession = Solar Precession

bull Gyro rotational axis always oriented towards Sun

23

See Appendix for calculation

24

Orbit Initial Orbit

SS DawnDusk Orbit

Orbit Initial Orbit

Launch

bull Vandenberg AFB CA

bull Atlas V Launch Vehicle

bull Secondary Payload

bull Insertion into near Polar Orbit via Centaur Upper Stage

bull Further transfer necessary to achieve SS orbit

25

Orbit Blade Size

Maximum Solar Radiation Pressure Calculation

bull Assumptions

bull Perfectly reflecting surface

bull α = 0

(incident radiation perpendicular to surface)

26

Preflect2W

cR2cos2 = 908 Pa

where W = 1361 Wm2 c = 30x10 8 ms amp R = 100 AU

Orbit Blade Size

Minimum Solar Blade Surface Area for

Necessary Thrust

bull Assumptions

bull m = 8 kg (based on 8U Volume CubeSat 1 kgU)

27

a ac 01 mms2 requirement

sreflectc APmaFmax Asmac

Preflect8811 m2

bull 4 solar blades

As

42203 m2 per blade

Orbit Transfer

bull Example

bull LV delivers sc into 1100 km circular polar orbit

bull 1) Orbit raising maneuver to 1500 km

bull 2) Inclination change maneuver to i = 10196

bull How long will this take with GHOSTrsquos capabilities

28

29

Orbit Transfer

Orbit Raising Maneuver

Hohmann Transfer

Dual tangential

burn coplanar orbit

transfer

Initial Orbit

Final Orbit

Transfer Orbit

Orbit Transfer

Orbit Raising Maneuver

bull Calculated using Hohmann Transfer Equations

30

initial transfer vi 945 ms

transfer final v f 933 ms

vtotal 1877 ms

torbit raise 123 days

45o Preflect 454 Pa ain plane 177x10 5 ms2

Two blades pitched at

45

producing thrust in along track direction

See appendix for detailed orbit transfer diagrams

Orbit Transfer

Orbit Inclination Change

bull Calculated using inclination change only equations

31

v inc 2v initialcos( fpa)sini

2where vinitial v f fpa 0o amp i 1196o

vinc 148 kms i 00028 oorbit

a ac 01 mms2 P 6959 s Thrust acts over northern hemisphere of orbit (12 of Period)

tinc change 3437 days

Orbit Transfer

Final Destination

bull Δttotal = 4667 days or ~ 155 months bull time it takes to transfer from LV Delivery 1100 km polar orbit to 1500 km SS

orbit

bull this BOTE calculation has huge implications on both

bull mission duration

bull life span of sc components materials etc

bull Validates the high performance orbit transfer capabilities of the heliogyro architecture

32

Integration CubeSat

Pitch Test Validation

Sensor(s) to measure

torque and

Purpose Demonstrate coordinated pitching with equivalent mass and

realistic bus rotation

bull Rotation of 1 RPM

bull Measure torque on bus

bull Measure and compare actual pitching angles

to commanded

pitching angles

Sensors Needed

bull 3 axis Accelerometer (torque measurement)

bull 3 axis Gyroscope (pitch angle measurement)

bull 12 bit resolution (greater than pitching motors)

bull Fit onto or on 8U CubeSat

ADI516xxxIM4

bull 3 axis gyroscope

bull 3 axis magnetometer

bull 3 axis accelerometer

bull 14 bit resolution

bull 1

volume

bull Available free for checkout in ITLL

Sail Equivalent

mass

33

Integration CubeSat

Feasibility of our Baseline Design

bull To achieve characteristic acceleration for an 8U (8kg) CubeSat we needed each sail to be 2203

bull The diameter of the rolled spool inside the CubeSat (pre-deployment) varies with the width of the sail

bull To find the diameter of the rolled spool we calculated the length of one sail for a chosen width Assuming a Mylar thickness of 5 um due to the crinkling effect the spool width was calculated by iterating each rotation with increasing diameter as the blade rolls up

Iterate for rolling up sail until finished

(cm)

(m)

12 1836 247

10 2203 270

8 2754 300

34

Integration CubeSat

Sizing the Blades

bull CubeSat constrained by 20 cm on each side

bull Need to perform 180 degree independent rotation and maximize room inside the satellite for pitching motors controls and communication

Top Down Views of each size ( Scaled to correct dimensions)

12 cm blade width 10 cm blade width 8 cm blade width

bull Not intrusive on inner area

bull Full 180 motion

bull Infringes on space inside

bull Full 180 motion

bull Not intrusive on inner area

bull No Full 180 motion

35

Integration CubeSat

Housing the Rolled Sail

bull The solar sail blades will be controlled by a pitching axle but there must be an interface to connect to the axle

bull Cylindrical plate housing

bull Protects blades

bull Easy to connect to axle

bull No gears

bull Ability to provide counterweight

to deployment motor

bull With the tight volume constraints of our cube the Cylindrical plate must be altered to avoid interference with other sides

36

Integration CubeSat

Fitting the cylindrical Plate

bull Clearance for rolled sail

bull 2 cm clearance on each side

bull 06 cm clearance on behind the motor

bull This leaves overlapping corners

bull To prevent overlap we will make a 45ordm cut around the entire cylinder

2 cm

06 cm

Rolled Sail

Plate Encasing

Overlapping

Corners

45ordm cut to get rid

of corners

37

Integration CubeSat

Fitting the cylindrical Plate

bull The 45ordm cut will give us a 0 cm clearance (with no thickness)

bull If we implement a high-low offset between adjacent plates the distance between the two closest points increases

bull For our 14 cm diameter plates a 2 cm offset from the center for each plate (4 cm total) the effective clearance becomes 251 cm

Two adjacent sides

on same axis

With a High-Low Offset

38

Integration CubeSat

High-Low Offset Plates

The high low offset will give each plate room to rotate a full 180ordm

1 cm clearance between the top of the

blade and the edge of the satellite to fit

the thin-set bearing

A 3mm plate thickness gives adjacent

plates a distance of 19 cm between

their closest points

39

Integration CubeSat

High Low Offset Performance Validation

bull The high-low offset will not effect the performance or stability of the deployment or pitching systems

bull Upon deployment the opposing extension on each side cancels out unwanted torque

View From high side View From low side

bull In a sun-synchronous orbit the high or low setting has no effect as the rotational axis of the satellite is always solar pointing

View From Sun

40

Integration Power

Electronics Feasibility Analysis

bull Project Constraints

bull CubeSat power source Li-Ion batteries (5 and 33 V is common) - Would require thermal protection

bull Communications System - Transceiver (UHF is common) [USART serial port] - Buffer may be needed depending on power constraints

bull Deployment Subsystem - 1 step-motor [output] - 1 encoder [MSSP input] OR direct deployment measurement via external sensor

bull Pitching Subsystem - 2 servomotors [output]

41

Integration Power

PIC18F Series Microchip

bull Inputs 2 USART and 2 MSSP ports available (for basic PICs) - More than 1 device may be connected to each port - 2-3 devices needed

bull Outputs 8 ports - 2 devices needed

bull 16 bit - Though different PICs may be acquired for higher resolution

bull Operating Range 2-55 V - Within provided parameters

42

PIC

Communications

Deployment

Motor

Encoder

Pitching

Motor 1

Pitching

Motor 2 Key

Power Lines

Input Lines

Output Lines

Integration Power

Microchip FBD

5V Battery

Possible Voltage

Buffer

Encoder

43

Integration Power

Motor Power Limitations

bull Power Constraints

Pmax = 100 W

Vmax = 50 V

bull P = IV (Power = CurrentVoltage)

bull Therefore Iave = 20 Amps

bull Blade Pitching (4 motors total needed) - Current limitations for power sources and number of simultaneous blades pitching

Number of Blades 5 V Input 36 V input 31 V input 2 V input

4 040 A 069 A 081 A 125 A

2 080 A 139 A 161 A 250 A

1 160 A 278 A 323 A 500 A

44

Integration Motors

Stepper vs Brushless Servo Motors

45

-Contain many poles (50+) -Contain only 4-12 poles

-Distinct steps cause

vibration during use -Do not suffer from

vibration and resonance

issues smooth movement

-Low maintenance easier to

commission mechanically

simple

-Efficient response to start

stop and reverse commands

-Rely on encoders for

position details in closed

loop response

-Physical sizes

are comparable

-Both available

in various

lengths at same

frame size -Torque can be readily

controlled

-Low cost and high

availability

-Complexity drives cost

upward

Chosen for

deployment motor

Chosen for

pitching motor

Stepper Servo

Integration Blade Deployment

Deployment Motor Feasibility

Required holding torque is calculated to be 18 mNm

Required driving torque is calculated to be 117

10-5 mN∙m

bull Micro Motion Solutions ndash miniature stepper motors bull Physical Properties

bull Diameter = 6-22 mm

bull Length = 93-20 mm

bull Weight = 55-12 g

bull Holding Torque = 24-10 mN∙m = 034-142 oz∙in

bull Resolution bull 1 or 2 phase half-step capability

bull Steps per turn = 20-24 rarr 15˚-18˚ per step

5 of full step accuracy

bull Power Requirements bull Nominal voltage per phase 2-5 V

bull Nominal current per phase 01-1 A

46

Integration Blade Pitching

Blade Pitching Motor Feasibility

Required driving torque is calculated to be 0019 mN∙m

bull Mabuchi Servo Motor bull Physical Size

bull Diameter = 17 mm

bull Length = 25 mm

bull Weight = 16 g

bull Torque

bull Holding Torque = 161 mN∙m = 0228 oz∙in

bull Driving Torque = 0385 mN∙m = 0055 oz∙in

bull Friction Torque = 403

10-3 mN∙m = 571

10-4 oz∙in

bull Power Requirements

bull Nominal voltage per phase 2-5 V

bull Nominal current per phase 006-02 A 47

Integration Launch

Feasibility for Pre-deployment locking mechanism

The tip of the solar sail will be wider than the body with the sail tip set outside the plate

The tip will be held in place vertically by stationary blade stabilizers and kept tight by the holding torque of the deployment motor

Stationary blade

stabilizers

Extra-wide

blade tip

Upon deployment the motor

turns and the blade extends

48

Integration Launch

Canesterized Satellite Dispenser (CSD)

bull Ride in a 12 U CSD

bull Width=239 cm Height=226 cm Length=366 cm

bull Mass=0-24 kg at launch

bull Center of Mass when stowed in

bull x is -40 to 40 mm

bull y is 50 to 125 mm

bull z is 133 to 233 mm

wwwplanetarysytemscorpcom 49

Integration Launch

Test Validation

bull Launch Vibration Test

bull Needs to be space applicable and strong enough to withstand vibration

bull Ball Aerospace can provide a shake table costing $250hr

bull Preparation for Testing using FEM modeling and adding support features

50

Financial

bull Total Budget $5000

bull Components

bull Stepper Motor $100-200

bull Servo Motor (x2) $50-500 each

bull Materials (made in-house) $500-1000

bull Electronics $0-500

bull Testing

bull Deployment amp Pitching Free (Performed on Campus)

bull Launch Survivability Vibration Stand - $250hr Ball Space Systems in Boulder

bull Total Estimation $700-2700 + Vibration Stand Testing

51

Baseline Design All Together

bull The 8u CubeSat and characteristic acceleration requirements create very strict volumetric restrictions

bull The size of the plates and the rolled sail blade must be validated

bull This design will be analyzed and verified in the feasibility requirements

Inner Control Area

bull Motor

bull Encoder

bull Control

bull Communication

bull Power

Possible Load-bearing

corners for deployment

Housed Solar Sail

Top-Down View

Extra room for third

party systems

52

Status Summary

53

SystemMechanism Final Choice Further

Studies

Needed

8U Structure Fit our CubeSat in 12U bus provided by Planetary Services Yes

Adequate Area of Sails to Provide

Orbit Transfer Capabilities

AR = 22001 No

Pitching Mechanism Using a servo motor Yes

Pitching Accuracy Pitching encoder Yes

Plate Integration System Using a two cylinder design with tapered edges so

everything will fit

No

Deployment Motor Using a stepper motor No

Launch Ability Must conform to standards set by Planetary Services Yes

Launch Survivability Verify that GHOST will survive launch Yes

Initial Spin-Up Carbon steel attached to solar blade material Yes 53

Strategy for Conducting

Remaining Studies

bull 8U GHOST inside 12U structure bull Create a SolidWorksCAD model

bull Pitching Mechanism bull Determine adequate motor within size power and cost constraints

bull Pitching Accuracy bull Determine pitching accuracy based on orbital sensitivity

bull Launch Ability bull Because design is symmetrical center of mass is in the center of the satellite during launch bull Further investigations is needed to determine how many counterweights

bull Launch Survivability bull FEM or Vibrations

bull Initial Spin-up bull Determine feasible method to attach carbon steel support structure to solar sail blade material

54

Resources

bull PAYLOAD SPECIFICATION FOR 3U 6U 12U AND 27U Np Planetary Systems Corporation 2013 Print

bull Davis Jason The Planetary Society The Planetary Society Blog Firefly Partners 11 Apr 2012 Web 12 Oct 2013 lthttpwwwplanetaryorgblogsguest-blogsjason-davis3450htmlgt

bull Mao Tengfei 01mm Thickness Measuring Tape Wwwalibabacom Alibabacom nd Web 12 Oct 2013 lthttpwwwalibabacomproduct-gs8359006940_1mm_thickness_measuring_tapehtmlgt

55

Resources

bull ldquoHow servos and steppers stack uprdquo Machine Design 9 February 2012 [httpmachinedesigncomnewshow-servos-and-steppers-stack Accessed 7 October 2013]

bull ldquoMiniature Stepper Motor Drive Systems - Data Sheetrdquo Micro Motion Solutions [httpwwwmicromocomstepper-motors-datasheetsaspx Accessed 11 October 2013]

bull ldquoData Sheet for TS-53 Servorsquos Electric Motorrdquo Mabuchi Motor [httpwwwprincetonedu~mae412TEXTNTRAK2002292-302pdf Accessed 11 October 2013]

56

Blade Deployment Space Model

Initial Spin Up

bull Carbon Steel Blade Supports at the end to replace end mass

bull 50 Carbon Steel

bull 01 mm thick

bull Deployment motor will deploy initial blade support structure for initial spin-up

CubeSat

Carbon-Steel

Blade Supports

Solar Blade

20

Blade Deployment Space Model

Initial Spin Up

bull Collective pitch of 35

to produce torque for spin up

bull Mass at end of sail=367g

bull Volume = 47e-6 cubic m

bull Two perpendicular rods rotating about oblate axis bull Both 4 kg

bull I=

bull Known bull Width=01 m

bull Length=047 m

bull Surface Area=00467 squared meters

21

Blade Deployment Space Model

Initial Spin Up

bull

=435

bull α=

bull Time = 24 days

bull Release the rest of sail and centrifugal tension will aid in deployment of sail

bull Solar sail thrust should keep CubeSat at 1 RPM while deploying

CubeSat

∆ω = Ω = 1 RPM

τ = L

F = Iα

L = 057 m

F = 023 μN

22

Orbit Initial Orbit

Final Orbit Selection

bull Sun-Synchronous 1500 km DawnDusk Orbit

bull Assumptions

bull Circular Orbit (e = 0 a = p)

bull No atmospheric drag above 1100 km altitude

bull Only orbital perturbation considered in orbit determination is the oblateness of the earth (second zonal constant J2)

bull All other orbital perturbations are neglected

bull For SS Orbit Node Precession = Solar Precession

bull Gyro rotational axis always oriented towards Sun

23

See Appendix for calculation

24

Orbit Initial Orbit

SS DawnDusk Orbit

Orbit Initial Orbit

Launch

bull Vandenberg AFB CA

bull Atlas V Launch Vehicle

bull Secondary Payload

bull Insertion into near Polar Orbit via Centaur Upper Stage

bull Further transfer necessary to achieve SS orbit

25

Orbit Blade Size

Maximum Solar Radiation Pressure Calculation

bull Assumptions

bull Perfectly reflecting surface

bull α = 0

(incident radiation perpendicular to surface)

26

Preflect2W

cR2cos2 = 908 Pa

where W = 1361 Wm2 c = 30x10 8 ms amp R = 100 AU

Orbit Blade Size

Minimum Solar Blade Surface Area for

Necessary Thrust

bull Assumptions

bull m = 8 kg (based on 8U Volume CubeSat 1 kgU)

27

a ac 01 mms2 requirement

sreflectc APmaFmax Asmac

Preflect8811 m2

bull 4 solar blades

As

42203 m2 per blade

Orbit Transfer

bull Example

bull LV delivers sc into 1100 km circular polar orbit

bull 1) Orbit raising maneuver to 1500 km

bull 2) Inclination change maneuver to i = 10196

bull How long will this take with GHOSTrsquos capabilities

28

29

Orbit Transfer

Orbit Raising Maneuver

Hohmann Transfer

Dual tangential

burn coplanar orbit

transfer

Initial Orbit

Final Orbit

Transfer Orbit

Orbit Transfer

Orbit Raising Maneuver

bull Calculated using Hohmann Transfer Equations

30

initial transfer vi 945 ms

transfer final v f 933 ms

vtotal 1877 ms

torbit raise 123 days

45o Preflect 454 Pa ain plane 177x10 5 ms2

Two blades pitched at

45

producing thrust in along track direction

See appendix for detailed orbit transfer diagrams

Orbit Transfer

Orbit Inclination Change

bull Calculated using inclination change only equations

31

v inc 2v initialcos( fpa)sini

2where vinitial v f fpa 0o amp i 1196o

vinc 148 kms i 00028 oorbit

a ac 01 mms2 P 6959 s Thrust acts over northern hemisphere of orbit (12 of Period)

tinc change 3437 days

Orbit Transfer

Final Destination

bull Δttotal = 4667 days or ~ 155 months bull time it takes to transfer from LV Delivery 1100 km polar orbit to 1500 km SS

orbit

bull this BOTE calculation has huge implications on both

bull mission duration

bull life span of sc components materials etc

bull Validates the high performance orbit transfer capabilities of the heliogyro architecture

32

Integration CubeSat

Pitch Test Validation

Sensor(s) to measure

torque and

Purpose Demonstrate coordinated pitching with equivalent mass and

realistic bus rotation

bull Rotation of 1 RPM

bull Measure torque on bus

bull Measure and compare actual pitching angles

to commanded

pitching angles

Sensors Needed

bull 3 axis Accelerometer (torque measurement)

bull 3 axis Gyroscope (pitch angle measurement)

bull 12 bit resolution (greater than pitching motors)

bull Fit onto or on 8U CubeSat

ADI516xxxIM4

bull 3 axis gyroscope

bull 3 axis magnetometer

bull 3 axis accelerometer

bull 14 bit resolution

bull 1

volume

bull Available free for checkout in ITLL

Sail Equivalent

mass

33

Integration CubeSat

Feasibility of our Baseline Design

bull To achieve characteristic acceleration for an 8U (8kg) CubeSat we needed each sail to be 2203

bull The diameter of the rolled spool inside the CubeSat (pre-deployment) varies with the width of the sail

bull To find the diameter of the rolled spool we calculated the length of one sail for a chosen width Assuming a Mylar thickness of 5 um due to the crinkling effect the spool width was calculated by iterating each rotation with increasing diameter as the blade rolls up

Iterate for rolling up sail until finished

(cm)

(m)

12 1836 247

10 2203 270

8 2754 300

34

Integration CubeSat

Sizing the Blades

bull CubeSat constrained by 20 cm on each side

bull Need to perform 180 degree independent rotation and maximize room inside the satellite for pitching motors controls and communication

Top Down Views of each size ( Scaled to correct dimensions)

12 cm blade width 10 cm blade width 8 cm blade width

bull Not intrusive on inner area

bull Full 180 motion

bull Infringes on space inside

bull Full 180 motion

bull Not intrusive on inner area

bull No Full 180 motion

35

Integration CubeSat

Housing the Rolled Sail

bull The solar sail blades will be controlled by a pitching axle but there must be an interface to connect to the axle

bull Cylindrical plate housing

bull Protects blades

bull Easy to connect to axle

bull No gears

bull Ability to provide counterweight

to deployment motor

bull With the tight volume constraints of our cube the Cylindrical plate must be altered to avoid interference with other sides

36

Integration CubeSat

Fitting the cylindrical Plate

bull Clearance for rolled sail

bull 2 cm clearance on each side

bull 06 cm clearance on behind the motor

bull This leaves overlapping corners

bull To prevent overlap we will make a 45ordm cut around the entire cylinder

2 cm

06 cm

Rolled Sail

Plate Encasing

Overlapping

Corners

45ordm cut to get rid

of corners

37

Integration CubeSat

Fitting the cylindrical Plate

bull The 45ordm cut will give us a 0 cm clearance (with no thickness)

bull If we implement a high-low offset between adjacent plates the distance between the two closest points increases

bull For our 14 cm diameter plates a 2 cm offset from the center for each plate (4 cm total) the effective clearance becomes 251 cm

Two adjacent sides

on same axis

With a High-Low Offset

38

Integration CubeSat

High-Low Offset Plates

The high low offset will give each plate room to rotate a full 180ordm

1 cm clearance between the top of the

blade and the edge of the satellite to fit

the thin-set bearing

A 3mm plate thickness gives adjacent

plates a distance of 19 cm between

their closest points

39

Integration CubeSat

High Low Offset Performance Validation

bull The high-low offset will not effect the performance or stability of the deployment or pitching systems

bull Upon deployment the opposing extension on each side cancels out unwanted torque

View From high side View From low side

bull In a sun-synchronous orbit the high or low setting has no effect as the rotational axis of the satellite is always solar pointing

View From Sun

40

Integration Power

Electronics Feasibility Analysis

bull Project Constraints

bull CubeSat power source Li-Ion batteries (5 and 33 V is common) - Would require thermal protection

bull Communications System - Transceiver (UHF is common) [USART serial port] - Buffer may be needed depending on power constraints

bull Deployment Subsystem - 1 step-motor [output] - 1 encoder [MSSP input] OR direct deployment measurement via external sensor

bull Pitching Subsystem - 2 servomotors [output]

41

Integration Power

PIC18F Series Microchip

bull Inputs 2 USART and 2 MSSP ports available (for basic PICs) - More than 1 device may be connected to each port - 2-3 devices needed

bull Outputs 8 ports - 2 devices needed

bull 16 bit - Though different PICs may be acquired for higher resolution

bull Operating Range 2-55 V - Within provided parameters

42

PIC

Communications

Deployment

Motor

Encoder

Pitching

Motor 1

Pitching

Motor 2 Key

Power Lines

Input Lines

Output Lines

Integration Power

Microchip FBD

5V Battery

Possible Voltage

Buffer

Encoder

43

Integration Power

Motor Power Limitations

bull Power Constraints

Pmax = 100 W

Vmax = 50 V

bull P = IV (Power = CurrentVoltage)

bull Therefore Iave = 20 Amps

bull Blade Pitching (4 motors total needed) - Current limitations for power sources and number of simultaneous blades pitching

Number of Blades 5 V Input 36 V input 31 V input 2 V input

4 040 A 069 A 081 A 125 A

2 080 A 139 A 161 A 250 A

1 160 A 278 A 323 A 500 A

44

Integration Motors

Stepper vs Brushless Servo Motors

45

-Contain many poles (50+) -Contain only 4-12 poles

-Distinct steps cause

vibration during use -Do not suffer from

vibration and resonance

issues smooth movement

-Low maintenance easier to

commission mechanically

simple

-Efficient response to start

stop and reverse commands

-Rely on encoders for

position details in closed

loop response

-Physical sizes

are comparable

-Both available

in various

lengths at same

frame size -Torque can be readily

controlled

-Low cost and high

availability

-Complexity drives cost

upward

Chosen for

deployment motor

Chosen for

pitching motor

Stepper Servo

Integration Blade Deployment

Deployment Motor Feasibility

Required holding torque is calculated to be 18 mNm

Required driving torque is calculated to be 117

10-5 mN∙m

bull Micro Motion Solutions ndash miniature stepper motors bull Physical Properties

bull Diameter = 6-22 mm

bull Length = 93-20 mm

bull Weight = 55-12 g

bull Holding Torque = 24-10 mN∙m = 034-142 oz∙in

bull Resolution bull 1 or 2 phase half-step capability

bull Steps per turn = 20-24 rarr 15˚-18˚ per step

5 of full step accuracy

bull Power Requirements bull Nominal voltage per phase 2-5 V

bull Nominal current per phase 01-1 A

46

Integration Blade Pitching

Blade Pitching Motor Feasibility

Required driving torque is calculated to be 0019 mN∙m

bull Mabuchi Servo Motor bull Physical Size

bull Diameter = 17 mm

bull Length = 25 mm

bull Weight = 16 g

bull Torque

bull Holding Torque = 161 mN∙m = 0228 oz∙in

bull Driving Torque = 0385 mN∙m = 0055 oz∙in

bull Friction Torque = 403

10-3 mN∙m = 571

10-4 oz∙in

bull Power Requirements

bull Nominal voltage per phase 2-5 V

bull Nominal current per phase 006-02 A 47

Integration Launch

Feasibility for Pre-deployment locking mechanism

The tip of the solar sail will be wider than the body with the sail tip set outside the plate

The tip will be held in place vertically by stationary blade stabilizers and kept tight by the holding torque of the deployment motor

Stationary blade

stabilizers

Extra-wide

blade tip

Upon deployment the motor

turns and the blade extends

48

Integration Launch

Canesterized Satellite Dispenser (CSD)

bull Ride in a 12 U CSD

bull Width=239 cm Height=226 cm Length=366 cm

bull Mass=0-24 kg at launch

bull Center of Mass when stowed in

bull x is -40 to 40 mm

bull y is 50 to 125 mm

bull z is 133 to 233 mm

wwwplanetarysytemscorpcom 49

Integration Launch

Test Validation

bull Launch Vibration Test

bull Needs to be space applicable and strong enough to withstand vibration

bull Ball Aerospace can provide a shake table costing $250hr

bull Preparation for Testing using FEM modeling and adding support features

50

Financial

bull Total Budget $5000

bull Components

bull Stepper Motor $100-200

bull Servo Motor (x2) $50-500 each

bull Materials (made in-house) $500-1000

bull Electronics $0-500

bull Testing

bull Deployment amp Pitching Free (Performed on Campus)

bull Launch Survivability Vibration Stand - $250hr Ball Space Systems in Boulder

bull Total Estimation $700-2700 + Vibration Stand Testing

51

Baseline Design All Together

bull The 8u CubeSat and characteristic acceleration requirements create very strict volumetric restrictions

bull The size of the plates and the rolled sail blade must be validated

bull This design will be analyzed and verified in the feasibility requirements

Inner Control Area

bull Motor

bull Encoder

bull Control

bull Communication

bull Power

Possible Load-bearing

corners for deployment

Housed Solar Sail

Top-Down View

Extra room for third

party systems

52

Status Summary

53

SystemMechanism Final Choice Further

Studies

Needed

8U Structure Fit our CubeSat in 12U bus provided by Planetary Services Yes

Adequate Area of Sails to Provide

Orbit Transfer Capabilities

AR = 22001 No

Pitching Mechanism Using a servo motor Yes

Pitching Accuracy Pitching encoder Yes

Plate Integration System Using a two cylinder design with tapered edges so

everything will fit

No

Deployment Motor Using a stepper motor No

Launch Ability Must conform to standards set by Planetary Services Yes

Launch Survivability Verify that GHOST will survive launch Yes

Initial Spin-Up Carbon steel attached to solar blade material Yes 53

Strategy for Conducting

Remaining Studies

bull 8U GHOST inside 12U structure bull Create a SolidWorksCAD model

bull Pitching Mechanism bull Determine adequate motor within size power and cost constraints

bull Pitching Accuracy bull Determine pitching accuracy based on orbital sensitivity

bull Launch Ability bull Because design is symmetrical center of mass is in the center of the satellite during launch bull Further investigations is needed to determine how many counterweights

bull Launch Survivability bull FEM or Vibrations

bull Initial Spin-up bull Determine feasible method to attach carbon steel support structure to solar sail blade material

54

Resources

bull PAYLOAD SPECIFICATION FOR 3U 6U 12U AND 27U Np Planetary Systems Corporation 2013 Print

bull Davis Jason The Planetary Society The Planetary Society Blog Firefly Partners 11 Apr 2012 Web 12 Oct 2013 lthttpwwwplanetaryorgblogsguest-blogsjason-davis3450htmlgt

bull Mao Tengfei 01mm Thickness Measuring Tape Wwwalibabacom Alibabacom nd Web 12 Oct 2013 lthttpwwwalibabacomproduct-gs8359006940_1mm_thickness_measuring_tapehtmlgt

55

Resources

bull ldquoHow servos and steppers stack uprdquo Machine Design 9 February 2012 [httpmachinedesigncomnewshow-servos-and-steppers-stack Accessed 7 October 2013]

bull ldquoMiniature Stepper Motor Drive Systems - Data Sheetrdquo Micro Motion Solutions [httpwwwmicromocomstepper-motors-datasheetsaspx Accessed 11 October 2013]

bull ldquoData Sheet for TS-53 Servorsquos Electric Motorrdquo Mabuchi Motor [httpwwwprincetonedu~mae412TEXTNTRAK2002292-302pdf Accessed 11 October 2013]

56

Blade Deployment Space Model

Initial Spin Up

bull Collective pitch of 35

to produce torque for spin up

bull Mass at end of sail=367g

bull Volume = 47e-6 cubic m

bull Two perpendicular rods rotating about oblate axis bull Both 4 kg

bull I=

bull Known bull Width=01 m

bull Length=047 m

bull Surface Area=00467 squared meters

21

Blade Deployment Space Model

Initial Spin Up

bull

=435

bull α=

bull Time = 24 days

bull Release the rest of sail and centrifugal tension will aid in deployment of sail

bull Solar sail thrust should keep CubeSat at 1 RPM while deploying

CubeSat

∆ω = Ω = 1 RPM

τ = L

F = Iα

L = 057 m

F = 023 μN

22

Orbit Initial Orbit

Final Orbit Selection

bull Sun-Synchronous 1500 km DawnDusk Orbit

bull Assumptions

bull Circular Orbit (e = 0 a = p)

bull No atmospheric drag above 1100 km altitude

bull Only orbital perturbation considered in orbit determination is the oblateness of the earth (second zonal constant J2)

bull All other orbital perturbations are neglected

bull For SS Orbit Node Precession = Solar Precession

bull Gyro rotational axis always oriented towards Sun

23

See Appendix for calculation

24

Orbit Initial Orbit

SS DawnDusk Orbit

Orbit Initial Orbit

Launch

bull Vandenberg AFB CA

bull Atlas V Launch Vehicle

bull Secondary Payload

bull Insertion into near Polar Orbit via Centaur Upper Stage

bull Further transfer necessary to achieve SS orbit

25

Orbit Blade Size

Maximum Solar Radiation Pressure Calculation

bull Assumptions

bull Perfectly reflecting surface

bull α = 0

(incident radiation perpendicular to surface)

26

Preflect2W

cR2cos2 = 908 Pa

where W = 1361 Wm2 c = 30x10 8 ms amp R = 100 AU

Orbit Blade Size

Minimum Solar Blade Surface Area for

Necessary Thrust

bull Assumptions

bull m = 8 kg (based on 8U Volume CubeSat 1 kgU)

27

a ac 01 mms2 requirement

sreflectc APmaFmax Asmac

Preflect8811 m2

bull 4 solar blades

As

42203 m2 per blade

Orbit Transfer

bull Example

bull LV delivers sc into 1100 km circular polar orbit

bull 1) Orbit raising maneuver to 1500 km

bull 2) Inclination change maneuver to i = 10196

bull How long will this take with GHOSTrsquos capabilities

28

29

Orbit Transfer

Orbit Raising Maneuver

Hohmann Transfer

Dual tangential

burn coplanar orbit

transfer

Initial Orbit

Final Orbit

Transfer Orbit

Orbit Transfer

Orbit Raising Maneuver

bull Calculated using Hohmann Transfer Equations

30

initial transfer vi 945 ms

transfer final v f 933 ms

vtotal 1877 ms

torbit raise 123 days

45o Preflect 454 Pa ain plane 177x10 5 ms2

Two blades pitched at

45

producing thrust in along track direction

See appendix for detailed orbit transfer diagrams

Orbit Transfer

Orbit Inclination Change

bull Calculated using inclination change only equations

31

v inc 2v initialcos( fpa)sini

2where vinitial v f fpa 0o amp i 1196o

vinc 148 kms i 00028 oorbit

a ac 01 mms2 P 6959 s Thrust acts over northern hemisphere of orbit (12 of Period)

tinc change 3437 days

Orbit Transfer

Final Destination

bull Δttotal = 4667 days or ~ 155 months bull time it takes to transfer from LV Delivery 1100 km polar orbit to 1500 km SS

orbit

bull this BOTE calculation has huge implications on both

bull mission duration

bull life span of sc components materials etc

bull Validates the high performance orbit transfer capabilities of the heliogyro architecture

32

Integration CubeSat

Pitch Test Validation

Sensor(s) to measure

torque and

Purpose Demonstrate coordinated pitching with equivalent mass and

realistic bus rotation

bull Rotation of 1 RPM

bull Measure torque on bus

bull Measure and compare actual pitching angles

to commanded

pitching angles

Sensors Needed

bull 3 axis Accelerometer (torque measurement)

bull 3 axis Gyroscope (pitch angle measurement)

bull 12 bit resolution (greater than pitching motors)

bull Fit onto or on 8U CubeSat

ADI516xxxIM4

bull 3 axis gyroscope

bull 3 axis magnetometer

bull 3 axis accelerometer

bull 14 bit resolution

bull 1

volume

bull Available free for checkout in ITLL

Sail Equivalent

mass

33

Integration CubeSat

Feasibility of our Baseline Design

bull To achieve characteristic acceleration for an 8U (8kg) CubeSat we needed each sail to be 2203

bull The diameter of the rolled spool inside the CubeSat (pre-deployment) varies with the width of the sail

bull To find the diameter of the rolled spool we calculated the length of one sail for a chosen width Assuming a Mylar thickness of 5 um due to the crinkling effect the spool width was calculated by iterating each rotation with increasing diameter as the blade rolls up

Iterate for rolling up sail until finished

(cm)

(m)

12 1836 247

10 2203 270

8 2754 300

34

Integration CubeSat

Sizing the Blades

bull CubeSat constrained by 20 cm on each side

bull Need to perform 180 degree independent rotation and maximize room inside the satellite for pitching motors controls and communication

Top Down Views of each size ( Scaled to correct dimensions)

12 cm blade width 10 cm blade width 8 cm blade width

bull Not intrusive on inner area

bull Full 180 motion

bull Infringes on space inside

bull Full 180 motion

bull Not intrusive on inner area

bull No Full 180 motion

35

Integration CubeSat

Housing the Rolled Sail

bull The solar sail blades will be controlled by a pitching axle but there must be an interface to connect to the axle

bull Cylindrical plate housing

bull Protects blades

bull Easy to connect to axle

bull No gears

bull Ability to provide counterweight

to deployment motor

bull With the tight volume constraints of our cube the Cylindrical plate must be altered to avoid interference with other sides

36

Integration CubeSat

Fitting the cylindrical Plate

bull Clearance for rolled sail

bull 2 cm clearance on each side

bull 06 cm clearance on behind the motor

bull This leaves overlapping corners

bull To prevent overlap we will make a 45ordm cut around the entire cylinder

2 cm

06 cm

Rolled Sail

Plate Encasing

Overlapping

Corners

45ordm cut to get rid

of corners

37

Integration CubeSat

Fitting the cylindrical Plate

bull The 45ordm cut will give us a 0 cm clearance (with no thickness)

bull If we implement a high-low offset between adjacent plates the distance between the two closest points increases

bull For our 14 cm diameter plates a 2 cm offset from the center for each plate (4 cm total) the effective clearance becomes 251 cm

Two adjacent sides

on same axis

With a High-Low Offset

38

Integration CubeSat

High-Low Offset Plates

The high low offset will give each plate room to rotate a full 180ordm

1 cm clearance between the top of the

blade and the edge of the satellite to fit

the thin-set bearing

A 3mm plate thickness gives adjacent

plates a distance of 19 cm between

their closest points

39

Integration CubeSat

High Low Offset Performance Validation

bull The high-low offset will not effect the performance or stability of the deployment or pitching systems

bull Upon deployment the opposing extension on each side cancels out unwanted torque

View From high side View From low side

bull In a sun-synchronous orbit the high or low setting has no effect as the rotational axis of the satellite is always solar pointing

View From Sun

40

Integration Power

Electronics Feasibility Analysis

bull Project Constraints

bull CubeSat power source Li-Ion batteries (5 and 33 V is common) - Would require thermal protection

bull Communications System - Transceiver (UHF is common) [USART serial port] - Buffer may be needed depending on power constraints

bull Deployment Subsystem - 1 step-motor [output] - 1 encoder [MSSP input] OR direct deployment measurement via external sensor

bull Pitching Subsystem - 2 servomotors [output]

41

Integration Power

PIC18F Series Microchip

bull Inputs 2 USART and 2 MSSP ports available (for basic PICs) - More than 1 device may be connected to each port - 2-3 devices needed

bull Outputs 8 ports - 2 devices needed

bull 16 bit - Though different PICs may be acquired for higher resolution

bull Operating Range 2-55 V - Within provided parameters

42

PIC

Communications

Deployment

Motor

Encoder

Pitching

Motor 1

Pitching

Motor 2 Key

Power Lines

Input Lines

Output Lines

Integration Power

Microchip FBD

5V Battery

Possible Voltage

Buffer

Encoder

43

Integration Power

Motor Power Limitations

bull Power Constraints

Pmax = 100 W

Vmax = 50 V

bull P = IV (Power = CurrentVoltage)

bull Therefore Iave = 20 Amps

bull Blade Pitching (4 motors total needed) - Current limitations for power sources and number of simultaneous blades pitching

Number of Blades 5 V Input 36 V input 31 V input 2 V input

4 040 A 069 A 081 A 125 A

2 080 A 139 A 161 A 250 A

1 160 A 278 A 323 A 500 A

44

Integration Motors

Stepper vs Brushless Servo Motors

45

-Contain many poles (50+) -Contain only 4-12 poles

-Distinct steps cause

vibration during use -Do not suffer from

vibration and resonance

issues smooth movement

-Low maintenance easier to

commission mechanically

simple

-Efficient response to start

stop and reverse commands

-Rely on encoders for

position details in closed

loop response

-Physical sizes

are comparable

-Both available

in various

lengths at same

frame size -Torque can be readily

controlled

-Low cost and high

availability

-Complexity drives cost

upward

Chosen for

deployment motor

Chosen for

pitching motor

Stepper Servo

Integration Blade Deployment

Deployment Motor Feasibility

Required holding torque is calculated to be 18 mNm

Required driving torque is calculated to be 117

10-5 mN∙m

bull Micro Motion Solutions ndash miniature stepper motors bull Physical Properties

bull Diameter = 6-22 mm

bull Length = 93-20 mm

bull Weight = 55-12 g

bull Holding Torque = 24-10 mN∙m = 034-142 oz∙in

bull Resolution bull 1 or 2 phase half-step capability

bull Steps per turn = 20-24 rarr 15˚-18˚ per step

5 of full step accuracy

bull Power Requirements bull Nominal voltage per phase 2-5 V

bull Nominal current per phase 01-1 A

46

Integration Blade Pitching

Blade Pitching Motor Feasibility

Required driving torque is calculated to be 0019 mN∙m

bull Mabuchi Servo Motor bull Physical Size

bull Diameter = 17 mm

bull Length = 25 mm

bull Weight = 16 g

bull Torque

bull Holding Torque = 161 mN∙m = 0228 oz∙in

bull Driving Torque = 0385 mN∙m = 0055 oz∙in

bull Friction Torque = 403

10-3 mN∙m = 571

10-4 oz∙in

bull Power Requirements

bull Nominal voltage per phase 2-5 V

bull Nominal current per phase 006-02 A 47

Integration Launch

Feasibility for Pre-deployment locking mechanism

The tip of the solar sail will be wider than the body with the sail tip set outside the plate

The tip will be held in place vertically by stationary blade stabilizers and kept tight by the holding torque of the deployment motor

Stationary blade

stabilizers

Extra-wide

blade tip

Upon deployment the motor

turns and the blade extends

48

Integration Launch

Canesterized Satellite Dispenser (CSD)

bull Ride in a 12 U CSD

bull Width=239 cm Height=226 cm Length=366 cm

bull Mass=0-24 kg at launch

bull Center of Mass when stowed in

bull x is -40 to 40 mm

bull y is 50 to 125 mm

bull z is 133 to 233 mm

wwwplanetarysytemscorpcom 49

Integration Launch

Test Validation

bull Launch Vibration Test

bull Needs to be space applicable and strong enough to withstand vibration

bull Ball Aerospace can provide a shake table costing $250hr

bull Preparation for Testing using FEM modeling and adding support features

50

Financial

bull Total Budget $5000

bull Components

bull Stepper Motor $100-200

bull Servo Motor (x2) $50-500 each

bull Materials (made in-house) $500-1000

bull Electronics $0-500

bull Testing

bull Deployment amp Pitching Free (Performed on Campus)

bull Launch Survivability Vibration Stand - $250hr Ball Space Systems in Boulder

bull Total Estimation $700-2700 + Vibration Stand Testing

51

Baseline Design All Together

bull The 8u CubeSat and characteristic acceleration requirements create very strict volumetric restrictions

bull The size of the plates and the rolled sail blade must be validated

bull This design will be analyzed and verified in the feasibility requirements

Inner Control Area

bull Motor

bull Encoder

bull Control

bull Communication

bull Power

Possible Load-bearing

corners for deployment

Housed Solar Sail

Top-Down View

Extra room for third

party systems

52

Status Summary

53

SystemMechanism Final Choice Further

Studies

Needed

8U Structure Fit our CubeSat in 12U bus provided by Planetary Services Yes

Adequate Area of Sails to Provide

Orbit Transfer Capabilities

AR = 22001 No

Pitching Mechanism Using a servo motor Yes

Pitching Accuracy Pitching encoder Yes

Plate Integration System Using a two cylinder design with tapered edges so

everything will fit

No

Deployment Motor Using a stepper motor No

Launch Ability Must conform to standards set by Planetary Services Yes

Launch Survivability Verify that GHOST will survive launch Yes

Initial Spin-Up Carbon steel attached to solar blade material Yes 53

Strategy for Conducting

Remaining Studies

bull 8U GHOST inside 12U structure bull Create a SolidWorksCAD model

bull Pitching Mechanism bull Determine adequate motor within size power and cost constraints

bull Pitching Accuracy bull Determine pitching accuracy based on orbital sensitivity

bull Launch Ability bull Because design is symmetrical center of mass is in the center of the satellite during launch bull Further investigations is needed to determine how many counterweights

bull Launch Survivability bull FEM or Vibrations

bull Initial Spin-up bull Determine feasible method to attach carbon steel support structure to solar sail blade material

54

Resources

bull PAYLOAD SPECIFICATION FOR 3U 6U 12U AND 27U Np Planetary Systems Corporation 2013 Print

bull Davis Jason The Planetary Society The Planetary Society Blog Firefly Partners 11 Apr 2012 Web 12 Oct 2013 lthttpwwwplanetaryorgblogsguest-blogsjason-davis3450htmlgt

bull Mao Tengfei 01mm Thickness Measuring Tape Wwwalibabacom Alibabacom nd Web 12 Oct 2013 lthttpwwwalibabacomproduct-gs8359006940_1mm_thickness_measuring_tapehtmlgt

55

Resources

bull ldquoHow servos and steppers stack uprdquo Machine Design 9 February 2012 [httpmachinedesigncomnewshow-servos-and-steppers-stack Accessed 7 October 2013]

bull ldquoMiniature Stepper Motor Drive Systems - Data Sheetrdquo Micro Motion Solutions [httpwwwmicromocomstepper-motors-datasheetsaspx Accessed 11 October 2013]

bull ldquoData Sheet for TS-53 Servorsquos Electric Motorrdquo Mabuchi Motor [httpwwwprincetonedu~mae412TEXTNTRAK2002292-302pdf Accessed 11 October 2013]

56

Blade Deployment Space Model

Initial Spin Up

bull

=435

bull α=

bull Time = 24 days

bull Release the rest of sail and centrifugal tension will aid in deployment of sail

bull Solar sail thrust should keep CubeSat at 1 RPM while deploying

CubeSat

∆ω = Ω = 1 RPM

τ = L

F = Iα

L = 057 m

F = 023 μN

22

Orbit Initial Orbit

Final Orbit Selection

bull Sun-Synchronous 1500 km DawnDusk Orbit

bull Assumptions

bull Circular Orbit (e = 0 a = p)

bull No atmospheric drag above 1100 km altitude

bull Only orbital perturbation considered in orbit determination is the oblateness of the earth (second zonal constant J2)

bull All other orbital perturbations are neglected

bull For SS Orbit Node Precession = Solar Precession

bull Gyro rotational axis always oriented towards Sun

23

See Appendix for calculation

24

Orbit Initial Orbit

SS DawnDusk Orbit

Orbit Initial Orbit

Launch

bull Vandenberg AFB CA

bull Atlas V Launch Vehicle

bull Secondary Payload

bull Insertion into near Polar Orbit via Centaur Upper Stage

bull Further transfer necessary to achieve SS orbit

25

Orbit Blade Size

Maximum Solar Radiation Pressure Calculation

bull Assumptions

bull Perfectly reflecting surface

bull α = 0

(incident radiation perpendicular to surface)

26

Preflect2W

cR2cos2 = 908 Pa

where W = 1361 Wm2 c = 30x10 8 ms amp R = 100 AU

Orbit Blade Size

Minimum Solar Blade Surface Area for

Necessary Thrust

bull Assumptions

bull m = 8 kg (based on 8U Volume CubeSat 1 kgU)

27

a ac 01 mms2 requirement

sreflectc APmaFmax Asmac

Preflect8811 m2

bull 4 solar blades

As

42203 m2 per blade

Orbit Transfer

bull Example

bull LV delivers sc into 1100 km circular polar orbit

bull 1) Orbit raising maneuver to 1500 km

bull 2) Inclination change maneuver to i = 10196

bull How long will this take with GHOSTrsquos capabilities

28

29

Orbit Transfer

Orbit Raising Maneuver

Hohmann Transfer

Dual tangential

burn coplanar orbit

transfer

Initial Orbit

Final Orbit

Transfer Orbit

Orbit Transfer

Orbit Raising Maneuver

bull Calculated using Hohmann Transfer Equations

30

initial transfer vi 945 ms

transfer final v f 933 ms

vtotal 1877 ms

torbit raise 123 days

45o Preflect 454 Pa ain plane 177x10 5 ms2

Two blades pitched at

45

producing thrust in along track direction

See appendix for detailed orbit transfer diagrams

Orbit Transfer

Orbit Inclination Change

bull Calculated using inclination change only equations

31

v inc 2v initialcos( fpa)sini

2where vinitial v f fpa 0o amp i 1196o

vinc 148 kms i 00028 oorbit

a ac 01 mms2 P 6959 s Thrust acts over northern hemisphere of orbit (12 of Period)

tinc change 3437 days

Orbit Transfer

Final Destination

bull Δttotal = 4667 days or ~ 155 months bull time it takes to transfer from LV Delivery 1100 km polar orbit to 1500 km SS

orbit

bull this BOTE calculation has huge implications on both

bull mission duration

bull life span of sc components materials etc

bull Validates the high performance orbit transfer capabilities of the heliogyro architecture

32

Integration CubeSat

Pitch Test Validation

Sensor(s) to measure

torque and

Purpose Demonstrate coordinated pitching with equivalent mass and

realistic bus rotation

bull Rotation of 1 RPM

bull Measure torque on bus

bull Measure and compare actual pitching angles

to commanded

pitching angles

Sensors Needed

bull 3 axis Accelerometer (torque measurement)

bull 3 axis Gyroscope (pitch angle measurement)

bull 12 bit resolution (greater than pitching motors)

bull Fit onto or on 8U CubeSat

ADI516xxxIM4

bull 3 axis gyroscope

bull 3 axis magnetometer

bull 3 axis accelerometer

bull 14 bit resolution

bull 1

volume

bull Available free for checkout in ITLL

Sail Equivalent

mass

33

Integration CubeSat

Feasibility of our Baseline Design

bull To achieve characteristic acceleration for an 8U (8kg) CubeSat we needed each sail to be 2203

bull The diameter of the rolled spool inside the CubeSat (pre-deployment) varies with the width of the sail

bull To find the diameter of the rolled spool we calculated the length of one sail for a chosen width Assuming a Mylar thickness of 5 um due to the crinkling effect the spool width was calculated by iterating each rotation with increasing diameter as the blade rolls up

Iterate for rolling up sail until finished

(cm)

(m)

12 1836 247

10 2203 270

8 2754 300

34

Integration CubeSat

Sizing the Blades

bull CubeSat constrained by 20 cm on each side

bull Need to perform 180 degree independent rotation and maximize room inside the satellite for pitching motors controls and communication

Top Down Views of each size ( Scaled to correct dimensions)

12 cm blade width 10 cm blade width 8 cm blade width

bull Not intrusive on inner area

bull Full 180 motion

bull Infringes on space inside

bull Full 180 motion

bull Not intrusive on inner area

bull No Full 180 motion

35

Integration CubeSat

Housing the Rolled Sail

bull The solar sail blades will be controlled by a pitching axle but there must be an interface to connect to the axle

bull Cylindrical plate housing

bull Protects blades

bull Easy to connect to axle

bull No gears

bull Ability to provide counterweight

to deployment motor

bull With the tight volume constraints of our cube the Cylindrical plate must be altered to avoid interference with other sides

36

Integration CubeSat

Fitting the cylindrical Plate

bull Clearance for rolled sail

bull 2 cm clearance on each side

bull 06 cm clearance on behind the motor

bull This leaves overlapping corners

bull To prevent overlap we will make a 45ordm cut around the entire cylinder

2 cm

06 cm

Rolled Sail

Plate Encasing

Overlapping

Corners

45ordm cut to get rid

of corners

37

Integration CubeSat

Fitting the cylindrical Plate

bull The 45ordm cut will give us a 0 cm clearance (with no thickness)

bull If we implement a high-low offset between adjacent plates the distance between the two closest points increases

bull For our 14 cm diameter plates a 2 cm offset from the center for each plate (4 cm total) the effective clearance becomes 251 cm

Two adjacent sides

on same axis

With a High-Low Offset

38

Integration CubeSat

High-Low Offset Plates

The high low offset will give each plate room to rotate a full 180ordm

1 cm clearance between the top of the

blade and the edge of the satellite to fit

the thin-set bearing

A 3mm plate thickness gives adjacent

plates a distance of 19 cm between

their closest points

39

Integration CubeSat

High Low Offset Performance Validation

bull The high-low offset will not effect the performance or stability of the deployment or pitching systems

bull Upon deployment the opposing extension on each side cancels out unwanted torque

View From high side View From low side

bull In a sun-synchronous orbit the high or low setting has no effect as the rotational axis of the satellite is always solar pointing

View From Sun

40

Integration Power

Electronics Feasibility Analysis

bull Project Constraints

bull CubeSat power source Li-Ion batteries (5 and 33 V is common) - Would require thermal protection

bull Communications System - Transceiver (UHF is common) [USART serial port] - Buffer may be needed depending on power constraints

bull Deployment Subsystem - 1 step-motor [output] - 1 encoder [MSSP input] OR direct deployment measurement via external sensor

bull Pitching Subsystem - 2 servomotors [output]

41

Integration Power

PIC18F Series Microchip

bull Inputs 2 USART and 2 MSSP ports available (for basic PICs) - More than 1 device may be connected to each port - 2-3 devices needed

bull Outputs 8 ports - 2 devices needed

bull 16 bit - Though different PICs may be acquired for higher resolution

bull Operating Range 2-55 V - Within provided parameters

42

PIC

Communications

Deployment

Motor

Encoder

Pitching

Motor 1

Pitching

Motor 2 Key

Power Lines

Input Lines

Output Lines

Integration Power

Microchip FBD

5V Battery

Possible Voltage

Buffer

Encoder

43

Integration Power

Motor Power Limitations

bull Power Constraints

Pmax = 100 W

Vmax = 50 V

bull P = IV (Power = CurrentVoltage)

bull Therefore Iave = 20 Amps

bull Blade Pitching (4 motors total needed) - Current limitations for power sources and number of simultaneous blades pitching

Number of Blades 5 V Input 36 V input 31 V input 2 V input

4 040 A 069 A 081 A 125 A

2 080 A 139 A 161 A 250 A

1 160 A 278 A 323 A 500 A

44

Integration Motors

Stepper vs Brushless Servo Motors

45

-Contain many poles (50+) -Contain only 4-12 poles

-Distinct steps cause

vibration during use -Do not suffer from

vibration and resonance

issues smooth movement

-Low maintenance easier to

commission mechanically

simple

-Efficient response to start

stop and reverse commands

-Rely on encoders for

position details in closed

loop response

-Physical sizes

are comparable

-Both available

in various

lengths at same

frame size -Torque can be readily

controlled

-Low cost and high

availability

-Complexity drives cost

upward

Chosen for

deployment motor

Chosen for

pitching motor

Stepper Servo

Integration Blade Deployment

Deployment Motor Feasibility

Required holding torque is calculated to be 18 mNm

Required driving torque is calculated to be 117

10-5 mN∙m

bull Micro Motion Solutions ndash miniature stepper motors bull Physical Properties

bull Diameter = 6-22 mm

bull Length = 93-20 mm

bull Weight = 55-12 g

bull Holding Torque = 24-10 mN∙m = 034-142 oz∙in

bull Resolution bull 1 or 2 phase half-step capability

bull Steps per turn = 20-24 rarr 15˚-18˚ per step

5 of full step accuracy

bull Power Requirements bull Nominal voltage per phase 2-5 V

bull Nominal current per phase 01-1 A

46

Integration Blade Pitching

Blade Pitching Motor Feasibility

Required driving torque is calculated to be 0019 mN∙m

bull Mabuchi Servo Motor bull Physical Size

bull Diameter = 17 mm

bull Length = 25 mm

bull Weight = 16 g

bull Torque

bull Holding Torque = 161 mN∙m = 0228 oz∙in

bull Driving Torque = 0385 mN∙m = 0055 oz∙in

bull Friction Torque = 403

10-3 mN∙m = 571

10-4 oz∙in

bull Power Requirements

bull Nominal voltage per phase 2-5 V

bull Nominal current per phase 006-02 A 47

Integration Launch

Feasibility for Pre-deployment locking mechanism

The tip of the solar sail will be wider than the body with the sail tip set outside the plate

The tip will be held in place vertically by stationary blade stabilizers and kept tight by the holding torque of the deployment motor

Stationary blade

stabilizers

Extra-wide

blade tip

Upon deployment the motor

turns and the blade extends

48

Integration Launch

Canesterized Satellite Dispenser (CSD)

bull Ride in a 12 U CSD

bull Width=239 cm Height=226 cm Length=366 cm

bull Mass=0-24 kg at launch

bull Center of Mass when stowed in

bull x is -40 to 40 mm

bull y is 50 to 125 mm

bull z is 133 to 233 mm

wwwplanetarysytemscorpcom 49

Integration Launch

Test Validation

bull Launch Vibration Test

bull Needs to be space applicable and strong enough to withstand vibration

bull Ball Aerospace can provide a shake table costing $250hr

bull Preparation for Testing using FEM modeling and adding support features

50

Financial

bull Total Budget $5000

bull Components

bull Stepper Motor $100-200

bull Servo Motor (x2) $50-500 each

bull Materials (made in-house) $500-1000

bull Electronics $0-500

bull Testing

bull Deployment amp Pitching Free (Performed on Campus)

bull Launch Survivability Vibration Stand - $250hr Ball Space Systems in Boulder

bull Total Estimation $700-2700 + Vibration Stand Testing

51

Baseline Design All Together

bull The 8u CubeSat and characteristic acceleration requirements create very strict volumetric restrictions

bull The size of the plates and the rolled sail blade must be validated

bull This design will be analyzed and verified in the feasibility requirements

Inner Control Area

bull Motor

bull Encoder

bull Control

bull Communication

bull Power

Possible Load-bearing

corners for deployment

Housed Solar Sail

Top-Down View

Extra room for third

party systems

52

Status Summary

53

SystemMechanism Final Choice Further

Studies

Needed

8U Structure Fit our CubeSat in 12U bus provided by Planetary Services Yes

Adequate Area of Sails to Provide

Orbit Transfer Capabilities

AR = 22001 No

Pitching Mechanism Using a servo motor Yes

Pitching Accuracy Pitching encoder Yes

Plate Integration System Using a two cylinder design with tapered edges so

everything will fit

No

Deployment Motor Using a stepper motor No

Launch Ability Must conform to standards set by Planetary Services Yes

Launch Survivability Verify that GHOST will survive launch Yes

Initial Spin-Up Carbon steel attached to solar blade material Yes 53

Strategy for Conducting

Remaining Studies

bull 8U GHOST inside 12U structure bull Create a SolidWorksCAD model

bull Pitching Mechanism bull Determine adequate motor within size power and cost constraints

bull Pitching Accuracy bull Determine pitching accuracy based on orbital sensitivity

bull Launch Ability bull Because design is symmetrical center of mass is in the center of the satellite during launch bull Further investigations is needed to determine how many counterweights

bull Launch Survivability bull FEM or Vibrations

bull Initial Spin-up bull Determine feasible method to attach carbon steel support structure to solar sail blade material

54

Resources

bull PAYLOAD SPECIFICATION FOR 3U 6U 12U AND 27U Np Planetary Systems Corporation 2013 Print

bull Davis Jason The Planetary Society The Planetary Society Blog Firefly Partners 11 Apr 2012 Web 12 Oct 2013 lthttpwwwplanetaryorgblogsguest-blogsjason-davis3450htmlgt

bull Mao Tengfei 01mm Thickness Measuring Tape Wwwalibabacom Alibabacom nd Web 12 Oct 2013 lthttpwwwalibabacomproduct-gs8359006940_1mm_thickness_measuring_tapehtmlgt

55

Resources

bull ldquoHow servos and steppers stack uprdquo Machine Design 9 February 2012 [httpmachinedesigncomnewshow-servos-and-steppers-stack Accessed 7 October 2013]

bull ldquoMiniature Stepper Motor Drive Systems - Data Sheetrdquo Micro Motion Solutions [httpwwwmicromocomstepper-motors-datasheetsaspx Accessed 11 October 2013]

bull ldquoData Sheet for TS-53 Servorsquos Electric Motorrdquo Mabuchi Motor [httpwwwprincetonedu~mae412TEXTNTRAK2002292-302pdf Accessed 11 October 2013]

56

Orbit Initial Orbit

Final Orbit Selection

bull Sun-Synchronous 1500 km DawnDusk Orbit

bull Assumptions

bull Circular Orbit (e = 0 a = p)

bull No atmospheric drag above 1100 km altitude

bull Only orbital perturbation considered in orbit determination is the oblateness of the earth (second zonal constant J2)

bull All other orbital perturbations are neglected

bull For SS Orbit Node Precession = Solar Precession

bull Gyro rotational axis always oriented towards Sun

23

See Appendix for calculation

24

Orbit Initial Orbit

SS DawnDusk Orbit

Orbit Initial Orbit

Launch

bull Vandenberg AFB CA

bull Atlas V Launch Vehicle

bull Secondary Payload

bull Insertion into near Polar Orbit via Centaur Upper Stage

bull Further transfer necessary to achieve SS orbit

25

Orbit Blade Size

Maximum Solar Radiation Pressure Calculation

bull Assumptions

bull Perfectly reflecting surface

bull α = 0

(incident radiation perpendicular to surface)

26

Preflect2W

cR2cos2 = 908 Pa

where W = 1361 Wm2 c = 30x10 8 ms amp R = 100 AU

Orbit Blade Size

Minimum Solar Blade Surface Area for

Necessary Thrust

bull Assumptions

bull m = 8 kg (based on 8U Volume CubeSat 1 kgU)

27

a ac 01 mms2 requirement

sreflectc APmaFmax Asmac

Preflect8811 m2

bull 4 solar blades

As

42203 m2 per blade

Orbit Transfer

bull Example

bull LV delivers sc into 1100 km circular polar orbit

bull 1) Orbit raising maneuver to 1500 km

bull 2) Inclination change maneuver to i = 10196

bull How long will this take with GHOSTrsquos capabilities

28

29

Orbit Transfer

Orbit Raising Maneuver

Hohmann Transfer

Dual tangential

burn coplanar orbit

transfer

Initial Orbit

Final Orbit

Transfer Orbit

Orbit Transfer

Orbit Raising Maneuver

bull Calculated using Hohmann Transfer Equations

30

initial transfer vi 945 ms

transfer final v f 933 ms

vtotal 1877 ms

torbit raise 123 days

45o Preflect 454 Pa ain plane 177x10 5 ms2

Two blades pitched at

45

producing thrust in along track direction

See appendix for detailed orbit transfer diagrams

Orbit Transfer

Orbit Inclination Change

bull Calculated using inclination change only equations

31

v inc 2v initialcos( fpa)sini

2where vinitial v f fpa 0o amp i 1196o

vinc 148 kms i 00028 oorbit

a ac 01 mms2 P 6959 s Thrust acts over northern hemisphere of orbit (12 of Period)

tinc change 3437 days

Orbit Transfer

Final Destination

bull Δttotal = 4667 days or ~ 155 months bull time it takes to transfer from LV Delivery 1100 km polar orbit to 1500 km SS

orbit

bull this BOTE calculation has huge implications on both

bull mission duration

bull life span of sc components materials etc

bull Validates the high performance orbit transfer capabilities of the heliogyro architecture

32

Integration CubeSat

Pitch Test Validation

Sensor(s) to measure

torque and

Purpose Demonstrate coordinated pitching with equivalent mass and

realistic bus rotation

bull Rotation of 1 RPM

bull Measure torque on bus

bull Measure and compare actual pitching angles

to commanded

pitching angles

Sensors Needed

bull 3 axis Accelerometer (torque measurement)

bull 3 axis Gyroscope (pitch angle measurement)

bull 12 bit resolution (greater than pitching motors)

bull Fit onto or on 8U CubeSat

ADI516xxxIM4

bull 3 axis gyroscope

bull 3 axis magnetometer

bull 3 axis accelerometer

bull 14 bit resolution

bull 1

volume

bull Available free for checkout in ITLL

Sail Equivalent

mass

33

Integration CubeSat

Feasibility of our Baseline Design

bull To achieve characteristic acceleration for an 8U (8kg) CubeSat we needed each sail to be 2203

bull The diameter of the rolled spool inside the CubeSat (pre-deployment) varies with the width of the sail

bull To find the diameter of the rolled spool we calculated the length of one sail for a chosen width Assuming a Mylar thickness of 5 um due to the crinkling effect the spool width was calculated by iterating each rotation with increasing diameter as the blade rolls up

Iterate for rolling up sail until finished

(cm)

(m)

12 1836 247

10 2203 270

8 2754 300

34

Integration CubeSat

Sizing the Blades

bull CubeSat constrained by 20 cm on each side

bull Need to perform 180 degree independent rotation and maximize room inside the satellite for pitching motors controls and communication

Top Down Views of each size ( Scaled to correct dimensions)

12 cm blade width 10 cm blade width 8 cm blade width

bull Not intrusive on inner area

bull Full 180 motion

bull Infringes on space inside

bull Full 180 motion

bull Not intrusive on inner area

bull No Full 180 motion

35

Integration CubeSat

Housing the Rolled Sail

bull The solar sail blades will be controlled by a pitching axle but there must be an interface to connect to the axle

bull Cylindrical plate housing

bull Protects blades

bull Easy to connect to axle

bull No gears

bull Ability to provide counterweight

to deployment motor

bull With the tight volume constraints of our cube the Cylindrical plate must be altered to avoid interference with other sides

36

Integration CubeSat

Fitting the cylindrical Plate

bull Clearance for rolled sail

bull 2 cm clearance on each side

bull 06 cm clearance on behind the motor

bull This leaves overlapping corners

bull To prevent overlap we will make a 45ordm cut around the entire cylinder

2 cm

06 cm

Rolled Sail

Plate Encasing

Overlapping

Corners

45ordm cut to get rid

of corners

37

Integration CubeSat

Fitting the cylindrical Plate

bull The 45ordm cut will give us a 0 cm clearance (with no thickness)

bull If we implement a high-low offset between adjacent plates the distance between the two closest points increases

bull For our 14 cm diameter plates a 2 cm offset from the center for each plate (4 cm total) the effective clearance becomes 251 cm

Two adjacent sides

on same axis

With a High-Low Offset

38

Integration CubeSat

High-Low Offset Plates

The high low offset will give each plate room to rotate a full 180ordm

1 cm clearance between the top of the

blade and the edge of the satellite to fit

the thin-set bearing

A 3mm plate thickness gives adjacent

plates a distance of 19 cm between

their closest points

39

Integration CubeSat

High Low Offset Performance Validation

bull The high-low offset will not effect the performance or stability of the deployment or pitching systems

bull Upon deployment the opposing extension on each side cancels out unwanted torque

View From high side View From low side

bull In a sun-synchronous orbit the high or low setting has no effect as the rotational axis of the satellite is always solar pointing

View From Sun

40

Integration Power

Electronics Feasibility Analysis

bull Project Constraints

bull CubeSat power source Li-Ion batteries (5 and 33 V is common) - Would require thermal protection

bull Communications System - Transceiver (UHF is common) [USART serial port] - Buffer may be needed depending on power constraints

bull Deployment Subsystem - 1 step-motor [output] - 1 encoder [MSSP input] OR direct deployment measurement via external sensor

bull Pitching Subsystem - 2 servomotors [output]

41

Integration Power

PIC18F Series Microchip

bull Inputs 2 USART and 2 MSSP ports available (for basic PICs) - More than 1 device may be connected to each port - 2-3 devices needed

bull Outputs 8 ports - 2 devices needed

bull 16 bit - Though different PICs may be acquired for higher resolution

bull Operating Range 2-55 V - Within provided parameters

42

PIC

Communications

Deployment

Motor

Encoder

Pitching

Motor 1

Pitching

Motor 2 Key

Power Lines

Input Lines

Output Lines

Integration Power

Microchip FBD

5V Battery

Possible Voltage

Buffer

Encoder

43

Integration Power

Motor Power Limitations

bull Power Constraints

Pmax = 100 W

Vmax = 50 V

bull P = IV (Power = CurrentVoltage)

bull Therefore Iave = 20 Amps

bull Blade Pitching (4 motors total needed) - Current limitations for power sources and number of simultaneous blades pitching

Number of Blades 5 V Input 36 V input 31 V input 2 V input

4 040 A 069 A 081 A 125 A

2 080 A 139 A 161 A 250 A

1 160 A 278 A 323 A 500 A

44

Integration Motors

Stepper vs Brushless Servo Motors

45

-Contain many poles (50+) -Contain only 4-12 poles

-Distinct steps cause

vibration during use -Do not suffer from

vibration and resonance

issues smooth movement

-Low maintenance easier to

commission mechanically

simple

-Efficient response to start

stop and reverse commands

-Rely on encoders for

position details in closed

loop response

-Physical sizes

are comparable

-Both available

in various

lengths at same

frame size -Torque can be readily

controlled

-Low cost and high

availability

-Complexity drives cost

upward

Chosen for

deployment motor

Chosen for

pitching motor

Stepper Servo

Integration Blade Deployment

Deployment Motor Feasibility

Required holding torque is calculated to be 18 mNm

Required driving torque is calculated to be 117

10-5 mN∙m

bull Micro Motion Solutions ndash miniature stepper motors bull Physical Properties

bull Diameter = 6-22 mm

bull Length = 93-20 mm

bull Weight = 55-12 g

bull Holding Torque = 24-10 mN∙m = 034-142 oz∙in

bull Resolution bull 1 or 2 phase half-step capability

bull Steps per turn = 20-24 rarr 15˚-18˚ per step

5 of full step accuracy

bull Power Requirements bull Nominal voltage per phase 2-5 V

bull Nominal current per phase 01-1 A

46

Integration Blade Pitching

Blade Pitching Motor Feasibility

Required driving torque is calculated to be 0019 mN∙m

bull Mabuchi Servo Motor bull Physical Size

bull Diameter = 17 mm

bull Length = 25 mm

bull Weight = 16 g

bull Torque

bull Holding Torque = 161 mN∙m = 0228 oz∙in

bull Driving Torque = 0385 mN∙m = 0055 oz∙in

bull Friction Torque = 403

10-3 mN∙m = 571

10-4 oz∙in

bull Power Requirements

bull Nominal voltage per phase 2-5 V

bull Nominal current per phase 006-02 A 47

Integration Launch

Feasibility for Pre-deployment locking mechanism

The tip of the solar sail will be wider than the body with the sail tip set outside the plate

The tip will be held in place vertically by stationary blade stabilizers and kept tight by the holding torque of the deployment motor

Stationary blade

stabilizers

Extra-wide

blade tip

Upon deployment the motor

turns and the blade extends

48

Integration Launch

Canesterized Satellite Dispenser (CSD)

bull Ride in a 12 U CSD

bull Width=239 cm Height=226 cm Length=366 cm

bull Mass=0-24 kg at launch

bull Center of Mass when stowed in

bull x is -40 to 40 mm

bull y is 50 to 125 mm

bull z is 133 to 233 mm

wwwplanetarysytemscorpcom 49

Integration Launch

Test Validation

bull Launch Vibration Test

bull Needs to be space applicable and strong enough to withstand vibration

bull Ball Aerospace can provide a shake table costing $250hr

bull Preparation for Testing using FEM modeling and adding support features

50

Financial

bull Total Budget $5000

bull Components

bull Stepper Motor $100-200

bull Servo Motor (x2) $50-500 each

bull Materials (made in-house) $500-1000

bull Electronics $0-500

bull Testing

bull Deployment amp Pitching Free (Performed on Campus)

bull Launch Survivability Vibration Stand - $250hr Ball Space Systems in Boulder

bull Total Estimation $700-2700 + Vibration Stand Testing

51

Baseline Design All Together

bull The 8u CubeSat and characteristic acceleration requirements create very strict volumetric restrictions

bull The size of the plates and the rolled sail blade must be validated

bull This design will be analyzed and verified in the feasibility requirements

Inner Control Area

bull Motor

bull Encoder

bull Control

bull Communication

bull Power

Possible Load-bearing

corners for deployment

Housed Solar Sail

Top-Down View

Extra room for third

party systems

52

Status Summary

53

SystemMechanism Final Choice Further

Studies

Needed

8U Structure Fit our CubeSat in 12U bus provided by Planetary Services Yes

Adequate Area of Sails to Provide

Orbit Transfer Capabilities

AR = 22001 No

Pitching Mechanism Using a servo motor Yes

Pitching Accuracy Pitching encoder Yes

Plate Integration System Using a two cylinder design with tapered edges so

everything will fit

No

Deployment Motor Using a stepper motor No

Launch Ability Must conform to standards set by Planetary Services Yes

Launch Survivability Verify that GHOST will survive launch Yes

Initial Spin-Up Carbon steel attached to solar blade material Yes 53

Strategy for Conducting

Remaining Studies

bull 8U GHOST inside 12U structure bull Create a SolidWorksCAD model

bull Pitching Mechanism bull Determine adequate motor within size power and cost constraints

bull Pitching Accuracy bull Determine pitching accuracy based on orbital sensitivity

bull Launch Ability bull Because design is symmetrical center of mass is in the center of the satellite during launch bull Further investigations is needed to determine how many counterweights

bull Launch Survivability bull FEM or Vibrations

bull Initial Spin-up bull Determine feasible method to attach carbon steel support structure to solar sail blade material

54

Resources

bull PAYLOAD SPECIFICATION FOR 3U 6U 12U AND 27U Np Planetary Systems Corporation 2013 Print

bull Davis Jason The Planetary Society The Planetary Society Blog Firefly Partners 11 Apr 2012 Web 12 Oct 2013 lthttpwwwplanetaryorgblogsguest-blogsjason-davis3450htmlgt

bull Mao Tengfei 01mm Thickness Measuring Tape Wwwalibabacom Alibabacom nd Web 12 Oct 2013 lthttpwwwalibabacomproduct-gs8359006940_1mm_thickness_measuring_tapehtmlgt

55

Resources

bull ldquoHow servos and steppers stack uprdquo Machine Design 9 February 2012 [httpmachinedesigncomnewshow-servos-and-steppers-stack Accessed 7 October 2013]

bull ldquoMiniature Stepper Motor Drive Systems - Data Sheetrdquo Micro Motion Solutions [httpwwwmicromocomstepper-motors-datasheetsaspx Accessed 11 October 2013]

bull ldquoData Sheet for TS-53 Servorsquos Electric Motorrdquo Mabuchi Motor [httpwwwprincetonedu~mae412TEXTNTRAK2002292-302pdf Accessed 11 October 2013]

56

24

Orbit Initial Orbit

SS DawnDusk Orbit

Orbit Initial Orbit

Launch

bull Vandenberg AFB CA

bull Atlas V Launch Vehicle

bull Secondary Payload

bull Insertion into near Polar Orbit via Centaur Upper Stage

bull Further transfer necessary to achieve SS orbit

25

Orbit Blade Size

Maximum Solar Radiation Pressure Calculation

bull Assumptions

bull Perfectly reflecting surface

bull α = 0

(incident radiation perpendicular to surface)

26

Preflect2W

cR2cos2 = 908 Pa

where W = 1361 Wm2 c = 30x10 8 ms amp R = 100 AU

Orbit Blade Size

Minimum Solar Blade Surface Area for

Necessary Thrust

bull Assumptions

bull m = 8 kg (based on 8U Volume CubeSat 1 kgU)

27

a ac 01 mms2 requirement

sreflectc APmaFmax Asmac

Preflect8811 m2

bull 4 solar blades

As

42203 m2 per blade

Orbit Transfer

bull Example

bull LV delivers sc into 1100 km circular polar orbit

bull 1) Orbit raising maneuver to 1500 km

bull 2) Inclination change maneuver to i = 10196

bull How long will this take with GHOSTrsquos capabilities

28

29

Orbit Transfer

Orbit Raising Maneuver

Hohmann Transfer

Dual tangential

burn coplanar orbit

transfer

Initial Orbit

Final Orbit

Transfer Orbit

Orbit Transfer

Orbit Raising Maneuver

bull Calculated using Hohmann Transfer Equations

30

initial transfer vi 945 ms

transfer final v f 933 ms

vtotal 1877 ms

torbit raise 123 days

45o Preflect 454 Pa ain plane 177x10 5 ms2

Two blades pitched at

45

producing thrust in along track direction

See appendix for detailed orbit transfer diagrams

Orbit Transfer

Orbit Inclination Change

bull Calculated using inclination change only equations

31

v inc 2v initialcos( fpa)sini

2where vinitial v f fpa 0o amp i 1196o

vinc 148 kms i 00028 oorbit

a ac 01 mms2 P 6959 s Thrust acts over northern hemisphere of orbit (12 of Period)

tinc change 3437 days

Orbit Transfer

Final Destination

bull Δttotal = 4667 days or ~ 155 months bull time it takes to transfer from LV Delivery 1100 km polar orbit to 1500 km SS

orbit

bull this BOTE calculation has huge implications on both

bull mission duration

bull life span of sc components materials etc

bull Validates the high performance orbit transfer capabilities of the heliogyro architecture

32

Integration CubeSat

Pitch Test Validation

Sensor(s) to measure

torque and

Purpose Demonstrate coordinated pitching with equivalent mass and

realistic bus rotation

bull Rotation of 1 RPM

bull Measure torque on bus

bull Measure and compare actual pitching angles

to commanded

pitching angles

Sensors Needed

bull 3 axis Accelerometer (torque measurement)

bull 3 axis Gyroscope (pitch angle measurement)

bull 12 bit resolution (greater than pitching motors)

bull Fit onto or on 8U CubeSat

ADI516xxxIM4

bull 3 axis gyroscope

bull 3 axis magnetometer

bull 3 axis accelerometer

bull 14 bit resolution

bull 1

volume

bull Available free for checkout in ITLL

Sail Equivalent

mass

33

Integration CubeSat

Feasibility of our Baseline Design

bull To achieve characteristic acceleration for an 8U (8kg) CubeSat we needed each sail to be 2203

bull The diameter of the rolled spool inside the CubeSat (pre-deployment) varies with the width of the sail

bull To find the diameter of the rolled spool we calculated the length of one sail for a chosen width Assuming a Mylar thickness of 5 um due to the crinkling effect the spool width was calculated by iterating each rotation with increasing diameter as the blade rolls up

Iterate for rolling up sail until finished

(cm)

(m)

12 1836 247

10 2203 270

8 2754 300

34

Integration CubeSat

Sizing the Blades

bull CubeSat constrained by 20 cm on each side

bull Need to perform 180 degree independent rotation and maximize room inside the satellite for pitching motors controls and communication

Top Down Views of each size ( Scaled to correct dimensions)

12 cm blade width 10 cm blade width 8 cm blade width

bull Not intrusive on inner area

bull Full 180 motion

bull Infringes on space inside

bull Full 180 motion

bull Not intrusive on inner area

bull No Full 180 motion

35

Integration CubeSat

Housing the Rolled Sail

bull The solar sail blades will be controlled by a pitching axle but there must be an interface to connect to the axle

bull Cylindrical plate housing

bull Protects blades

bull Easy to connect to axle

bull No gears

bull Ability to provide counterweight

to deployment motor

bull With the tight volume constraints of our cube the Cylindrical plate must be altered to avoid interference with other sides

36

Integration CubeSat

Fitting the cylindrical Plate

bull Clearance for rolled sail

bull 2 cm clearance on each side

bull 06 cm clearance on behind the motor

bull This leaves overlapping corners

bull To prevent overlap we will make a 45ordm cut around the entire cylinder

2 cm

06 cm

Rolled Sail

Plate Encasing

Overlapping

Corners

45ordm cut to get rid

of corners

37

Integration CubeSat

Fitting the cylindrical Plate

bull The 45ordm cut will give us a 0 cm clearance (with no thickness)

bull If we implement a high-low offset between adjacent plates the distance between the two closest points increases

bull For our 14 cm diameter plates a 2 cm offset from the center for each plate (4 cm total) the effective clearance becomes 251 cm

Two adjacent sides

on same axis

With a High-Low Offset

38

Integration CubeSat

High-Low Offset Plates

The high low offset will give each plate room to rotate a full 180ordm

1 cm clearance between the top of the

blade and the edge of the satellite to fit

the thin-set bearing

A 3mm plate thickness gives adjacent

plates a distance of 19 cm between

their closest points

39

Integration CubeSat

High Low Offset Performance Validation

bull The high-low offset will not effect the performance or stability of the deployment or pitching systems

bull Upon deployment the opposing extension on each side cancels out unwanted torque

View From high side View From low side

bull In a sun-synchronous orbit the high or low setting has no effect as the rotational axis of the satellite is always solar pointing

View From Sun

40

Integration Power

Electronics Feasibility Analysis

bull Project Constraints

bull CubeSat power source Li-Ion batteries (5 and 33 V is common) - Would require thermal protection

bull Communications System - Transceiver (UHF is common) [USART serial port] - Buffer may be needed depending on power constraints

bull Deployment Subsystem - 1 step-motor [output] - 1 encoder [MSSP input] OR direct deployment measurement via external sensor

bull Pitching Subsystem - 2 servomotors [output]

41

Integration Power

PIC18F Series Microchip

bull Inputs 2 USART and 2 MSSP ports available (for basic PICs) - More than 1 device may be connected to each port - 2-3 devices needed

bull Outputs 8 ports - 2 devices needed

bull 16 bit - Though different PICs may be acquired for higher resolution

bull Operating Range 2-55 V - Within provided parameters

42

PIC

Communications

Deployment

Motor

Encoder

Pitching

Motor 1

Pitching

Motor 2 Key

Power Lines

Input Lines

Output Lines

Integration Power

Microchip FBD

5V Battery

Possible Voltage

Buffer

Encoder

43

Integration Power

Motor Power Limitations

bull Power Constraints

Pmax = 100 W

Vmax = 50 V

bull P = IV (Power = CurrentVoltage)

bull Therefore Iave = 20 Amps

bull Blade Pitching (4 motors total needed) - Current limitations for power sources and number of simultaneous blades pitching

Number of Blades 5 V Input 36 V input 31 V input 2 V input

4 040 A 069 A 081 A 125 A

2 080 A 139 A 161 A 250 A

1 160 A 278 A 323 A 500 A

44

Integration Motors

Stepper vs Brushless Servo Motors

45

-Contain many poles (50+) -Contain only 4-12 poles

-Distinct steps cause

vibration during use -Do not suffer from

vibration and resonance

issues smooth movement

-Low maintenance easier to

commission mechanically

simple

-Efficient response to start

stop and reverse commands

-Rely on encoders for

position details in closed

loop response

-Physical sizes

are comparable

-Both available

in various

lengths at same

frame size -Torque can be readily

controlled

-Low cost and high

availability

-Complexity drives cost

upward

Chosen for

deployment motor

Chosen for

pitching motor

Stepper Servo

Integration Blade Deployment

Deployment Motor Feasibility

Required holding torque is calculated to be 18 mNm

Required driving torque is calculated to be 117

10-5 mN∙m

bull Micro Motion Solutions ndash miniature stepper motors bull Physical Properties

bull Diameter = 6-22 mm

bull Length = 93-20 mm

bull Weight = 55-12 g

bull Holding Torque = 24-10 mN∙m = 034-142 oz∙in

bull Resolution bull 1 or 2 phase half-step capability

bull Steps per turn = 20-24 rarr 15˚-18˚ per step

5 of full step accuracy

bull Power Requirements bull Nominal voltage per phase 2-5 V

bull Nominal current per phase 01-1 A

46

Integration Blade Pitching

Blade Pitching Motor Feasibility

Required driving torque is calculated to be 0019 mN∙m

bull Mabuchi Servo Motor bull Physical Size

bull Diameter = 17 mm

bull Length = 25 mm

bull Weight = 16 g

bull Torque

bull Holding Torque = 161 mN∙m = 0228 oz∙in

bull Driving Torque = 0385 mN∙m = 0055 oz∙in

bull Friction Torque = 403

10-3 mN∙m = 571

10-4 oz∙in

bull Power Requirements

bull Nominal voltage per phase 2-5 V

bull Nominal current per phase 006-02 A 47

Integration Launch

Feasibility for Pre-deployment locking mechanism

The tip of the solar sail will be wider than the body with the sail tip set outside the plate

The tip will be held in place vertically by stationary blade stabilizers and kept tight by the holding torque of the deployment motor

Stationary blade

stabilizers

Extra-wide

blade tip

Upon deployment the motor

turns and the blade extends

48

Integration Launch

Canesterized Satellite Dispenser (CSD)

bull Ride in a 12 U CSD

bull Width=239 cm Height=226 cm Length=366 cm

bull Mass=0-24 kg at launch

bull Center of Mass when stowed in

bull x is -40 to 40 mm

bull y is 50 to 125 mm

bull z is 133 to 233 mm

wwwplanetarysytemscorpcom 49

Integration Launch

Test Validation

bull Launch Vibration Test

bull Needs to be space applicable and strong enough to withstand vibration

bull Ball Aerospace can provide a shake table costing $250hr

bull Preparation for Testing using FEM modeling and adding support features

50

Financial

bull Total Budget $5000

bull Components

bull Stepper Motor $100-200

bull Servo Motor (x2) $50-500 each

bull Materials (made in-house) $500-1000

bull Electronics $0-500

bull Testing

bull Deployment amp Pitching Free (Performed on Campus)

bull Launch Survivability Vibration Stand - $250hr Ball Space Systems in Boulder

bull Total Estimation $700-2700 + Vibration Stand Testing

51

Baseline Design All Together

bull The 8u CubeSat and characteristic acceleration requirements create very strict volumetric restrictions

bull The size of the plates and the rolled sail blade must be validated

bull This design will be analyzed and verified in the feasibility requirements

Inner Control Area

bull Motor

bull Encoder

bull Control

bull Communication

bull Power

Possible Load-bearing

corners for deployment

Housed Solar Sail

Top-Down View

Extra room for third

party systems

52

Status Summary

53

SystemMechanism Final Choice Further

Studies

Needed

8U Structure Fit our CubeSat in 12U bus provided by Planetary Services Yes

Adequate Area of Sails to Provide

Orbit Transfer Capabilities

AR = 22001 No

Pitching Mechanism Using a servo motor Yes

Pitching Accuracy Pitching encoder Yes

Plate Integration System Using a two cylinder design with tapered edges so

everything will fit

No

Deployment Motor Using a stepper motor No

Launch Ability Must conform to standards set by Planetary Services Yes

Launch Survivability Verify that GHOST will survive launch Yes

Initial Spin-Up Carbon steel attached to solar blade material Yes 53

Strategy for Conducting

Remaining Studies

bull 8U GHOST inside 12U structure bull Create a SolidWorksCAD model

bull Pitching Mechanism bull Determine adequate motor within size power and cost constraints

bull Pitching Accuracy bull Determine pitching accuracy based on orbital sensitivity

bull Launch Ability bull Because design is symmetrical center of mass is in the center of the satellite during launch bull Further investigations is needed to determine how many counterweights

bull Launch Survivability bull FEM or Vibrations

bull Initial Spin-up bull Determine feasible method to attach carbon steel support structure to solar sail blade material

54

Resources

bull PAYLOAD SPECIFICATION FOR 3U 6U 12U AND 27U Np Planetary Systems Corporation 2013 Print

bull Davis Jason The Planetary Society The Planetary Society Blog Firefly Partners 11 Apr 2012 Web 12 Oct 2013 lthttpwwwplanetaryorgblogsguest-blogsjason-davis3450htmlgt

bull Mao Tengfei 01mm Thickness Measuring Tape Wwwalibabacom Alibabacom nd Web 12 Oct 2013 lthttpwwwalibabacomproduct-gs8359006940_1mm_thickness_measuring_tapehtmlgt

55

Resources

bull ldquoHow servos and steppers stack uprdquo Machine Design 9 February 2012 [httpmachinedesigncomnewshow-servos-and-steppers-stack Accessed 7 October 2013]

bull ldquoMiniature Stepper Motor Drive Systems - Data Sheetrdquo Micro Motion Solutions [httpwwwmicromocomstepper-motors-datasheetsaspx Accessed 11 October 2013]

bull ldquoData Sheet for TS-53 Servorsquos Electric Motorrdquo Mabuchi Motor [httpwwwprincetonedu~mae412TEXTNTRAK2002292-302pdf Accessed 11 October 2013]

56

Orbit Initial Orbit

Launch

bull Vandenberg AFB CA

bull Atlas V Launch Vehicle

bull Secondary Payload

bull Insertion into near Polar Orbit via Centaur Upper Stage

bull Further transfer necessary to achieve SS orbit

25

Orbit Blade Size

Maximum Solar Radiation Pressure Calculation

bull Assumptions

bull Perfectly reflecting surface

bull α = 0

(incident radiation perpendicular to surface)

26

Preflect2W

cR2cos2 = 908 Pa

where W = 1361 Wm2 c = 30x10 8 ms amp R = 100 AU

Orbit Blade Size

Minimum Solar Blade Surface Area for

Necessary Thrust

bull Assumptions

bull m = 8 kg (based on 8U Volume CubeSat 1 kgU)

27

a ac 01 mms2 requirement

sreflectc APmaFmax Asmac

Preflect8811 m2

bull 4 solar blades

As

42203 m2 per blade

Orbit Transfer

bull Example

bull LV delivers sc into 1100 km circular polar orbit

bull 1) Orbit raising maneuver to 1500 km

bull 2) Inclination change maneuver to i = 10196

bull How long will this take with GHOSTrsquos capabilities

28

29

Orbit Transfer

Orbit Raising Maneuver

Hohmann Transfer

Dual tangential

burn coplanar orbit

transfer

Initial Orbit

Final Orbit

Transfer Orbit

Orbit Transfer

Orbit Raising Maneuver

bull Calculated using Hohmann Transfer Equations

30

initial transfer vi 945 ms

transfer final v f 933 ms

vtotal 1877 ms

torbit raise 123 days

45o Preflect 454 Pa ain plane 177x10 5 ms2

Two blades pitched at

45

producing thrust in along track direction

See appendix for detailed orbit transfer diagrams

Orbit Transfer

Orbit Inclination Change

bull Calculated using inclination change only equations

31

v inc 2v initialcos( fpa)sini

2where vinitial v f fpa 0o amp i 1196o

vinc 148 kms i 00028 oorbit

a ac 01 mms2 P 6959 s Thrust acts over northern hemisphere of orbit (12 of Period)

tinc change 3437 days

Orbit Transfer

Final Destination

bull Δttotal = 4667 days or ~ 155 months bull time it takes to transfer from LV Delivery 1100 km polar orbit to 1500 km SS

orbit

bull this BOTE calculation has huge implications on both

bull mission duration

bull life span of sc components materials etc

bull Validates the high performance orbit transfer capabilities of the heliogyro architecture

32

Integration CubeSat

Pitch Test Validation

Sensor(s) to measure

torque and

Purpose Demonstrate coordinated pitching with equivalent mass and

realistic bus rotation

bull Rotation of 1 RPM

bull Measure torque on bus

bull Measure and compare actual pitching angles

to commanded

pitching angles

Sensors Needed

bull 3 axis Accelerometer (torque measurement)

bull 3 axis Gyroscope (pitch angle measurement)

bull 12 bit resolution (greater than pitching motors)

bull Fit onto or on 8U CubeSat

ADI516xxxIM4

bull 3 axis gyroscope

bull 3 axis magnetometer

bull 3 axis accelerometer

bull 14 bit resolution

bull 1

volume

bull Available free for checkout in ITLL

Sail Equivalent

mass

33

Integration CubeSat

Feasibility of our Baseline Design

bull To achieve characteristic acceleration for an 8U (8kg) CubeSat we needed each sail to be 2203

bull The diameter of the rolled spool inside the CubeSat (pre-deployment) varies with the width of the sail

bull To find the diameter of the rolled spool we calculated the length of one sail for a chosen width Assuming a Mylar thickness of 5 um due to the crinkling effect the spool width was calculated by iterating each rotation with increasing diameter as the blade rolls up

Iterate for rolling up sail until finished

(cm)

(m)

12 1836 247

10 2203 270

8 2754 300

34

Integration CubeSat

Sizing the Blades

bull CubeSat constrained by 20 cm on each side

bull Need to perform 180 degree independent rotation and maximize room inside the satellite for pitching motors controls and communication

Top Down Views of each size ( Scaled to correct dimensions)

12 cm blade width 10 cm blade width 8 cm blade width

bull Not intrusive on inner area

bull Full 180 motion

bull Infringes on space inside

bull Full 180 motion

bull Not intrusive on inner area

bull No Full 180 motion

35

Integration CubeSat

Housing the Rolled Sail

bull The solar sail blades will be controlled by a pitching axle but there must be an interface to connect to the axle

bull Cylindrical plate housing

bull Protects blades

bull Easy to connect to axle

bull No gears

bull Ability to provide counterweight

to deployment motor

bull With the tight volume constraints of our cube the Cylindrical plate must be altered to avoid interference with other sides

36

Integration CubeSat

Fitting the cylindrical Plate

bull Clearance for rolled sail

bull 2 cm clearance on each side

bull 06 cm clearance on behind the motor

bull This leaves overlapping corners

bull To prevent overlap we will make a 45ordm cut around the entire cylinder

2 cm

06 cm

Rolled Sail

Plate Encasing

Overlapping

Corners

45ordm cut to get rid

of corners

37

Integration CubeSat

Fitting the cylindrical Plate

bull The 45ordm cut will give us a 0 cm clearance (with no thickness)

bull If we implement a high-low offset between adjacent plates the distance between the two closest points increases

bull For our 14 cm diameter plates a 2 cm offset from the center for each plate (4 cm total) the effective clearance becomes 251 cm

Two adjacent sides

on same axis

With a High-Low Offset

38

Integration CubeSat

High-Low Offset Plates

The high low offset will give each plate room to rotate a full 180ordm

1 cm clearance between the top of the

blade and the edge of the satellite to fit

the thin-set bearing

A 3mm plate thickness gives adjacent

plates a distance of 19 cm between

their closest points

39

Integration CubeSat

High Low Offset Performance Validation

bull The high-low offset will not effect the performance or stability of the deployment or pitching systems

bull Upon deployment the opposing extension on each side cancels out unwanted torque

View From high side View From low side

bull In a sun-synchronous orbit the high or low setting has no effect as the rotational axis of the satellite is always solar pointing

View From Sun

40

Integration Power

Electronics Feasibility Analysis

bull Project Constraints

bull CubeSat power source Li-Ion batteries (5 and 33 V is common) - Would require thermal protection

bull Communications System - Transceiver (UHF is common) [USART serial port] - Buffer may be needed depending on power constraints

bull Deployment Subsystem - 1 step-motor [output] - 1 encoder [MSSP input] OR direct deployment measurement via external sensor

bull Pitching Subsystem - 2 servomotors [output]

41

Integration Power

PIC18F Series Microchip

bull Inputs 2 USART and 2 MSSP ports available (for basic PICs) - More than 1 device may be connected to each port - 2-3 devices needed

bull Outputs 8 ports - 2 devices needed

bull 16 bit - Though different PICs may be acquired for higher resolution

bull Operating Range 2-55 V - Within provided parameters

42

PIC

Communications

Deployment

Motor

Encoder

Pitching

Motor 1

Pitching

Motor 2 Key

Power Lines

Input Lines

Output Lines

Integration Power

Microchip FBD

5V Battery

Possible Voltage

Buffer

Encoder

43

Integration Power

Motor Power Limitations

bull Power Constraints

Pmax = 100 W

Vmax = 50 V

bull P = IV (Power = CurrentVoltage)

bull Therefore Iave = 20 Amps

bull Blade Pitching (4 motors total needed) - Current limitations for power sources and number of simultaneous blades pitching

Number of Blades 5 V Input 36 V input 31 V input 2 V input

4 040 A 069 A 081 A 125 A

2 080 A 139 A 161 A 250 A

1 160 A 278 A 323 A 500 A

44

Integration Motors

Stepper vs Brushless Servo Motors

45

-Contain many poles (50+) -Contain only 4-12 poles

-Distinct steps cause

vibration during use -Do not suffer from

vibration and resonance

issues smooth movement

-Low maintenance easier to

commission mechanically

simple

-Efficient response to start

stop and reverse commands

-Rely on encoders for

position details in closed

loop response

-Physical sizes

are comparable

-Both available

in various

lengths at same

frame size -Torque can be readily

controlled

-Low cost and high

availability

-Complexity drives cost

upward

Chosen for

deployment motor

Chosen for

pitching motor

Stepper Servo

Integration Blade Deployment

Deployment Motor Feasibility

Required holding torque is calculated to be 18 mNm

Required driving torque is calculated to be 117

10-5 mN∙m

bull Micro Motion Solutions ndash miniature stepper motors bull Physical Properties

bull Diameter = 6-22 mm

bull Length = 93-20 mm

bull Weight = 55-12 g

bull Holding Torque = 24-10 mN∙m = 034-142 oz∙in

bull Resolution bull 1 or 2 phase half-step capability

bull Steps per turn = 20-24 rarr 15˚-18˚ per step

5 of full step accuracy

bull Power Requirements bull Nominal voltage per phase 2-5 V

bull Nominal current per phase 01-1 A

46

Integration Blade Pitching

Blade Pitching Motor Feasibility

Required driving torque is calculated to be 0019 mN∙m

bull Mabuchi Servo Motor bull Physical Size

bull Diameter = 17 mm

bull Length = 25 mm

bull Weight = 16 g

bull Torque

bull Holding Torque = 161 mN∙m = 0228 oz∙in

bull Driving Torque = 0385 mN∙m = 0055 oz∙in

bull Friction Torque = 403

10-3 mN∙m = 571

10-4 oz∙in

bull Power Requirements

bull Nominal voltage per phase 2-5 V

bull Nominal current per phase 006-02 A 47

Integration Launch

Feasibility for Pre-deployment locking mechanism

The tip of the solar sail will be wider than the body with the sail tip set outside the plate

The tip will be held in place vertically by stationary blade stabilizers and kept tight by the holding torque of the deployment motor

Stationary blade

stabilizers

Extra-wide

blade tip

Upon deployment the motor

turns and the blade extends

48

Integration Launch

Canesterized Satellite Dispenser (CSD)

bull Ride in a 12 U CSD

bull Width=239 cm Height=226 cm Length=366 cm

bull Mass=0-24 kg at launch

bull Center of Mass when stowed in

bull x is -40 to 40 mm

bull y is 50 to 125 mm

bull z is 133 to 233 mm

wwwplanetarysytemscorpcom 49

Integration Launch

Test Validation

bull Launch Vibration Test

bull Needs to be space applicable and strong enough to withstand vibration

bull Ball Aerospace can provide a shake table costing $250hr

bull Preparation for Testing using FEM modeling and adding support features

50

Financial

bull Total Budget $5000

bull Components

bull Stepper Motor $100-200

bull Servo Motor (x2) $50-500 each

bull Materials (made in-house) $500-1000

bull Electronics $0-500

bull Testing

bull Deployment amp Pitching Free (Performed on Campus)

bull Launch Survivability Vibration Stand - $250hr Ball Space Systems in Boulder

bull Total Estimation $700-2700 + Vibration Stand Testing

51

Baseline Design All Together

bull The 8u CubeSat and characteristic acceleration requirements create very strict volumetric restrictions

bull The size of the plates and the rolled sail blade must be validated

bull This design will be analyzed and verified in the feasibility requirements

Inner Control Area

bull Motor

bull Encoder

bull Control

bull Communication

bull Power

Possible Load-bearing

corners for deployment

Housed Solar Sail

Top-Down View

Extra room for third

party systems

52

Status Summary

53

SystemMechanism Final Choice Further

Studies

Needed

8U Structure Fit our CubeSat in 12U bus provided by Planetary Services Yes

Adequate Area of Sails to Provide

Orbit Transfer Capabilities

AR = 22001 No

Pitching Mechanism Using a servo motor Yes

Pitching Accuracy Pitching encoder Yes

Plate Integration System Using a two cylinder design with tapered edges so

everything will fit

No

Deployment Motor Using a stepper motor No

Launch Ability Must conform to standards set by Planetary Services Yes

Launch Survivability Verify that GHOST will survive launch Yes

Initial Spin-Up Carbon steel attached to solar blade material Yes 53

Strategy for Conducting

Remaining Studies

bull 8U GHOST inside 12U structure bull Create a SolidWorksCAD model

bull Pitching Mechanism bull Determine adequate motor within size power and cost constraints

bull Pitching Accuracy bull Determine pitching accuracy based on orbital sensitivity

bull Launch Ability bull Because design is symmetrical center of mass is in the center of the satellite during launch bull Further investigations is needed to determine how many counterweights

bull Launch Survivability bull FEM or Vibrations

bull Initial Spin-up bull Determine feasible method to attach carbon steel support structure to solar sail blade material

54

Resources

bull PAYLOAD SPECIFICATION FOR 3U 6U 12U AND 27U Np Planetary Systems Corporation 2013 Print

bull Davis Jason The Planetary Society The Planetary Society Blog Firefly Partners 11 Apr 2012 Web 12 Oct 2013 lthttpwwwplanetaryorgblogsguest-blogsjason-davis3450htmlgt

bull Mao Tengfei 01mm Thickness Measuring Tape Wwwalibabacom Alibabacom nd Web 12 Oct 2013 lthttpwwwalibabacomproduct-gs8359006940_1mm_thickness_measuring_tapehtmlgt

55

Resources

bull ldquoHow servos and steppers stack uprdquo Machine Design 9 February 2012 [httpmachinedesigncomnewshow-servos-and-steppers-stack Accessed 7 October 2013]

bull ldquoMiniature Stepper Motor Drive Systems - Data Sheetrdquo Micro Motion Solutions [httpwwwmicromocomstepper-motors-datasheetsaspx Accessed 11 October 2013]

bull ldquoData Sheet for TS-53 Servorsquos Electric Motorrdquo Mabuchi Motor [httpwwwprincetonedu~mae412TEXTNTRAK2002292-302pdf Accessed 11 October 2013]

56

Orbit Blade Size

Maximum Solar Radiation Pressure Calculation

bull Assumptions

bull Perfectly reflecting surface

bull α = 0

(incident radiation perpendicular to surface)

26

Preflect2W

cR2cos2 = 908 Pa

where W = 1361 Wm2 c = 30x10 8 ms amp R = 100 AU

Orbit Blade Size

Minimum Solar Blade Surface Area for

Necessary Thrust

bull Assumptions

bull m = 8 kg (based on 8U Volume CubeSat 1 kgU)

27

a ac 01 mms2 requirement

sreflectc APmaFmax Asmac

Preflect8811 m2

bull 4 solar blades

As

42203 m2 per blade

Orbit Transfer

bull Example

bull LV delivers sc into 1100 km circular polar orbit

bull 1) Orbit raising maneuver to 1500 km

bull 2) Inclination change maneuver to i = 10196

bull How long will this take with GHOSTrsquos capabilities

28

29

Orbit Transfer

Orbit Raising Maneuver

Hohmann Transfer

Dual tangential

burn coplanar orbit

transfer

Initial Orbit

Final Orbit

Transfer Orbit

Orbit Transfer

Orbit Raising Maneuver

bull Calculated using Hohmann Transfer Equations

30

initial transfer vi 945 ms

transfer final v f 933 ms

vtotal 1877 ms

torbit raise 123 days

45o Preflect 454 Pa ain plane 177x10 5 ms2

Two blades pitched at

45

producing thrust in along track direction

See appendix for detailed orbit transfer diagrams

Orbit Transfer

Orbit Inclination Change

bull Calculated using inclination change only equations

31

v inc 2v initialcos( fpa)sini

2where vinitial v f fpa 0o amp i 1196o

vinc 148 kms i 00028 oorbit

a ac 01 mms2 P 6959 s Thrust acts over northern hemisphere of orbit (12 of Period)

tinc change 3437 days

Orbit Transfer

Final Destination

bull Δttotal = 4667 days or ~ 155 months bull time it takes to transfer from LV Delivery 1100 km polar orbit to 1500 km SS

orbit

bull this BOTE calculation has huge implications on both

bull mission duration

bull life span of sc components materials etc

bull Validates the high performance orbit transfer capabilities of the heliogyro architecture

32

Integration CubeSat

Pitch Test Validation

Sensor(s) to measure

torque and

Purpose Demonstrate coordinated pitching with equivalent mass and

realistic bus rotation

bull Rotation of 1 RPM

bull Measure torque on bus

bull Measure and compare actual pitching angles

to commanded

pitching angles

Sensors Needed

bull 3 axis Accelerometer (torque measurement)

bull 3 axis Gyroscope (pitch angle measurement)

bull 12 bit resolution (greater than pitching motors)

bull Fit onto or on 8U CubeSat

ADI516xxxIM4

bull 3 axis gyroscope

bull 3 axis magnetometer

bull 3 axis accelerometer

bull 14 bit resolution

bull 1

volume

bull Available free for checkout in ITLL

Sail Equivalent

mass

33

Integration CubeSat

Feasibility of our Baseline Design

bull To achieve characteristic acceleration for an 8U (8kg) CubeSat we needed each sail to be 2203

bull The diameter of the rolled spool inside the CubeSat (pre-deployment) varies with the width of the sail

bull To find the diameter of the rolled spool we calculated the length of one sail for a chosen width Assuming a Mylar thickness of 5 um due to the crinkling effect the spool width was calculated by iterating each rotation with increasing diameter as the blade rolls up

Iterate for rolling up sail until finished

(cm)

(m)

12 1836 247

10 2203 270

8 2754 300

34

Integration CubeSat

Sizing the Blades

bull CubeSat constrained by 20 cm on each side

bull Need to perform 180 degree independent rotation and maximize room inside the satellite for pitching motors controls and communication

Top Down Views of each size ( Scaled to correct dimensions)

12 cm blade width 10 cm blade width 8 cm blade width

bull Not intrusive on inner area

bull Full 180 motion

bull Infringes on space inside

bull Full 180 motion

bull Not intrusive on inner area

bull No Full 180 motion

35

Integration CubeSat

Housing the Rolled Sail

bull The solar sail blades will be controlled by a pitching axle but there must be an interface to connect to the axle

bull Cylindrical plate housing

bull Protects blades

bull Easy to connect to axle

bull No gears

bull Ability to provide counterweight

to deployment motor

bull With the tight volume constraints of our cube the Cylindrical plate must be altered to avoid interference with other sides

36

Integration CubeSat

Fitting the cylindrical Plate

bull Clearance for rolled sail

bull 2 cm clearance on each side

bull 06 cm clearance on behind the motor

bull This leaves overlapping corners

bull To prevent overlap we will make a 45ordm cut around the entire cylinder

2 cm

06 cm

Rolled Sail

Plate Encasing

Overlapping

Corners

45ordm cut to get rid

of corners

37

Integration CubeSat

Fitting the cylindrical Plate

bull The 45ordm cut will give us a 0 cm clearance (with no thickness)

bull If we implement a high-low offset between adjacent plates the distance between the two closest points increases

bull For our 14 cm diameter plates a 2 cm offset from the center for each plate (4 cm total) the effective clearance becomes 251 cm

Two adjacent sides

on same axis

With a High-Low Offset

38

Integration CubeSat

High-Low Offset Plates

The high low offset will give each plate room to rotate a full 180ordm

1 cm clearance between the top of the

blade and the edge of the satellite to fit

the thin-set bearing

A 3mm plate thickness gives adjacent

plates a distance of 19 cm between

their closest points

39

Integration CubeSat

High Low Offset Performance Validation

bull The high-low offset will not effect the performance or stability of the deployment or pitching systems

bull Upon deployment the opposing extension on each side cancels out unwanted torque

View From high side View From low side

bull In a sun-synchronous orbit the high or low setting has no effect as the rotational axis of the satellite is always solar pointing

View From Sun

40

Integration Power

Electronics Feasibility Analysis

bull Project Constraints

bull CubeSat power source Li-Ion batteries (5 and 33 V is common) - Would require thermal protection

bull Communications System - Transceiver (UHF is common) [USART serial port] - Buffer may be needed depending on power constraints

bull Deployment Subsystem - 1 step-motor [output] - 1 encoder [MSSP input] OR direct deployment measurement via external sensor

bull Pitching Subsystem - 2 servomotors [output]

41

Integration Power

PIC18F Series Microchip

bull Inputs 2 USART and 2 MSSP ports available (for basic PICs) - More than 1 device may be connected to each port - 2-3 devices needed

bull Outputs 8 ports - 2 devices needed

bull 16 bit - Though different PICs may be acquired for higher resolution

bull Operating Range 2-55 V - Within provided parameters

42

PIC

Communications

Deployment

Motor

Encoder

Pitching

Motor 1

Pitching

Motor 2 Key

Power Lines

Input Lines

Output Lines

Integration Power

Microchip FBD

5V Battery

Possible Voltage

Buffer

Encoder

43

Integration Power

Motor Power Limitations

bull Power Constraints

Pmax = 100 W

Vmax = 50 V

bull P = IV (Power = CurrentVoltage)

bull Therefore Iave = 20 Amps

bull Blade Pitching (4 motors total needed) - Current limitations for power sources and number of simultaneous blades pitching

Number of Blades 5 V Input 36 V input 31 V input 2 V input

4 040 A 069 A 081 A 125 A

2 080 A 139 A 161 A 250 A

1 160 A 278 A 323 A 500 A

44

Integration Motors

Stepper vs Brushless Servo Motors

45

-Contain many poles (50+) -Contain only 4-12 poles

-Distinct steps cause

vibration during use -Do not suffer from

vibration and resonance

issues smooth movement

-Low maintenance easier to

commission mechanically

simple

-Efficient response to start

stop and reverse commands

-Rely on encoders for

position details in closed

loop response

-Physical sizes

are comparable

-Both available

in various

lengths at same

frame size -Torque can be readily

controlled

-Low cost and high

availability

-Complexity drives cost

upward

Chosen for

deployment motor

Chosen for

pitching motor

Stepper Servo

Integration Blade Deployment

Deployment Motor Feasibility

Required holding torque is calculated to be 18 mNm

Required driving torque is calculated to be 117

10-5 mN∙m

bull Micro Motion Solutions ndash miniature stepper motors bull Physical Properties

bull Diameter = 6-22 mm

bull Length = 93-20 mm

bull Weight = 55-12 g

bull Holding Torque = 24-10 mN∙m = 034-142 oz∙in

bull Resolution bull 1 or 2 phase half-step capability

bull Steps per turn = 20-24 rarr 15˚-18˚ per step

5 of full step accuracy

bull Power Requirements bull Nominal voltage per phase 2-5 V

bull Nominal current per phase 01-1 A

46

Integration Blade Pitching

Blade Pitching Motor Feasibility

Required driving torque is calculated to be 0019 mN∙m

bull Mabuchi Servo Motor bull Physical Size

bull Diameter = 17 mm

bull Length = 25 mm

bull Weight = 16 g

bull Torque

bull Holding Torque = 161 mN∙m = 0228 oz∙in

bull Driving Torque = 0385 mN∙m = 0055 oz∙in

bull Friction Torque = 403

10-3 mN∙m = 571

10-4 oz∙in

bull Power Requirements

bull Nominal voltage per phase 2-5 V

bull Nominal current per phase 006-02 A 47

Integration Launch

Feasibility for Pre-deployment locking mechanism

The tip of the solar sail will be wider than the body with the sail tip set outside the plate

The tip will be held in place vertically by stationary blade stabilizers and kept tight by the holding torque of the deployment motor

Stationary blade

stabilizers

Extra-wide

blade tip

Upon deployment the motor

turns and the blade extends

48

Integration Launch

Canesterized Satellite Dispenser (CSD)

bull Ride in a 12 U CSD

bull Width=239 cm Height=226 cm Length=366 cm

bull Mass=0-24 kg at launch

bull Center of Mass when stowed in

bull x is -40 to 40 mm

bull y is 50 to 125 mm

bull z is 133 to 233 mm

wwwplanetarysytemscorpcom 49

Integration Launch

Test Validation

bull Launch Vibration Test

bull Needs to be space applicable and strong enough to withstand vibration

bull Ball Aerospace can provide a shake table costing $250hr

bull Preparation for Testing using FEM modeling and adding support features

50

Financial

bull Total Budget $5000

bull Components

bull Stepper Motor $100-200

bull Servo Motor (x2) $50-500 each

bull Materials (made in-house) $500-1000

bull Electronics $0-500

bull Testing

bull Deployment amp Pitching Free (Performed on Campus)

bull Launch Survivability Vibration Stand - $250hr Ball Space Systems in Boulder

bull Total Estimation $700-2700 + Vibration Stand Testing

51

Baseline Design All Together

bull The 8u CubeSat and characteristic acceleration requirements create very strict volumetric restrictions

bull The size of the plates and the rolled sail blade must be validated

bull This design will be analyzed and verified in the feasibility requirements

Inner Control Area

bull Motor

bull Encoder

bull Control

bull Communication

bull Power

Possible Load-bearing

corners for deployment

Housed Solar Sail

Top-Down View

Extra room for third

party systems

52

Status Summary

53

SystemMechanism Final Choice Further

Studies

Needed

8U Structure Fit our CubeSat in 12U bus provided by Planetary Services Yes

Adequate Area of Sails to Provide

Orbit Transfer Capabilities

AR = 22001 No

Pitching Mechanism Using a servo motor Yes

Pitching Accuracy Pitching encoder Yes

Plate Integration System Using a two cylinder design with tapered edges so

everything will fit

No

Deployment Motor Using a stepper motor No

Launch Ability Must conform to standards set by Planetary Services Yes

Launch Survivability Verify that GHOST will survive launch Yes

Initial Spin-Up Carbon steel attached to solar blade material Yes 53

Strategy for Conducting

Remaining Studies

bull 8U GHOST inside 12U structure bull Create a SolidWorksCAD model

bull Pitching Mechanism bull Determine adequate motor within size power and cost constraints

bull Pitching Accuracy bull Determine pitching accuracy based on orbital sensitivity

bull Launch Ability bull Because design is symmetrical center of mass is in the center of the satellite during launch bull Further investigations is needed to determine how many counterweights

bull Launch Survivability bull FEM or Vibrations

bull Initial Spin-up bull Determine feasible method to attach carbon steel support structure to solar sail blade material

54

Resources

bull PAYLOAD SPECIFICATION FOR 3U 6U 12U AND 27U Np Planetary Systems Corporation 2013 Print

bull Davis Jason The Planetary Society The Planetary Society Blog Firefly Partners 11 Apr 2012 Web 12 Oct 2013 lthttpwwwplanetaryorgblogsguest-blogsjason-davis3450htmlgt

bull Mao Tengfei 01mm Thickness Measuring Tape Wwwalibabacom Alibabacom nd Web 12 Oct 2013 lthttpwwwalibabacomproduct-gs8359006940_1mm_thickness_measuring_tapehtmlgt

55

Resources

bull ldquoHow servos and steppers stack uprdquo Machine Design 9 February 2012 [httpmachinedesigncomnewshow-servos-and-steppers-stack Accessed 7 October 2013]

bull ldquoMiniature Stepper Motor Drive Systems - Data Sheetrdquo Micro Motion Solutions [httpwwwmicromocomstepper-motors-datasheetsaspx Accessed 11 October 2013]

bull ldquoData Sheet for TS-53 Servorsquos Electric Motorrdquo Mabuchi Motor [httpwwwprincetonedu~mae412TEXTNTRAK2002292-302pdf Accessed 11 October 2013]

56

Orbit Blade Size

Minimum Solar Blade Surface Area for

Necessary Thrust

bull Assumptions

bull m = 8 kg (based on 8U Volume CubeSat 1 kgU)

27

a ac 01 mms2 requirement

sreflectc APmaFmax Asmac

Preflect8811 m2

bull 4 solar blades

As

42203 m2 per blade

Orbit Transfer

bull Example

bull LV delivers sc into 1100 km circular polar orbit

bull 1) Orbit raising maneuver to 1500 km

bull 2) Inclination change maneuver to i = 10196

bull How long will this take with GHOSTrsquos capabilities

28

29

Orbit Transfer

Orbit Raising Maneuver

Hohmann Transfer

Dual tangential

burn coplanar orbit

transfer

Initial Orbit

Final Orbit

Transfer Orbit

Orbit Transfer

Orbit Raising Maneuver

bull Calculated using Hohmann Transfer Equations

30

initial transfer vi 945 ms

transfer final v f 933 ms

vtotal 1877 ms

torbit raise 123 days

45o Preflect 454 Pa ain plane 177x10 5 ms2

Two blades pitched at

45

producing thrust in along track direction

See appendix for detailed orbit transfer diagrams

Orbit Transfer

Orbit Inclination Change

bull Calculated using inclination change only equations

31

v inc 2v initialcos( fpa)sini

2where vinitial v f fpa 0o amp i 1196o

vinc 148 kms i 00028 oorbit

a ac 01 mms2 P 6959 s Thrust acts over northern hemisphere of orbit (12 of Period)

tinc change 3437 days

Orbit Transfer

Final Destination

bull Δttotal = 4667 days or ~ 155 months bull time it takes to transfer from LV Delivery 1100 km polar orbit to 1500 km SS

orbit

bull this BOTE calculation has huge implications on both

bull mission duration

bull life span of sc components materials etc

bull Validates the high performance orbit transfer capabilities of the heliogyro architecture

32

Integration CubeSat

Pitch Test Validation

Sensor(s) to measure

torque and

Purpose Demonstrate coordinated pitching with equivalent mass and

realistic bus rotation

bull Rotation of 1 RPM

bull Measure torque on bus

bull Measure and compare actual pitching angles

to commanded

pitching angles

Sensors Needed

bull 3 axis Accelerometer (torque measurement)

bull 3 axis Gyroscope (pitch angle measurement)

bull 12 bit resolution (greater than pitching motors)

bull Fit onto or on 8U CubeSat

ADI516xxxIM4

bull 3 axis gyroscope

bull 3 axis magnetometer

bull 3 axis accelerometer

bull 14 bit resolution

bull 1

volume

bull Available free for checkout in ITLL

Sail Equivalent

mass

33

Integration CubeSat

Feasibility of our Baseline Design

bull To achieve characteristic acceleration for an 8U (8kg) CubeSat we needed each sail to be 2203

bull The diameter of the rolled spool inside the CubeSat (pre-deployment) varies with the width of the sail

bull To find the diameter of the rolled spool we calculated the length of one sail for a chosen width Assuming a Mylar thickness of 5 um due to the crinkling effect the spool width was calculated by iterating each rotation with increasing diameter as the blade rolls up

Iterate for rolling up sail until finished

(cm)

(m)

12 1836 247

10 2203 270

8 2754 300

34

Integration CubeSat

Sizing the Blades

bull CubeSat constrained by 20 cm on each side

bull Need to perform 180 degree independent rotation and maximize room inside the satellite for pitching motors controls and communication

Top Down Views of each size ( Scaled to correct dimensions)

12 cm blade width 10 cm blade width 8 cm blade width

bull Not intrusive on inner area

bull Full 180 motion

bull Infringes on space inside

bull Full 180 motion

bull Not intrusive on inner area

bull No Full 180 motion

35

Integration CubeSat

Housing the Rolled Sail

bull The solar sail blades will be controlled by a pitching axle but there must be an interface to connect to the axle

bull Cylindrical plate housing

bull Protects blades

bull Easy to connect to axle

bull No gears

bull Ability to provide counterweight

to deployment motor

bull With the tight volume constraints of our cube the Cylindrical plate must be altered to avoid interference with other sides

36

Integration CubeSat

Fitting the cylindrical Plate

bull Clearance for rolled sail

bull 2 cm clearance on each side

bull 06 cm clearance on behind the motor

bull This leaves overlapping corners

bull To prevent overlap we will make a 45ordm cut around the entire cylinder

2 cm

06 cm

Rolled Sail

Plate Encasing

Overlapping

Corners

45ordm cut to get rid

of corners

37

Integration CubeSat

Fitting the cylindrical Plate

bull The 45ordm cut will give us a 0 cm clearance (with no thickness)

bull If we implement a high-low offset between adjacent plates the distance between the two closest points increases

bull For our 14 cm diameter plates a 2 cm offset from the center for each plate (4 cm total) the effective clearance becomes 251 cm

Two adjacent sides

on same axis

With a High-Low Offset

38

Integration CubeSat

High-Low Offset Plates

The high low offset will give each plate room to rotate a full 180ordm

1 cm clearance between the top of the

blade and the edge of the satellite to fit

the thin-set bearing

A 3mm plate thickness gives adjacent

plates a distance of 19 cm between

their closest points

39

Integration CubeSat

High Low Offset Performance Validation

bull The high-low offset will not effect the performance or stability of the deployment or pitching systems

bull Upon deployment the opposing extension on each side cancels out unwanted torque

View From high side View From low side

bull In a sun-synchronous orbit the high or low setting has no effect as the rotational axis of the satellite is always solar pointing

View From Sun

40

Integration Power

Electronics Feasibility Analysis

bull Project Constraints

bull CubeSat power source Li-Ion batteries (5 and 33 V is common) - Would require thermal protection

bull Communications System - Transceiver (UHF is common) [USART serial port] - Buffer may be needed depending on power constraints

bull Deployment Subsystem - 1 step-motor [output] - 1 encoder [MSSP input] OR direct deployment measurement via external sensor

bull Pitching Subsystem - 2 servomotors [output]

41

Integration Power

PIC18F Series Microchip

bull Inputs 2 USART and 2 MSSP ports available (for basic PICs) - More than 1 device may be connected to each port - 2-3 devices needed

bull Outputs 8 ports - 2 devices needed

bull 16 bit - Though different PICs may be acquired for higher resolution

bull Operating Range 2-55 V - Within provided parameters

42

PIC

Communications

Deployment

Motor

Encoder

Pitching

Motor 1

Pitching

Motor 2 Key

Power Lines

Input Lines

Output Lines

Integration Power

Microchip FBD

5V Battery

Possible Voltage

Buffer

Encoder

43

Integration Power

Motor Power Limitations

bull Power Constraints

Pmax = 100 W

Vmax = 50 V

bull P = IV (Power = CurrentVoltage)

bull Therefore Iave = 20 Amps

bull Blade Pitching (4 motors total needed) - Current limitations for power sources and number of simultaneous blades pitching

Number of Blades 5 V Input 36 V input 31 V input 2 V input

4 040 A 069 A 081 A 125 A

2 080 A 139 A 161 A 250 A

1 160 A 278 A 323 A 500 A

44

Integration Motors

Stepper vs Brushless Servo Motors

45

-Contain many poles (50+) -Contain only 4-12 poles

-Distinct steps cause

vibration during use -Do not suffer from

vibration and resonance

issues smooth movement

-Low maintenance easier to

commission mechanically

simple

-Efficient response to start

stop and reverse commands

-Rely on encoders for

position details in closed

loop response

-Physical sizes

are comparable

-Both available

in various

lengths at same

frame size -Torque can be readily

controlled

-Low cost and high

availability

-Complexity drives cost

upward

Chosen for

deployment motor

Chosen for

pitching motor

Stepper Servo

Integration Blade Deployment

Deployment Motor Feasibility

Required holding torque is calculated to be 18 mNm

Required driving torque is calculated to be 117

10-5 mN∙m

bull Micro Motion Solutions ndash miniature stepper motors bull Physical Properties

bull Diameter = 6-22 mm

bull Length = 93-20 mm

bull Weight = 55-12 g

bull Holding Torque = 24-10 mN∙m = 034-142 oz∙in

bull Resolution bull 1 or 2 phase half-step capability

bull Steps per turn = 20-24 rarr 15˚-18˚ per step

5 of full step accuracy

bull Power Requirements bull Nominal voltage per phase 2-5 V

bull Nominal current per phase 01-1 A

46

Integration Blade Pitching

Blade Pitching Motor Feasibility

Required driving torque is calculated to be 0019 mN∙m

bull Mabuchi Servo Motor bull Physical Size

bull Diameter = 17 mm

bull Length = 25 mm

bull Weight = 16 g

bull Torque

bull Holding Torque = 161 mN∙m = 0228 oz∙in

bull Driving Torque = 0385 mN∙m = 0055 oz∙in

bull Friction Torque = 403

10-3 mN∙m = 571

10-4 oz∙in

bull Power Requirements

bull Nominal voltage per phase 2-5 V

bull Nominal current per phase 006-02 A 47

Integration Launch

Feasibility for Pre-deployment locking mechanism

The tip of the solar sail will be wider than the body with the sail tip set outside the plate

The tip will be held in place vertically by stationary blade stabilizers and kept tight by the holding torque of the deployment motor

Stationary blade

stabilizers

Extra-wide

blade tip

Upon deployment the motor

turns and the blade extends

48

Integration Launch

Canesterized Satellite Dispenser (CSD)

bull Ride in a 12 U CSD

bull Width=239 cm Height=226 cm Length=366 cm

bull Mass=0-24 kg at launch

bull Center of Mass when stowed in

bull x is -40 to 40 mm

bull y is 50 to 125 mm

bull z is 133 to 233 mm

wwwplanetarysytemscorpcom 49

Integration Launch

Test Validation

bull Launch Vibration Test

bull Needs to be space applicable and strong enough to withstand vibration

bull Ball Aerospace can provide a shake table costing $250hr

bull Preparation for Testing using FEM modeling and adding support features

50

Financial

bull Total Budget $5000

bull Components

bull Stepper Motor $100-200

bull Servo Motor (x2) $50-500 each

bull Materials (made in-house) $500-1000

bull Electronics $0-500

bull Testing

bull Deployment amp Pitching Free (Performed on Campus)

bull Launch Survivability Vibration Stand - $250hr Ball Space Systems in Boulder

bull Total Estimation $700-2700 + Vibration Stand Testing

51

Baseline Design All Together

bull The 8u CubeSat and characteristic acceleration requirements create very strict volumetric restrictions

bull The size of the plates and the rolled sail blade must be validated

bull This design will be analyzed and verified in the feasibility requirements

Inner Control Area

bull Motor

bull Encoder

bull Control

bull Communication

bull Power

Possible Load-bearing

corners for deployment

Housed Solar Sail

Top-Down View

Extra room for third

party systems

52

Status Summary

53

SystemMechanism Final Choice Further

Studies

Needed

8U Structure Fit our CubeSat in 12U bus provided by Planetary Services Yes

Adequate Area of Sails to Provide

Orbit Transfer Capabilities

AR = 22001 No

Pitching Mechanism Using a servo motor Yes

Pitching Accuracy Pitching encoder Yes

Plate Integration System Using a two cylinder design with tapered edges so

everything will fit

No

Deployment Motor Using a stepper motor No

Launch Ability Must conform to standards set by Planetary Services Yes

Launch Survivability Verify that GHOST will survive launch Yes

Initial Spin-Up Carbon steel attached to solar blade material Yes 53

Strategy for Conducting

Remaining Studies

bull 8U GHOST inside 12U structure bull Create a SolidWorksCAD model

bull Pitching Mechanism bull Determine adequate motor within size power and cost constraints

bull Pitching Accuracy bull Determine pitching accuracy based on orbital sensitivity

bull Launch Ability bull Because design is symmetrical center of mass is in the center of the satellite during launch bull Further investigations is needed to determine how many counterweights

bull Launch Survivability bull FEM or Vibrations

bull Initial Spin-up bull Determine feasible method to attach carbon steel support structure to solar sail blade material

54

Resources

bull PAYLOAD SPECIFICATION FOR 3U 6U 12U AND 27U Np Planetary Systems Corporation 2013 Print

bull Davis Jason The Planetary Society The Planetary Society Blog Firefly Partners 11 Apr 2012 Web 12 Oct 2013 lthttpwwwplanetaryorgblogsguest-blogsjason-davis3450htmlgt

bull Mao Tengfei 01mm Thickness Measuring Tape Wwwalibabacom Alibabacom nd Web 12 Oct 2013 lthttpwwwalibabacomproduct-gs8359006940_1mm_thickness_measuring_tapehtmlgt

55

Resources

bull ldquoHow servos and steppers stack uprdquo Machine Design 9 February 2012 [httpmachinedesigncomnewshow-servos-and-steppers-stack Accessed 7 October 2013]

bull ldquoMiniature Stepper Motor Drive Systems - Data Sheetrdquo Micro Motion Solutions [httpwwwmicromocomstepper-motors-datasheetsaspx Accessed 11 October 2013]

bull ldquoData Sheet for TS-53 Servorsquos Electric Motorrdquo Mabuchi Motor [httpwwwprincetonedu~mae412TEXTNTRAK2002292-302pdf Accessed 11 October 2013]

56

Orbit Transfer

bull Example

bull LV delivers sc into 1100 km circular polar orbit

bull 1) Orbit raising maneuver to 1500 km

bull 2) Inclination change maneuver to i = 10196

bull How long will this take with GHOSTrsquos capabilities

28

29

Orbit Transfer

Orbit Raising Maneuver

Hohmann Transfer

Dual tangential

burn coplanar orbit

transfer

Initial Orbit

Final Orbit

Transfer Orbit

Orbit Transfer

Orbit Raising Maneuver

bull Calculated using Hohmann Transfer Equations

30

initial transfer vi 945 ms

transfer final v f 933 ms

vtotal 1877 ms

torbit raise 123 days

45o Preflect 454 Pa ain plane 177x10 5 ms2

Two blades pitched at

45

producing thrust in along track direction

See appendix for detailed orbit transfer diagrams

Orbit Transfer

Orbit Inclination Change

bull Calculated using inclination change only equations

31

v inc 2v initialcos( fpa)sini

2where vinitial v f fpa 0o amp i 1196o

vinc 148 kms i 00028 oorbit

a ac 01 mms2 P 6959 s Thrust acts over northern hemisphere of orbit (12 of Period)

tinc change 3437 days

Orbit Transfer

Final Destination

bull Δttotal = 4667 days or ~ 155 months bull time it takes to transfer from LV Delivery 1100 km polar orbit to 1500 km SS

orbit

bull this BOTE calculation has huge implications on both

bull mission duration

bull life span of sc components materials etc

bull Validates the high performance orbit transfer capabilities of the heliogyro architecture

32

Integration CubeSat

Pitch Test Validation

Sensor(s) to measure

torque and

Purpose Demonstrate coordinated pitching with equivalent mass and

realistic bus rotation

bull Rotation of 1 RPM

bull Measure torque on bus

bull Measure and compare actual pitching angles

to commanded

pitching angles

Sensors Needed

bull 3 axis Accelerometer (torque measurement)

bull 3 axis Gyroscope (pitch angle measurement)

bull 12 bit resolution (greater than pitching motors)

bull Fit onto or on 8U CubeSat

ADI516xxxIM4

bull 3 axis gyroscope

bull 3 axis magnetometer

bull 3 axis accelerometer

bull 14 bit resolution

bull 1

volume

bull Available free for checkout in ITLL

Sail Equivalent

mass

33

Integration CubeSat

Feasibility of our Baseline Design

bull To achieve characteristic acceleration for an 8U (8kg) CubeSat we needed each sail to be 2203

bull The diameter of the rolled spool inside the CubeSat (pre-deployment) varies with the width of the sail

bull To find the diameter of the rolled spool we calculated the length of one sail for a chosen width Assuming a Mylar thickness of 5 um due to the crinkling effect the spool width was calculated by iterating each rotation with increasing diameter as the blade rolls up

Iterate for rolling up sail until finished

(cm)

(m)

12 1836 247

10 2203 270

8 2754 300

34

Integration CubeSat

Sizing the Blades

bull CubeSat constrained by 20 cm on each side

bull Need to perform 180 degree independent rotation and maximize room inside the satellite for pitching motors controls and communication

Top Down Views of each size ( Scaled to correct dimensions)

12 cm blade width 10 cm blade width 8 cm blade width

bull Not intrusive on inner area

bull Full 180 motion

bull Infringes on space inside

bull Full 180 motion

bull Not intrusive on inner area

bull No Full 180 motion

35

Integration CubeSat

Housing the Rolled Sail

bull The solar sail blades will be controlled by a pitching axle but there must be an interface to connect to the axle

bull Cylindrical plate housing

bull Protects blades

bull Easy to connect to axle

bull No gears

bull Ability to provide counterweight

to deployment motor

bull With the tight volume constraints of our cube the Cylindrical plate must be altered to avoid interference with other sides

36

Integration CubeSat

Fitting the cylindrical Plate

bull Clearance for rolled sail

bull 2 cm clearance on each side

bull 06 cm clearance on behind the motor

bull This leaves overlapping corners

bull To prevent overlap we will make a 45ordm cut around the entire cylinder

2 cm

06 cm

Rolled Sail

Plate Encasing

Overlapping

Corners

45ordm cut to get rid

of corners

37

Integration CubeSat

Fitting the cylindrical Plate

bull The 45ordm cut will give us a 0 cm clearance (with no thickness)

bull If we implement a high-low offset between adjacent plates the distance between the two closest points increases

bull For our 14 cm diameter plates a 2 cm offset from the center for each plate (4 cm total) the effective clearance becomes 251 cm

Two adjacent sides

on same axis

With a High-Low Offset

38

Integration CubeSat

High-Low Offset Plates

The high low offset will give each plate room to rotate a full 180ordm

1 cm clearance between the top of the

blade and the edge of the satellite to fit

the thin-set bearing

A 3mm plate thickness gives adjacent

plates a distance of 19 cm between

their closest points

39

Integration CubeSat

High Low Offset Performance Validation

bull The high-low offset will not effect the performance or stability of the deployment or pitching systems

bull Upon deployment the opposing extension on each side cancels out unwanted torque

View From high side View From low side

bull In a sun-synchronous orbit the high or low setting has no effect as the rotational axis of the satellite is always solar pointing

View From Sun

40

Integration Power

Electronics Feasibility Analysis

bull Project Constraints

bull CubeSat power source Li-Ion batteries (5 and 33 V is common) - Would require thermal protection

bull Communications System - Transceiver (UHF is common) [USART serial port] - Buffer may be needed depending on power constraints

bull Deployment Subsystem - 1 step-motor [output] - 1 encoder [MSSP input] OR direct deployment measurement via external sensor

bull Pitching Subsystem - 2 servomotors [output]

41

Integration Power

PIC18F Series Microchip

bull Inputs 2 USART and 2 MSSP ports available (for basic PICs) - More than 1 device may be connected to each port - 2-3 devices needed

bull Outputs 8 ports - 2 devices needed

bull 16 bit - Though different PICs may be acquired for higher resolution

bull Operating Range 2-55 V - Within provided parameters

42

PIC

Communications

Deployment

Motor

Encoder

Pitching

Motor 1

Pitching

Motor 2 Key

Power Lines

Input Lines

Output Lines

Integration Power

Microchip FBD

5V Battery

Possible Voltage

Buffer

Encoder

43

Integration Power

Motor Power Limitations

bull Power Constraints

Pmax = 100 W

Vmax = 50 V

bull P = IV (Power = CurrentVoltage)

bull Therefore Iave = 20 Amps

bull Blade Pitching (4 motors total needed) - Current limitations for power sources and number of simultaneous blades pitching

Number of Blades 5 V Input 36 V input 31 V input 2 V input

4 040 A 069 A 081 A 125 A

2 080 A 139 A 161 A 250 A

1 160 A 278 A 323 A 500 A

44

Integration Motors

Stepper vs Brushless Servo Motors

45

-Contain many poles (50+) -Contain only 4-12 poles

-Distinct steps cause

vibration during use -Do not suffer from

vibration and resonance

issues smooth movement

-Low maintenance easier to

commission mechanically

simple

-Efficient response to start

stop and reverse commands

-Rely on encoders for

position details in closed

loop response

-Physical sizes

are comparable

-Both available

in various

lengths at same

frame size -Torque can be readily

controlled

-Low cost and high

availability

-Complexity drives cost

upward

Chosen for

deployment motor

Chosen for

pitching motor

Stepper Servo

Integration Blade Deployment

Deployment Motor Feasibility

Required holding torque is calculated to be 18 mNm

Required driving torque is calculated to be 117

10-5 mN∙m

bull Micro Motion Solutions ndash miniature stepper motors bull Physical Properties

bull Diameter = 6-22 mm

bull Length = 93-20 mm

bull Weight = 55-12 g

bull Holding Torque = 24-10 mN∙m = 034-142 oz∙in

bull Resolution bull 1 or 2 phase half-step capability

bull Steps per turn = 20-24 rarr 15˚-18˚ per step

5 of full step accuracy

bull Power Requirements bull Nominal voltage per phase 2-5 V

bull Nominal current per phase 01-1 A

46

Integration Blade Pitching

Blade Pitching Motor Feasibility

Required driving torque is calculated to be 0019 mN∙m

bull Mabuchi Servo Motor bull Physical Size

bull Diameter = 17 mm

bull Length = 25 mm

bull Weight = 16 g

bull Torque

bull Holding Torque = 161 mN∙m = 0228 oz∙in

bull Driving Torque = 0385 mN∙m = 0055 oz∙in

bull Friction Torque = 403

10-3 mN∙m = 571

10-4 oz∙in

bull Power Requirements

bull Nominal voltage per phase 2-5 V

bull Nominal current per phase 006-02 A 47

Integration Launch

Feasibility for Pre-deployment locking mechanism

The tip of the solar sail will be wider than the body with the sail tip set outside the plate

The tip will be held in place vertically by stationary blade stabilizers and kept tight by the holding torque of the deployment motor

Stationary blade

stabilizers

Extra-wide

blade tip

Upon deployment the motor

turns and the blade extends

48

Integration Launch

Canesterized Satellite Dispenser (CSD)

bull Ride in a 12 U CSD

bull Width=239 cm Height=226 cm Length=366 cm

bull Mass=0-24 kg at launch

bull Center of Mass when stowed in

bull x is -40 to 40 mm

bull y is 50 to 125 mm

bull z is 133 to 233 mm

wwwplanetarysytemscorpcom 49

Integration Launch

Test Validation

bull Launch Vibration Test

bull Needs to be space applicable and strong enough to withstand vibration

bull Ball Aerospace can provide a shake table costing $250hr

bull Preparation for Testing using FEM modeling and adding support features

50

Financial

bull Total Budget $5000

bull Components

bull Stepper Motor $100-200

bull Servo Motor (x2) $50-500 each

bull Materials (made in-house) $500-1000

bull Electronics $0-500

bull Testing

bull Deployment amp Pitching Free (Performed on Campus)

bull Launch Survivability Vibration Stand - $250hr Ball Space Systems in Boulder

bull Total Estimation $700-2700 + Vibration Stand Testing

51

Baseline Design All Together

bull The 8u CubeSat and characteristic acceleration requirements create very strict volumetric restrictions

bull The size of the plates and the rolled sail blade must be validated

bull This design will be analyzed and verified in the feasibility requirements

Inner Control Area

bull Motor

bull Encoder

bull Control

bull Communication

bull Power

Possible Load-bearing

corners for deployment

Housed Solar Sail

Top-Down View

Extra room for third

party systems

52

Status Summary

53

SystemMechanism Final Choice Further

Studies

Needed

8U Structure Fit our CubeSat in 12U bus provided by Planetary Services Yes

Adequate Area of Sails to Provide

Orbit Transfer Capabilities

AR = 22001 No

Pitching Mechanism Using a servo motor Yes

Pitching Accuracy Pitching encoder Yes

Plate Integration System Using a two cylinder design with tapered edges so

everything will fit

No

Deployment Motor Using a stepper motor No

Launch Ability Must conform to standards set by Planetary Services Yes

Launch Survivability Verify that GHOST will survive launch Yes

Initial Spin-Up Carbon steel attached to solar blade material Yes 53

Strategy for Conducting

Remaining Studies

bull 8U GHOST inside 12U structure bull Create a SolidWorksCAD model

bull Pitching Mechanism bull Determine adequate motor within size power and cost constraints

bull Pitching Accuracy bull Determine pitching accuracy based on orbital sensitivity

bull Launch Ability bull Because design is symmetrical center of mass is in the center of the satellite during launch bull Further investigations is needed to determine how many counterweights

bull Launch Survivability bull FEM or Vibrations

bull Initial Spin-up bull Determine feasible method to attach carbon steel support structure to solar sail blade material

54

Resources

bull PAYLOAD SPECIFICATION FOR 3U 6U 12U AND 27U Np Planetary Systems Corporation 2013 Print

bull Davis Jason The Planetary Society The Planetary Society Blog Firefly Partners 11 Apr 2012 Web 12 Oct 2013 lthttpwwwplanetaryorgblogsguest-blogsjason-davis3450htmlgt

bull Mao Tengfei 01mm Thickness Measuring Tape Wwwalibabacom Alibabacom nd Web 12 Oct 2013 lthttpwwwalibabacomproduct-gs8359006940_1mm_thickness_measuring_tapehtmlgt

55

Resources

bull ldquoHow servos and steppers stack uprdquo Machine Design 9 February 2012 [httpmachinedesigncomnewshow-servos-and-steppers-stack Accessed 7 October 2013]

bull ldquoMiniature Stepper Motor Drive Systems - Data Sheetrdquo Micro Motion Solutions [httpwwwmicromocomstepper-motors-datasheetsaspx Accessed 11 October 2013]

bull ldquoData Sheet for TS-53 Servorsquos Electric Motorrdquo Mabuchi Motor [httpwwwprincetonedu~mae412TEXTNTRAK2002292-302pdf Accessed 11 October 2013]

56

29

Orbit Transfer

Orbit Raising Maneuver

Hohmann Transfer

Dual tangential

burn coplanar orbit

transfer

Initial Orbit

Final Orbit

Transfer Orbit

Orbit Transfer

Orbit Raising Maneuver

bull Calculated using Hohmann Transfer Equations

30

initial transfer vi 945 ms

transfer final v f 933 ms

vtotal 1877 ms

torbit raise 123 days

45o Preflect 454 Pa ain plane 177x10 5 ms2

Two blades pitched at

45

producing thrust in along track direction

See appendix for detailed orbit transfer diagrams

Orbit Transfer

Orbit Inclination Change

bull Calculated using inclination change only equations

31

v inc 2v initialcos( fpa)sini

2where vinitial v f fpa 0o amp i 1196o

vinc 148 kms i 00028 oorbit

a ac 01 mms2 P 6959 s Thrust acts over northern hemisphere of orbit (12 of Period)

tinc change 3437 days

Orbit Transfer

Final Destination

bull Δttotal = 4667 days or ~ 155 months bull time it takes to transfer from LV Delivery 1100 km polar orbit to 1500 km SS

orbit

bull this BOTE calculation has huge implications on both

bull mission duration

bull life span of sc components materials etc

bull Validates the high performance orbit transfer capabilities of the heliogyro architecture

32

Integration CubeSat

Pitch Test Validation

Sensor(s) to measure

torque and

Purpose Demonstrate coordinated pitching with equivalent mass and

realistic bus rotation

bull Rotation of 1 RPM

bull Measure torque on bus

bull Measure and compare actual pitching angles

to commanded

pitching angles

Sensors Needed

bull 3 axis Accelerometer (torque measurement)

bull 3 axis Gyroscope (pitch angle measurement)

bull 12 bit resolution (greater than pitching motors)

bull Fit onto or on 8U CubeSat

ADI516xxxIM4

bull 3 axis gyroscope

bull 3 axis magnetometer

bull 3 axis accelerometer

bull 14 bit resolution

bull 1

volume

bull Available free for checkout in ITLL

Sail Equivalent

mass

33

Integration CubeSat

Feasibility of our Baseline Design

bull To achieve characteristic acceleration for an 8U (8kg) CubeSat we needed each sail to be 2203

bull The diameter of the rolled spool inside the CubeSat (pre-deployment) varies with the width of the sail

bull To find the diameter of the rolled spool we calculated the length of one sail for a chosen width Assuming a Mylar thickness of 5 um due to the crinkling effect the spool width was calculated by iterating each rotation with increasing diameter as the blade rolls up

Iterate for rolling up sail until finished

(cm)

(m)

12 1836 247

10 2203 270

8 2754 300

34

Integration CubeSat

Sizing the Blades

bull CubeSat constrained by 20 cm on each side

bull Need to perform 180 degree independent rotation and maximize room inside the satellite for pitching motors controls and communication

Top Down Views of each size ( Scaled to correct dimensions)

12 cm blade width 10 cm blade width 8 cm blade width

bull Not intrusive on inner area

bull Full 180 motion

bull Infringes on space inside

bull Full 180 motion

bull Not intrusive on inner area

bull No Full 180 motion

35

Integration CubeSat

Housing the Rolled Sail

bull The solar sail blades will be controlled by a pitching axle but there must be an interface to connect to the axle

bull Cylindrical plate housing

bull Protects blades

bull Easy to connect to axle

bull No gears

bull Ability to provide counterweight

to deployment motor

bull With the tight volume constraints of our cube the Cylindrical plate must be altered to avoid interference with other sides

36

Integration CubeSat

Fitting the cylindrical Plate

bull Clearance for rolled sail

bull 2 cm clearance on each side

bull 06 cm clearance on behind the motor

bull This leaves overlapping corners

bull To prevent overlap we will make a 45ordm cut around the entire cylinder

2 cm

06 cm

Rolled Sail

Plate Encasing

Overlapping

Corners

45ordm cut to get rid

of corners

37

Integration CubeSat

Fitting the cylindrical Plate

bull The 45ordm cut will give us a 0 cm clearance (with no thickness)

bull If we implement a high-low offset between adjacent plates the distance between the two closest points increases

bull For our 14 cm diameter plates a 2 cm offset from the center for each plate (4 cm total) the effective clearance becomes 251 cm

Two adjacent sides

on same axis

With a High-Low Offset

38

Integration CubeSat

High-Low Offset Plates

The high low offset will give each plate room to rotate a full 180ordm

1 cm clearance between the top of the

blade and the edge of the satellite to fit

the thin-set bearing

A 3mm plate thickness gives adjacent

plates a distance of 19 cm between

their closest points

39

Integration CubeSat

High Low Offset Performance Validation

bull The high-low offset will not effect the performance or stability of the deployment or pitching systems

bull Upon deployment the opposing extension on each side cancels out unwanted torque

View From high side View From low side

bull In a sun-synchronous orbit the high or low setting has no effect as the rotational axis of the satellite is always solar pointing

View From Sun

40

Integration Power

Electronics Feasibility Analysis

bull Project Constraints

bull CubeSat power source Li-Ion batteries (5 and 33 V is common) - Would require thermal protection

bull Communications System - Transceiver (UHF is common) [USART serial port] - Buffer may be needed depending on power constraints

bull Deployment Subsystem - 1 step-motor [output] - 1 encoder [MSSP input] OR direct deployment measurement via external sensor

bull Pitching Subsystem - 2 servomotors [output]

41

Integration Power

PIC18F Series Microchip

bull Inputs 2 USART and 2 MSSP ports available (for basic PICs) - More than 1 device may be connected to each port - 2-3 devices needed

bull Outputs 8 ports - 2 devices needed

bull 16 bit - Though different PICs may be acquired for higher resolution

bull Operating Range 2-55 V - Within provided parameters

42

PIC

Communications

Deployment

Motor

Encoder

Pitching

Motor 1

Pitching

Motor 2 Key

Power Lines

Input Lines

Output Lines

Integration Power

Microchip FBD

5V Battery

Possible Voltage

Buffer

Encoder

43

Integration Power

Motor Power Limitations

bull Power Constraints

Pmax = 100 W

Vmax = 50 V

bull P = IV (Power = CurrentVoltage)

bull Therefore Iave = 20 Amps

bull Blade Pitching (4 motors total needed) - Current limitations for power sources and number of simultaneous blades pitching

Number of Blades 5 V Input 36 V input 31 V input 2 V input

4 040 A 069 A 081 A 125 A

2 080 A 139 A 161 A 250 A

1 160 A 278 A 323 A 500 A

44

Integration Motors

Stepper vs Brushless Servo Motors

45

-Contain many poles (50+) -Contain only 4-12 poles

-Distinct steps cause

vibration during use -Do not suffer from

vibration and resonance

issues smooth movement

-Low maintenance easier to

commission mechanically

simple

-Efficient response to start

stop and reverse commands

-Rely on encoders for

position details in closed

loop response

-Physical sizes

are comparable

-Both available

in various

lengths at same

frame size -Torque can be readily

controlled

-Low cost and high

availability

-Complexity drives cost

upward

Chosen for

deployment motor

Chosen for

pitching motor

Stepper Servo

Integration Blade Deployment

Deployment Motor Feasibility

Required holding torque is calculated to be 18 mNm

Required driving torque is calculated to be 117

10-5 mN∙m

bull Micro Motion Solutions ndash miniature stepper motors bull Physical Properties

bull Diameter = 6-22 mm

bull Length = 93-20 mm

bull Weight = 55-12 g

bull Holding Torque = 24-10 mN∙m = 034-142 oz∙in

bull Resolution bull 1 or 2 phase half-step capability

bull Steps per turn = 20-24 rarr 15˚-18˚ per step

5 of full step accuracy

bull Power Requirements bull Nominal voltage per phase 2-5 V

bull Nominal current per phase 01-1 A

46

Integration Blade Pitching

Blade Pitching Motor Feasibility

Required driving torque is calculated to be 0019 mN∙m

bull Mabuchi Servo Motor bull Physical Size

bull Diameter = 17 mm

bull Length = 25 mm

bull Weight = 16 g

bull Torque

bull Holding Torque = 161 mN∙m = 0228 oz∙in

bull Driving Torque = 0385 mN∙m = 0055 oz∙in

bull Friction Torque = 403

10-3 mN∙m = 571

10-4 oz∙in

bull Power Requirements

bull Nominal voltage per phase 2-5 V

bull Nominal current per phase 006-02 A 47

Integration Launch

Feasibility for Pre-deployment locking mechanism

The tip of the solar sail will be wider than the body with the sail tip set outside the plate

The tip will be held in place vertically by stationary blade stabilizers and kept tight by the holding torque of the deployment motor

Stationary blade

stabilizers

Extra-wide

blade tip

Upon deployment the motor

turns and the blade extends

48

Integration Launch

Canesterized Satellite Dispenser (CSD)

bull Ride in a 12 U CSD

bull Width=239 cm Height=226 cm Length=366 cm

bull Mass=0-24 kg at launch

bull Center of Mass when stowed in

bull x is -40 to 40 mm

bull y is 50 to 125 mm

bull z is 133 to 233 mm

wwwplanetarysytemscorpcom 49

Integration Launch

Test Validation

bull Launch Vibration Test

bull Needs to be space applicable and strong enough to withstand vibration

bull Ball Aerospace can provide a shake table costing $250hr

bull Preparation for Testing using FEM modeling and adding support features

50

Financial

bull Total Budget $5000

bull Components

bull Stepper Motor $100-200

bull Servo Motor (x2) $50-500 each

bull Materials (made in-house) $500-1000

bull Electronics $0-500

bull Testing

bull Deployment amp Pitching Free (Performed on Campus)

bull Launch Survivability Vibration Stand - $250hr Ball Space Systems in Boulder

bull Total Estimation $700-2700 + Vibration Stand Testing

51

Baseline Design All Together

bull The 8u CubeSat and characteristic acceleration requirements create very strict volumetric restrictions

bull The size of the plates and the rolled sail blade must be validated

bull This design will be analyzed and verified in the feasibility requirements

Inner Control Area

bull Motor

bull Encoder

bull Control

bull Communication

bull Power

Possible Load-bearing

corners for deployment

Housed Solar Sail

Top-Down View

Extra room for third

party systems

52

Status Summary

53

SystemMechanism Final Choice Further

Studies

Needed

8U Structure Fit our CubeSat in 12U bus provided by Planetary Services Yes

Adequate Area of Sails to Provide

Orbit Transfer Capabilities

AR = 22001 No

Pitching Mechanism Using a servo motor Yes

Pitching Accuracy Pitching encoder Yes

Plate Integration System Using a two cylinder design with tapered edges so

everything will fit

No

Deployment Motor Using a stepper motor No

Launch Ability Must conform to standards set by Planetary Services Yes

Launch Survivability Verify that GHOST will survive launch Yes

Initial Spin-Up Carbon steel attached to solar blade material Yes 53

Strategy for Conducting

Remaining Studies

bull 8U GHOST inside 12U structure bull Create a SolidWorksCAD model

bull Pitching Mechanism bull Determine adequate motor within size power and cost constraints

bull Pitching Accuracy bull Determine pitching accuracy based on orbital sensitivity

bull Launch Ability bull Because design is symmetrical center of mass is in the center of the satellite during launch bull Further investigations is needed to determine how many counterweights

bull Launch Survivability bull FEM or Vibrations

bull Initial Spin-up bull Determine feasible method to attach carbon steel support structure to solar sail blade material

54

Resources

bull PAYLOAD SPECIFICATION FOR 3U 6U 12U AND 27U Np Planetary Systems Corporation 2013 Print

bull Davis Jason The Planetary Society The Planetary Society Blog Firefly Partners 11 Apr 2012 Web 12 Oct 2013 lthttpwwwplanetaryorgblogsguest-blogsjason-davis3450htmlgt

bull Mao Tengfei 01mm Thickness Measuring Tape Wwwalibabacom Alibabacom nd Web 12 Oct 2013 lthttpwwwalibabacomproduct-gs8359006940_1mm_thickness_measuring_tapehtmlgt

55

Resources

bull ldquoHow servos and steppers stack uprdquo Machine Design 9 February 2012 [httpmachinedesigncomnewshow-servos-and-steppers-stack Accessed 7 October 2013]

bull ldquoMiniature Stepper Motor Drive Systems - Data Sheetrdquo Micro Motion Solutions [httpwwwmicromocomstepper-motors-datasheetsaspx Accessed 11 October 2013]

bull ldquoData Sheet for TS-53 Servorsquos Electric Motorrdquo Mabuchi Motor [httpwwwprincetonedu~mae412TEXTNTRAK2002292-302pdf Accessed 11 October 2013]

56

Orbit Transfer

Orbit Raising Maneuver

bull Calculated using Hohmann Transfer Equations

30

initial transfer vi 945 ms

transfer final v f 933 ms

vtotal 1877 ms

torbit raise 123 days

45o Preflect 454 Pa ain plane 177x10 5 ms2

Two blades pitched at

45

producing thrust in along track direction

See appendix for detailed orbit transfer diagrams

Orbit Transfer

Orbit Inclination Change

bull Calculated using inclination change only equations

31

v inc 2v initialcos( fpa)sini

2where vinitial v f fpa 0o amp i 1196o

vinc 148 kms i 00028 oorbit

a ac 01 mms2 P 6959 s Thrust acts over northern hemisphere of orbit (12 of Period)

tinc change 3437 days

Orbit Transfer

Final Destination

bull Δttotal = 4667 days or ~ 155 months bull time it takes to transfer from LV Delivery 1100 km polar orbit to 1500 km SS

orbit

bull this BOTE calculation has huge implications on both

bull mission duration

bull life span of sc components materials etc

bull Validates the high performance orbit transfer capabilities of the heliogyro architecture

32

Integration CubeSat

Pitch Test Validation

Sensor(s) to measure

torque and

Purpose Demonstrate coordinated pitching with equivalent mass and

realistic bus rotation

bull Rotation of 1 RPM

bull Measure torque on bus

bull Measure and compare actual pitching angles

to commanded

pitching angles

Sensors Needed

bull 3 axis Accelerometer (torque measurement)

bull 3 axis Gyroscope (pitch angle measurement)

bull 12 bit resolution (greater than pitching motors)

bull Fit onto or on 8U CubeSat

ADI516xxxIM4

bull 3 axis gyroscope

bull 3 axis magnetometer

bull 3 axis accelerometer

bull 14 bit resolution

bull 1

volume

bull Available free for checkout in ITLL

Sail Equivalent

mass

33

Integration CubeSat

Feasibility of our Baseline Design

bull To achieve characteristic acceleration for an 8U (8kg) CubeSat we needed each sail to be 2203

bull The diameter of the rolled spool inside the CubeSat (pre-deployment) varies with the width of the sail

bull To find the diameter of the rolled spool we calculated the length of one sail for a chosen width Assuming a Mylar thickness of 5 um due to the crinkling effect the spool width was calculated by iterating each rotation with increasing diameter as the blade rolls up

Iterate for rolling up sail until finished

(cm)

(m)

12 1836 247

10 2203 270

8 2754 300

34

Integration CubeSat

Sizing the Blades

bull CubeSat constrained by 20 cm on each side

bull Need to perform 180 degree independent rotation and maximize room inside the satellite for pitching motors controls and communication

Top Down Views of each size ( Scaled to correct dimensions)

12 cm blade width 10 cm blade width 8 cm blade width

bull Not intrusive on inner area

bull Full 180 motion

bull Infringes on space inside

bull Full 180 motion

bull Not intrusive on inner area

bull No Full 180 motion

35

Integration CubeSat

Housing the Rolled Sail

bull The solar sail blades will be controlled by a pitching axle but there must be an interface to connect to the axle

bull Cylindrical plate housing

bull Protects blades

bull Easy to connect to axle

bull No gears

bull Ability to provide counterweight

to deployment motor

bull With the tight volume constraints of our cube the Cylindrical plate must be altered to avoid interference with other sides

36

Integration CubeSat

Fitting the cylindrical Plate

bull Clearance for rolled sail

bull 2 cm clearance on each side

bull 06 cm clearance on behind the motor

bull This leaves overlapping corners

bull To prevent overlap we will make a 45ordm cut around the entire cylinder

2 cm

06 cm

Rolled Sail

Plate Encasing

Overlapping

Corners

45ordm cut to get rid

of corners

37

Integration CubeSat

Fitting the cylindrical Plate

bull The 45ordm cut will give us a 0 cm clearance (with no thickness)

bull If we implement a high-low offset between adjacent plates the distance between the two closest points increases

bull For our 14 cm diameter plates a 2 cm offset from the center for each plate (4 cm total) the effective clearance becomes 251 cm

Two adjacent sides

on same axis

With a High-Low Offset

38

Integration CubeSat

High-Low Offset Plates

The high low offset will give each plate room to rotate a full 180ordm

1 cm clearance between the top of the

blade and the edge of the satellite to fit

the thin-set bearing

A 3mm plate thickness gives adjacent

plates a distance of 19 cm between

their closest points

39

Integration CubeSat

High Low Offset Performance Validation

bull The high-low offset will not effect the performance or stability of the deployment or pitching systems

bull Upon deployment the opposing extension on each side cancels out unwanted torque

View From high side View From low side

bull In a sun-synchronous orbit the high or low setting has no effect as the rotational axis of the satellite is always solar pointing

View From Sun

40

Integration Power

Electronics Feasibility Analysis

bull Project Constraints

bull CubeSat power source Li-Ion batteries (5 and 33 V is common) - Would require thermal protection

bull Communications System - Transceiver (UHF is common) [USART serial port] - Buffer may be needed depending on power constraints

bull Deployment Subsystem - 1 step-motor [output] - 1 encoder [MSSP input] OR direct deployment measurement via external sensor

bull Pitching Subsystem - 2 servomotors [output]

41

Integration Power

PIC18F Series Microchip

bull Inputs 2 USART and 2 MSSP ports available (for basic PICs) - More than 1 device may be connected to each port - 2-3 devices needed

bull Outputs 8 ports - 2 devices needed

bull 16 bit - Though different PICs may be acquired for higher resolution

bull Operating Range 2-55 V - Within provided parameters

42

PIC

Communications

Deployment

Motor

Encoder

Pitching

Motor 1

Pitching

Motor 2 Key

Power Lines

Input Lines

Output Lines

Integration Power

Microchip FBD

5V Battery

Possible Voltage

Buffer

Encoder

43

Integration Power

Motor Power Limitations

bull Power Constraints

Pmax = 100 W

Vmax = 50 V

bull P = IV (Power = CurrentVoltage)

bull Therefore Iave = 20 Amps

bull Blade Pitching (4 motors total needed) - Current limitations for power sources and number of simultaneous blades pitching

Number of Blades 5 V Input 36 V input 31 V input 2 V input

4 040 A 069 A 081 A 125 A

2 080 A 139 A 161 A 250 A

1 160 A 278 A 323 A 500 A

44

Integration Motors

Stepper vs Brushless Servo Motors

45

-Contain many poles (50+) -Contain only 4-12 poles

-Distinct steps cause

vibration during use -Do not suffer from

vibration and resonance

issues smooth movement

-Low maintenance easier to

commission mechanically

simple

-Efficient response to start

stop and reverse commands

-Rely on encoders for

position details in closed

loop response

-Physical sizes

are comparable

-Both available

in various

lengths at same

frame size -Torque can be readily

controlled

-Low cost and high

availability

-Complexity drives cost

upward

Chosen for

deployment motor

Chosen for

pitching motor

Stepper Servo

Integration Blade Deployment

Deployment Motor Feasibility

Required holding torque is calculated to be 18 mNm

Required driving torque is calculated to be 117

10-5 mN∙m

bull Micro Motion Solutions ndash miniature stepper motors bull Physical Properties

bull Diameter = 6-22 mm

bull Length = 93-20 mm

bull Weight = 55-12 g

bull Holding Torque = 24-10 mN∙m = 034-142 oz∙in

bull Resolution bull 1 or 2 phase half-step capability

bull Steps per turn = 20-24 rarr 15˚-18˚ per step

5 of full step accuracy

bull Power Requirements bull Nominal voltage per phase 2-5 V

bull Nominal current per phase 01-1 A

46

Integration Blade Pitching

Blade Pitching Motor Feasibility

Required driving torque is calculated to be 0019 mN∙m

bull Mabuchi Servo Motor bull Physical Size

bull Diameter = 17 mm

bull Length = 25 mm

bull Weight = 16 g

bull Torque

bull Holding Torque = 161 mN∙m = 0228 oz∙in

bull Driving Torque = 0385 mN∙m = 0055 oz∙in

bull Friction Torque = 403

10-3 mN∙m = 571

10-4 oz∙in

bull Power Requirements

bull Nominal voltage per phase 2-5 V

bull Nominal current per phase 006-02 A 47

Integration Launch

Feasibility for Pre-deployment locking mechanism

The tip of the solar sail will be wider than the body with the sail tip set outside the plate

The tip will be held in place vertically by stationary blade stabilizers and kept tight by the holding torque of the deployment motor

Stationary blade

stabilizers

Extra-wide

blade tip

Upon deployment the motor

turns and the blade extends

48

Integration Launch

Canesterized Satellite Dispenser (CSD)

bull Ride in a 12 U CSD

bull Width=239 cm Height=226 cm Length=366 cm

bull Mass=0-24 kg at launch

bull Center of Mass when stowed in

bull x is -40 to 40 mm

bull y is 50 to 125 mm

bull z is 133 to 233 mm

wwwplanetarysytemscorpcom 49

Integration Launch

Test Validation

bull Launch Vibration Test

bull Needs to be space applicable and strong enough to withstand vibration

bull Ball Aerospace can provide a shake table costing $250hr

bull Preparation for Testing using FEM modeling and adding support features

50

Financial

bull Total Budget $5000

bull Components

bull Stepper Motor $100-200

bull Servo Motor (x2) $50-500 each

bull Materials (made in-house) $500-1000

bull Electronics $0-500

bull Testing

bull Deployment amp Pitching Free (Performed on Campus)

bull Launch Survivability Vibration Stand - $250hr Ball Space Systems in Boulder

bull Total Estimation $700-2700 + Vibration Stand Testing

51

Baseline Design All Together

bull The 8u CubeSat and characteristic acceleration requirements create very strict volumetric restrictions

bull The size of the plates and the rolled sail blade must be validated

bull This design will be analyzed and verified in the feasibility requirements

Inner Control Area

bull Motor

bull Encoder

bull Control

bull Communication

bull Power

Possible Load-bearing

corners for deployment

Housed Solar Sail

Top-Down View

Extra room for third

party systems

52

Status Summary

53

SystemMechanism Final Choice Further

Studies

Needed

8U Structure Fit our CubeSat in 12U bus provided by Planetary Services Yes

Adequate Area of Sails to Provide

Orbit Transfer Capabilities

AR = 22001 No

Pitching Mechanism Using a servo motor Yes

Pitching Accuracy Pitching encoder Yes

Plate Integration System Using a two cylinder design with tapered edges so

everything will fit

No

Deployment Motor Using a stepper motor No

Launch Ability Must conform to standards set by Planetary Services Yes

Launch Survivability Verify that GHOST will survive launch Yes

Initial Spin-Up Carbon steel attached to solar blade material Yes 53

Strategy for Conducting

Remaining Studies

bull 8U GHOST inside 12U structure bull Create a SolidWorksCAD model

bull Pitching Mechanism bull Determine adequate motor within size power and cost constraints

bull Pitching Accuracy bull Determine pitching accuracy based on orbital sensitivity

bull Launch Ability bull Because design is symmetrical center of mass is in the center of the satellite during launch bull Further investigations is needed to determine how many counterweights

bull Launch Survivability bull FEM or Vibrations

bull Initial Spin-up bull Determine feasible method to attach carbon steel support structure to solar sail blade material

54

Resources

bull PAYLOAD SPECIFICATION FOR 3U 6U 12U AND 27U Np Planetary Systems Corporation 2013 Print

bull Davis Jason The Planetary Society The Planetary Society Blog Firefly Partners 11 Apr 2012 Web 12 Oct 2013 lthttpwwwplanetaryorgblogsguest-blogsjason-davis3450htmlgt

bull Mao Tengfei 01mm Thickness Measuring Tape Wwwalibabacom Alibabacom nd Web 12 Oct 2013 lthttpwwwalibabacomproduct-gs8359006940_1mm_thickness_measuring_tapehtmlgt

55

Resources

bull ldquoHow servos and steppers stack uprdquo Machine Design 9 February 2012 [httpmachinedesigncomnewshow-servos-and-steppers-stack Accessed 7 October 2013]

bull ldquoMiniature Stepper Motor Drive Systems - Data Sheetrdquo Micro Motion Solutions [httpwwwmicromocomstepper-motors-datasheetsaspx Accessed 11 October 2013]

bull ldquoData Sheet for TS-53 Servorsquos Electric Motorrdquo Mabuchi Motor [httpwwwprincetonedu~mae412TEXTNTRAK2002292-302pdf Accessed 11 October 2013]

56

Orbit Transfer

Orbit Inclination Change

bull Calculated using inclination change only equations

31

v inc 2v initialcos( fpa)sini

2where vinitial v f fpa 0o amp i 1196o

vinc 148 kms i 00028 oorbit

a ac 01 mms2 P 6959 s Thrust acts over northern hemisphere of orbit (12 of Period)

tinc change 3437 days

Orbit Transfer

Final Destination

bull Δttotal = 4667 days or ~ 155 months bull time it takes to transfer from LV Delivery 1100 km polar orbit to 1500 km SS

orbit

bull this BOTE calculation has huge implications on both

bull mission duration

bull life span of sc components materials etc

bull Validates the high performance orbit transfer capabilities of the heliogyro architecture

32

Integration CubeSat

Pitch Test Validation

Sensor(s) to measure

torque and

Purpose Demonstrate coordinated pitching with equivalent mass and

realistic bus rotation

bull Rotation of 1 RPM

bull Measure torque on bus

bull Measure and compare actual pitching angles

to commanded

pitching angles

Sensors Needed

bull 3 axis Accelerometer (torque measurement)

bull 3 axis Gyroscope (pitch angle measurement)

bull 12 bit resolution (greater than pitching motors)

bull Fit onto or on 8U CubeSat

ADI516xxxIM4

bull 3 axis gyroscope

bull 3 axis magnetometer

bull 3 axis accelerometer

bull 14 bit resolution

bull 1

volume

bull Available free for checkout in ITLL

Sail Equivalent

mass

33

Integration CubeSat

Feasibility of our Baseline Design

bull To achieve characteristic acceleration for an 8U (8kg) CubeSat we needed each sail to be 2203

bull The diameter of the rolled spool inside the CubeSat (pre-deployment) varies with the width of the sail

bull To find the diameter of the rolled spool we calculated the length of one sail for a chosen width Assuming a Mylar thickness of 5 um due to the crinkling effect the spool width was calculated by iterating each rotation with increasing diameter as the blade rolls up

Iterate for rolling up sail until finished

(cm)

(m)

12 1836 247

10 2203 270

8 2754 300

34

Integration CubeSat

Sizing the Blades

bull CubeSat constrained by 20 cm on each side

bull Need to perform 180 degree independent rotation and maximize room inside the satellite for pitching motors controls and communication

Top Down Views of each size ( Scaled to correct dimensions)

12 cm blade width 10 cm blade width 8 cm blade width

bull Not intrusive on inner area

bull Full 180 motion

bull Infringes on space inside

bull Full 180 motion

bull Not intrusive on inner area

bull No Full 180 motion

35

Integration CubeSat

Housing the Rolled Sail

bull The solar sail blades will be controlled by a pitching axle but there must be an interface to connect to the axle

bull Cylindrical plate housing

bull Protects blades

bull Easy to connect to axle

bull No gears

bull Ability to provide counterweight

to deployment motor

bull With the tight volume constraints of our cube the Cylindrical plate must be altered to avoid interference with other sides

36

Integration CubeSat

Fitting the cylindrical Plate

bull Clearance for rolled sail

bull 2 cm clearance on each side

bull 06 cm clearance on behind the motor

bull This leaves overlapping corners

bull To prevent overlap we will make a 45ordm cut around the entire cylinder

2 cm

06 cm

Rolled Sail

Plate Encasing

Overlapping

Corners

45ordm cut to get rid

of corners

37

Integration CubeSat

Fitting the cylindrical Plate

bull The 45ordm cut will give us a 0 cm clearance (with no thickness)

bull If we implement a high-low offset between adjacent plates the distance between the two closest points increases

bull For our 14 cm diameter plates a 2 cm offset from the center for each plate (4 cm total) the effective clearance becomes 251 cm

Two adjacent sides

on same axis

With a High-Low Offset

38

Integration CubeSat

High-Low Offset Plates

The high low offset will give each plate room to rotate a full 180ordm

1 cm clearance between the top of the

blade and the edge of the satellite to fit

the thin-set bearing

A 3mm plate thickness gives adjacent

plates a distance of 19 cm between

their closest points

39

Integration CubeSat

High Low Offset Performance Validation

bull The high-low offset will not effect the performance or stability of the deployment or pitching systems

bull Upon deployment the opposing extension on each side cancels out unwanted torque

View From high side View From low side

bull In a sun-synchronous orbit the high or low setting has no effect as the rotational axis of the satellite is always solar pointing

View From Sun

40

Integration Power

Electronics Feasibility Analysis

bull Project Constraints

bull CubeSat power source Li-Ion batteries (5 and 33 V is common) - Would require thermal protection

bull Communications System - Transceiver (UHF is common) [USART serial port] - Buffer may be needed depending on power constraints

bull Deployment Subsystem - 1 step-motor [output] - 1 encoder [MSSP input] OR direct deployment measurement via external sensor

bull Pitching Subsystem - 2 servomotors [output]

41

Integration Power

PIC18F Series Microchip

bull Inputs 2 USART and 2 MSSP ports available (for basic PICs) - More than 1 device may be connected to each port - 2-3 devices needed

bull Outputs 8 ports - 2 devices needed

bull 16 bit - Though different PICs may be acquired for higher resolution

bull Operating Range 2-55 V - Within provided parameters

42

PIC

Communications

Deployment

Motor

Encoder

Pitching

Motor 1

Pitching

Motor 2 Key

Power Lines

Input Lines

Output Lines

Integration Power

Microchip FBD

5V Battery

Possible Voltage

Buffer

Encoder

43

Integration Power

Motor Power Limitations

bull Power Constraints

Pmax = 100 W

Vmax = 50 V

bull P = IV (Power = CurrentVoltage)

bull Therefore Iave = 20 Amps

bull Blade Pitching (4 motors total needed) - Current limitations for power sources and number of simultaneous blades pitching

Number of Blades 5 V Input 36 V input 31 V input 2 V input

4 040 A 069 A 081 A 125 A

2 080 A 139 A 161 A 250 A

1 160 A 278 A 323 A 500 A

44

Integration Motors

Stepper vs Brushless Servo Motors

45

-Contain many poles (50+) -Contain only 4-12 poles

-Distinct steps cause

vibration during use -Do not suffer from

vibration and resonance

issues smooth movement

-Low maintenance easier to

commission mechanically

simple

-Efficient response to start

stop and reverse commands

-Rely on encoders for

position details in closed

loop response

-Physical sizes

are comparable

-Both available

in various

lengths at same

frame size -Torque can be readily

controlled

-Low cost and high

availability

-Complexity drives cost

upward

Chosen for

deployment motor

Chosen for

pitching motor

Stepper Servo

Integration Blade Deployment

Deployment Motor Feasibility

Required holding torque is calculated to be 18 mNm

Required driving torque is calculated to be 117

10-5 mN∙m

bull Micro Motion Solutions ndash miniature stepper motors bull Physical Properties

bull Diameter = 6-22 mm

bull Length = 93-20 mm

bull Weight = 55-12 g

bull Holding Torque = 24-10 mN∙m = 034-142 oz∙in

bull Resolution bull 1 or 2 phase half-step capability

bull Steps per turn = 20-24 rarr 15˚-18˚ per step

5 of full step accuracy

bull Power Requirements bull Nominal voltage per phase 2-5 V

bull Nominal current per phase 01-1 A

46

Integration Blade Pitching

Blade Pitching Motor Feasibility

Required driving torque is calculated to be 0019 mN∙m

bull Mabuchi Servo Motor bull Physical Size

bull Diameter = 17 mm

bull Length = 25 mm

bull Weight = 16 g

bull Torque

bull Holding Torque = 161 mN∙m = 0228 oz∙in

bull Driving Torque = 0385 mN∙m = 0055 oz∙in

bull Friction Torque = 403

10-3 mN∙m = 571

10-4 oz∙in

bull Power Requirements

bull Nominal voltage per phase 2-5 V

bull Nominal current per phase 006-02 A 47

Integration Launch

Feasibility for Pre-deployment locking mechanism

The tip of the solar sail will be wider than the body with the sail tip set outside the plate

The tip will be held in place vertically by stationary blade stabilizers and kept tight by the holding torque of the deployment motor

Stationary blade

stabilizers

Extra-wide

blade tip

Upon deployment the motor

turns and the blade extends

48

Integration Launch

Canesterized Satellite Dispenser (CSD)

bull Ride in a 12 U CSD

bull Width=239 cm Height=226 cm Length=366 cm

bull Mass=0-24 kg at launch

bull Center of Mass when stowed in

bull x is -40 to 40 mm

bull y is 50 to 125 mm

bull z is 133 to 233 mm

wwwplanetarysytemscorpcom 49

Integration Launch

Test Validation

bull Launch Vibration Test

bull Needs to be space applicable and strong enough to withstand vibration

bull Ball Aerospace can provide a shake table costing $250hr

bull Preparation for Testing using FEM modeling and adding support features

50

Financial

bull Total Budget $5000

bull Components

bull Stepper Motor $100-200

bull Servo Motor (x2) $50-500 each

bull Materials (made in-house) $500-1000

bull Electronics $0-500

bull Testing

bull Deployment amp Pitching Free (Performed on Campus)

bull Launch Survivability Vibration Stand - $250hr Ball Space Systems in Boulder

bull Total Estimation $700-2700 + Vibration Stand Testing

51

Baseline Design All Together

bull The 8u CubeSat and characteristic acceleration requirements create very strict volumetric restrictions

bull The size of the plates and the rolled sail blade must be validated

bull This design will be analyzed and verified in the feasibility requirements

Inner Control Area

bull Motor

bull Encoder

bull Control

bull Communication

bull Power

Possible Load-bearing

corners for deployment

Housed Solar Sail

Top-Down View

Extra room for third

party systems

52

Status Summary

53

SystemMechanism Final Choice Further

Studies

Needed

8U Structure Fit our CubeSat in 12U bus provided by Planetary Services Yes

Adequate Area of Sails to Provide

Orbit Transfer Capabilities

AR = 22001 No

Pitching Mechanism Using a servo motor Yes

Pitching Accuracy Pitching encoder Yes

Plate Integration System Using a two cylinder design with tapered edges so

everything will fit

No

Deployment Motor Using a stepper motor No

Launch Ability Must conform to standards set by Planetary Services Yes

Launch Survivability Verify that GHOST will survive launch Yes

Initial Spin-Up Carbon steel attached to solar blade material Yes 53

Strategy for Conducting

Remaining Studies

bull 8U GHOST inside 12U structure bull Create a SolidWorksCAD model

bull Pitching Mechanism bull Determine adequate motor within size power and cost constraints

bull Pitching Accuracy bull Determine pitching accuracy based on orbital sensitivity

bull Launch Ability bull Because design is symmetrical center of mass is in the center of the satellite during launch bull Further investigations is needed to determine how many counterweights

bull Launch Survivability bull FEM or Vibrations

bull Initial Spin-up bull Determine feasible method to attach carbon steel support structure to solar sail blade material

54

Resources

bull PAYLOAD SPECIFICATION FOR 3U 6U 12U AND 27U Np Planetary Systems Corporation 2013 Print

bull Davis Jason The Planetary Society The Planetary Society Blog Firefly Partners 11 Apr 2012 Web 12 Oct 2013 lthttpwwwplanetaryorgblogsguest-blogsjason-davis3450htmlgt

bull Mao Tengfei 01mm Thickness Measuring Tape Wwwalibabacom Alibabacom nd Web 12 Oct 2013 lthttpwwwalibabacomproduct-gs8359006940_1mm_thickness_measuring_tapehtmlgt

55

Resources

bull ldquoHow servos and steppers stack uprdquo Machine Design 9 February 2012 [httpmachinedesigncomnewshow-servos-and-steppers-stack Accessed 7 October 2013]

bull ldquoMiniature Stepper Motor Drive Systems - Data Sheetrdquo Micro Motion Solutions [httpwwwmicromocomstepper-motors-datasheetsaspx Accessed 11 October 2013]

bull ldquoData Sheet for TS-53 Servorsquos Electric Motorrdquo Mabuchi Motor [httpwwwprincetonedu~mae412TEXTNTRAK2002292-302pdf Accessed 11 October 2013]

56

Orbit Transfer

Final Destination

bull Δttotal = 4667 days or ~ 155 months bull time it takes to transfer from LV Delivery 1100 km polar orbit to 1500 km SS

orbit

bull this BOTE calculation has huge implications on both

bull mission duration

bull life span of sc components materials etc

bull Validates the high performance orbit transfer capabilities of the heliogyro architecture

32

Integration CubeSat

Pitch Test Validation

Sensor(s) to measure

torque and

Purpose Demonstrate coordinated pitching with equivalent mass and

realistic bus rotation

bull Rotation of 1 RPM

bull Measure torque on bus

bull Measure and compare actual pitching angles

to commanded

pitching angles

Sensors Needed

bull 3 axis Accelerometer (torque measurement)

bull 3 axis Gyroscope (pitch angle measurement)

bull 12 bit resolution (greater than pitching motors)

bull Fit onto or on 8U CubeSat

ADI516xxxIM4

bull 3 axis gyroscope

bull 3 axis magnetometer

bull 3 axis accelerometer

bull 14 bit resolution

bull 1

volume

bull Available free for checkout in ITLL

Sail Equivalent

mass

33

Integration CubeSat

Feasibility of our Baseline Design

bull To achieve characteristic acceleration for an 8U (8kg) CubeSat we needed each sail to be 2203

bull The diameter of the rolled spool inside the CubeSat (pre-deployment) varies with the width of the sail

bull To find the diameter of the rolled spool we calculated the length of one sail for a chosen width Assuming a Mylar thickness of 5 um due to the crinkling effect the spool width was calculated by iterating each rotation with increasing diameter as the blade rolls up

Iterate for rolling up sail until finished

(cm)

(m)

12 1836 247

10 2203 270

8 2754 300

34

Integration CubeSat

Sizing the Blades

bull CubeSat constrained by 20 cm on each side

bull Need to perform 180 degree independent rotation and maximize room inside the satellite for pitching motors controls and communication

Top Down Views of each size ( Scaled to correct dimensions)

12 cm blade width 10 cm blade width 8 cm blade width

bull Not intrusive on inner area

bull Full 180 motion

bull Infringes on space inside

bull Full 180 motion

bull Not intrusive on inner area

bull No Full 180 motion

35

Integration CubeSat

Housing the Rolled Sail

bull The solar sail blades will be controlled by a pitching axle but there must be an interface to connect to the axle

bull Cylindrical plate housing

bull Protects blades

bull Easy to connect to axle

bull No gears

bull Ability to provide counterweight

to deployment motor

bull With the tight volume constraints of our cube the Cylindrical plate must be altered to avoid interference with other sides

36

Integration CubeSat

Fitting the cylindrical Plate

bull Clearance for rolled sail

bull 2 cm clearance on each side

bull 06 cm clearance on behind the motor

bull This leaves overlapping corners

bull To prevent overlap we will make a 45ordm cut around the entire cylinder

2 cm

06 cm

Rolled Sail

Plate Encasing

Overlapping

Corners

45ordm cut to get rid

of corners

37

Integration CubeSat

Fitting the cylindrical Plate

bull The 45ordm cut will give us a 0 cm clearance (with no thickness)

bull If we implement a high-low offset between adjacent plates the distance between the two closest points increases

bull For our 14 cm diameter plates a 2 cm offset from the center for each plate (4 cm total) the effective clearance becomes 251 cm

Two adjacent sides

on same axis

With a High-Low Offset

38

Integration CubeSat

High-Low Offset Plates

The high low offset will give each plate room to rotate a full 180ordm

1 cm clearance between the top of the

blade and the edge of the satellite to fit

the thin-set bearing

A 3mm plate thickness gives adjacent

plates a distance of 19 cm between

their closest points

39

Integration CubeSat

High Low Offset Performance Validation

bull The high-low offset will not effect the performance or stability of the deployment or pitching systems

bull Upon deployment the opposing extension on each side cancels out unwanted torque

View From high side View From low side

bull In a sun-synchronous orbit the high or low setting has no effect as the rotational axis of the satellite is always solar pointing

View From Sun

40

Integration Power

Electronics Feasibility Analysis

bull Project Constraints

bull CubeSat power source Li-Ion batteries (5 and 33 V is common) - Would require thermal protection

bull Communications System - Transceiver (UHF is common) [USART serial port] - Buffer may be needed depending on power constraints

bull Deployment Subsystem - 1 step-motor [output] - 1 encoder [MSSP input] OR direct deployment measurement via external sensor

bull Pitching Subsystem - 2 servomotors [output]

41

Integration Power

PIC18F Series Microchip

bull Inputs 2 USART and 2 MSSP ports available (for basic PICs) - More than 1 device may be connected to each port - 2-3 devices needed

bull Outputs 8 ports - 2 devices needed

bull 16 bit - Though different PICs may be acquired for higher resolution

bull Operating Range 2-55 V - Within provided parameters

42

PIC

Communications

Deployment

Motor

Encoder

Pitching

Motor 1

Pitching

Motor 2 Key

Power Lines

Input Lines

Output Lines

Integration Power

Microchip FBD

5V Battery

Possible Voltage

Buffer

Encoder

43

Integration Power

Motor Power Limitations

bull Power Constraints

Pmax = 100 W

Vmax = 50 V

bull P = IV (Power = CurrentVoltage)

bull Therefore Iave = 20 Amps

bull Blade Pitching (4 motors total needed) - Current limitations for power sources and number of simultaneous blades pitching

Number of Blades 5 V Input 36 V input 31 V input 2 V input

4 040 A 069 A 081 A 125 A

2 080 A 139 A 161 A 250 A

1 160 A 278 A 323 A 500 A

44

Integration Motors

Stepper vs Brushless Servo Motors

45

-Contain many poles (50+) -Contain only 4-12 poles

-Distinct steps cause

vibration during use -Do not suffer from

vibration and resonance

issues smooth movement

-Low maintenance easier to

commission mechanically

simple

-Efficient response to start

stop and reverse commands

-Rely on encoders for

position details in closed

loop response

-Physical sizes

are comparable

-Both available

in various

lengths at same

frame size -Torque can be readily

controlled

-Low cost and high

availability

-Complexity drives cost

upward

Chosen for

deployment motor

Chosen for

pitching motor

Stepper Servo

Integration Blade Deployment

Deployment Motor Feasibility

Required holding torque is calculated to be 18 mNm

Required driving torque is calculated to be 117

10-5 mN∙m

bull Micro Motion Solutions ndash miniature stepper motors bull Physical Properties

bull Diameter = 6-22 mm

bull Length = 93-20 mm

bull Weight = 55-12 g

bull Holding Torque = 24-10 mN∙m = 034-142 oz∙in

bull Resolution bull 1 or 2 phase half-step capability

bull Steps per turn = 20-24 rarr 15˚-18˚ per step

5 of full step accuracy

bull Power Requirements bull Nominal voltage per phase 2-5 V

bull Nominal current per phase 01-1 A

46

Integration Blade Pitching

Blade Pitching Motor Feasibility

Required driving torque is calculated to be 0019 mN∙m

bull Mabuchi Servo Motor bull Physical Size

bull Diameter = 17 mm

bull Length = 25 mm

bull Weight = 16 g

bull Torque

bull Holding Torque = 161 mN∙m = 0228 oz∙in

bull Driving Torque = 0385 mN∙m = 0055 oz∙in

bull Friction Torque = 403

10-3 mN∙m = 571

10-4 oz∙in

bull Power Requirements

bull Nominal voltage per phase 2-5 V

bull Nominal current per phase 006-02 A 47

Integration Launch

Feasibility for Pre-deployment locking mechanism

The tip of the solar sail will be wider than the body with the sail tip set outside the plate

The tip will be held in place vertically by stationary blade stabilizers and kept tight by the holding torque of the deployment motor

Stationary blade

stabilizers

Extra-wide

blade tip

Upon deployment the motor

turns and the blade extends

48

Integration Launch

Canesterized Satellite Dispenser (CSD)

bull Ride in a 12 U CSD

bull Width=239 cm Height=226 cm Length=366 cm

bull Mass=0-24 kg at launch

bull Center of Mass when stowed in

bull x is -40 to 40 mm

bull y is 50 to 125 mm

bull z is 133 to 233 mm

wwwplanetarysytemscorpcom 49

Integration Launch

Test Validation

bull Launch Vibration Test

bull Needs to be space applicable and strong enough to withstand vibration

bull Ball Aerospace can provide a shake table costing $250hr

bull Preparation for Testing using FEM modeling and adding support features

50

Financial

bull Total Budget $5000

bull Components

bull Stepper Motor $100-200

bull Servo Motor (x2) $50-500 each

bull Materials (made in-house) $500-1000

bull Electronics $0-500

bull Testing

bull Deployment amp Pitching Free (Performed on Campus)

bull Launch Survivability Vibration Stand - $250hr Ball Space Systems in Boulder

bull Total Estimation $700-2700 + Vibration Stand Testing

51

Baseline Design All Together

bull The 8u CubeSat and characteristic acceleration requirements create very strict volumetric restrictions

bull The size of the plates and the rolled sail blade must be validated

bull This design will be analyzed and verified in the feasibility requirements

Inner Control Area

bull Motor

bull Encoder

bull Control

bull Communication

bull Power

Possible Load-bearing

corners for deployment

Housed Solar Sail

Top-Down View

Extra room for third

party systems

52

Status Summary

53

SystemMechanism Final Choice Further

Studies

Needed

8U Structure Fit our CubeSat in 12U bus provided by Planetary Services Yes

Adequate Area of Sails to Provide

Orbit Transfer Capabilities

AR = 22001 No

Pitching Mechanism Using a servo motor Yes

Pitching Accuracy Pitching encoder Yes

Plate Integration System Using a two cylinder design with tapered edges so

everything will fit

No

Deployment Motor Using a stepper motor No

Launch Ability Must conform to standards set by Planetary Services Yes

Launch Survivability Verify that GHOST will survive launch Yes

Initial Spin-Up Carbon steel attached to solar blade material Yes 53

Strategy for Conducting

Remaining Studies

bull 8U GHOST inside 12U structure bull Create a SolidWorksCAD model

bull Pitching Mechanism bull Determine adequate motor within size power and cost constraints

bull Pitching Accuracy bull Determine pitching accuracy based on orbital sensitivity

bull Launch Ability bull Because design is symmetrical center of mass is in the center of the satellite during launch bull Further investigations is needed to determine how many counterweights

bull Launch Survivability bull FEM or Vibrations

bull Initial Spin-up bull Determine feasible method to attach carbon steel support structure to solar sail blade material

54

Resources

bull PAYLOAD SPECIFICATION FOR 3U 6U 12U AND 27U Np Planetary Systems Corporation 2013 Print

bull Davis Jason The Planetary Society The Planetary Society Blog Firefly Partners 11 Apr 2012 Web 12 Oct 2013 lthttpwwwplanetaryorgblogsguest-blogsjason-davis3450htmlgt

bull Mao Tengfei 01mm Thickness Measuring Tape Wwwalibabacom Alibabacom nd Web 12 Oct 2013 lthttpwwwalibabacomproduct-gs8359006940_1mm_thickness_measuring_tapehtmlgt

55

Resources

bull ldquoHow servos and steppers stack uprdquo Machine Design 9 February 2012 [httpmachinedesigncomnewshow-servos-and-steppers-stack Accessed 7 October 2013]

bull ldquoMiniature Stepper Motor Drive Systems - Data Sheetrdquo Micro Motion Solutions [httpwwwmicromocomstepper-motors-datasheetsaspx Accessed 11 October 2013]

bull ldquoData Sheet for TS-53 Servorsquos Electric Motorrdquo Mabuchi Motor [httpwwwprincetonedu~mae412TEXTNTRAK2002292-302pdf Accessed 11 October 2013]

56

Integration CubeSat

Pitch Test Validation

Sensor(s) to measure

torque and

Purpose Demonstrate coordinated pitching with equivalent mass and

realistic bus rotation

bull Rotation of 1 RPM

bull Measure torque on bus

bull Measure and compare actual pitching angles

to commanded

pitching angles

Sensors Needed

bull 3 axis Accelerometer (torque measurement)

bull 3 axis Gyroscope (pitch angle measurement)

bull 12 bit resolution (greater than pitching motors)

bull Fit onto or on 8U CubeSat

ADI516xxxIM4

bull 3 axis gyroscope

bull 3 axis magnetometer

bull 3 axis accelerometer

bull 14 bit resolution

bull 1

volume

bull Available free for checkout in ITLL

Sail Equivalent

mass

33

Integration CubeSat

Feasibility of our Baseline Design

bull To achieve characteristic acceleration for an 8U (8kg) CubeSat we needed each sail to be 2203

bull The diameter of the rolled spool inside the CubeSat (pre-deployment) varies with the width of the sail

bull To find the diameter of the rolled spool we calculated the length of one sail for a chosen width Assuming a Mylar thickness of 5 um due to the crinkling effect the spool width was calculated by iterating each rotation with increasing diameter as the blade rolls up

Iterate for rolling up sail until finished

(cm)

(m)

12 1836 247

10 2203 270

8 2754 300

34

Integration CubeSat

Sizing the Blades

bull CubeSat constrained by 20 cm on each side

bull Need to perform 180 degree independent rotation and maximize room inside the satellite for pitching motors controls and communication

Top Down Views of each size ( Scaled to correct dimensions)

12 cm blade width 10 cm blade width 8 cm blade width

bull Not intrusive on inner area

bull Full 180 motion

bull Infringes on space inside

bull Full 180 motion

bull Not intrusive on inner area

bull No Full 180 motion

35

Integration CubeSat

Housing the Rolled Sail

bull The solar sail blades will be controlled by a pitching axle but there must be an interface to connect to the axle

bull Cylindrical plate housing

bull Protects blades

bull Easy to connect to axle

bull No gears

bull Ability to provide counterweight

to deployment motor

bull With the tight volume constraints of our cube the Cylindrical plate must be altered to avoid interference with other sides

36

Integration CubeSat

Fitting the cylindrical Plate

bull Clearance for rolled sail

bull 2 cm clearance on each side

bull 06 cm clearance on behind the motor

bull This leaves overlapping corners

bull To prevent overlap we will make a 45ordm cut around the entire cylinder

2 cm

06 cm

Rolled Sail

Plate Encasing

Overlapping

Corners

45ordm cut to get rid

of corners

37

Integration CubeSat

Fitting the cylindrical Plate

bull The 45ordm cut will give us a 0 cm clearance (with no thickness)

bull If we implement a high-low offset between adjacent plates the distance between the two closest points increases

bull For our 14 cm diameter plates a 2 cm offset from the center for each plate (4 cm total) the effective clearance becomes 251 cm

Two adjacent sides

on same axis

With a High-Low Offset

38

Integration CubeSat

High-Low Offset Plates

The high low offset will give each plate room to rotate a full 180ordm

1 cm clearance between the top of the

blade and the edge of the satellite to fit

the thin-set bearing

A 3mm plate thickness gives adjacent

plates a distance of 19 cm between

their closest points

39

Integration CubeSat

High Low Offset Performance Validation

bull The high-low offset will not effect the performance or stability of the deployment or pitching systems

bull Upon deployment the opposing extension on each side cancels out unwanted torque

View From high side View From low side

bull In a sun-synchronous orbit the high or low setting has no effect as the rotational axis of the satellite is always solar pointing

View From Sun

40

Integration Power

Electronics Feasibility Analysis

bull Project Constraints

bull CubeSat power source Li-Ion batteries (5 and 33 V is common) - Would require thermal protection

bull Communications System - Transceiver (UHF is common) [USART serial port] - Buffer may be needed depending on power constraints

bull Deployment Subsystem - 1 step-motor [output] - 1 encoder [MSSP input] OR direct deployment measurement via external sensor

bull Pitching Subsystem - 2 servomotors [output]

41

Integration Power

PIC18F Series Microchip

bull Inputs 2 USART and 2 MSSP ports available (for basic PICs) - More than 1 device may be connected to each port - 2-3 devices needed

bull Outputs 8 ports - 2 devices needed

bull 16 bit - Though different PICs may be acquired for higher resolution

bull Operating Range 2-55 V - Within provided parameters

42

PIC

Communications

Deployment

Motor

Encoder

Pitching

Motor 1

Pitching

Motor 2 Key

Power Lines

Input Lines

Output Lines

Integration Power

Microchip FBD

5V Battery

Possible Voltage

Buffer

Encoder

43

Integration Power

Motor Power Limitations

bull Power Constraints

Pmax = 100 W

Vmax = 50 V

bull P = IV (Power = CurrentVoltage)

bull Therefore Iave = 20 Amps

bull Blade Pitching (4 motors total needed) - Current limitations for power sources and number of simultaneous blades pitching

Number of Blades 5 V Input 36 V input 31 V input 2 V input

4 040 A 069 A 081 A 125 A

2 080 A 139 A 161 A 250 A

1 160 A 278 A 323 A 500 A

44

Integration Motors

Stepper vs Brushless Servo Motors

45

-Contain many poles (50+) -Contain only 4-12 poles

-Distinct steps cause

vibration during use -Do not suffer from

vibration and resonance

issues smooth movement

-Low maintenance easier to

commission mechanically

simple

-Efficient response to start

stop and reverse commands

-Rely on encoders for

position details in closed

loop response

-Physical sizes

are comparable

-Both available

in various

lengths at same

frame size -Torque can be readily

controlled

-Low cost and high

availability

-Complexity drives cost

upward

Chosen for

deployment motor

Chosen for

pitching motor

Stepper Servo

Integration Blade Deployment

Deployment Motor Feasibility

Required holding torque is calculated to be 18 mNm

Required driving torque is calculated to be 117

10-5 mN∙m

bull Micro Motion Solutions ndash miniature stepper motors bull Physical Properties

bull Diameter = 6-22 mm

bull Length = 93-20 mm

bull Weight = 55-12 g

bull Holding Torque = 24-10 mN∙m = 034-142 oz∙in

bull Resolution bull 1 or 2 phase half-step capability

bull Steps per turn = 20-24 rarr 15˚-18˚ per step

5 of full step accuracy

bull Power Requirements bull Nominal voltage per phase 2-5 V

bull Nominal current per phase 01-1 A

46

Integration Blade Pitching

Blade Pitching Motor Feasibility

Required driving torque is calculated to be 0019 mN∙m

bull Mabuchi Servo Motor bull Physical Size

bull Diameter = 17 mm

bull Length = 25 mm

bull Weight = 16 g

bull Torque

bull Holding Torque = 161 mN∙m = 0228 oz∙in

bull Driving Torque = 0385 mN∙m = 0055 oz∙in

bull Friction Torque = 403

10-3 mN∙m = 571

10-4 oz∙in

bull Power Requirements

bull Nominal voltage per phase 2-5 V

bull Nominal current per phase 006-02 A 47

Integration Launch

Feasibility for Pre-deployment locking mechanism

The tip of the solar sail will be wider than the body with the sail tip set outside the plate

The tip will be held in place vertically by stationary blade stabilizers and kept tight by the holding torque of the deployment motor

Stationary blade

stabilizers

Extra-wide

blade tip

Upon deployment the motor

turns and the blade extends

48

Integration Launch

Canesterized Satellite Dispenser (CSD)

bull Ride in a 12 U CSD

bull Width=239 cm Height=226 cm Length=366 cm

bull Mass=0-24 kg at launch

bull Center of Mass when stowed in

bull x is -40 to 40 mm

bull y is 50 to 125 mm

bull z is 133 to 233 mm

wwwplanetarysytemscorpcom 49

Integration Launch

Test Validation

bull Launch Vibration Test

bull Needs to be space applicable and strong enough to withstand vibration

bull Ball Aerospace can provide a shake table costing $250hr

bull Preparation for Testing using FEM modeling and adding support features

50

Financial

bull Total Budget $5000

bull Components

bull Stepper Motor $100-200

bull Servo Motor (x2) $50-500 each

bull Materials (made in-house) $500-1000

bull Electronics $0-500

bull Testing

bull Deployment amp Pitching Free (Performed on Campus)

bull Launch Survivability Vibration Stand - $250hr Ball Space Systems in Boulder

bull Total Estimation $700-2700 + Vibration Stand Testing

51

Baseline Design All Together

bull The 8u CubeSat and characteristic acceleration requirements create very strict volumetric restrictions

bull The size of the plates and the rolled sail blade must be validated

bull This design will be analyzed and verified in the feasibility requirements

Inner Control Area

bull Motor

bull Encoder

bull Control

bull Communication

bull Power

Possible Load-bearing

corners for deployment

Housed Solar Sail

Top-Down View

Extra room for third

party systems

52

Status Summary

53

SystemMechanism Final Choice Further

Studies

Needed

8U Structure Fit our CubeSat in 12U bus provided by Planetary Services Yes

Adequate Area of Sails to Provide

Orbit Transfer Capabilities

AR = 22001 No

Pitching Mechanism Using a servo motor Yes

Pitching Accuracy Pitching encoder Yes

Plate Integration System Using a two cylinder design with tapered edges so

everything will fit

No

Deployment Motor Using a stepper motor No

Launch Ability Must conform to standards set by Planetary Services Yes

Launch Survivability Verify that GHOST will survive launch Yes

Initial Spin-Up Carbon steel attached to solar blade material Yes 53

Strategy for Conducting

Remaining Studies

bull 8U GHOST inside 12U structure bull Create a SolidWorksCAD model

bull Pitching Mechanism bull Determine adequate motor within size power and cost constraints

bull Pitching Accuracy bull Determine pitching accuracy based on orbital sensitivity

bull Launch Ability bull Because design is symmetrical center of mass is in the center of the satellite during launch bull Further investigations is needed to determine how many counterweights

bull Launch Survivability bull FEM or Vibrations

bull Initial Spin-up bull Determine feasible method to attach carbon steel support structure to solar sail blade material

54

Resources

bull PAYLOAD SPECIFICATION FOR 3U 6U 12U AND 27U Np Planetary Systems Corporation 2013 Print

bull Davis Jason The Planetary Society The Planetary Society Blog Firefly Partners 11 Apr 2012 Web 12 Oct 2013 lthttpwwwplanetaryorgblogsguest-blogsjason-davis3450htmlgt

bull Mao Tengfei 01mm Thickness Measuring Tape Wwwalibabacom Alibabacom nd Web 12 Oct 2013 lthttpwwwalibabacomproduct-gs8359006940_1mm_thickness_measuring_tapehtmlgt

55

Resources

bull ldquoHow servos and steppers stack uprdquo Machine Design 9 February 2012 [httpmachinedesigncomnewshow-servos-and-steppers-stack Accessed 7 October 2013]

bull ldquoMiniature Stepper Motor Drive Systems - Data Sheetrdquo Micro Motion Solutions [httpwwwmicromocomstepper-motors-datasheetsaspx Accessed 11 October 2013]

bull ldquoData Sheet for TS-53 Servorsquos Electric Motorrdquo Mabuchi Motor [httpwwwprincetonedu~mae412TEXTNTRAK2002292-302pdf Accessed 11 October 2013]

56

Integration CubeSat

Feasibility of our Baseline Design

bull To achieve characteristic acceleration for an 8U (8kg) CubeSat we needed each sail to be 2203

bull The diameter of the rolled spool inside the CubeSat (pre-deployment) varies with the width of the sail

bull To find the diameter of the rolled spool we calculated the length of one sail for a chosen width Assuming a Mylar thickness of 5 um due to the crinkling effect the spool width was calculated by iterating each rotation with increasing diameter as the blade rolls up

Iterate for rolling up sail until finished

(cm)

(m)

12 1836 247

10 2203 270

8 2754 300

34

Integration CubeSat

Sizing the Blades

bull CubeSat constrained by 20 cm on each side

bull Need to perform 180 degree independent rotation and maximize room inside the satellite for pitching motors controls and communication

Top Down Views of each size ( Scaled to correct dimensions)

12 cm blade width 10 cm blade width 8 cm blade width

bull Not intrusive on inner area

bull Full 180 motion

bull Infringes on space inside

bull Full 180 motion

bull Not intrusive on inner area

bull No Full 180 motion

35

Integration CubeSat

Housing the Rolled Sail

bull The solar sail blades will be controlled by a pitching axle but there must be an interface to connect to the axle

bull Cylindrical plate housing

bull Protects blades

bull Easy to connect to axle

bull No gears

bull Ability to provide counterweight

to deployment motor

bull With the tight volume constraints of our cube the Cylindrical plate must be altered to avoid interference with other sides

36

Integration CubeSat

Fitting the cylindrical Plate

bull Clearance for rolled sail

bull 2 cm clearance on each side

bull 06 cm clearance on behind the motor

bull This leaves overlapping corners

bull To prevent overlap we will make a 45ordm cut around the entire cylinder

2 cm

06 cm

Rolled Sail

Plate Encasing

Overlapping

Corners

45ordm cut to get rid

of corners

37

Integration CubeSat

Fitting the cylindrical Plate

bull The 45ordm cut will give us a 0 cm clearance (with no thickness)

bull If we implement a high-low offset between adjacent plates the distance between the two closest points increases

bull For our 14 cm diameter plates a 2 cm offset from the center for each plate (4 cm total) the effective clearance becomes 251 cm

Two adjacent sides

on same axis

With a High-Low Offset

38

Integration CubeSat

High-Low Offset Plates

The high low offset will give each plate room to rotate a full 180ordm

1 cm clearance between the top of the

blade and the edge of the satellite to fit

the thin-set bearing

A 3mm plate thickness gives adjacent

plates a distance of 19 cm between

their closest points

39

Integration CubeSat

High Low Offset Performance Validation

bull The high-low offset will not effect the performance or stability of the deployment or pitching systems

bull Upon deployment the opposing extension on each side cancels out unwanted torque

View From high side View From low side

bull In a sun-synchronous orbit the high or low setting has no effect as the rotational axis of the satellite is always solar pointing

View From Sun

40

Integration Power

Electronics Feasibility Analysis

bull Project Constraints

bull CubeSat power source Li-Ion batteries (5 and 33 V is common) - Would require thermal protection

bull Communications System - Transceiver (UHF is common) [USART serial port] - Buffer may be needed depending on power constraints

bull Deployment Subsystem - 1 step-motor [output] - 1 encoder [MSSP input] OR direct deployment measurement via external sensor

bull Pitching Subsystem - 2 servomotors [output]

41

Integration Power

PIC18F Series Microchip

bull Inputs 2 USART and 2 MSSP ports available (for basic PICs) - More than 1 device may be connected to each port - 2-3 devices needed

bull Outputs 8 ports - 2 devices needed

bull 16 bit - Though different PICs may be acquired for higher resolution

bull Operating Range 2-55 V - Within provided parameters

42

PIC

Communications

Deployment

Motor

Encoder

Pitching

Motor 1

Pitching

Motor 2 Key

Power Lines

Input Lines

Output Lines

Integration Power

Microchip FBD

5V Battery

Possible Voltage

Buffer

Encoder

43

Integration Power

Motor Power Limitations

bull Power Constraints

Pmax = 100 W

Vmax = 50 V

bull P = IV (Power = CurrentVoltage)

bull Therefore Iave = 20 Amps

bull Blade Pitching (4 motors total needed) - Current limitations for power sources and number of simultaneous blades pitching

Number of Blades 5 V Input 36 V input 31 V input 2 V input

4 040 A 069 A 081 A 125 A

2 080 A 139 A 161 A 250 A

1 160 A 278 A 323 A 500 A

44

Integration Motors

Stepper vs Brushless Servo Motors

45

-Contain many poles (50+) -Contain only 4-12 poles

-Distinct steps cause

vibration during use -Do not suffer from

vibration and resonance

issues smooth movement

-Low maintenance easier to

commission mechanically

simple

-Efficient response to start

stop and reverse commands

-Rely on encoders for

position details in closed

loop response

-Physical sizes

are comparable

-Both available

in various

lengths at same

frame size -Torque can be readily

controlled

-Low cost and high

availability

-Complexity drives cost

upward

Chosen for

deployment motor

Chosen for

pitching motor

Stepper Servo

Integration Blade Deployment

Deployment Motor Feasibility

Required holding torque is calculated to be 18 mNm

Required driving torque is calculated to be 117

10-5 mN∙m

bull Micro Motion Solutions ndash miniature stepper motors bull Physical Properties

bull Diameter = 6-22 mm

bull Length = 93-20 mm

bull Weight = 55-12 g

bull Holding Torque = 24-10 mN∙m = 034-142 oz∙in

bull Resolution bull 1 or 2 phase half-step capability

bull Steps per turn = 20-24 rarr 15˚-18˚ per step

5 of full step accuracy

bull Power Requirements bull Nominal voltage per phase 2-5 V

bull Nominal current per phase 01-1 A

46

Integration Blade Pitching

Blade Pitching Motor Feasibility

Required driving torque is calculated to be 0019 mN∙m

bull Mabuchi Servo Motor bull Physical Size

bull Diameter = 17 mm

bull Length = 25 mm

bull Weight = 16 g

bull Torque

bull Holding Torque = 161 mN∙m = 0228 oz∙in

bull Driving Torque = 0385 mN∙m = 0055 oz∙in

bull Friction Torque = 403

10-3 mN∙m = 571

10-4 oz∙in

bull Power Requirements

bull Nominal voltage per phase 2-5 V

bull Nominal current per phase 006-02 A 47

Integration Launch

Feasibility for Pre-deployment locking mechanism

The tip of the solar sail will be wider than the body with the sail tip set outside the plate

The tip will be held in place vertically by stationary blade stabilizers and kept tight by the holding torque of the deployment motor

Stationary blade

stabilizers

Extra-wide

blade tip

Upon deployment the motor

turns and the blade extends

48

Integration Launch

Canesterized Satellite Dispenser (CSD)

bull Ride in a 12 U CSD

bull Width=239 cm Height=226 cm Length=366 cm

bull Mass=0-24 kg at launch

bull Center of Mass when stowed in

bull x is -40 to 40 mm

bull y is 50 to 125 mm

bull z is 133 to 233 mm

wwwplanetarysytemscorpcom 49

Integration Launch

Test Validation

bull Launch Vibration Test

bull Needs to be space applicable and strong enough to withstand vibration

bull Ball Aerospace can provide a shake table costing $250hr

bull Preparation for Testing using FEM modeling and adding support features

50

Financial

bull Total Budget $5000

bull Components

bull Stepper Motor $100-200

bull Servo Motor (x2) $50-500 each

bull Materials (made in-house) $500-1000

bull Electronics $0-500

bull Testing

bull Deployment amp Pitching Free (Performed on Campus)

bull Launch Survivability Vibration Stand - $250hr Ball Space Systems in Boulder

bull Total Estimation $700-2700 + Vibration Stand Testing

51

Baseline Design All Together

bull The 8u CubeSat and characteristic acceleration requirements create very strict volumetric restrictions

bull The size of the plates and the rolled sail blade must be validated

bull This design will be analyzed and verified in the feasibility requirements

Inner Control Area

bull Motor

bull Encoder

bull Control

bull Communication

bull Power

Possible Load-bearing

corners for deployment

Housed Solar Sail

Top-Down View

Extra room for third

party systems

52

Status Summary

53

SystemMechanism Final Choice Further

Studies

Needed

8U Structure Fit our CubeSat in 12U bus provided by Planetary Services Yes

Adequate Area of Sails to Provide

Orbit Transfer Capabilities

AR = 22001 No

Pitching Mechanism Using a servo motor Yes

Pitching Accuracy Pitching encoder Yes

Plate Integration System Using a two cylinder design with tapered edges so

everything will fit

No

Deployment Motor Using a stepper motor No

Launch Ability Must conform to standards set by Planetary Services Yes

Launch Survivability Verify that GHOST will survive launch Yes

Initial Spin-Up Carbon steel attached to solar blade material Yes 53

Strategy for Conducting

Remaining Studies

bull 8U GHOST inside 12U structure bull Create a SolidWorksCAD model

bull Pitching Mechanism bull Determine adequate motor within size power and cost constraints

bull Pitching Accuracy bull Determine pitching accuracy based on orbital sensitivity

bull Launch Ability bull Because design is symmetrical center of mass is in the center of the satellite during launch bull Further investigations is needed to determine how many counterweights

bull Launch Survivability bull FEM or Vibrations

bull Initial Spin-up bull Determine feasible method to attach carbon steel support structure to solar sail blade material

54

Resources

bull PAYLOAD SPECIFICATION FOR 3U 6U 12U AND 27U Np Planetary Systems Corporation 2013 Print

bull Davis Jason The Planetary Society The Planetary Society Blog Firefly Partners 11 Apr 2012 Web 12 Oct 2013 lthttpwwwplanetaryorgblogsguest-blogsjason-davis3450htmlgt

bull Mao Tengfei 01mm Thickness Measuring Tape Wwwalibabacom Alibabacom nd Web 12 Oct 2013 lthttpwwwalibabacomproduct-gs8359006940_1mm_thickness_measuring_tapehtmlgt

55

Resources

bull ldquoHow servos and steppers stack uprdquo Machine Design 9 February 2012 [httpmachinedesigncomnewshow-servos-and-steppers-stack Accessed 7 October 2013]

bull ldquoMiniature Stepper Motor Drive Systems - Data Sheetrdquo Micro Motion Solutions [httpwwwmicromocomstepper-motors-datasheetsaspx Accessed 11 October 2013]

bull ldquoData Sheet for TS-53 Servorsquos Electric Motorrdquo Mabuchi Motor [httpwwwprincetonedu~mae412TEXTNTRAK2002292-302pdf Accessed 11 October 2013]

56

Integration CubeSat

Sizing the Blades

bull CubeSat constrained by 20 cm on each side

bull Need to perform 180 degree independent rotation and maximize room inside the satellite for pitching motors controls and communication

Top Down Views of each size ( Scaled to correct dimensions)

12 cm blade width 10 cm blade width 8 cm blade width

bull Not intrusive on inner area

bull Full 180 motion

bull Infringes on space inside

bull Full 180 motion

bull Not intrusive on inner area

bull No Full 180 motion

35

Integration CubeSat

Housing the Rolled Sail

bull The solar sail blades will be controlled by a pitching axle but there must be an interface to connect to the axle

bull Cylindrical plate housing

bull Protects blades

bull Easy to connect to axle

bull No gears

bull Ability to provide counterweight

to deployment motor

bull With the tight volume constraints of our cube the Cylindrical plate must be altered to avoid interference with other sides

36

Integration CubeSat

Fitting the cylindrical Plate

bull Clearance for rolled sail

bull 2 cm clearance on each side

bull 06 cm clearance on behind the motor

bull This leaves overlapping corners

bull To prevent overlap we will make a 45ordm cut around the entire cylinder

2 cm

06 cm

Rolled Sail

Plate Encasing

Overlapping

Corners

45ordm cut to get rid

of corners

37

Integration CubeSat

Fitting the cylindrical Plate

bull The 45ordm cut will give us a 0 cm clearance (with no thickness)

bull If we implement a high-low offset between adjacent plates the distance between the two closest points increases

bull For our 14 cm diameter plates a 2 cm offset from the center for each plate (4 cm total) the effective clearance becomes 251 cm

Two adjacent sides

on same axis

With a High-Low Offset

38

Integration CubeSat

High-Low Offset Plates

The high low offset will give each plate room to rotate a full 180ordm

1 cm clearance between the top of the

blade and the edge of the satellite to fit

the thin-set bearing

A 3mm plate thickness gives adjacent

plates a distance of 19 cm between

their closest points

39

Integration CubeSat

High Low Offset Performance Validation

bull The high-low offset will not effect the performance or stability of the deployment or pitching systems

bull Upon deployment the opposing extension on each side cancels out unwanted torque

View From high side View From low side

bull In a sun-synchronous orbit the high or low setting has no effect as the rotational axis of the satellite is always solar pointing

View From Sun

40

Integration Power

Electronics Feasibility Analysis

bull Project Constraints

bull CubeSat power source Li-Ion batteries (5 and 33 V is common) - Would require thermal protection

bull Communications System - Transceiver (UHF is common) [USART serial port] - Buffer may be needed depending on power constraints

bull Deployment Subsystem - 1 step-motor [output] - 1 encoder [MSSP input] OR direct deployment measurement via external sensor

bull Pitching Subsystem - 2 servomotors [output]

41

Integration Power

PIC18F Series Microchip

bull Inputs 2 USART and 2 MSSP ports available (for basic PICs) - More than 1 device may be connected to each port - 2-3 devices needed

bull Outputs 8 ports - 2 devices needed

bull 16 bit - Though different PICs may be acquired for higher resolution

bull Operating Range 2-55 V - Within provided parameters

42

PIC

Communications

Deployment

Motor

Encoder

Pitching

Motor 1

Pitching

Motor 2 Key

Power Lines

Input Lines

Output Lines

Integration Power

Microchip FBD

5V Battery

Possible Voltage

Buffer

Encoder

43

Integration Power

Motor Power Limitations

bull Power Constraints

Pmax = 100 W

Vmax = 50 V

bull P = IV (Power = CurrentVoltage)

bull Therefore Iave = 20 Amps

bull Blade Pitching (4 motors total needed) - Current limitations for power sources and number of simultaneous blades pitching

Number of Blades 5 V Input 36 V input 31 V input 2 V input

4 040 A 069 A 081 A 125 A

2 080 A 139 A 161 A 250 A

1 160 A 278 A 323 A 500 A

44

Integration Motors

Stepper vs Brushless Servo Motors

45

-Contain many poles (50+) -Contain only 4-12 poles

-Distinct steps cause

vibration during use -Do not suffer from

vibration and resonance

issues smooth movement

-Low maintenance easier to

commission mechanically

simple

-Efficient response to start

stop and reverse commands

-Rely on encoders for

position details in closed

loop response

-Physical sizes

are comparable

-Both available

in various

lengths at same

frame size -Torque can be readily

controlled

-Low cost and high

availability

-Complexity drives cost

upward

Chosen for

deployment motor

Chosen for

pitching motor

Stepper Servo

Integration Blade Deployment

Deployment Motor Feasibility

Required holding torque is calculated to be 18 mNm

Required driving torque is calculated to be 117

10-5 mN∙m

bull Micro Motion Solutions ndash miniature stepper motors bull Physical Properties

bull Diameter = 6-22 mm

bull Length = 93-20 mm

bull Weight = 55-12 g

bull Holding Torque = 24-10 mN∙m = 034-142 oz∙in

bull Resolution bull 1 or 2 phase half-step capability

bull Steps per turn = 20-24 rarr 15˚-18˚ per step

5 of full step accuracy

bull Power Requirements bull Nominal voltage per phase 2-5 V

bull Nominal current per phase 01-1 A

46

Integration Blade Pitching

Blade Pitching Motor Feasibility

Required driving torque is calculated to be 0019 mN∙m

bull Mabuchi Servo Motor bull Physical Size

bull Diameter = 17 mm

bull Length = 25 mm

bull Weight = 16 g

bull Torque

bull Holding Torque = 161 mN∙m = 0228 oz∙in

bull Driving Torque = 0385 mN∙m = 0055 oz∙in

bull Friction Torque = 403

10-3 mN∙m = 571

10-4 oz∙in

bull Power Requirements

bull Nominal voltage per phase 2-5 V

bull Nominal current per phase 006-02 A 47

Integration Launch

Feasibility for Pre-deployment locking mechanism

The tip of the solar sail will be wider than the body with the sail tip set outside the plate

The tip will be held in place vertically by stationary blade stabilizers and kept tight by the holding torque of the deployment motor

Stationary blade

stabilizers

Extra-wide

blade tip

Upon deployment the motor

turns and the blade extends

48

Integration Launch

Canesterized Satellite Dispenser (CSD)

bull Ride in a 12 U CSD

bull Width=239 cm Height=226 cm Length=366 cm

bull Mass=0-24 kg at launch

bull Center of Mass when stowed in

bull x is -40 to 40 mm

bull y is 50 to 125 mm

bull z is 133 to 233 mm

wwwplanetarysytemscorpcom 49

Integration Launch

Test Validation

bull Launch Vibration Test

bull Needs to be space applicable and strong enough to withstand vibration

bull Ball Aerospace can provide a shake table costing $250hr

bull Preparation for Testing using FEM modeling and adding support features

50

Financial

bull Total Budget $5000

bull Components

bull Stepper Motor $100-200

bull Servo Motor (x2) $50-500 each

bull Materials (made in-house) $500-1000

bull Electronics $0-500

bull Testing

bull Deployment amp Pitching Free (Performed on Campus)

bull Launch Survivability Vibration Stand - $250hr Ball Space Systems in Boulder

bull Total Estimation $700-2700 + Vibration Stand Testing

51

Baseline Design All Together

bull The 8u CubeSat and characteristic acceleration requirements create very strict volumetric restrictions

bull The size of the plates and the rolled sail blade must be validated

bull This design will be analyzed and verified in the feasibility requirements

Inner Control Area

bull Motor

bull Encoder

bull Control

bull Communication

bull Power

Possible Load-bearing

corners for deployment

Housed Solar Sail

Top-Down View

Extra room for third

party systems

52

Status Summary

53

SystemMechanism Final Choice Further

Studies

Needed

8U Structure Fit our CubeSat in 12U bus provided by Planetary Services Yes

Adequate Area of Sails to Provide

Orbit Transfer Capabilities

AR = 22001 No

Pitching Mechanism Using a servo motor Yes

Pitching Accuracy Pitching encoder Yes

Plate Integration System Using a two cylinder design with tapered edges so

everything will fit

No

Deployment Motor Using a stepper motor No

Launch Ability Must conform to standards set by Planetary Services Yes

Launch Survivability Verify that GHOST will survive launch Yes

Initial Spin-Up Carbon steel attached to solar blade material Yes 53

Strategy for Conducting

Remaining Studies

bull 8U GHOST inside 12U structure bull Create a SolidWorksCAD model

bull Pitching Mechanism bull Determine adequate motor within size power and cost constraints

bull Pitching Accuracy bull Determine pitching accuracy based on orbital sensitivity

bull Launch Ability bull Because design is symmetrical center of mass is in the center of the satellite during launch bull Further investigations is needed to determine how many counterweights

bull Launch Survivability bull FEM or Vibrations

bull Initial Spin-up bull Determine feasible method to attach carbon steel support structure to solar sail blade material

54

Resources

bull PAYLOAD SPECIFICATION FOR 3U 6U 12U AND 27U Np Planetary Systems Corporation 2013 Print

bull Davis Jason The Planetary Society The Planetary Society Blog Firefly Partners 11 Apr 2012 Web 12 Oct 2013 lthttpwwwplanetaryorgblogsguest-blogsjason-davis3450htmlgt

bull Mao Tengfei 01mm Thickness Measuring Tape Wwwalibabacom Alibabacom nd Web 12 Oct 2013 lthttpwwwalibabacomproduct-gs8359006940_1mm_thickness_measuring_tapehtmlgt

55

Resources

bull ldquoHow servos and steppers stack uprdquo Machine Design 9 February 2012 [httpmachinedesigncomnewshow-servos-and-steppers-stack Accessed 7 October 2013]

bull ldquoMiniature Stepper Motor Drive Systems - Data Sheetrdquo Micro Motion Solutions [httpwwwmicromocomstepper-motors-datasheetsaspx Accessed 11 October 2013]

bull ldquoData Sheet for TS-53 Servorsquos Electric Motorrdquo Mabuchi Motor [httpwwwprincetonedu~mae412TEXTNTRAK2002292-302pdf Accessed 11 October 2013]

56

Integration CubeSat

Housing the Rolled Sail

bull The solar sail blades will be controlled by a pitching axle but there must be an interface to connect to the axle

bull Cylindrical plate housing

bull Protects blades

bull Easy to connect to axle

bull No gears

bull Ability to provide counterweight

to deployment motor

bull With the tight volume constraints of our cube the Cylindrical plate must be altered to avoid interference with other sides

36

Integration CubeSat

Fitting the cylindrical Plate

bull Clearance for rolled sail

bull 2 cm clearance on each side

bull 06 cm clearance on behind the motor

bull This leaves overlapping corners

bull To prevent overlap we will make a 45ordm cut around the entire cylinder

2 cm

06 cm

Rolled Sail

Plate Encasing

Overlapping

Corners

45ordm cut to get rid

of corners

37

Integration CubeSat

Fitting the cylindrical Plate

bull The 45ordm cut will give us a 0 cm clearance (with no thickness)

bull If we implement a high-low offset between adjacent plates the distance between the two closest points increases

bull For our 14 cm diameter plates a 2 cm offset from the center for each plate (4 cm total) the effective clearance becomes 251 cm

Two adjacent sides

on same axis

With a High-Low Offset

38

Integration CubeSat

High-Low Offset Plates

The high low offset will give each plate room to rotate a full 180ordm

1 cm clearance between the top of the

blade and the edge of the satellite to fit

the thin-set bearing

A 3mm plate thickness gives adjacent

plates a distance of 19 cm between

their closest points

39

Integration CubeSat

High Low Offset Performance Validation

bull The high-low offset will not effect the performance or stability of the deployment or pitching systems

bull Upon deployment the opposing extension on each side cancels out unwanted torque

View From high side View From low side

bull In a sun-synchronous orbit the high or low setting has no effect as the rotational axis of the satellite is always solar pointing

View From Sun

40

Integration Power

Electronics Feasibility Analysis

bull Project Constraints

bull CubeSat power source Li-Ion batteries (5 and 33 V is common) - Would require thermal protection

bull Communications System - Transceiver (UHF is common) [USART serial port] - Buffer may be needed depending on power constraints

bull Deployment Subsystem - 1 step-motor [output] - 1 encoder [MSSP input] OR direct deployment measurement via external sensor

bull Pitching Subsystem - 2 servomotors [output]

41

Integration Power

PIC18F Series Microchip

bull Inputs 2 USART and 2 MSSP ports available (for basic PICs) - More than 1 device may be connected to each port - 2-3 devices needed

bull Outputs 8 ports - 2 devices needed

bull 16 bit - Though different PICs may be acquired for higher resolution

bull Operating Range 2-55 V - Within provided parameters

42

PIC

Communications

Deployment

Motor

Encoder

Pitching

Motor 1

Pitching

Motor 2 Key

Power Lines

Input Lines

Output Lines

Integration Power

Microchip FBD

5V Battery

Possible Voltage

Buffer

Encoder

43

Integration Power

Motor Power Limitations

bull Power Constraints

Pmax = 100 W

Vmax = 50 V

bull P = IV (Power = CurrentVoltage)

bull Therefore Iave = 20 Amps

bull Blade Pitching (4 motors total needed) - Current limitations for power sources and number of simultaneous blades pitching

Number of Blades 5 V Input 36 V input 31 V input 2 V input

4 040 A 069 A 081 A 125 A

2 080 A 139 A 161 A 250 A

1 160 A 278 A 323 A 500 A

44

Integration Motors

Stepper vs Brushless Servo Motors

45

-Contain many poles (50+) -Contain only 4-12 poles

-Distinct steps cause

vibration during use -Do not suffer from

vibration and resonance

issues smooth movement

-Low maintenance easier to

commission mechanically

simple

-Efficient response to start

stop and reverse commands

-Rely on encoders for

position details in closed

loop response

-Physical sizes

are comparable

-Both available

in various

lengths at same

frame size -Torque can be readily

controlled

-Low cost and high

availability

-Complexity drives cost

upward

Chosen for

deployment motor

Chosen for

pitching motor

Stepper Servo

Integration Blade Deployment

Deployment Motor Feasibility

Required holding torque is calculated to be 18 mNm

Required driving torque is calculated to be 117

10-5 mN∙m

bull Micro Motion Solutions ndash miniature stepper motors bull Physical Properties

bull Diameter = 6-22 mm

bull Length = 93-20 mm

bull Weight = 55-12 g

bull Holding Torque = 24-10 mN∙m = 034-142 oz∙in

bull Resolution bull 1 or 2 phase half-step capability

bull Steps per turn = 20-24 rarr 15˚-18˚ per step

5 of full step accuracy

bull Power Requirements bull Nominal voltage per phase 2-5 V

bull Nominal current per phase 01-1 A

46

Integration Blade Pitching

Blade Pitching Motor Feasibility

Required driving torque is calculated to be 0019 mN∙m

bull Mabuchi Servo Motor bull Physical Size

bull Diameter = 17 mm

bull Length = 25 mm

bull Weight = 16 g

bull Torque

bull Holding Torque = 161 mN∙m = 0228 oz∙in

bull Driving Torque = 0385 mN∙m = 0055 oz∙in

bull Friction Torque = 403

10-3 mN∙m = 571

10-4 oz∙in

bull Power Requirements

bull Nominal voltage per phase 2-5 V

bull Nominal current per phase 006-02 A 47

Integration Launch

Feasibility for Pre-deployment locking mechanism

The tip of the solar sail will be wider than the body with the sail tip set outside the plate

The tip will be held in place vertically by stationary blade stabilizers and kept tight by the holding torque of the deployment motor

Stationary blade

stabilizers

Extra-wide

blade tip

Upon deployment the motor

turns and the blade extends

48

Integration Launch

Canesterized Satellite Dispenser (CSD)

bull Ride in a 12 U CSD

bull Width=239 cm Height=226 cm Length=366 cm

bull Mass=0-24 kg at launch

bull Center of Mass when stowed in

bull x is -40 to 40 mm

bull y is 50 to 125 mm

bull z is 133 to 233 mm

wwwplanetarysytemscorpcom 49

Integration Launch

Test Validation

bull Launch Vibration Test

bull Needs to be space applicable and strong enough to withstand vibration

bull Ball Aerospace can provide a shake table costing $250hr

bull Preparation for Testing using FEM modeling and adding support features

50

Financial

bull Total Budget $5000

bull Components

bull Stepper Motor $100-200

bull Servo Motor (x2) $50-500 each

bull Materials (made in-house) $500-1000

bull Electronics $0-500

bull Testing

bull Deployment amp Pitching Free (Performed on Campus)

bull Launch Survivability Vibration Stand - $250hr Ball Space Systems in Boulder

bull Total Estimation $700-2700 + Vibration Stand Testing

51

Baseline Design All Together

bull The 8u CubeSat and characteristic acceleration requirements create very strict volumetric restrictions

bull The size of the plates and the rolled sail blade must be validated

bull This design will be analyzed and verified in the feasibility requirements

Inner Control Area

bull Motor

bull Encoder

bull Control

bull Communication

bull Power

Possible Load-bearing

corners for deployment

Housed Solar Sail

Top-Down View

Extra room for third

party systems

52

Status Summary

53

SystemMechanism Final Choice Further

Studies

Needed

8U Structure Fit our CubeSat in 12U bus provided by Planetary Services Yes

Adequate Area of Sails to Provide

Orbit Transfer Capabilities

AR = 22001 No

Pitching Mechanism Using a servo motor Yes

Pitching Accuracy Pitching encoder Yes

Plate Integration System Using a two cylinder design with tapered edges so

everything will fit

No

Deployment Motor Using a stepper motor No

Launch Ability Must conform to standards set by Planetary Services Yes

Launch Survivability Verify that GHOST will survive launch Yes

Initial Spin-Up Carbon steel attached to solar blade material Yes 53

Strategy for Conducting

Remaining Studies

bull 8U GHOST inside 12U structure bull Create a SolidWorksCAD model

bull Pitching Mechanism bull Determine adequate motor within size power and cost constraints

bull Pitching Accuracy bull Determine pitching accuracy based on orbital sensitivity

bull Launch Ability bull Because design is symmetrical center of mass is in the center of the satellite during launch bull Further investigations is needed to determine how many counterweights

bull Launch Survivability bull FEM or Vibrations

bull Initial Spin-up bull Determine feasible method to attach carbon steel support structure to solar sail blade material

54

Resources

bull PAYLOAD SPECIFICATION FOR 3U 6U 12U AND 27U Np Planetary Systems Corporation 2013 Print

bull Davis Jason The Planetary Society The Planetary Society Blog Firefly Partners 11 Apr 2012 Web 12 Oct 2013 lthttpwwwplanetaryorgblogsguest-blogsjason-davis3450htmlgt

bull Mao Tengfei 01mm Thickness Measuring Tape Wwwalibabacom Alibabacom nd Web 12 Oct 2013 lthttpwwwalibabacomproduct-gs8359006940_1mm_thickness_measuring_tapehtmlgt

55

Resources

bull ldquoHow servos and steppers stack uprdquo Machine Design 9 February 2012 [httpmachinedesigncomnewshow-servos-and-steppers-stack Accessed 7 October 2013]

bull ldquoMiniature Stepper Motor Drive Systems - Data Sheetrdquo Micro Motion Solutions [httpwwwmicromocomstepper-motors-datasheetsaspx Accessed 11 October 2013]

bull ldquoData Sheet for TS-53 Servorsquos Electric Motorrdquo Mabuchi Motor [httpwwwprincetonedu~mae412TEXTNTRAK2002292-302pdf Accessed 11 October 2013]

56

Integration CubeSat

Fitting the cylindrical Plate

bull Clearance for rolled sail

bull 2 cm clearance on each side

bull 06 cm clearance on behind the motor

bull This leaves overlapping corners

bull To prevent overlap we will make a 45ordm cut around the entire cylinder

2 cm

06 cm

Rolled Sail

Plate Encasing

Overlapping

Corners

45ordm cut to get rid

of corners

37

Integration CubeSat

Fitting the cylindrical Plate

bull The 45ordm cut will give us a 0 cm clearance (with no thickness)

bull If we implement a high-low offset between adjacent plates the distance between the two closest points increases

bull For our 14 cm diameter plates a 2 cm offset from the center for each plate (4 cm total) the effective clearance becomes 251 cm

Two adjacent sides

on same axis

With a High-Low Offset

38

Integration CubeSat

High-Low Offset Plates

The high low offset will give each plate room to rotate a full 180ordm

1 cm clearance between the top of the

blade and the edge of the satellite to fit

the thin-set bearing

A 3mm plate thickness gives adjacent

plates a distance of 19 cm between

their closest points

39

Integration CubeSat

High Low Offset Performance Validation

bull The high-low offset will not effect the performance or stability of the deployment or pitching systems

bull Upon deployment the opposing extension on each side cancels out unwanted torque

View From high side View From low side

bull In a sun-synchronous orbit the high or low setting has no effect as the rotational axis of the satellite is always solar pointing

View From Sun

40

Integration Power

Electronics Feasibility Analysis

bull Project Constraints

bull CubeSat power source Li-Ion batteries (5 and 33 V is common) - Would require thermal protection

bull Communications System - Transceiver (UHF is common) [USART serial port] - Buffer may be needed depending on power constraints

bull Deployment Subsystem - 1 step-motor [output] - 1 encoder [MSSP input] OR direct deployment measurement via external sensor

bull Pitching Subsystem - 2 servomotors [output]

41

Integration Power

PIC18F Series Microchip

bull Inputs 2 USART and 2 MSSP ports available (for basic PICs) - More than 1 device may be connected to each port - 2-3 devices needed

bull Outputs 8 ports - 2 devices needed

bull 16 bit - Though different PICs may be acquired for higher resolution

bull Operating Range 2-55 V - Within provided parameters

42

PIC

Communications

Deployment

Motor

Encoder

Pitching

Motor 1

Pitching

Motor 2 Key

Power Lines

Input Lines

Output Lines

Integration Power

Microchip FBD

5V Battery

Possible Voltage

Buffer

Encoder

43

Integration Power

Motor Power Limitations

bull Power Constraints

Pmax = 100 W

Vmax = 50 V

bull P = IV (Power = CurrentVoltage)

bull Therefore Iave = 20 Amps

bull Blade Pitching (4 motors total needed) - Current limitations for power sources and number of simultaneous blades pitching

Number of Blades 5 V Input 36 V input 31 V input 2 V input

4 040 A 069 A 081 A 125 A

2 080 A 139 A 161 A 250 A

1 160 A 278 A 323 A 500 A

44

Integration Motors

Stepper vs Brushless Servo Motors

45

-Contain many poles (50+) -Contain only 4-12 poles

-Distinct steps cause

vibration during use -Do not suffer from

vibration and resonance

issues smooth movement

-Low maintenance easier to

commission mechanically

simple

-Efficient response to start

stop and reverse commands

-Rely on encoders for

position details in closed

loop response

-Physical sizes

are comparable

-Both available

in various

lengths at same

frame size -Torque can be readily

controlled

-Low cost and high

availability

-Complexity drives cost

upward

Chosen for

deployment motor

Chosen for

pitching motor

Stepper Servo

Integration Blade Deployment

Deployment Motor Feasibility

Required holding torque is calculated to be 18 mNm

Required driving torque is calculated to be 117

10-5 mN∙m

bull Micro Motion Solutions ndash miniature stepper motors bull Physical Properties

bull Diameter = 6-22 mm

bull Length = 93-20 mm

bull Weight = 55-12 g

bull Holding Torque = 24-10 mN∙m = 034-142 oz∙in

bull Resolution bull 1 or 2 phase half-step capability

bull Steps per turn = 20-24 rarr 15˚-18˚ per step

5 of full step accuracy

bull Power Requirements bull Nominal voltage per phase 2-5 V

bull Nominal current per phase 01-1 A

46

Integration Blade Pitching

Blade Pitching Motor Feasibility

Required driving torque is calculated to be 0019 mN∙m

bull Mabuchi Servo Motor bull Physical Size

bull Diameter = 17 mm

bull Length = 25 mm

bull Weight = 16 g

bull Torque

bull Holding Torque = 161 mN∙m = 0228 oz∙in

bull Driving Torque = 0385 mN∙m = 0055 oz∙in

bull Friction Torque = 403

10-3 mN∙m = 571

10-4 oz∙in

bull Power Requirements

bull Nominal voltage per phase 2-5 V

bull Nominal current per phase 006-02 A 47

Integration Launch

Feasibility for Pre-deployment locking mechanism

The tip of the solar sail will be wider than the body with the sail tip set outside the plate

The tip will be held in place vertically by stationary blade stabilizers and kept tight by the holding torque of the deployment motor

Stationary blade

stabilizers

Extra-wide

blade tip

Upon deployment the motor

turns and the blade extends

48

Integration Launch

Canesterized Satellite Dispenser (CSD)

bull Ride in a 12 U CSD

bull Width=239 cm Height=226 cm Length=366 cm

bull Mass=0-24 kg at launch

bull Center of Mass when stowed in

bull x is -40 to 40 mm

bull y is 50 to 125 mm

bull z is 133 to 233 mm

wwwplanetarysytemscorpcom 49

Integration Launch

Test Validation

bull Launch Vibration Test

bull Needs to be space applicable and strong enough to withstand vibration

bull Ball Aerospace can provide a shake table costing $250hr

bull Preparation for Testing using FEM modeling and adding support features

50

Financial

bull Total Budget $5000

bull Components

bull Stepper Motor $100-200

bull Servo Motor (x2) $50-500 each

bull Materials (made in-house) $500-1000

bull Electronics $0-500

bull Testing

bull Deployment amp Pitching Free (Performed on Campus)

bull Launch Survivability Vibration Stand - $250hr Ball Space Systems in Boulder

bull Total Estimation $700-2700 + Vibration Stand Testing

51

Baseline Design All Together

bull The 8u CubeSat and characteristic acceleration requirements create very strict volumetric restrictions

bull The size of the plates and the rolled sail blade must be validated

bull This design will be analyzed and verified in the feasibility requirements

Inner Control Area

bull Motor

bull Encoder

bull Control

bull Communication

bull Power

Possible Load-bearing

corners for deployment

Housed Solar Sail

Top-Down View

Extra room for third

party systems

52

Status Summary

53

SystemMechanism Final Choice Further

Studies

Needed

8U Structure Fit our CubeSat in 12U bus provided by Planetary Services Yes

Adequate Area of Sails to Provide

Orbit Transfer Capabilities

AR = 22001 No

Pitching Mechanism Using a servo motor Yes

Pitching Accuracy Pitching encoder Yes

Plate Integration System Using a two cylinder design with tapered edges so

everything will fit

No

Deployment Motor Using a stepper motor No

Launch Ability Must conform to standards set by Planetary Services Yes

Launch Survivability Verify that GHOST will survive launch Yes

Initial Spin-Up Carbon steel attached to solar blade material Yes 53

Strategy for Conducting

Remaining Studies

bull 8U GHOST inside 12U structure bull Create a SolidWorksCAD model

bull Pitching Mechanism bull Determine adequate motor within size power and cost constraints

bull Pitching Accuracy bull Determine pitching accuracy based on orbital sensitivity

bull Launch Ability bull Because design is symmetrical center of mass is in the center of the satellite during launch bull Further investigations is needed to determine how many counterweights

bull Launch Survivability bull FEM or Vibrations

bull Initial Spin-up bull Determine feasible method to attach carbon steel support structure to solar sail blade material

54

Resources

bull PAYLOAD SPECIFICATION FOR 3U 6U 12U AND 27U Np Planetary Systems Corporation 2013 Print

bull Davis Jason The Planetary Society The Planetary Society Blog Firefly Partners 11 Apr 2012 Web 12 Oct 2013 lthttpwwwplanetaryorgblogsguest-blogsjason-davis3450htmlgt

bull Mao Tengfei 01mm Thickness Measuring Tape Wwwalibabacom Alibabacom nd Web 12 Oct 2013 lthttpwwwalibabacomproduct-gs8359006940_1mm_thickness_measuring_tapehtmlgt

55

Resources

bull ldquoHow servos and steppers stack uprdquo Machine Design 9 February 2012 [httpmachinedesigncomnewshow-servos-and-steppers-stack Accessed 7 October 2013]

bull ldquoMiniature Stepper Motor Drive Systems - Data Sheetrdquo Micro Motion Solutions [httpwwwmicromocomstepper-motors-datasheetsaspx Accessed 11 October 2013]

bull ldquoData Sheet for TS-53 Servorsquos Electric Motorrdquo Mabuchi Motor [httpwwwprincetonedu~mae412TEXTNTRAK2002292-302pdf Accessed 11 October 2013]

56

Integration CubeSat

Fitting the cylindrical Plate

bull The 45ordm cut will give us a 0 cm clearance (with no thickness)

bull If we implement a high-low offset between adjacent plates the distance between the two closest points increases

bull For our 14 cm diameter plates a 2 cm offset from the center for each plate (4 cm total) the effective clearance becomes 251 cm

Two adjacent sides

on same axis

With a High-Low Offset

38

Integration CubeSat

High-Low Offset Plates

The high low offset will give each plate room to rotate a full 180ordm

1 cm clearance between the top of the

blade and the edge of the satellite to fit

the thin-set bearing

A 3mm plate thickness gives adjacent

plates a distance of 19 cm between

their closest points

39

Integration CubeSat

High Low Offset Performance Validation

bull The high-low offset will not effect the performance or stability of the deployment or pitching systems

bull Upon deployment the opposing extension on each side cancels out unwanted torque

View From high side View From low side

bull In a sun-synchronous orbit the high or low setting has no effect as the rotational axis of the satellite is always solar pointing

View From Sun

40

Integration Power

Electronics Feasibility Analysis

bull Project Constraints

bull CubeSat power source Li-Ion batteries (5 and 33 V is common) - Would require thermal protection

bull Communications System - Transceiver (UHF is common) [USART serial port] - Buffer may be needed depending on power constraints

bull Deployment Subsystem - 1 step-motor [output] - 1 encoder [MSSP input] OR direct deployment measurement via external sensor

bull Pitching Subsystem - 2 servomotors [output]

41

Integration Power

PIC18F Series Microchip

bull Inputs 2 USART and 2 MSSP ports available (for basic PICs) - More than 1 device may be connected to each port - 2-3 devices needed

bull Outputs 8 ports - 2 devices needed

bull 16 bit - Though different PICs may be acquired for higher resolution

bull Operating Range 2-55 V - Within provided parameters

42

PIC

Communications

Deployment

Motor

Encoder

Pitching

Motor 1

Pitching

Motor 2 Key

Power Lines

Input Lines

Output Lines

Integration Power

Microchip FBD

5V Battery

Possible Voltage

Buffer

Encoder

43

Integration Power

Motor Power Limitations

bull Power Constraints

Pmax = 100 W

Vmax = 50 V

bull P = IV (Power = CurrentVoltage)

bull Therefore Iave = 20 Amps

bull Blade Pitching (4 motors total needed) - Current limitations for power sources and number of simultaneous blades pitching

Number of Blades 5 V Input 36 V input 31 V input 2 V input

4 040 A 069 A 081 A 125 A

2 080 A 139 A 161 A 250 A

1 160 A 278 A 323 A 500 A

44

Integration Motors

Stepper vs Brushless Servo Motors

45

-Contain many poles (50+) -Contain only 4-12 poles

-Distinct steps cause

vibration during use -Do not suffer from

vibration and resonance

issues smooth movement

-Low maintenance easier to

commission mechanically

simple

-Efficient response to start

stop and reverse commands

-Rely on encoders for

position details in closed

loop response

-Physical sizes

are comparable

-Both available

in various

lengths at same

frame size -Torque can be readily

controlled

-Low cost and high

availability

-Complexity drives cost

upward

Chosen for

deployment motor

Chosen for

pitching motor

Stepper Servo

Integration Blade Deployment

Deployment Motor Feasibility

Required holding torque is calculated to be 18 mNm

Required driving torque is calculated to be 117

10-5 mN∙m

bull Micro Motion Solutions ndash miniature stepper motors bull Physical Properties

bull Diameter = 6-22 mm

bull Length = 93-20 mm

bull Weight = 55-12 g

bull Holding Torque = 24-10 mN∙m = 034-142 oz∙in

bull Resolution bull 1 or 2 phase half-step capability

bull Steps per turn = 20-24 rarr 15˚-18˚ per step

5 of full step accuracy

bull Power Requirements bull Nominal voltage per phase 2-5 V

bull Nominal current per phase 01-1 A

46

Integration Blade Pitching

Blade Pitching Motor Feasibility

Required driving torque is calculated to be 0019 mN∙m

bull Mabuchi Servo Motor bull Physical Size

bull Diameter = 17 mm

bull Length = 25 mm

bull Weight = 16 g

bull Torque

bull Holding Torque = 161 mN∙m = 0228 oz∙in

bull Driving Torque = 0385 mN∙m = 0055 oz∙in

bull Friction Torque = 403

10-3 mN∙m = 571

10-4 oz∙in

bull Power Requirements

bull Nominal voltage per phase 2-5 V

bull Nominal current per phase 006-02 A 47

Integration Launch

Feasibility for Pre-deployment locking mechanism

The tip of the solar sail will be wider than the body with the sail tip set outside the plate

The tip will be held in place vertically by stationary blade stabilizers and kept tight by the holding torque of the deployment motor

Stationary blade

stabilizers

Extra-wide

blade tip

Upon deployment the motor

turns and the blade extends

48

Integration Launch

Canesterized Satellite Dispenser (CSD)

bull Ride in a 12 U CSD

bull Width=239 cm Height=226 cm Length=366 cm

bull Mass=0-24 kg at launch

bull Center of Mass when stowed in

bull x is -40 to 40 mm

bull y is 50 to 125 mm

bull z is 133 to 233 mm

wwwplanetarysytemscorpcom 49

Integration Launch

Test Validation

bull Launch Vibration Test

bull Needs to be space applicable and strong enough to withstand vibration

bull Ball Aerospace can provide a shake table costing $250hr

bull Preparation for Testing using FEM modeling and adding support features

50

Financial

bull Total Budget $5000

bull Components

bull Stepper Motor $100-200

bull Servo Motor (x2) $50-500 each

bull Materials (made in-house) $500-1000

bull Electronics $0-500

bull Testing

bull Deployment amp Pitching Free (Performed on Campus)

bull Launch Survivability Vibration Stand - $250hr Ball Space Systems in Boulder

bull Total Estimation $700-2700 + Vibration Stand Testing

51

Baseline Design All Together

bull The 8u CubeSat and characteristic acceleration requirements create very strict volumetric restrictions

bull The size of the plates and the rolled sail blade must be validated

bull This design will be analyzed and verified in the feasibility requirements

Inner Control Area

bull Motor

bull Encoder

bull Control

bull Communication

bull Power

Possible Load-bearing

corners for deployment

Housed Solar Sail

Top-Down View

Extra room for third

party systems

52

Status Summary

53

SystemMechanism Final Choice Further

Studies

Needed

8U Structure Fit our CubeSat in 12U bus provided by Planetary Services Yes

Adequate Area of Sails to Provide

Orbit Transfer Capabilities

AR = 22001 No

Pitching Mechanism Using a servo motor Yes

Pitching Accuracy Pitching encoder Yes

Plate Integration System Using a two cylinder design with tapered edges so

everything will fit

No

Deployment Motor Using a stepper motor No

Launch Ability Must conform to standards set by Planetary Services Yes

Launch Survivability Verify that GHOST will survive launch Yes

Initial Spin-Up Carbon steel attached to solar blade material Yes 53

Strategy for Conducting

Remaining Studies

bull 8U GHOST inside 12U structure bull Create a SolidWorksCAD model

bull Pitching Mechanism bull Determine adequate motor within size power and cost constraints

bull Pitching Accuracy bull Determine pitching accuracy based on orbital sensitivity

bull Launch Ability bull Because design is symmetrical center of mass is in the center of the satellite during launch bull Further investigations is needed to determine how many counterweights

bull Launch Survivability bull FEM or Vibrations

bull Initial Spin-up bull Determine feasible method to attach carbon steel support structure to solar sail blade material

54

Resources

bull PAYLOAD SPECIFICATION FOR 3U 6U 12U AND 27U Np Planetary Systems Corporation 2013 Print

bull Davis Jason The Planetary Society The Planetary Society Blog Firefly Partners 11 Apr 2012 Web 12 Oct 2013 lthttpwwwplanetaryorgblogsguest-blogsjason-davis3450htmlgt

bull Mao Tengfei 01mm Thickness Measuring Tape Wwwalibabacom Alibabacom nd Web 12 Oct 2013 lthttpwwwalibabacomproduct-gs8359006940_1mm_thickness_measuring_tapehtmlgt

55

Resources

bull ldquoHow servos and steppers stack uprdquo Machine Design 9 February 2012 [httpmachinedesigncomnewshow-servos-and-steppers-stack Accessed 7 October 2013]

bull ldquoMiniature Stepper Motor Drive Systems - Data Sheetrdquo Micro Motion Solutions [httpwwwmicromocomstepper-motors-datasheetsaspx Accessed 11 October 2013]

bull ldquoData Sheet for TS-53 Servorsquos Electric Motorrdquo Mabuchi Motor [httpwwwprincetonedu~mae412TEXTNTRAK2002292-302pdf Accessed 11 October 2013]

56

Integration CubeSat

High-Low Offset Plates

The high low offset will give each plate room to rotate a full 180ordm

1 cm clearance between the top of the

blade and the edge of the satellite to fit

the thin-set bearing

A 3mm plate thickness gives adjacent

plates a distance of 19 cm between

their closest points

39

Integration CubeSat

High Low Offset Performance Validation

bull The high-low offset will not effect the performance or stability of the deployment or pitching systems

bull Upon deployment the opposing extension on each side cancels out unwanted torque

View From high side View From low side

bull In a sun-synchronous orbit the high or low setting has no effect as the rotational axis of the satellite is always solar pointing

View From Sun

40

Integration Power

Electronics Feasibility Analysis

bull Project Constraints

bull CubeSat power source Li-Ion batteries (5 and 33 V is common) - Would require thermal protection

bull Communications System - Transceiver (UHF is common) [USART serial port] - Buffer may be needed depending on power constraints

bull Deployment Subsystem - 1 step-motor [output] - 1 encoder [MSSP input] OR direct deployment measurement via external sensor

bull Pitching Subsystem - 2 servomotors [output]

41

Integration Power

PIC18F Series Microchip

bull Inputs 2 USART and 2 MSSP ports available (for basic PICs) - More than 1 device may be connected to each port - 2-3 devices needed

bull Outputs 8 ports - 2 devices needed

bull 16 bit - Though different PICs may be acquired for higher resolution

bull Operating Range 2-55 V - Within provided parameters

42

PIC

Communications

Deployment

Motor

Encoder

Pitching

Motor 1

Pitching

Motor 2 Key

Power Lines

Input Lines

Output Lines

Integration Power

Microchip FBD

5V Battery

Possible Voltage

Buffer

Encoder

43

Integration Power

Motor Power Limitations

bull Power Constraints

Pmax = 100 W

Vmax = 50 V

bull P = IV (Power = CurrentVoltage)

bull Therefore Iave = 20 Amps

bull Blade Pitching (4 motors total needed) - Current limitations for power sources and number of simultaneous blades pitching

Number of Blades 5 V Input 36 V input 31 V input 2 V input

4 040 A 069 A 081 A 125 A

2 080 A 139 A 161 A 250 A

1 160 A 278 A 323 A 500 A

44

Integration Motors

Stepper vs Brushless Servo Motors

45

-Contain many poles (50+) -Contain only 4-12 poles

-Distinct steps cause

vibration during use -Do not suffer from

vibration and resonance

issues smooth movement

-Low maintenance easier to

commission mechanically

simple

-Efficient response to start

stop and reverse commands

-Rely on encoders for

position details in closed

loop response

-Physical sizes

are comparable

-Both available

in various

lengths at same

frame size -Torque can be readily

controlled

-Low cost and high

availability

-Complexity drives cost

upward

Chosen for

deployment motor

Chosen for

pitching motor

Stepper Servo

Integration Blade Deployment

Deployment Motor Feasibility

Required holding torque is calculated to be 18 mNm

Required driving torque is calculated to be 117

10-5 mN∙m

bull Micro Motion Solutions ndash miniature stepper motors bull Physical Properties

bull Diameter = 6-22 mm

bull Length = 93-20 mm

bull Weight = 55-12 g

bull Holding Torque = 24-10 mN∙m = 034-142 oz∙in

bull Resolution bull 1 or 2 phase half-step capability

bull Steps per turn = 20-24 rarr 15˚-18˚ per step

5 of full step accuracy

bull Power Requirements bull Nominal voltage per phase 2-5 V

bull Nominal current per phase 01-1 A

46

Integration Blade Pitching

Blade Pitching Motor Feasibility

Required driving torque is calculated to be 0019 mN∙m

bull Mabuchi Servo Motor bull Physical Size

bull Diameter = 17 mm

bull Length = 25 mm

bull Weight = 16 g

bull Torque

bull Holding Torque = 161 mN∙m = 0228 oz∙in

bull Driving Torque = 0385 mN∙m = 0055 oz∙in

bull Friction Torque = 403

10-3 mN∙m = 571

10-4 oz∙in

bull Power Requirements

bull Nominal voltage per phase 2-5 V

bull Nominal current per phase 006-02 A 47

Integration Launch

Feasibility for Pre-deployment locking mechanism

The tip of the solar sail will be wider than the body with the sail tip set outside the plate

The tip will be held in place vertically by stationary blade stabilizers and kept tight by the holding torque of the deployment motor

Stationary blade

stabilizers

Extra-wide

blade tip

Upon deployment the motor

turns and the blade extends

48

Integration Launch

Canesterized Satellite Dispenser (CSD)

bull Ride in a 12 U CSD

bull Width=239 cm Height=226 cm Length=366 cm

bull Mass=0-24 kg at launch

bull Center of Mass when stowed in

bull x is -40 to 40 mm

bull y is 50 to 125 mm

bull z is 133 to 233 mm

wwwplanetarysytemscorpcom 49

Integration Launch

Test Validation

bull Launch Vibration Test

bull Needs to be space applicable and strong enough to withstand vibration

bull Ball Aerospace can provide a shake table costing $250hr

bull Preparation for Testing using FEM modeling and adding support features

50

Financial

bull Total Budget $5000

bull Components

bull Stepper Motor $100-200

bull Servo Motor (x2) $50-500 each

bull Materials (made in-house) $500-1000

bull Electronics $0-500

bull Testing

bull Deployment amp Pitching Free (Performed on Campus)

bull Launch Survivability Vibration Stand - $250hr Ball Space Systems in Boulder

bull Total Estimation $700-2700 + Vibration Stand Testing

51

Baseline Design All Together

bull The 8u CubeSat and characteristic acceleration requirements create very strict volumetric restrictions

bull The size of the plates and the rolled sail blade must be validated

bull This design will be analyzed and verified in the feasibility requirements

Inner Control Area

bull Motor

bull Encoder

bull Control

bull Communication

bull Power

Possible Load-bearing

corners for deployment

Housed Solar Sail

Top-Down View

Extra room for third

party systems

52

Status Summary

53

SystemMechanism Final Choice Further

Studies

Needed

8U Structure Fit our CubeSat in 12U bus provided by Planetary Services Yes

Adequate Area of Sails to Provide

Orbit Transfer Capabilities

AR = 22001 No

Pitching Mechanism Using a servo motor Yes

Pitching Accuracy Pitching encoder Yes

Plate Integration System Using a two cylinder design with tapered edges so

everything will fit

No

Deployment Motor Using a stepper motor No

Launch Ability Must conform to standards set by Planetary Services Yes

Launch Survivability Verify that GHOST will survive launch Yes

Initial Spin-Up Carbon steel attached to solar blade material Yes 53

Strategy for Conducting

Remaining Studies

bull 8U GHOST inside 12U structure bull Create a SolidWorksCAD model

bull Pitching Mechanism bull Determine adequate motor within size power and cost constraints

bull Pitching Accuracy bull Determine pitching accuracy based on orbital sensitivity

bull Launch Ability bull Because design is symmetrical center of mass is in the center of the satellite during launch bull Further investigations is needed to determine how many counterweights

bull Launch Survivability bull FEM or Vibrations

bull Initial Spin-up bull Determine feasible method to attach carbon steel support structure to solar sail blade material

54

Resources

bull PAYLOAD SPECIFICATION FOR 3U 6U 12U AND 27U Np Planetary Systems Corporation 2013 Print

bull Davis Jason The Planetary Society The Planetary Society Blog Firefly Partners 11 Apr 2012 Web 12 Oct 2013 lthttpwwwplanetaryorgblogsguest-blogsjason-davis3450htmlgt

bull Mao Tengfei 01mm Thickness Measuring Tape Wwwalibabacom Alibabacom nd Web 12 Oct 2013 lthttpwwwalibabacomproduct-gs8359006940_1mm_thickness_measuring_tapehtmlgt

55

Resources

bull ldquoHow servos and steppers stack uprdquo Machine Design 9 February 2012 [httpmachinedesigncomnewshow-servos-and-steppers-stack Accessed 7 October 2013]

bull ldquoMiniature Stepper Motor Drive Systems - Data Sheetrdquo Micro Motion Solutions [httpwwwmicromocomstepper-motors-datasheetsaspx Accessed 11 October 2013]

bull ldquoData Sheet for TS-53 Servorsquos Electric Motorrdquo Mabuchi Motor [httpwwwprincetonedu~mae412TEXTNTRAK2002292-302pdf Accessed 11 October 2013]

56

Integration CubeSat

High Low Offset Performance Validation

bull The high-low offset will not effect the performance or stability of the deployment or pitching systems

bull Upon deployment the opposing extension on each side cancels out unwanted torque

View From high side View From low side

bull In a sun-synchronous orbit the high or low setting has no effect as the rotational axis of the satellite is always solar pointing

View From Sun

40

Integration Power

Electronics Feasibility Analysis

bull Project Constraints

bull CubeSat power source Li-Ion batteries (5 and 33 V is common) - Would require thermal protection

bull Communications System - Transceiver (UHF is common) [USART serial port] - Buffer may be needed depending on power constraints

bull Deployment Subsystem - 1 step-motor [output] - 1 encoder [MSSP input] OR direct deployment measurement via external sensor

bull Pitching Subsystem - 2 servomotors [output]

41

Integration Power

PIC18F Series Microchip

bull Inputs 2 USART and 2 MSSP ports available (for basic PICs) - More than 1 device may be connected to each port - 2-3 devices needed

bull Outputs 8 ports - 2 devices needed

bull 16 bit - Though different PICs may be acquired for higher resolution

bull Operating Range 2-55 V - Within provided parameters

42

PIC

Communications

Deployment

Motor

Encoder

Pitching

Motor 1

Pitching

Motor 2 Key

Power Lines

Input Lines

Output Lines

Integration Power

Microchip FBD

5V Battery

Possible Voltage

Buffer

Encoder

43

Integration Power

Motor Power Limitations

bull Power Constraints

Pmax = 100 W

Vmax = 50 V

bull P = IV (Power = CurrentVoltage)

bull Therefore Iave = 20 Amps

bull Blade Pitching (4 motors total needed) - Current limitations for power sources and number of simultaneous blades pitching

Number of Blades 5 V Input 36 V input 31 V input 2 V input

4 040 A 069 A 081 A 125 A

2 080 A 139 A 161 A 250 A

1 160 A 278 A 323 A 500 A

44

Integration Motors

Stepper vs Brushless Servo Motors

45

-Contain many poles (50+) -Contain only 4-12 poles

-Distinct steps cause

vibration during use -Do not suffer from

vibration and resonance

issues smooth movement

-Low maintenance easier to

commission mechanically

simple

-Efficient response to start

stop and reverse commands

-Rely on encoders for

position details in closed

loop response

-Physical sizes

are comparable

-Both available

in various

lengths at same

frame size -Torque can be readily

controlled

-Low cost and high

availability

-Complexity drives cost

upward

Chosen for

deployment motor

Chosen for

pitching motor

Stepper Servo

Integration Blade Deployment

Deployment Motor Feasibility

Required holding torque is calculated to be 18 mNm

Required driving torque is calculated to be 117

10-5 mN∙m

bull Micro Motion Solutions ndash miniature stepper motors bull Physical Properties

bull Diameter = 6-22 mm

bull Length = 93-20 mm

bull Weight = 55-12 g

bull Holding Torque = 24-10 mN∙m = 034-142 oz∙in

bull Resolution bull 1 or 2 phase half-step capability

bull Steps per turn = 20-24 rarr 15˚-18˚ per step

5 of full step accuracy

bull Power Requirements bull Nominal voltage per phase 2-5 V

bull Nominal current per phase 01-1 A

46

Integration Blade Pitching

Blade Pitching Motor Feasibility

Required driving torque is calculated to be 0019 mN∙m

bull Mabuchi Servo Motor bull Physical Size

bull Diameter = 17 mm

bull Length = 25 mm

bull Weight = 16 g

bull Torque

bull Holding Torque = 161 mN∙m = 0228 oz∙in

bull Driving Torque = 0385 mN∙m = 0055 oz∙in

bull Friction Torque = 403

10-3 mN∙m = 571

10-4 oz∙in

bull Power Requirements

bull Nominal voltage per phase 2-5 V

bull Nominal current per phase 006-02 A 47

Integration Launch

Feasibility for Pre-deployment locking mechanism

The tip of the solar sail will be wider than the body with the sail tip set outside the plate

The tip will be held in place vertically by stationary blade stabilizers and kept tight by the holding torque of the deployment motor

Stationary blade

stabilizers

Extra-wide

blade tip

Upon deployment the motor

turns and the blade extends

48

Integration Launch

Canesterized Satellite Dispenser (CSD)

bull Ride in a 12 U CSD

bull Width=239 cm Height=226 cm Length=366 cm

bull Mass=0-24 kg at launch

bull Center of Mass when stowed in

bull x is -40 to 40 mm

bull y is 50 to 125 mm

bull z is 133 to 233 mm

wwwplanetarysytemscorpcom 49

Integration Launch

Test Validation

bull Launch Vibration Test

bull Needs to be space applicable and strong enough to withstand vibration

bull Ball Aerospace can provide a shake table costing $250hr

bull Preparation for Testing using FEM modeling and adding support features

50

Financial

bull Total Budget $5000

bull Components

bull Stepper Motor $100-200

bull Servo Motor (x2) $50-500 each

bull Materials (made in-house) $500-1000

bull Electronics $0-500

bull Testing

bull Deployment amp Pitching Free (Performed on Campus)

bull Launch Survivability Vibration Stand - $250hr Ball Space Systems in Boulder

bull Total Estimation $700-2700 + Vibration Stand Testing

51

Baseline Design All Together

bull The 8u CubeSat and characteristic acceleration requirements create very strict volumetric restrictions

bull The size of the plates and the rolled sail blade must be validated

bull This design will be analyzed and verified in the feasibility requirements

Inner Control Area

bull Motor

bull Encoder

bull Control

bull Communication

bull Power

Possible Load-bearing

corners for deployment

Housed Solar Sail

Top-Down View

Extra room for third

party systems

52

Status Summary

53

SystemMechanism Final Choice Further

Studies

Needed

8U Structure Fit our CubeSat in 12U bus provided by Planetary Services Yes

Adequate Area of Sails to Provide

Orbit Transfer Capabilities

AR = 22001 No

Pitching Mechanism Using a servo motor Yes

Pitching Accuracy Pitching encoder Yes

Plate Integration System Using a two cylinder design with tapered edges so

everything will fit

No

Deployment Motor Using a stepper motor No

Launch Ability Must conform to standards set by Planetary Services Yes

Launch Survivability Verify that GHOST will survive launch Yes

Initial Spin-Up Carbon steel attached to solar blade material Yes 53

Strategy for Conducting

Remaining Studies

bull 8U GHOST inside 12U structure bull Create a SolidWorksCAD model

bull Pitching Mechanism bull Determine adequate motor within size power and cost constraints

bull Pitching Accuracy bull Determine pitching accuracy based on orbital sensitivity

bull Launch Ability bull Because design is symmetrical center of mass is in the center of the satellite during launch bull Further investigations is needed to determine how many counterweights

bull Launch Survivability bull FEM or Vibrations

bull Initial Spin-up bull Determine feasible method to attach carbon steel support structure to solar sail blade material

54

Resources

bull PAYLOAD SPECIFICATION FOR 3U 6U 12U AND 27U Np Planetary Systems Corporation 2013 Print

bull Davis Jason The Planetary Society The Planetary Society Blog Firefly Partners 11 Apr 2012 Web 12 Oct 2013 lthttpwwwplanetaryorgblogsguest-blogsjason-davis3450htmlgt

bull Mao Tengfei 01mm Thickness Measuring Tape Wwwalibabacom Alibabacom nd Web 12 Oct 2013 lthttpwwwalibabacomproduct-gs8359006940_1mm_thickness_measuring_tapehtmlgt

55

Resources

bull ldquoHow servos and steppers stack uprdquo Machine Design 9 February 2012 [httpmachinedesigncomnewshow-servos-and-steppers-stack Accessed 7 October 2013]

bull ldquoMiniature Stepper Motor Drive Systems - Data Sheetrdquo Micro Motion Solutions [httpwwwmicromocomstepper-motors-datasheetsaspx Accessed 11 October 2013]

bull ldquoData Sheet for TS-53 Servorsquos Electric Motorrdquo Mabuchi Motor [httpwwwprincetonedu~mae412TEXTNTRAK2002292-302pdf Accessed 11 October 2013]

56

Integration Power

Electronics Feasibility Analysis

bull Project Constraints

bull CubeSat power source Li-Ion batteries (5 and 33 V is common) - Would require thermal protection

bull Communications System - Transceiver (UHF is common) [USART serial port] - Buffer may be needed depending on power constraints

bull Deployment Subsystem - 1 step-motor [output] - 1 encoder [MSSP input] OR direct deployment measurement via external sensor

bull Pitching Subsystem - 2 servomotors [output]

41

Integration Power

PIC18F Series Microchip

bull Inputs 2 USART and 2 MSSP ports available (for basic PICs) - More than 1 device may be connected to each port - 2-3 devices needed

bull Outputs 8 ports - 2 devices needed

bull 16 bit - Though different PICs may be acquired for higher resolution

bull Operating Range 2-55 V - Within provided parameters

42

PIC

Communications

Deployment

Motor

Encoder

Pitching

Motor 1

Pitching

Motor 2 Key

Power Lines

Input Lines

Output Lines

Integration Power

Microchip FBD

5V Battery

Possible Voltage

Buffer

Encoder

43

Integration Power

Motor Power Limitations

bull Power Constraints

Pmax = 100 W

Vmax = 50 V

bull P = IV (Power = CurrentVoltage)

bull Therefore Iave = 20 Amps

bull Blade Pitching (4 motors total needed) - Current limitations for power sources and number of simultaneous blades pitching

Number of Blades 5 V Input 36 V input 31 V input 2 V input

4 040 A 069 A 081 A 125 A

2 080 A 139 A 161 A 250 A

1 160 A 278 A 323 A 500 A

44

Integration Motors

Stepper vs Brushless Servo Motors

45

-Contain many poles (50+) -Contain only 4-12 poles

-Distinct steps cause

vibration during use -Do not suffer from

vibration and resonance

issues smooth movement

-Low maintenance easier to

commission mechanically

simple

-Efficient response to start

stop and reverse commands

-Rely on encoders for

position details in closed

loop response

-Physical sizes

are comparable

-Both available

in various

lengths at same

frame size -Torque can be readily

controlled

-Low cost and high

availability

-Complexity drives cost

upward

Chosen for

deployment motor

Chosen for

pitching motor

Stepper Servo

Integration Blade Deployment

Deployment Motor Feasibility

Required holding torque is calculated to be 18 mNm

Required driving torque is calculated to be 117

10-5 mN∙m

bull Micro Motion Solutions ndash miniature stepper motors bull Physical Properties

bull Diameter = 6-22 mm

bull Length = 93-20 mm

bull Weight = 55-12 g

bull Holding Torque = 24-10 mN∙m = 034-142 oz∙in

bull Resolution bull 1 or 2 phase half-step capability

bull Steps per turn = 20-24 rarr 15˚-18˚ per step

5 of full step accuracy

bull Power Requirements bull Nominal voltage per phase 2-5 V

bull Nominal current per phase 01-1 A

46

Integration Blade Pitching

Blade Pitching Motor Feasibility

Required driving torque is calculated to be 0019 mN∙m

bull Mabuchi Servo Motor bull Physical Size

bull Diameter = 17 mm

bull Length = 25 mm

bull Weight = 16 g

bull Torque

bull Holding Torque = 161 mN∙m = 0228 oz∙in

bull Driving Torque = 0385 mN∙m = 0055 oz∙in

bull Friction Torque = 403

10-3 mN∙m = 571

10-4 oz∙in

bull Power Requirements

bull Nominal voltage per phase 2-5 V

bull Nominal current per phase 006-02 A 47

Integration Launch

Feasibility for Pre-deployment locking mechanism

The tip of the solar sail will be wider than the body with the sail tip set outside the plate

The tip will be held in place vertically by stationary blade stabilizers and kept tight by the holding torque of the deployment motor

Stationary blade

stabilizers

Extra-wide

blade tip

Upon deployment the motor

turns and the blade extends

48

Integration Launch

Canesterized Satellite Dispenser (CSD)

bull Ride in a 12 U CSD

bull Width=239 cm Height=226 cm Length=366 cm

bull Mass=0-24 kg at launch

bull Center of Mass when stowed in

bull x is -40 to 40 mm

bull y is 50 to 125 mm

bull z is 133 to 233 mm

wwwplanetarysytemscorpcom 49

Integration Launch

Test Validation

bull Launch Vibration Test

bull Needs to be space applicable and strong enough to withstand vibration

bull Ball Aerospace can provide a shake table costing $250hr

bull Preparation for Testing using FEM modeling and adding support features

50

Financial

bull Total Budget $5000

bull Components

bull Stepper Motor $100-200

bull Servo Motor (x2) $50-500 each

bull Materials (made in-house) $500-1000

bull Electronics $0-500

bull Testing

bull Deployment amp Pitching Free (Performed on Campus)

bull Launch Survivability Vibration Stand - $250hr Ball Space Systems in Boulder

bull Total Estimation $700-2700 + Vibration Stand Testing

51

Baseline Design All Together

bull The 8u CubeSat and characteristic acceleration requirements create very strict volumetric restrictions

bull The size of the plates and the rolled sail blade must be validated

bull This design will be analyzed and verified in the feasibility requirements

Inner Control Area

bull Motor

bull Encoder

bull Control

bull Communication

bull Power

Possible Load-bearing

corners for deployment

Housed Solar Sail

Top-Down View

Extra room for third

party systems

52

Status Summary

53

SystemMechanism Final Choice Further

Studies

Needed

8U Structure Fit our CubeSat in 12U bus provided by Planetary Services Yes

Adequate Area of Sails to Provide

Orbit Transfer Capabilities

AR = 22001 No

Pitching Mechanism Using a servo motor Yes

Pitching Accuracy Pitching encoder Yes

Plate Integration System Using a two cylinder design with tapered edges so

everything will fit

No

Deployment Motor Using a stepper motor No

Launch Ability Must conform to standards set by Planetary Services Yes

Launch Survivability Verify that GHOST will survive launch Yes

Initial Spin-Up Carbon steel attached to solar blade material Yes 53

Strategy for Conducting

Remaining Studies

bull 8U GHOST inside 12U structure bull Create a SolidWorksCAD model

bull Pitching Mechanism bull Determine adequate motor within size power and cost constraints

bull Pitching Accuracy bull Determine pitching accuracy based on orbital sensitivity

bull Launch Ability bull Because design is symmetrical center of mass is in the center of the satellite during launch bull Further investigations is needed to determine how many counterweights

bull Launch Survivability bull FEM or Vibrations

bull Initial Spin-up bull Determine feasible method to attach carbon steel support structure to solar sail blade material

54

Resources

bull PAYLOAD SPECIFICATION FOR 3U 6U 12U AND 27U Np Planetary Systems Corporation 2013 Print

bull Davis Jason The Planetary Society The Planetary Society Blog Firefly Partners 11 Apr 2012 Web 12 Oct 2013 lthttpwwwplanetaryorgblogsguest-blogsjason-davis3450htmlgt

bull Mao Tengfei 01mm Thickness Measuring Tape Wwwalibabacom Alibabacom nd Web 12 Oct 2013 lthttpwwwalibabacomproduct-gs8359006940_1mm_thickness_measuring_tapehtmlgt

55

Resources

bull ldquoHow servos and steppers stack uprdquo Machine Design 9 February 2012 [httpmachinedesigncomnewshow-servos-and-steppers-stack Accessed 7 October 2013]

bull ldquoMiniature Stepper Motor Drive Systems - Data Sheetrdquo Micro Motion Solutions [httpwwwmicromocomstepper-motors-datasheetsaspx Accessed 11 October 2013]

bull ldquoData Sheet for TS-53 Servorsquos Electric Motorrdquo Mabuchi Motor [httpwwwprincetonedu~mae412TEXTNTRAK2002292-302pdf Accessed 11 October 2013]

56

Integration Power

PIC18F Series Microchip

bull Inputs 2 USART and 2 MSSP ports available (for basic PICs) - More than 1 device may be connected to each port - 2-3 devices needed

bull Outputs 8 ports - 2 devices needed

bull 16 bit - Though different PICs may be acquired for higher resolution

bull Operating Range 2-55 V - Within provided parameters

42

PIC

Communications

Deployment

Motor

Encoder

Pitching

Motor 1

Pitching

Motor 2 Key

Power Lines

Input Lines

Output Lines

Integration Power

Microchip FBD

5V Battery

Possible Voltage

Buffer

Encoder

43

Integration Power

Motor Power Limitations

bull Power Constraints

Pmax = 100 W

Vmax = 50 V

bull P = IV (Power = CurrentVoltage)

bull Therefore Iave = 20 Amps

bull Blade Pitching (4 motors total needed) - Current limitations for power sources and number of simultaneous blades pitching

Number of Blades 5 V Input 36 V input 31 V input 2 V input

4 040 A 069 A 081 A 125 A

2 080 A 139 A 161 A 250 A

1 160 A 278 A 323 A 500 A

44

Integration Motors

Stepper vs Brushless Servo Motors

45

-Contain many poles (50+) -Contain only 4-12 poles

-Distinct steps cause

vibration during use -Do not suffer from

vibration and resonance

issues smooth movement

-Low maintenance easier to

commission mechanically

simple

-Efficient response to start

stop and reverse commands

-Rely on encoders for

position details in closed

loop response

-Physical sizes

are comparable

-Both available

in various

lengths at same

frame size -Torque can be readily

controlled

-Low cost and high

availability

-Complexity drives cost

upward

Chosen for

deployment motor

Chosen for

pitching motor

Stepper Servo

Integration Blade Deployment

Deployment Motor Feasibility

Required holding torque is calculated to be 18 mNm

Required driving torque is calculated to be 117

10-5 mN∙m

bull Micro Motion Solutions ndash miniature stepper motors bull Physical Properties

bull Diameter = 6-22 mm

bull Length = 93-20 mm

bull Weight = 55-12 g

bull Holding Torque = 24-10 mN∙m = 034-142 oz∙in

bull Resolution bull 1 or 2 phase half-step capability

bull Steps per turn = 20-24 rarr 15˚-18˚ per step

5 of full step accuracy

bull Power Requirements bull Nominal voltage per phase 2-5 V

bull Nominal current per phase 01-1 A

46

Integration Blade Pitching

Blade Pitching Motor Feasibility

Required driving torque is calculated to be 0019 mN∙m

bull Mabuchi Servo Motor bull Physical Size

bull Diameter = 17 mm

bull Length = 25 mm

bull Weight = 16 g

bull Torque

bull Holding Torque = 161 mN∙m = 0228 oz∙in

bull Driving Torque = 0385 mN∙m = 0055 oz∙in

bull Friction Torque = 403

10-3 mN∙m = 571

10-4 oz∙in

bull Power Requirements

bull Nominal voltage per phase 2-5 V

bull Nominal current per phase 006-02 A 47

Integration Launch

Feasibility for Pre-deployment locking mechanism

The tip of the solar sail will be wider than the body with the sail tip set outside the plate

The tip will be held in place vertically by stationary blade stabilizers and kept tight by the holding torque of the deployment motor

Stationary blade

stabilizers

Extra-wide

blade tip

Upon deployment the motor

turns and the blade extends

48

Integration Launch

Canesterized Satellite Dispenser (CSD)

bull Ride in a 12 U CSD

bull Width=239 cm Height=226 cm Length=366 cm

bull Mass=0-24 kg at launch

bull Center of Mass when stowed in

bull x is -40 to 40 mm

bull y is 50 to 125 mm

bull z is 133 to 233 mm

wwwplanetarysytemscorpcom 49

Integration Launch

Test Validation

bull Launch Vibration Test

bull Needs to be space applicable and strong enough to withstand vibration

bull Ball Aerospace can provide a shake table costing $250hr

bull Preparation for Testing using FEM modeling and adding support features

50

Financial

bull Total Budget $5000

bull Components

bull Stepper Motor $100-200

bull Servo Motor (x2) $50-500 each

bull Materials (made in-house) $500-1000

bull Electronics $0-500

bull Testing

bull Deployment amp Pitching Free (Performed on Campus)

bull Launch Survivability Vibration Stand - $250hr Ball Space Systems in Boulder

bull Total Estimation $700-2700 + Vibration Stand Testing

51

Baseline Design All Together

bull The 8u CubeSat and characteristic acceleration requirements create very strict volumetric restrictions

bull The size of the plates and the rolled sail blade must be validated

bull This design will be analyzed and verified in the feasibility requirements

Inner Control Area

bull Motor

bull Encoder

bull Control

bull Communication

bull Power

Possible Load-bearing

corners for deployment

Housed Solar Sail

Top-Down View

Extra room for third

party systems

52

Status Summary

53

SystemMechanism Final Choice Further

Studies

Needed

8U Structure Fit our CubeSat in 12U bus provided by Planetary Services Yes

Adequate Area of Sails to Provide

Orbit Transfer Capabilities

AR = 22001 No

Pitching Mechanism Using a servo motor Yes

Pitching Accuracy Pitching encoder Yes

Plate Integration System Using a two cylinder design with tapered edges so

everything will fit

No

Deployment Motor Using a stepper motor No

Launch Ability Must conform to standards set by Planetary Services Yes

Launch Survivability Verify that GHOST will survive launch Yes

Initial Spin-Up Carbon steel attached to solar blade material Yes 53

Strategy for Conducting

Remaining Studies

bull 8U GHOST inside 12U structure bull Create a SolidWorksCAD model

bull Pitching Mechanism bull Determine adequate motor within size power and cost constraints

bull Pitching Accuracy bull Determine pitching accuracy based on orbital sensitivity

bull Launch Ability bull Because design is symmetrical center of mass is in the center of the satellite during launch bull Further investigations is needed to determine how many counterweights

bull Launch Survivability bull FEM or Vibrations

bull Initial Spin-up bull Determine feasible method to attach carbon steel support structure to solar sail blade material

54

Resources

bull PAYLOAD SPECIFICATION FOR 3U 6U 12U AND 27U Np Planetary Systems Corporation 2013 Print

bull Davis Jason The Planetary Society The Planetary Society Blog Firefly Partners 11 Apr 2012 Web 12 Oct 2013 lthttpwwwplanetaryorgblogsguest-blogsjason-davis3450htmlgt

bull Mao Tengfei 01mm Thickness Measuring Tape Wwwalibabacom Alibabacom nd Web 12 Oct 2013 lthttpwwwalibabacomproduct-gs8359006940_1mm_thickness_measuring_tapehtmlgt

55

Resources

bull ldquoHow servos and steppers stack uprdquo Machine Design 9 February 2012 [httpmachinedesigncomnewshow-servos-and-steppers-stack Accessed 7 October 2013]

bull ldquoMiniature Stepper Motor Drive Systems - Data Sheetrdquo Micro Motion Solutions [httpwwwmicromocomstepper-motors-datasheetsaspx Accessed 11 October 2013]

bull ldquoData Sheet for TS-53 Servorsquos Electric Motorrdquo Mabuchi Motor [httpwwwprincetonedu~mae412TEXTNTRAK2002292-302pdf Accessed 11 October 2013]

56

PIC

Communications

Deployment

Motor

Encoder

Pitching

Motor 1

Pitching

Motor 2 Key

Power Lines

Input Lines

Output Lines

Integration Power

Microchip FBD

5V Battery

Possible Voltage

Buffer

Encoder

43

Integration Power

Motor Power Limitations

bull Power Constraints

Pmax = 100 W

Vmax = 50 V

bull P = IV (Power = CurrentVoltage)

bull Therefore Iave = 20 Amps

bull Blade Pitching (4 motors total needed) - Current limitations for power sources and number of simultaneous blades pitching

Number of Blades 5 V Input 36 V input 31 V input 2 V input

4 040 A 069 A 081 A 125 A

2 080 A 139 A 161 A 250 A

1 160 A 278 A 323 A 500 A

44

Integration Motors

Stepper vs Brushless Servo Motors

45

-Contain many poles (50+) -Contain only 4-12 poles

-Distinct steps cause

vibration during use -Do not suffer from

vibration and resonance

issues smooth movement

-Low maintenance easier to

commission mechanically

simple

-Efficient response to start

stop and reverse commands

-Rely on encoders for

position details in closed

loop response

-Physical sizes

are comparable

-Both available

in various

lengths at same

frame size -Torque can be readily

controlled

-Low cost and high

availability

-Complexity drives cost

upward

Chosen for

deployment motor

Chosen for

pitching motor

Stepper Servo

Integration Blade Deployment

Deployment Motor Feasibility

Required holding torque is calculated to be 18 mNm

Required driving torque is calculated to be 117

10-5 mN∙m

bull Micro Motion Solutions ndash miniature stepper motors bull Physical Properties

bull Diameter = 6-22 mm

bull Length = 93-20 mm

bull Weight = 55-12 g

bull Holding Torque = 24-10 mN∙m = 034-142 oz∙in

bull Resolution bull 1 or 2 phase half-step capability

bull Steps per turn = 20-24 rarr 15˚-18˚ per step

5 of full step accuracy

bull Power Requirements bull Nominal voltage per phase 2-5 V

bull Nominal current per phase 01-1 A

46

Integration Blade Pitching

Blade Pitching Motor Feasibility

Required driving torque is calculated to be 0019 mN∙m

bull Mabuchi Servo Motor bull Physical Size

bull Diameter = 17 mm

bull Length = 25 mm

bull Weight = 16 g

bull Torque

bull Holding Torque = 161 mN∙m = 0228 oz∙in

bull Driving Torque = 0385 mN∙m = 0055 oz∙in

bull Friction Torque = 403

10-3 mN∙m = 571

10-4 oz∙in

bull Power Requirements

bull Nominal voltage per phase 2-5 V

bull Nominal current per phase 006-02 A 47

Integration Launch

Feasibility for Pre-deployment locking mechanism

The tip of the solar sail will be wider than the body with the sail tip set outside the plate

The tip will be held in place vertically by stationary blade stabilizers and kept tight by the holding torque of the deployment motor

Stationary blade

stabilizers

Extra-wide

blade tip

Upon deployment the motor

turns and the blade extends

48

Integration Launch

Canesterized Satellite Dispenser (CSD)

bull Ride in a 12 U CSD

bull Width=239 cm Height=226 cm Length=366 cm

bull Mass=0-24 kg at launch

bull Center of Mass when stowed in

bull x is -40 to 40 mm

bull y is 50 to 125 mm

bull z is 133 to 233 mm

wwwplanetarysytemscorpcom 49

Integration Launch

Test Validation

bull Launch Vibration Test

bull Needs to be space applicable and strong enough to withstand vibration

bull Ball Aerospace can provide a shake table costing $250hr

bull Preparation for Testing using FEM modeling and adding support features

50

Financial

bull Total Budget $5000

bull Components

bull Stepper Motor $100-200

bull Servo Motor (x2) $50-500 each

bull Materials (made in-house) $500-1000

bull Electronics $0-500

bull Testing

bull Deployment amp Pitching Free (Performed on Campus)

bull Launch Survivability Vibration Stand - $250hr Ball Space Systems in Boulder

bull Total Estimation $700-2700 + Vibration Stand Testing

51

Baseline Design All Together

bull The 8u CubeSat and characteristic acceleration requirements create very strict volumetric restrictions

bull The size of the plates and the rolled sail blade must be validated

bull This design will be analyzed and verified in the feasibility requirements

Inner Control Area

bull Motor

bull Encoder

bull Control

bull Communication

bull Power

Possible Load-bearing

corners for deployment

Housed Solar Sail

Top-Down View

Extra room for third

party systems

52

Status Summary

53

SystemMechanism Final Choice Further

Studies

Needed

8U Structure Fit our CubeSat in 12U bus provided by Planetary Services Yes

Adequate Area of Sails to Provide

Orbit Transfer Capabilities

AR = 22001 No

Pitching Mechanism Using a servo motor Yes

Pitching Accuracy Pitching encoder Yes

Plate Integration System Using a two cylinder design with tapered edges so

everything will fit

No

Deployment Motor Using a stepper motor No

Launch Ability Must conform to standards set by Planetary Services Yes

Launch Survivability Verify that GHOST will survive launch Yes

Initial Spin-Up Carbon steel attached to solar blade material Yes 53

Strategy for Conducting

Remaining Studies

bull 8U GHOST inside 12U structure bull Create a SolidWorksCAD model

bull Pitching Mechanism bull Determine adequate motor within size power and cost constraints

bull Pitching Accuracy bull Determine pitching accuracy based on orbital sensitivity

bull Launch Ability bull Because design is symmetrical center of mass is in the center of the satellite during launch bull Further investigations is needed to determine how many counterweights

bull Launch Survivability bull FEM or Vibrations

bull Initial Spin-up bull Determine feasible method to attach carbon steel support structure to solar sail blade material

54

Resources

bull PAYLOAD SPECIFICATION FOR 3U 6U 12U AND 27U Np Planetary Systems Corporation 2013 Print

bull Davis Jason The Planetary Society The Planetary Society Blog Firefly Partners 11 Apr 2012 Web 12 Oct 2013 lthttpwwwplanetaryorgblogsguest-blogsjason-davis3450htmlgt

bull Mao Tengfei 01mm Thickness Measuring Tape Wwwalibabacom Alibabacom nd Web 12 Oct 2013 lthttpwwwalibabacomproduct-gs8359006940_1mm_thickness_measuring_tapehtmlgt

55

Resources

bull ldquoHow servos and steppers stack uprdquo Machine Design 9 February 2012 [httpmachinedesigncomnewshow-servos-and-steppers-stack Accessed 7 October 2013]

bull ldquoMiniature Stepper Motor Drive Systems - Data Sheetrdquo Micro Motion Solutions [httpwwwmicromocomstepper-motors-datasheetsaspx Accessed 11 October 2013]

bull ldquoData Sheet for TS-53 Servorsquos Electric Motorrdquo Mabuchi Motor [httpwwwprincetonedu~mae412TEXTNTRAK2002292-302pdf Accessed 11 October 2013]

56

Integration Power

Motor Power Limitations

bull Power Constraints

Pmax = 100 W

Vmax = 50 V

bull P = IV (Power = CurrentVoltage)

bull Therefore Iave = 20 Amps

bull Blade Pitching (4 motors total needed) - Current limitations for power sources and number of simultaneous blades pitching

Number of Blades 5 V Input 36 V input 31 V input 2 V input

4 040 A 069 A 081 A 125 A

2 080 A 139 A 161 A 250 A

1 160 A 278 A 323 A 500 A

44

Integration Motors

Stepper vs Brushless Servo Motors

45

-Contain many poles (50+) -Contain only 4-12 poles

-Distinct steps cause

vibration during use -Do not suffer from

vibration and resonance

issues smooth movement

-Low maintenance easier to

commission mechanically

simple

-Efficient response to start

stop and reverse commands

-Rely on encoders for

position details in closed

loop response

-Physical sizes

are comparable

-Both available

in various

lengths at same

frame size -Torque can be readily

controlled

-Low cost and high

availability

-Complexity drives cost

upward

Chosen for

deployment motor

Chosen for

pitching motor

Stepper Servo

Integration Blade Deployment

Deployment Motor Feasibility

Required holding torque is calculated to be 18 mNm

Required driving torque is calculated to be 117

10-5 mN∙m

bull Micro Motion Solutions ndash miniature stepper motors bull Physical Properties

bull Diameter = 6-22 mm

bull Length = 93-20 mm

bull Weight = 55-12 g

bull Holding Torque = 24-10 mN∙m = 034-142 oz∙in

bull Resolution bull 1 or 2 phase half-step capability

bull Steps per turn = 20-24 rarr 15˚-18˚ per step

5 of full step accuracy

bull Power Requirements bull Nominal voltage per phase 2-5 V

bull Nominal current per phase 01-1 A

46

Integration Blade Pitching

Blade Pitching Motor Feasibility

Required driving torque is calculated to be 0019 mN∙m

bull Mabuchi Servo Motor bull Physical Size

bull Diameter = 17 mm

bull Length = 25 mm

bull Weight = 16 g

bull Torque

bull Holding Torque = 161 mN∙m = 0228 oz∙in

bull Driving Torque = 0385 mN∙m = 0055 oz∙in

bull Friction Torque = 403

10-3 mN∙m = 571

10-4 oz∙in

bull Power Requirements

bull Nominal voltage per phase 2-5 V

bull Nominal current per phase 006-02 A 47

Integration Launch

Feasibility for Pre-deployment locking mechanism

The tip of the solar sail will be wider than the body with the sail tip set outside the plate

The tip will be held in place vertically by stationary blade stabilizers and kept tight by the holding torque of the deployment motor

Stationary blade

stabilizers

Extra-wide

blade tip

Upon deployment the motor

turns and the blade extends

48

Integration Launch

Canesterized Satellite Dispenser (CSD)

bull Ride in a 12 U CSD

bull Width=239 cm Height=226 cm Length=366 cm

bull Mass=0-24 kg at launch

bull Center of Mass when stowed in

bull x is -40 to 40 mm

bull y is 50 to 125 mm

bull z is 133 to 233 mm

wwwplanetarysytemscorpcom 49

Integration Launch

Test Validation

bull Launch Vibration Test

bull Needs to be space applicable and strong enough to withstand vibration

bull Ball Aerospace can provide a shake table costing $250hr

bull Preparation for Testing using FEM modeling and adding support features

50

Financial

bull Total Budget $5000

bull Components

bull Stepper Motor $100-200

bull Servo Motor (x2) $50-500 each

bull Materials (made in-house) $500-1000

bull Electronics $0-500

bull Testing

bull Deployment amp Pitching Free (Performed on Campus)

bull Launch Survivability Vibration Stand - $250hr Ball Space Systems in Boulder

bull Total Estimation $700-2700 + Vibration Stand Testing

51

Baseline Design All Together

bull The 8u CubeSat and characteristic acceleration requirements create very strict volumetric restrictions

bull The size of the plates and the rolled sail blade must be validated

bull This design will be analyzed and verified in the feasibility requirements

Inner Control Area

bull Motor

bull Encoder

bull Control

bull Communication

bull Power

Possible Load-bearing

corners for deployment

Housed Solar Sail

Top-Down View

Extra room for third

party systems

52

Status Summary

53

SystemMechanism Final Choice Further

Studies

Needed

8U Structure Fit our CubeSat in 12U bus provided by Planetary Services Yes

Adequate Area of Sails to Provide

Orbit Transfer Capabilities

AR = 22001 No

Pitching Mechanism Using a servo motor Yes

Pitching Accuracy Pitching encoder Yes

Plate Integration System Using a two cylinder design with tapered edges so

everything will fit

No

Deployment Motor Using a stepper motor No

Launch Ability Must conform to standards set by Planetary Services Yes

Launch Survivability Verify that GHOST will survive launch Yes

Initial Spin-Up Carbon steel attached to solar blade material Yes 53

Strategy for Conducting

Remaining Studies

bull 8U GHOST inside 12U structure bull Create a SolidWorksCAD model

bull Pitching Mechanism bull Determine adequate motor within size power and cost constraints

bull Pitching Accuracy bull Determine pitching accuracy based on orbital sensitivity

bull Launch Ability bull Because design is symmetrical center of mass is in the center of the satellite during launch bull Further investigations is needed to determine how many counterweights

bull Launch Survivability bull FEM or Vibrations

bull Initial Spin-up bull Determine feasible method to attach carbon steel support structure to solar sail blade material

54

Resources

bull PAYLOAD SPECIFICATION FOR 3U 6U 12U AND 27U Np Planetary Systems Corporation 2013 Print

bull Davis Jason The Planetary Society The Planetary Society Blog Firefly Partners 11 Apr 2012 Web 12 Oct 2013 lthttpwwwplanetaryorgblogsguest-blogsjason-davis3450htmlgt

bull Mao Tengfei 01mm Thickness Measuring Tape Wwwalibabacom Alibabacom nd Web 12 Oct 2013 lthttpwwwalibabacomproduct-gs8359006940_1mm_thickness_measuring_tapehtmlgt

55

Resources

bull ldquoHow servos and steppers stack uprdquo Machine Design 9 February 2012 [httpmachinedesigncomnewshow-servos-and-steppers-stack Accessed 7 October 2013]

bull ldquoMiniature Stepper Motor Drive Systems - Data Sheetrdquo Micro Motion Solutions [httpwwwmicromocomstepper-motors-datasheetsaspx Accessed 11 October 2013]

bull ldquoData Sheet for TS-53 Servorsquos Electric Motorrdquo Mabuchi Motor [httpwwwprincetonedu~mae412TEXTNTRAK2002292-302pdf Accessed 11 October 2013]

56

Integration Motors

Stepper vs Brushless Servo Motors

45

-Contain many poles (50+) -Contain only 4-12 poles

-Distinct steps cause

vibration during use -Do not suffer from

vibration and resonance

issues smooth movement

-Low maintenance easier to

commission mechanically

simple

-Efficient response to start

stop and reverse commands

-Rely on encoders for

position details in closed

loop response

-Physical sizes

are comparable

-Both available

in various

lengths at same

frame size -Torque can be readily

controlled

-Low cost and high

availability

-Complexity drives cost

upward

Chosen for

deployment motor

Chosen for

pitching motor

Stepper Servo

Integration Blade Deployment

Deployment Motor Feasibility

Required holding torque is calculated to be 18 mNm

Required driving torque is calculated to be 117

10-5 mN∙m

bull Micro Motion Solutions ndash miniature stepper motors bull Physical Properties

bull Diameter = 6-22 mm

bull Length = 93-20 mm

bull Weight = 55-12 g

bull Holding Torque = 24-10 mN∙m = 034-142 oz∙in

bull Resolution bull 1 or 2 phase half-step capability

bull Steps per turn = 20-24 rarr 15˚-18˚ per step

5 of full step accuracy

bull Power Requirements bull Nominal voltage per phase 2-5 V

bull Nominal current per phase 01-1 A

46

Integration Blade Pitching

Blade Pitching Motor Feasibility

Required driving torque is calculated to be 0019 mN∙m

bull Mabuchi Servo Motor bull Physical Size

bull Diameter = 17 mm

bull Length = 25 mm

bull Weight = 16 g

bull Torque

bull Holding Torque = 161 mN∙m = 0228 oz∙in

bull Driving Torque = 0385 mN∙m = 0055 oz∙in

bull Friction Torque = 403

10-3 mN∙m = 571

10-4 oz∙in

bull Power Requirements

bull Nominal voltage per phase 2-5 V

bull Nominal current per phase 006-02 A 47

Integration Launch

Feasibility for Pre-deployment locking mechanism

The tip of the solar sail will be wider than the body with the sail tip set outside the plate

The tip will be held in place vertically by stationary blade stabilizers and kept tight by the holding torque of the deployment motor

Stationary blade

stabilizers

Extra-wide

blade tip

Upon deployment the motor

turns and the blade extends

48

Integration Launch

Canesterized Satellite Dispenser (CSD)

bull Ride in a 12 U CSD

bull Width=239 cm Height=226 cm Length=366 cm

bull Mass=0-24 kg at launch

bull Center of Mass when stowed in

bull x is -40 to 40 mm

bull y is 50 to 125 mm

bull z is 133 to 233 mm

wwwplanetarysytemscorpcom 49

Integration Launch

Test Validation

bull Launch Vibration Test

bull Needs to be space applicable and strong enough to withstand vibration

bull Ball Aerospace can provide a shake table costing $250hr

bull Preparation for Testing using FEM modeling and adding support features

50

Financial

bull Total Budget $5000

bull Components

bull Stepper Motor $100-200

bull Servo Motor (x2) $50-500 each

bull Materials (made in-house) $500-1000

bull Electronics $0-500

bull Testing

bull Deployment amp Pitching Free (Performed on Campus)

bull Launch Survivability Vibration Stand - $250hr Ball Space Systems in Boulder

bull Total Estimation $700-2700 + Vibration Stand Testing

51

Baseline Design All Together

bull The 8u CubeSat and characteristic acceleration requirements create very strict volumetric restrictions

bull The size of the plates and the rolled sail blade must be validated

bull This design will be analyzed and verified in the feasibility requirements

Inner Control Area

bull Motor

bull Encoder

bull Control

bull Communication

bull Power

Possible Load-bearing

corners for deployment

Housed Solar Sail

Top-Down View

Extra room for third

party systems

52

Status Summary

53

SystemMechanism Final Choice Further

Studies

Needed

8U Structure Fit our CubeSat in 12U bus provided by Planetary Services Yes

Adequate Area of Sails to Provide

Orbit Transfer Capabilities

AR = 22001 No

Pitching Mechanism Using a servo motor Yes

Pitching Accuracy Pitching encoder Yes

Plate Integration System Using a two cylinder design with tapered edges so

everything will fit

No

Deployment Motor Using a stepper motor No

Launch Ability Must conform to standards set by Planetary Services Yes

Launch Survivability Verify that GHOST will survive launch Yes

Initial Spin-Up Carbon steel attached to solar blade material Yes 53

Strategy for Conducting

Remaining Studies

bull 8U GHOST inside 12U structure bull Create a SolidWorksCAD model

bull Pitching Mechanism bull Determine adequate motor within size power and cost constraints

bull Pitching Accuracy bull Determine pitching accuracy based on orbital sensitivity

bull Launch Ability bull Because design is symmetrical center of mass is in the center of the satellite during launch bull Further investigations is needed to determine how many counterweights

bull Launch Survivability bull FEM or Vibrations

bull Initial Spin-up bull Determine feasible method to attach carbon steel support structure to solar sail blade material

54

Resources

bull PAYLOAD SPECIFICATION FOR 3U 6U 12U AND 27U Np Planetary Systems Corporation 2013 Print

bull Davis Jason The Planetary Society The Planetary Society Blog Firefly Partners 11 Apr 2012 Web 12 Oct 2013 lthttpwwwplanetaryorgblogsguest-blogsjason-davis3450htmlgt

bull Mao Tengfei 01mm Thickness Measuring Tape Wwwalibabacom Alibabacom nd Web 12 Oct 2013 lthttpwwwalibabacomproduct-gs8359006940_1mm_thickness_measuring_tapehtmlgt

55

Resources

bull ldquoHow servos and steppers stack uprdquo Machine Design 9 February 2012 [httpmachinedesigncomnewshow-servos-and-steppers-stack Accessed 7 October 2013]

bull ldquoMiniature Stepper Motor Drive Systems - Data Sheetrdquo Micro Motion Solutions [httpwwwmicromocomstepper-motors-datasheetsaspx Accessed 11 October 2013]

bull ldquoData Sheet for TS-53 Servorsquos Electric Motorrdquo Mabuchi Motor [httpwwwprincetonedu~mae412TEXTNTRAK2002292-302pdf Accessed 11 October 2013]

56

Integration Blade Deployment

Deployment Motor Feasibility

Required holding torque is calculated to be 18 mNm

Required driving torque is calculated to be 117

10-5 mN∙m

bull Micro Motion Solutions ndash miniature stepper motors bull Physical Properties

bull Diameter = 6-22 mm

bull Length = 93-20 mm

bull Weight = 55-12 g

bull Holding Torque = 24-10 mN∙m = 034-142 oz∙in

bull Resolution bull 1 or 2 phase half-step capability

bull Steps per turn = 20-24 rarr 15˚-18˚ per step

5 of full step accuracy

bull Power Requirements bull Nominal voltage per phase 2-5 V

bull Nominal current per phase 01-1 A

46

Integration Blade Pitching

Blade Pitching Motor Feasibility

Required driving torque is calculated to be 0019 mN∙m

bull Mabuchi Servo Motor bull Physical Size

bull Diameter = 17 mm

bull Length = 25 mm

bull Weight = 16 g

bull Torque

bull Holding Torque = 161 mN∙m = 0228 oz∙in

bull Driving Torque = 0385 mN∙m = 0055 oz∙in

bull Friction Torque = 403

10-3 mN∙m = 571

10-4 oz∙in

bull Power Requirements

bull Nominal voltage per phase 2-5 V

bull Nominal current per phase 006-02 A 47

Integration Launch

Feasibility for Pre-deployment locking mechanism

The tip of the solar sail will be wider than the body with the sail tip set outside the plate

The tip will be held in place vertically by stationary blade stabilizers and kept tight by the holding torque of the deployment motor

Stationary blade

stabilizers

Extra-wide

blade tip

Upon deployment the motor

turns and the blade extends

48

Integration Launch

Canesterized Satellite Dispenser (CSD)

bull Ride in a 12 U CSD

bull Width=239 cm Height=226 cm Length=366 cm

bull Mass=0-24 kg at launch

bull Center of Mass when stowed in

bull x is -40 to 40 mm

bull y is 50 to 125 mm

bull z is 133 to 233 mm

wwwplanetarysytemscorpcom 49

Integration Launch

Test Validation

bull Launch Vibration Test

bull Needs to be space applicable and strong enough to withstand vibration

bull Ball Aerospace can provide a shake table costing $250hr

bull Preparation for Testing using FEM modeling and adding support features

50

Financial

bull Total Budget $5000

bull Components

bull Stepper Motor $100-200

bull Servo Motor (x2) $50-500 each

bull Materials (made in-house) $500-1000

bull Electronics $0-500

bull Testing

bull Deployment amp Pitching Free (Performed on Campus)

bull Launch Survivability Vibration Stand - $250hr Ball Space Systems in Boulder

bull Total Estimation $700-2700 + Vibration Stand Testing

51

Baseline Design All Together

bull The 8u CubeSat and characteristic acceleration requirements create very strict volumetric restrictions

bull The size of the plates and the rolled sail blade must be validated

bull This design will be analyzed and verified in the feasibility requirements

Inner Control Area

bull Motor

bull Encoder

bull Control

bull Communication

bull Power

Possible Load-bearing

corners for deployment

Housed Solar Sail

Top-Down View

Extra room for third

party systems

52

Status Summary

53

SystemMechanism Final Choice Further

Studies

Needed

8U Structure Fit our CubeSat in 12U bus provided by Planetary Services Yes

Adequate Area of Sails to Provide

Orbit Transfer Capabilities

AR = 22001 No

Pitching Mechanism Using a servo motor Yes

Pitching Accuracy Pitching encoder Yes

Plate Integration System Using a two cylinder design with tapered edges so

everything will fit

No

Deployment Motor Using a stepper motor No

Launch Ability Must conform to standards set by Planetary Services Yes

Launch Survivability Verify that GHOST will survive launch Yes

Initial Spin-Up Carbon steel attached to solar blade material Yes 53

Strategy for Conducting

Remaining Studies

bull 8U GHOST inside 12U structure bull Create a SolidWorksCAD model

bull Pitching Mechanism bull Determine adequate motor within size power and cost constraints

bull Pitching Accuracy bull Determine pitching accuracy based on orbital sensitivity

bull Launch Ability bull Because design is symmetrical center of mass is in the center of the satellite during launch bull Further investigations is needed to determine how many counterweights

bull Launch Survivability bull FEM or Vibrations

bull Initial Spin-up bull Determine feasible method to attach carbon steel support structure to solar sail blade material

54

Resources

bull PAYLOAD SPECIFICATION FOR 3U 6U 12U AND 27U Np Planetary Systems Corporation 2013 Print

bull Davis Jason The Planetary Society The Planetary Society Blog Firefly Partners 11 Apr 2012 Web 12 Oct 2013 lthttpwwwplanetaryorgblogsguest-blogsjason-davis3450htmlgt

bull Mao Tengfei 01mm Thickness Measuring Tape Wwwalibabacom Alibabacom nd Web 12 Oct 2013 lthttpwwwalibabacomproduct-gs8359006940_1mm_thickness_measuring_tapehtmlgt

55

Resources

bull ldquoHow servos and steppers stack uprdquo Machine Design 9 February 2012 [httpmachinedesigncomnewshow-servos-and-steppers-stack Accessed 7 October 2013]

bull ldquoMiniature Stepper Motor Drive Systems - Data Sheetrdquo Micro Motion Solutions [httpwwwmicromocomstepper-motors-datasheetsaspx Accessed 11 October 2013]

bull ldquoData Sheet for TS-53 Servorsquos Electric Motorrdquo Mabuchi Motor [httpwwwprincetonedu~mae412TEXTNTRAK2002292-302pdf Accessed 11 October 2013]

56

Integration Blade Pitching

Blade Pitching Motor Feasibility

Required driving torque is calculated to be 0019 mN∙m

bull Mabuchi Servo Motor bull Physical Size

bull Diameter = 17 mm

bull Length = 25 mm

bull Weight = 16 g

bull Torque

bull Holding Torque = 161 mN∙m = 0228 oz∙in

bull Driving Torque = 0385 mN∙m = 0055 oz∙in

bull Friction Torque = 403

10-3 mN∙m = 571

10-4 oz∙in

bull Power Requirements

bull Nominal voltage per phase 2-5 V

bull Nominal current per phase 006-02 A 47

Integration Launch

Feasibility for Pre-deployment locking mechanism

The tip of the solar sail will be wider than the body with the sail tip set outside the plate

The tip will be held in place vertically by stationary blade stabilizers and kept tight by the holding torque of the deployment motor

Stationary blade

stabilizers

Extra-wide

blade tip

Upon deployment the motor

turns and the blade extends

48

Integration Launch

Canesterized Satellite Dispenser (CSD)

bull Ride in a 12 U CSD

bull Width=239 cm Height=226 cm Length=366 cm

bull Mass=0-24 kg at launch

bull Center of Mass when stowed in

bull x is -40 to 40 mm

bull y is 50 to 125 mm

bull z is 133 to 233 mm

wwwplanetarysytemscorpcom 49

Integration Launch

Test Validation

bull Launch Vibration Test

bull Needs to be space applicable and strong enough to withstand vibration

bull Ball Aerospace can provide a shake table costing $250hr

bull Preparation for Testing using FEM modeling and adding support features

50

Financial

bull Total Budget $5000

bull Components

bull Stepper Motor $100-200

bull Servo Motor (x2) $50-500 each

bull Materials (made in-house) $500-1000

bull Electronics $0-500

bull Testing

bull Deployment amp Pitching Free (Performed on Campus)

bull Launch Survivability Vibration Stand - $250hr Ball Space Systems in Boulder

bull Total Estimation $700-2700 + Vibration Stand Testing

51

Baseline Design All Together

bull The 8u CubeSat and characteristic acceleration requirements create very strict volumetric restrictions

bull The size of the plates and the rolled sail blade must be validated

bull This design will be analyzed and verified in the feasibility requirements

Inner Control Area

bull Motor

bull Encoder

bull Control

bull Communication

bull Power

Possible Load-bearing

corners for deployment

Housed Solar Sail

Top-Down View

Extra room for third

party systems

52

Status Summary

53

SystemMechanism Final Choice Further

Studies

Needed

8U Structure Fit our CubeSat in 12U bus provided by Planetary Services Yes

Adequate Area of Sails to Provide

Orbit Transfer Capabilities

AR = 22001 No

Pitching Mechanism Using a servo motor Yes

Pitching Accuracy Pitching encoder Yes

Plate Integration System Using a two cylinder design with tapered edges so

everything will fit

No

Deployment Motor Using a stepper motor No

Launch Ability Must conform to standards set by Planetary Services Yes

Launch Survivability Verify that GHOST will survive launch Yes

Initial Spin-Up Carbon steel attached to solar blade material Yes 53

Strategy for Conducting

Remaining Studies

bull 8U GHOST inside 12U structure bull Create a SolidWorksCAD model

bull Pitching Mechanism bull Determine adequate motor within size power and cost constraints

bull Pitching Accuracy bull Determine pitching accuracy based on orbital sensitivity

bull Launch Ability bull Because design is symmetrical center of mass is in the center of the satellite during launch bull Further investigations is needed to determine how many counterweights

bull Launch Survivability bull FEM or Vibrations

bull Initial Spin-up bull Determine feasible method to attach carbon steel support structure to solar sail blade material

54

Resources

bull PAYLOAD SPECIFICATION FOR 3U 6U 12U AND 27U Np Planetary Systems Corporation 2013 Print

bull Davis Jason The Planetary Society The Planetary Society Blog Firefly Partners 11 Apr 2012 Web 12 Oct 2013 lthttpwwwplanetaryorgblogsguest-blogsjason-davis3450htmlgt

bull Mao Tengfei 01mm Thickness Measuring Tape Wwwalibabacom Alibabacom nd Web 12 Oct 2013 lthttpwwwalibabacomproduct-gs8359006940_1mm_thickness_measuring_tapehtmlgt

55

Resources

bull ldquoHow servos and steppers stack uprdquo Machine Design 9 February 2012 [httpmachinedesigncomnewshow-servos-and-steppers-stack Accessed 7 October 2013]

bull ldquoMiniature Stepper Motor Drive Systems - Data Sheetrdquo Micro Motion Solutions [httpwwwmicromocomstepper-motors-datasheetsaspx Accessed 11 October 2013]

bull ldquoData Sheet for TS-53 Servorsquos Electric Motorrdquo Mabuchi Motor [httpwwwprincetonedu~mae412TEXTNTRAK2002292-302pdf Accessed 11 October 2013]

56

Integration Launch

Feasibility for Pre-deployment locking mechanism

The tip of the solar sail will be wider than the body with the sail tip set outside the plate

The tip will be held in place vertically by stationary blade stabilizers and kept tight by the holding torque of the deployment motor

Stationary blade

stabilizers

Extra-wide

blade tip

Upon deployment the motor

turns and the blade extends

48

Integration Launch

Canesterized Satellite Dispenser (CSD)

bull Ride in a 12 U CSD

bull Width=239 cm Height=226 cm Length=366 cm

bull Mass=0-24 kg at launch

bull Center of Mass when stowed in

bull x is -40 to 40 mm

bull y is 50 to 125 mm

bull z is 133 to 233 mm

wwwplanetarysytemscorpcom 49

Integration Launch

Test Validation

bull Launch Vibration Test

bull Needs to be space applicable and strong enough to withstand vibration

bull Ball Aerospace can provide a shake table costing $250hr

bull Preparation for Testing using FEM modeling and adding support features

50

Financial

bull Total Budget $5000

bull Components

bull Stepper Motor $100-200

bull Servo Motor (x2) $50-500 each

bull Materials (made in-house) $500-1000

bull Electronics $0-500

bull Testing

bull Deployment amp Pitching Free (Performed on Campus)

bull Launch Survivability Vibration Stand - $250hr Ball Space Systems in Boulder

bull Total Estimation $700-2700 + Vibration Stand Testing

51

Baseline Design All Together

bull The 8u CubeSat and characteristic acceleration requirements create very strict volumetric restrictions

bull The size of the plates and the rolled sail blade must be validated

bull This design will be analyzed and verified in the feasibility requirements

Inner Control Area

bull Motor

bull Encoder

bull Control

bull Communication

bull Power

Possible Load-bearing

corners for deployment

Housed Solar Sail

Top-Down View

Extra room for third

party systems

52

Status Summary

53

SystemMechanism Final Choice Further

Studies

Needed

8U Structure Fit our CubeSat in 12U bus provided by Planetary Services Yes

Adequate Area of Sails to Provide

Orbit Transfer Capabilities

AR = 22001 No

Pitching Mechanism Using a servo motor Yes

Pitching Accuracy Pitching encoder Yes

Plate Integration System Using a two cylinder design with tapered edges so

everything will fit

No

Deployment Motor Using a stepper motor No

Launch Ability Must conform to standards set by Planetary Services Yes

Launch Survivability Verify that GHOST will survive launch Yes

Initial Spin-Up Carbon steel attached to solar blade material Yes 53

Strategy for Conducting

Remaining Studies

bull 8U GHOST inside 12U structure bull Create a SolidWorksCAD model

bull Pitching Mechanism bull Determine adequate motor within size power and cost constraints

bull Pitching Accuracy bull Determine pitching accuracy based on orbital sensitivity

bull Launch Ability bull Because design is symmetrical center of mass is in the center of the satellite during launch bull Further investigations is needed to determine how many counterweights

bull Launch Survivability bull FEM or Vibrations

bull Initial Spin-up bull Determine feasible method to attach carbon steel support structure to solar sail blade material

54

Resources

bull PAYLOAD SPECIFICATION FOR 3U 6U 12U AND 27U Np Planetary Systems Corporation 2013 Print

bull Davis Jason The Planetary Society The Planetary Society Blog Firefly Partners 11 Apr 2012 Web 12 Oct 2013 lthttpwwwplanetaryorgblogsguest-blogsjason-davis3450htmlgt

bull Mao Tengfei 01mm Thickness Measuring Tape Wwwalibabacom Alibabacom nd Web 12 Oct 2013 lthttpwwwalibabacomproduct-gs8359006940_1mm_thickness_measuring_tapehtmlgt

55

Resources

bull ldquoHow servos and steppers stack uprdquo Machine Design 9 February 2012 [httpmachinedesigncomnewshow-servos-and-steppers-stack Accessed 7 October 2013]

bull ldquoMiniature Stepper Motor Drive Systems - Data Sheetrdquo Micro Motion Solutions [httpwwwmicromocomstepper-motors-datasheetsaspx Accessed 11 October 2013]

bull ldquoData Sheet for TS-53 Servorsquos Electric Motorrdquo Mabuchi Motor [httpwwwprincetonedu~mae412TEXTNTRAK2002292-302pdf Accessed 11 October 2013]

56

Integration Launch

Canesterized Satellite Dispenser (CSD)

bull Ride in a 12 U CSD

bull Width=239 cm Height=226 cm Length=366 cm

bull Mass=0-24 kg at launch

bull Center of Mass when stowed in

bull x is -40 to 40 mm

bull y is 50 to 125 mm

bull z is 133 to 233 mm

wwwplanetarysytemscorpcom 49

Integration Launch

Test Validation

bull Launch Vibration Test

bull Needs to be space applicable and strong enough to withstand vibration

bull Ball Aerospace can provide a shake table costing $250hr

bull Preparation for Testing using FEM modeling and adding support features

50

Financial

bull Total Budget $5000

bull Components

bull Stepper Motor $100-200

bull Servo Motor (x2) $50-500 each

bull Materials (made in-house) $500-1000

bull Electronics $0-500

bull Testing

bull Deployment amp Pitching Free (Performed on Campus)

bull Launch Survivability Vibration Stand - $250hr Ball Space Systems in Boulder

bull Total Estimation $700-2700 + Vibration Stand Testing

51

Baseline Design All Together

bull The 8u CubeSat and characteristic acceleration requirements create very strict volumetric restrictions

bull The size of the plates and the rolled sail blade must be validated

bull This design will be analyzed and verified in the feasibility requirements

Inner Control Area

bull Motor

bull Encoder

bull Control

bull Communication

bull Power

Possible Load-bearing

corners for deployment

Housed Solar Sail

Top-Down View

Extra room for third

party systems

52

Status Summary

53

SystemMechanism Final Choice Further

Studies

Needed

8U Structure Fit our CubeSat in 12U bus provided by Planetary Services Yes

Adequate Area of Sails to Provide

Orbit Transfer Capabilities

AR = 22001 No

Pitching Mechanism Using a servo motor Yes

Pitching Accuracy Pitching encoder Yes

Plate Integration System Using a two cylinder design with tapered edges so

everything will fit

No

Deployment Motor Using a stepper motor No

Launch Ability Must conform to standards set by Planetary Services Yes

Launch Survivability Verify that GHOST will survive launch Yes

Initial Spin-Up Carbon steel attached to solar blade material Yes 53

Strategy for Conducting

Remaining Studies

bull 8U GHOST inside 12U structure bull Create a SolidWorksCAD model

bull Pitching Mechanism bull Determine adequate motor within size power and cost constraints

bull Pitching Accuracy bull Determine pitching accuracy based on orbital sensitivity

bull Launch Ability bull Because design is symmetrical center of mass is in the center of the satellite during launch bull Further investigations is needed to determine how many counterweights

bull Launch Survivability bull FEM or Vibrations

bull Initial Spin-up bull Determine feasible method to attach carbon steel support structure to solar sail blade material

54

Resources

bull PAYLOAD SPECIFICATION FOR 3U 6U 12U AND 27U Np Planetary Systems Corporation 2013 Print

bull Davis Jason The Planetary Society The Planetary Society Blog Firefly Partners 11 Apr 2012 Web 12 Oct 2013 lthttpwwwplanetaryorgblogsguest-blogsjason-davis3450htmlgt

bull Mao Tengfei 01mm Thickness Measuring Tape Wwwalibabacom Alibabacom nd Web 12 Oct 2013 lthttpwwwalibabacomproduct-gs8359006940_1mm_thickness_measuring_tapehtmlgt

55

Resources

bull ldquoHow servos and steppers stack uprdquo Machine Design 9 February 2012 [httpmachinedesigncomnewshow-servos-and-steppers-stack Accessed 7 October 2013]

bull ldquoMiniature Stepper Motor Drive Systems - Data Sheetrdquo Micro Motion Solutions [httpwwwmicromocomstepper-motors-datasheetsaspx Accessed 11 October 2013]

bull ldquoData Sheet for TS-53 Servorsquos Electric Motorrdquo Mabuchi Motor [httpwwwprincetonedu~mae412TEXTNTRAK2002292-302pdf Accessed 11 October 2013]

56

Integration Launch

Test Validation

bull Launch Vibration Test

bull Needs to be space applicable and strong enough to withstand vibration

bull Ball Aerospace can provide a shake table costing $250hr

bull Preparation for Testing using FEM modeling and adding support features

50

Financial

bull Total Budget $5000

bull Components

bull Stepper Motor $100-200

bull Servo Motor (x2) $50-500 each

bull Materials (made in-house) $500-1000

bull Electronics $0-500

bull Testing

bull Deployment amp Pitching Free (Performed on Campus)

bull Launch Survivability Vibration Stand - $250hr Ball Space Systems in Boulder

bull Total Estimation $700-2700 + Vibration Stand Testing

51

Baseline Design All Together

bull The 8u CubeSat and characteristic acceleration requirements create very strict volumetric restrictions

bull The size of the plates and the rolled sail blade must be validated

bull This design will be analyzed and verified in the feasibility requirements

Inner Control Area

bull Motor

bull Encoder

bull Control

bull Communication

bull Power

Possible Load-bearing

corners for deployment

Housed Solar Sail

Top-Down View

Extra room for third

party systems

52

Status Summary

53

SystemMechanism Final Choice Further

Studies

Needed

8U Structure Fit our CubeSat in 12U bus provided by Planetary Services Yes

Adequate Area of Sails to Provide

Orbit Transfer Capabilities

AR = 22001 No

Pitching Mechanism Using a servo motor Yes

Pitching Accuracy Pitching encoder Yes

Plate Integration System Using a two cylinder design with tapered edges so

everything will fit

No

Deployment Motor Using a stepper motor No

Launch Ability Must conform to standards set by Planetary Services Yes

Launch Survivability Verify that GHOST will survive launch Yes

Initial Spin-Up Carbon steel attached to solar blade material Yes 53

Strategy for Conducting

Remaining Studies

bull 8U GHOST inside 12U structure bull Create a SolidWorksCAD model

bull Pitching Mechanism bull Determine adequate motor within size power and cost constraints

bull Pitching Accuracy bull Determine pitching accuracy based on orbital sensitivity

bull Launch Ability bull Because design is symmetrical center of mass is in the center of the satellite during launch bull Further investigations is needed to determine how many counterweights

bull Launch Survivability bull FEM or Vibrations

bull Initial Spin-up bull Determine feasible method to attach carbon steel support structure to solar sail blade material

54

Resources

bull PAYLOAD SPECIFICATION FOR 3U 6U 12U AND 27U Np Planetary Systems Corporation 2013 Print

bull Davis Jason The Planetary Society The Planetary Society Blog Firefly Partners 11 Apr 2012 Web 12 Oct 2013 lthttpwwwplanetaryorgblogsguest-blogsjason-davis3450htmlgt

bull Mao Tengfei 01mm Thickness Measuring Tape Wwwalibabacom Alibabacom nd Web 12 Oct 2013 lthttpwwwalibabacomproduct-gs8359006940_1mm_thickness_measuring_tapehtmlgt

55

Resources

bull ldquoHow servos and steppers stack uprdquo Machine Design 9 February 2012 [httpmachinedesigncomnewshow-servos-and-steppers-stack Accessed 7 October 2013]

bull ldquoMiniature Stepper Motor Drive Systems - Data Sheetrdquo Micro Motion Solutions [httpwwwmicromocomstepper-motors-datasheetsaspx Accessed 11 October 2013]

bull ldquoData Sheet for TS-53 Servorsquos Electric Motorrdquo Mabuchi Motor [httpwwwprincetonedu~mae412TEXTNTRAK2002292-302pdf Accessed 11 October 2013]

56

Financial

bull Total Budget $5000

bull Components

bull Stepper Motor $100-200

bull Servo Motor (x2) $50-500 each

bull Materials (made in-house) $500-1000

bull Electronics $0-500

bull Testing

bull Deployment amp Pitching Free (Performed on Campus)

bull Launch Survivability Vibration Stand - $250hr Ball Space Systems in Boulder

bull Total Estimation $700-2700 + Vibration Stand Testing

51

Baseline Design All Together

bull The 8u CubeSat and characteristic acceleration requirements create very strict volumetric restrictions

bull The size of the plates and the rolled sail blade must be validated

bull This design will be analyzed and verified in the feasibility requirements

Inner Control Area

bull Motor

bull Encoder

bull Control

bull Communication

bull Power

Possible Load-bearing

corners for deployment

Housed Solar Sail

Top-Down View

Extra room for third

party systems

52

Status Summary

53

SystemMechanism Final Choice Further

Studies

Needed

8U Structure Fit our CubeSat in 12U bus provided by Planetary Services Yes

Adequate Area of Sails to Provide

Orbit Transfer Capabilities

AR = 22001 No

Pitching Mechanism Using a servo motor Yes

Pitching Accuracy Pitching encoder Yes

Plate Integration System Using a two cylinder design with tapered edges so

everything will fit

No

Deployment Motor Using a stepper motor No

Launch Ability Must conform to standards set by Planetary Services Yes

Launch Survivability Verify that GHOST will survive launch Yes

Initial Spin-Up Carbon steel attached to solar blade material Yes 53

Strategy for Conducting

Remaining Studies

bull 8U GHOST inside 12U structure bull Create a SolidWorksCAD model

bull Pitching Mechanism bull Determine adequate motor within size power and cost constraints

bull Pitching Accuracy bull Determine pitching accuracy based on orbital sensitivity

bull Launch Ability bull Because design is symmetrical center of mass is in the center of the satellite during launch bull Further investigations is needed to determine how many counterweights

bull Launch Survivability bull FEM or Vibrations

bull Initial Spin-up bull Determine feasible method to attach carbon steel support structure to solar sail blade material

54

Resources

bull PAYLOAD SPECIFICATION FOR 3U 6U 12U AND 27U Np Planetary Systems Corporation 2013 Print

bull Davis Jason The Planetary Society The Planetary Society Blog Firefly Partners 11 Apr 2012 Web 12 Oct 2013 lthttpwwwplanetaryorgblogsguest-blogsjason-davis3450htmlgt

bull Mao Tengfei 01mm Thickness Measuring Tape Wwwalibabacom Alibabacom nd Web 12 Oct 2013 lthttpwwwalibabacomproduct-gs8359006940_1mm_thickness_measuring_tapehtmlgt

55

Resources

bull ldquoHow servos and steppers stack uprdquo Machine Design 9 February 2012 [httpmachinedesigncomnewshow-servos-and-steppers-stack Accessed 7 October 2013]

bull ldquoMiniature Stepper Motor Drive Systems - Data Sheetrdquo Micro Motion Solutions [httpwwwmicromocomstepper-motors-datasheetsaspx Accessed 11 October 2013]

bull ldquoData Sheet for TS-53 Servorsquos Electric Motorrdquo Mabuchi Motor [httpwwwprincetonedu~mae412TEXTNTRAK2002292-302pdf Accessed 11 October 2013]

56

Baseline Design All Together

bull The 8u CubeSat and characteristic acceleration requirements create very strict volumetric restrictions

bull The size of the plates and the rolled sail blade must be validated

bull This design will be analyzed and verified in the feasibility requirements

Inner Control Area

bull Motor

bull Encoder

bull Control

bull Communication

bull Power

Possible Load-bearing

corners for deployment

Housed Solar Sail

Top-Down View

Extra room for third

party systems

52

Status Summary

53

SystemMechanism Final Choice Further

Studies

Needed

8U Structure Fit our CubeSat in 12U bus provided by Planetary Services Yes

Adequate Area of Sails to Provide

Orbit Transfer Capabilities

AR = 22001 No

Pitching Mechanism Using a servo motor Yes

Pitching Accuracy Pitching encoder Yes

Plate Integration System Using a two cylinder design with tapered edges so

everything will fit

No

Deployment Motor Using a stepper motor No

Launch Ability Must conform to standards set by Planetary Services Yes

Launch Survivability Verify that GHOST will survive launch Yes

Initial Spin-Up Carbon steel attached to solar blade material Yes 53

Strategy for Conducting

Remaining Studies

bull 8U GHOST inside 12U structure bull Create a SolidWorksCAD model

bull Pitching Mechanism bull Determine adequate motor within size power and cost constraints

bull Pitching Accuracy bull Determine pitching accuracy based on orbital sensitivity

bull Launch Ability bull Because design is symmetrical center of mass is in the center of the satellite during launch bull Further investigations is needed to determine how many counterweights

bull Launch Survivability bull FEM or Vibrations

bull Initial Spin-up bull Determine feasible method to attach carbon steel support structure to solar sail blade material

54

Resources

bull PAYLOAD SPECIFICATION FOR 3U 6U 12U AND 27U Np Planetary Systems Corporation 2013 Print

bull Davis Jason The Planetary Society The Planetary Society Blog Firefly Partners 11 Apr 2012 Web 12 Oct 2013 lthttpwwwplanetaryorgblogsguest-blogsjason-davis3450htmlgt

bull Mao Tengfei 01mm Thickness Measuring Tape Wwwalibabacom Alibabacom nd Web 12 Oct 2013 lthttpwwwalibabacomproduct-gs8359006940_1mm_thickness_measuring_tapehtmlgt

55

Resources

bull ldquoHow servos and steppers stack uprdquo Machine Design 9 February 2012 [httpmachinedesigncomnewshow-servos-and-steppers-stack Accessed 7 October 2013]

bull ldquoMiniature Stepper Motor Drive Systems - Data Sheetrdquo Micro Motion Solutions [httpwwwmicromocomstepper-motors-datasheetsaspx Accessed 11 October 2013]

bull ldquoData Sheet for TS-53 Servorsquos Electric Motorrdquo Mabuchi Motor [httpwwwprincetonedu~mae412TEXTNTRAK2002292-302pdf Accessed 11 October 2013]

56

Status Summary

53

SystemMechanism Final Choice Further

Studies

Needed

8U Structure Fit our CubeSat in 12U bus provided by Planetary Services Yes

Adequate Area of Sails to Provide

Orbit Transfer Capabilities

AR = 22001 No

Pitching Mechanism Using a servo motor Yes

Pitching Accuracy Pitching encoder Yes

Plate Integration System Using a two cylinder design with tapered edges so

everything will fit

No

Deployment Motor Using a stepper motor No

Launch Ability Must conform to standards set by Planetary Services Yes

Launch Survivability Verify that GHOST will survive launch Yes

Initial Spin-Up Carbon steel attached to solar blade material Yes 53

Strategy for Conducting

Remaining Studies

bull 8U GHOST inside 12U structure bull Create a SolidWorksCAD model

bull Pitching Mechanism bull Determine adequate motor within size power and cost constraints

bull Pitching Accuracy bull Determine pitching accuracy based on orbital sensitivity

bull Launch Ability bull Because design is symmetrical center of mass is in the center of the satellite during launch bull Further investigations is needed to determine how many counterweights

bull Launch Survivability bull FEM or Vibrations

bull Initial Spin-up bull Determine feasible method to attach carbon steel support structure to solar sail blade material

54

Resources

bull PAYLOAD SPECIFICATION FOR 3U 6U 12U AND 27U Np Planetary Systems Corporation 2013 Print

bull Davis Jason The Planetary Society The Planetary Society Blog Firefly Partners 11 Apr 2012 Web 12 Oct 2013 lthttpwwwplanetaryorgblogsguest-blogsjason-davis3450htmlgt

bull Mao Tengfei 01mm Thickness Measuring Tape Wwwalibabacom Alibabacom nd Web 12 Oct 2013 lthttpwwwalibabacomproduct-gs8359006940_1mm_thickness_measuring_tapehtmlgt

55

Resources

bull ldquoHow servos and steppers stack uprdquo Machine Design 9 February 2012 [httpmachinedesigncomnewshow-servos-and-steppers-stack Accessed 7 October 2013]

bull ldquoMiniature Stepper Motor Drive Systems - Data Sheetrdquo Micro Motion Solutions [httpwwwmicromocomstepper-motors-datasheetsaspx Accessed 11 October 2013]

bull ldquoData Sheet for TS-53 Servorsquos Electric Motorrdquo Mabuchi Motor [httpwwwprincetonedu~mae412TEXTNTRAK2002292-302pdf Accessed 11 October 2013]

56

Strategy for Conducting

Remaining Studies

bull 8U GHOST inside 12U structure bull Create a SolidWorksCAD model

bull Pitching Mechanism bull Determine adequate motor within size power and cost constraints

bull Pitching Accuracy bull Determine pitching accuracy based on orbital sensitivity

bull Launch Ability bull Because design is symmetrical center of mass is in the center of the satellite during launch bull Further investigations is needed to determine how many counterweights

bull Launch Survivability bull FEM or Vibrations

bull Initial Spin-up bull Determine feasible method to attach carbon steel support structure to solar sail blade material

54

Resources

bull PAYLOAD SPECIFICATION FOR 3U 6U 12U AND 27U Np Planetary Systems Corporation 2013 Print

bull Davis Jason The Planetary Society The Planetary Society Blog Firefly Partners 11 Apr 2012 Web 12 Oct 2013 lthttpwwwplanetaryorgblogsguest-blogsjason-davis3450htmlgt

bull Mao Tengfei 01mm Thickness Measuring Tape Wwwalibabacom Alibabacom nd Web 12 Oct 2013 lthttpwwwalibabacomproduct-gs8359006940_1mm_thickness_measuring_tapehtmlgt

55

Resources

bull ldquoHow servos and steppers stack uprdquo Machine Design 9 February 2012 [httpmachinedesigncomnewshow-servos-and-steppers-stack Accessed 7 October 2013]

bull ldquoMiniature Stepper Motor Drive Systems - Data Sheetrdquo Micro Motion Solutions [httpwwwmicromocomstepper-motors-datasheetsaspx Accessed 11 October 2013]

bull ldquoData Sheet for TS-53 Servorsquos Electric Motorrdquo Mabuchi Motor [httpwwwprincetonedu~mae412TEXTNTRAK2002292-302pdf Accessed 11 October 2013]

56

Resources

bull PAYLOAD SPECIFICATION FOR 3U 6U 12U AND 27U Np Planetary Systems Corporation 2013 Print

bull Davis Jason The Planetary Society The Planetary Society Blog Firefly Partners 11 Apr 2012 Web 12 Oct 2013 lthttpwwwplanetaryorgblogsguest-blogsjason-davis3450htmlgt

bull Mao Tengfei 01mm Thickness Measuring Tape Wwwalibabacom Alibabacom nd Web 12 Oct 2013 lthttpwwwalibabacomproduct-gs8359006940_1mm_thickness_measuring_tapehtmlgt

55

Resources

bull ldquoHow servos and steppers stack uprdquo Machine Design 9 February 2012 [httpmachinedesigncomnewshow-servos-and-steppers-stack Accessed 7 October 2013]

bull ldquoMiniature Stepper Motor Drive Systems - Data Sheetrdquo Micro Motion Solutions [httpwwwmicromocomstepper-motors-datasheetsaspx Accessed 11 October 2013]

bull ldquoData Sheet for TS-53 Servorsquos Electric Motorrdquo Mabuchi Motor [httpwwwprincetonedu~mae412TEXTNTRAK2002292-302pdf Accessed 11 October 2013]

56

Resources

bull ldquoHow servos and steppers stack uprdquo Machine Design 9 February 2012 [httpmachinedesigncomnewshow-servos-and-steppers-stack Accessed 7 October 2013]

bull ldquoMiniature Stepper Motor Drive Systems - Data Sheetrdquo Micro Motion Solutions [httpwwwmicromocomstepper-motors-datasheetsaspx Accessed 11 October 2013]

bull ldquoData Sheet for TS-53 Servorsquos Electric Motorrdquo Mabuchi Motor [httpwwwprincetonedu~mae412TEXTNTRAK2002292-302pdf Accessed 11 October 2013]

56

Resources

bull David A Vallado ndash Fundamentals of Astrodynamics and Applications

bull Guerrant D Lawrence D Heaton A Earth Escape Capabilities of the Heliogyro Sail AIAA Paper

bull Wikipedia

bull httpenwikipediaorgwikiFileHohmann_transfer_orbitsvg

bull httpenwikipediaorgwikiSolar_radiation_pressure

bull Google

bull httpsearthesaintimageimage_galleryimg_id=18264

bull httpwwwsottnetimageimages5118715fullearth_magnetic_field_polesjpg

57

Appendix

Communications

bull CubeSats Commercial-Off-The-Shelf (COTS) Transceivers

bull UHFVHF range typical

bull Volume ~1x5x5 cm + antennae

bull Power 18-525 V (MicroLow-power transceivers) and I = 1-100 mA range (~25 mA typical)

bull Price ~$1000rsquos (out of scope of GHOST project)

58

Appendix

Aspect Ratio Calculation

59

As

4wl l 2203 m w 010 m

ARl2

As4

AR 100 requirementAR 22026

Appendix

Final Orbit Inclination Determination

60

e 0 a p z 1500 km = constant2510

2 x1075551 13636378 skmJkmRE

Assumption

Known

a r RE z 78781363 km

i 10196o retrograde orbit

and

rarr

Appendix

Orbit Raising SC Orientation

61

Appendix

Inclination Change Maneuver

View Facing Sun

Side View

62

Appendix

Inclination Change SC Orientation

63

Appendix

Important Profiles amp Orientations

64

Appendix

Blade Pitch Profiles

65

Appendix Polar Orbit Interaction

With Earthrsquos Magnetic Field

τ = B x M

τ lt 0

τ gt 0

τ = 0

τ = 0

66

Appendix

Brush vs Brushless DC Motors

bull Pros bull Inexpensive and reliable bull Simple two-wire control bull Extended operational life

bull Cons bull Increased speed rarr increased friction bull Inadequate heat dissipation bull Low speed range bull Electromagnetic interference

bull Pros bull Accurate positioning bull No power loss across brushes rarr efficient bull Small size bull Good heat dissipation bull Higher speed ranges

bull Cons bull Higher cost bull Require more complex control strategies

67

Appendix

Needed Torque for Pitching

68

Assume axle weight and plate are aluminum

Axle

(Rod)

Rolled Blade

(Hollow Cylinder)

Tip Mass

(Rod)

Plate

(Two Hollow

Cylinders)

Dimensions Diameter = 0005 m

Length = 0105 m

Width = 010 m

Length = 220264 m

Thickness = 25

10-6 m

Mass = 0036 kg

Diameter 1 = 014 m

Length 1 = 003 m

Diameter 2 = 0125 m

Length 2 = 0015 m

Thickness = 0003 m

Inertia (I) IA = 0051

IB = 0562

ITM = 0306

IP = 2116

Total Inertia (

)

Angular Acceleration (

)

Torque (τ)

Volume and mass of each part were found in order to determine inertia

Torque needed to pitch a single blade was found from inertia and angular acceleration

Appendix

Reducing Vibration in Motor Torque

Torque

Rotor

Position

Incremental Rotary Optical Encoder

-transparent disk with equally spaced opaque sections

-light emitting diode detected by photo detector

-causes light pulses used to determine position

-outputs signal before digitization two quadrature sine waves

bull Dimensions all in cm

70

Appendix

Baseline Design Dimensions

20

14

10

Deployment Motor Area lt 2x3

Pitching Motor Area lt 3x4

Outset Blade Stabilizers = 01x01

Plate Clearance = 19

Hollow Plate Thickness = 03

Inner Control Area = 11x11 Hollow Central Stabilizer 4x4x20(tall)

Appendix

Thin-set Bearing

bull Minimal friction with plate rotation I comparison to other methods

bull COTS Available size range of 12 -14 cm any of which will fit the Hollow Plate

wwwfrb-bearingscom afkthinbearingcom

71

Appendix

Aspect Ratio Calculation

59

As

4wl l 2203 m w 010 m

ARl2

As4

AR 100 requirementAR 22026

Appendix

Final Orbit Inclination Determination

60

e 0 a p z 1500 km = constant2510

2 x1075551 13636378 skmJkmRE

Assumption

Known

a r RE z 78781363 km

i 10196o retrograde orbit

and

rarr

Appendix

Orbit Raising SC Orientation

61

Appendix

Inclination Change Maneuver

View Facing Sun

Side View

62

Appendix

Inclination Change SC Orientation

63

Appendix

Important Profiles amp Orientations

64

Appendix

Blade Pitch Profiles

65

Appendix Polar Orbit Interaction

With Earthrsquos Magnetic Field

τ = B x M

τ lt 0

τ gt 0

τ = 0

τ = 0

66

Appendix

Brush vs Brushless DC Motors

bull Pros bull Inexpensive and reliable bull Simple two-wire control bull Extended operational life

bull Cons bull Increased speed rarr increased friction bull Inadequate heat dissipation bull Low speed range bull Electromagnetic interference

bull Pros bull Accurate positioning bull No power loss across brushes rarr efficient bull Small size bull Good heat dissipation bull Higher speed ranges

bull Cons bull Higher cost bull Require more complex control strategies

67

Appendix

Needed Torque for Pitching

68

Assume axle weight and plate are aluminum

Axle

(Rod)

Rolled Blade

(Hollow Cylinder)

Tip Mass

(Rod)

Plate

(Two Hollow

Cylinders)

Dimensions Diameter = 0005 m

Length = 0105 m

Width = 010 m

Length = 220264 m

Thickness = 25

10-6 m

Mass = 0036 kg

Diameter 1 = 014 m

Length 1 = 003 m

Diameter 2 = 0125 m

Length 2 = 0015 m

Thickness = 0003 m

Inertia (I) IA = 0051

IB = 0562

ITM = 0306

IP = 2116

Total Inertia (

)

Angular Acceleration (

)

Torque (τ)

Volume and mass of each part were found in order to determine inertia

Torque needed to pitch a single blade was found from inertia and angular acceleration

Appendix

Reducing Vibration in Motor Torque

Torque

Rotor

Position

Incremental Rotary Optical Encoder

-transparent disk with equally spaced opaque sections

-light emitting diode detected by photo detector

-causes light pulses used to determine position

-outputs signal before digitization two quadrature sine waves

bull Dimensions all in cm

70

Appendix

Baseline Design Dimensions

20

14

10

Deployment Motor Area lt 2x3

Pitching Motor Area lt 3x4

Outset Blade Stabilizers = 01x01

Plate Clearance = 19

Hollow Plate Thickness = 03

Inner Control Area = 11x11 Hollow Central Stabilizer 4x4x20(tall)

Appendix

Thin-set Bearing

bull Minimal friction with plate rotation I comparison to other methods

bull COTS Available size range of 12 -14 cm any of which will fit the Hollow Plate

wwwfrb-bearingscom afkthinbearingcom

71

Appendix

Final Orbit Inclination Determination

60

e 0 a p z 1500 km = constant2510

2 x1075551 13636378 skmJkmRE

Assumption

Known

a r RE z 78781363 km

i 10196o retrograde orbit

and

rarr

Appendix

Orbit Raising SC Orientation

61

Appendix

Inclination Change Maneuver

View Facing Sun

Side View

62

Appendix

Inclination Change SC Orientation

63

Appendix

Important Profiles amp Orientations

64

Appendix

Blade Pitch Profiles

65

Appendix Polar Orbit Interaction

With Earthrsquos Magnetic Field

τ = B x M

τ lt 0

τ gt 0

τ = 0

τ = 0

66

Appendix

Brush vs Brushless DC Motors

bull Pros bull Inexpensive and reliable bull Simple two-wire control bull Extended operational life

bull Cons bull Increased speed rarr increased friction bull Inadequate heat dissipation bull Low speed range bull Electromagnetic interference

bull Pros bull Accurate positioning bull No power loss across brushes rarr efficient bull Small size bull Good heat dissipation bull Higher speed ranges

bull Cons bull Higher cost bull Require more complex control strategies

67

Appendix

Needed Torque for Pitching

68

Assume axle weight and plate are aluminum

Axle

(Rod)

Rolled Blade

(Hollow Cylinder)

Tip Mass

(Rod)

Plate

(Two Hollow

Cylinders)

Dimensions Diameter = 0005 m

Length = 0105 m

Width = 010 m

Length = 220264 m

Thickness = 25

10-6 m

Mass = 0036 kg

Diameter 1 = 014 m

Length 1 = 003 m

Diameter 2 = 0125 m

Length 2 = 0015 m

Thickness = 0003 m

Inertia (I) IA = 0051

IB = 0562

ITM = 0306

IP = 2116

Total Inertia (

)

Angular Acceleration (

)

Torque (τ)

Volume and mass of each part were found in order to determine inertia

Torque needed to pitch a single blade was found from inertia and angular acceleration

Appendix

Reducing Vibration in Motor Torque

Torque

Rotor

Position

Incremental Rotary Optical Encoder

-transparent disk with equally spaced opaque sections

-light emitting diode detected by photo detector

-causes light pulses used to determine position

-outputs signal before digitization two quadrature sine waves

bull Dimensions all in cm

70

Appendix

Baseline Design Dimensions

20

14

10

Deployment Motor Area lt 2x3

Pitching Motor Area lt 3x4

Outset Blade Stabilizers = 01x01

Plate Clearance = 19

Hollow Plate Thickness = 03

Inner Control Area = 11x11 Hollow Central Stabilizer 4x4x20(tall)

Appendix

Thin-set Bearing

bull Minimal friction with plate rotation I comparison to other methods

bull COTS Available size range of 12 -14 cm any of which will fit the Hollow Plate

wwwfrb-bearingscom afkthinbearingcom

71

Appendix

Orbit Raising SC Orientation

61

Appendix

Inclination Change Maneuver

View Facing Sun

Side View

62

Appendix

Inclination Change SC Orientation

63

Appendix

Important Profiles amp Orientations

64

Appendix

Blade Pitch Profiles

65

Appendix Polar Orbit Interaction

With Earthrsquos Magnetic Field

τ = B x M

τ lt 0

τ gt 0

τ = 0

τ = 0

66

Appendix

Brush vs Brushless DC Motors

bull Pros bull Inexpensive and reliable bull Simple two-wire control bull Extended operational life

bull Cons bull Increased speed rarr increased friction bull Inadequate heat dissipation bull Low speed range bull Electromagnetic interference

bull Pros bull Accurate positioning bull No power loss across brushes rarr efficient bull Small size bull Good heat dissipation bull Higher speed ranges

bull Cons bull Higher cost bull Require more complex control strategies

67

Appendix

Needed Torque for Pitching

68

Assume axle weight and plate are aluminum

Axle

(Rod)

Rolled Blade

(Hollow Cylinder)

Tip Mass

(Rod)

Plate

(Two Hollow

Cylinders)

Dimensions Diameter = 0005 m

Length = 0105 m

Width = 010 m

Length = 220264 m

Thickness = 25

10-6 m

Mass = 0036 kg

Diameter 1 = 014 m

Length 1 = 003 m

Diameter 2 = 0125 m

Length 2 = 0015 m

Thickness = 0003 m

Inertia (I) IA = 0051

IB = 0562

ITM = 0306

IP = 2116

Total Inertia (

)

Angular Acceleration (

)

Torque (τ)

Volume and mass of each part were found in order to determine inertia

Torque needed to pitch a single blade was found from inertia and angular acceleration

Appendix

Reducing Vibration in Motor Torque

Torque

Rotor

Position

Incremental Rotary Optical Encoder

-transparent disk with equally spaced opaque sections

-light emitting diode detected by photo detector

-causes light pulses used to determine position

-outputs signal before digitization two quadrature sine waves

bull Dimensions all in cm

70

Appendix

Baseline Design Dimensions

20

14

10

Deployment Motor Area lt 2x3

Pitching Motor Area lt 3x4

Outset Blade Stabilizers = 01x01

Plate Clearance = 19

Hollow Plate Thickness = 03

Inner Control Area = 11x11 Hollow Central Stabilizer 4x4x20(tall)

Appendix

Thin-set Bearing

bull Minimal friction with plate rotation I comparison to other methods

bull COTS Available size range of 12 -14 cm any of which will fit the Hollow Plate

wwwfrb-bearingscom afkthinbearingcom

71

Appendix

Inclination Change Maneuver

View Facing Sun

Side View

62

Appendix

Inclination Change SC Orientation

63

Appendix

Important Profiles amp Orientations

64

Appendix

Blade Pitch Profiles

65

Appendix Polar Orbit Interaction

With Earthrsquos Magnetic Field

τ = B x M

τ lt 0

τ gt 0

τ = 0

τ = 0

66

Appendix

Brush vs Brushless DC Motors

bull Pros bull Inexpensive and reliable bull Simple two-wire control bull Extended operational life

bull Cons bull Increased speed rarr increased friction bull Inadequate heat dissipation bull Low speed range bull Electromagnetic interference

bull Pros bull Accurate positioning bull No power loss across brushes rarr efficient bull Small size bull Good heat dissipation bull Higher speed ranges

bull Cons bull Higher cost bull Require more complex control strategies

67

Appendix

Needed Torque for Pitching

68

Assume axle weight and plate are aluminum

Axle

(Rod)

Rolled Blade

(Hollow Cylinder)

Tip Mass

(Rod)

Plate

(Two Hollow

Cylinders)

Dimensions Diameter = 0005 m

Length = 0105 m

Width = 010 m

Length = 220264 m

Thickness = 25

10-6 m

Mass = 0036 kg

Diameter 1 = 014 m

Length 1 = 003 m

Diameter 2 = 0125 m

Length 2 = 0015 m

Thickness = 0003 m

Inertia (I) IA = 0051

IB = 0562

ITM = 0306

IP = 2116

Total Inertia (

)

Angular Acceleration (

)

Torque (τ)

Volume and mass of each part were found in order to determine inertia

Torque needed to pitch a single blade was found from inertia and angular acceleration

Appendix

Reducing Vibration in Motor Torque

Torque

Rotor

Position

Incremental Rotary Optical Encoder

-transparent disk with equally spaced opaque sections

-light emitting diode detected by photo detector

-causes light pulses used to determine position

-outputs signal before digitization two quadrature sine waves

bull Dimensions all in cm

70

Appendix

Baseline Design Dimensions

20

14

10

Deployment Motor Area lt 2x3

Pitching Motor Area lt 3x4

Outset Blade Stabilizers = 01x01

Plate Clearance = 19

Hollow Plate Thickness = 03

Inner Control Area = 11x11 Hollow Central Stabilizer 4x4x20(tall)

Appendix

Thin-set Bearing

bull Minimal friction with plate rotation I comparison to other methods

bull COTS Available size range of 12 -14 cm any of which will fit the Hollow Plate

wwwfrb-bearingscom afkthinbearingcom

71

Appendix

Inclination Change SC Orientation

63

Appendix

Important Profiles amp Orientations

64

Appendix

Blade Pitch Profiles

65

Appendix Polar Orbit Interaction

With Earthrsquos Magnetic Field

τ = B x M

τ lt 0

τ gt 0

τ = 0

τ = 0

66

Appendix

Brush vs Brushless DC Motors

bull Pros bull Inexpensive and reliable bull Simple two-wire control bull Extended operational life

bull Cons bull Increased speed rarr increased friction bull Inadequate heat dissipation bull Low speed range bull Electromagnetic interference

bull Pros bull Accurate positioning bull No power loss across brushes rarr efficient bull Small size bull Good heat dissipation bull Higher speed ranges

bull Cons bull Higher cost bull Require more complex control strategies

67

Appendix

Needed Torque for Pitching

68

Assume axle weight and plate are aluminum

Axle

(Rod)

Rolled Blade

(Hollow Cylinder)

Tip Mass

(Rod)

Plate

(Two Hollow

Cylinders)

Dimensions Diameter = 0005 m

Length = 0105 m

Width = 010 m

Length = 220264 m

Thickness = 25

10-6 m

Mass = 0036 kg

Diameter 1 = 014 m

Length 1 = 003 m

Diameter 2 = 0125 m

Length 2 = 0015 m

Thickness = 0003 m

Inertia (I) IA = 0051

IB = 0562

ITM = 0306

IP = 2116

Total Inertia (

)

Angular Acceleration (

)

Torque (τ)

Volume and mass of each part were found in order to determine inertia

Torque needed to pitch a single blade was found from inertia and angular acceleration

Appendix

Reducing Vibration in Motor Torque

Torque

Rotor

Position

Incremental Rotary Optical Encoder

-transparent disk with equally spaced opaque sections

-light emitting diode detected by photo detector

-causes light pulses used to determine position

-outputs signal before digitization two quadrature sine waves

bull Dimensions all in cm

70

Appendix

Baseline Design Dimensions

20

14

10

Deployment Motor Area lt 2x3

Pitching Motor Area lt 3x4

Outset Blade Stabilizers = 01x01

Plate Clearance = 19

Hollow Plate Thickness = 03

Inner Control Area = 11x11 Hollow Central Stabilizer 4x4x20(tall)

Appendix

Thin-set Bearing

bull Minimal friction with plate rotation I comparison to other methods

bull COTS Available size range of 12 -14 cm any of which will fit the Hollow Plate

wwwfrb-bearingscom afkthinbearingcom

71

Appendix

Important Profiles amp Orientations

64

Appendix

Blade Pitch Profiles

65

Appendix Polar Orbit Interaction

With Earthrsquos Magnetic Field

τ = B x M

τ lt 0

τ gt 0

τ = 0

τ = 0

66

Appendix

Brush vs Brushless DC Motors

bull Pros bull Inexpensive and reliable bull Simple two-wire control bull Extended operational life

bull Cons bull Increased speed rarr increased friction bull Inadequate heat dissipation bull Low speed range bull Electromagnetic interference

bull Pros bull Accurate positioning bull No power loss across brushes rarr efficient bull Small size bull Good heat dissipation bull Higher speed ranges

bull Cons bull Higher cost bull Require more complex control strategies

67

Appendix

Needed Torque for Pitching

68

Assume axle weight and plate are aluminum

Axle

(Rod)

Rolled Blade

(Hollow Cylinder)

Tip Mass

(Rod)

Plate

(Two Hollow

Cylinders)

Dimensions Diameter = 0005 m

Length = 0105 m

Width = 010 m

Length = 220264 m

Thickness = 25

10-6 m

Mass = 0036 kg

Diameter 1 = 014 m

Length 1 = 003 m

Diameter 2 = 0125 m

Length 2 = 0015 m

Thickness = 0003 m

Inertia (I) IA = 0051

IB = 0562

ITM = 0306

IP = 2116

Total Inertia (

)

Angular Acceleration (

)

Torque (τ)

Volume and mass of each part were found in order to determine inertia

Torque needed to pitch a single blade was found from inertia and angular acceleration

Appendix

Reducing Vibration in Motor Torque

Torque

Rotor

Position

Incremental Rotary Optical Encoder

-transparent disk with equally spaced opaque sections

-light emitting diode detected by photo detector

-causes light pulses used to determine position

-outputs signal before digitization two quadrature sine waves

bull Dimensions all in cm

70

Appendix

Baseline Design Dimensions

20

14

10

Deployment Motor Area lt 2x3

Pitching Motor Area lt 3x4

Outset Blade Stabilizers = 01x01

Plate Clearance = 19

Hollow Plate Thickness = 03

Inner Control Area = 11x11 Hollow Central Stabilizer 4x4x20(tall)

Appendix

Thin-set Bearing

bull Minimal friction with plate rotation I comparison to other methods

bull COTS Available size range of 12 -14 cm any of which will fit the Hollow Plate

wwwfrb-bearingscom afkthinbearingcom

71

Appendix

Blade Pitch Profiles

65

Appendix Polar Orbit Interaction

With Earthrsquos Magnetic Field

τ = B x M

τ lt 0

τ gt 0

τ = 0

τ = 0

66

Appendix

Brush vs Brushless DC Motors

bull Pros bull Inexpensive and reliable bull Simple two-wire control bull Extended operational life

bull Cons bull Increased speed rarr increased friction bull Inadequate heat dissipation bull Low speed range bull Electromagnetic interference

bull Pros bull Accurate positioning bull No power loss across brushes rarr efficient bull Small size bull Good heat dissipation bull Higher speed ranges

bull Cons bull Higher cost bull Require more complex control strategies

67

Appendix

Needed Torque for Pitching

68

Assume axle weight and plate are aluminum

Axle

(Rod)

Rolled Blade

(Hollow Cylinder)

Tip Mass

(Rod)

Plate

(Two Hollow

Cylinders)

Dimensions Diameter = 0005 m

Length = 0105 m

Width = 010 m

Length = 220264 m

Thickness = 25

10-6 m

Mass = 0036 kg

Diameter 1 = 014 m

Length 1 = 003 m

Diameter 2 = 0125 m

Length 2 = 0015 m

Thickness = 0003 m

Inertia (I) IA = 0051

IB = 0562

ITM = 0306

IP = 2116

Total Inertia (

)

Angular Acceleration (

)

Torque (τ)

Volume and mass of each part were found in order to determine inertia

Torque needed to pitch a single blade was found from inertia and angular acceleration

Appendix

Reducing Vibration in Motor Torque

Torque

Rotor

Position

Incremental Rotary Optical Encoder

-transparent disk with equally spaced opaque sections

-light emitting diode detected by photo detector

-causes light pulses used to determine position

-outputs signal before digitization two quadrature sine waves

bull Dimensions all in cm

70

Appendix

Baseline Design Dimensions

20

14

10

Deployment Motor Area lt 2x3

Pitching Motor Area lt 3x4

Outset Blade Stabilizers = 01x01

Plate Clearance = 19

Hollow Plate Thickness = 03

Inner Control Area = 11x11 Hollow Central Stabilizer 4x4x20(tall)

Appendix

Thin-set Bearing

bull Minimal friction with plate rotation I comparison to other methods

bull COTS Available size range of 12 -14 cm any of which will fit the Hollow Plate

wwwfrb-bearingscom afkthinbearingcom

71

Appendix Polar Orbit Interaction

With Earthrsquos Magnetic Field

τ = B x M

τ lt 0

τ gt 0

τ = 0

τ = 0

66

Appendix

Brush vs Brushless DC Motors

bull Pros bull Inexpensive and reliable bull Simple two-wire control bull Extended operational life

bull Cons bull Increased speed rarr increased friction bull Inadequate heat dissipation bull Low speed range bull Electromagnetic interference

bull Pros bull Accurate positioning bull No power loss across brushes rarr efficient bull Small size bull Good heat dissipation bull Higher speed ranges

bull Cons bull Higher cost bull Require more complex control strategies

67

Appendix

Needed Torque for Pitching

68

Assume axle weight and plate are aluminum

Axle

(Rod)

Rolled Blade

(Hollow Cylinder)

Tip Mass

(Rod)

Plate

(Two Hollow

Cylinders)

Dimensions Diameter = 0005 m

Length = 0105 m

Width = 010 m

Length = 220264 m

Thickness = 25

10-6 m

Mass = 0036 kg

Diameter 1 = 014 m

Length 1 = 003 m

Diameter 2 = 0125 m

Length 2 = 0015 m

Thickness = 0003 m

Inertia (I) IA = 0051

IB = 0562

ITM = 0306

IP = 2116

Total Inertia (

)

Angular Acceleration (

)

Torque (τ)

Volume and mass of each part were found in order to determine inertia

Torque needed to pitch a single blade was found from inertia and angular acceleration

Appendix

Reducing Vibration in Motor Torque

Torque

Rotor

Position

Incremental Rotary Optical Encoder

-transparent disk with equally spaced opaque sections

-light emitting diode detected by photo detector

-causes light pulses used to determine position

-outputs signal before digitization two quadrature sine waves

bull Dimensions all in cm

70

Appendix

Baseline Design Dimensions

20

14

10

Deployment Motor Area lt 2x3

Pitching Motor Area lt 3x4

Outset Blade Stabilizers = 01x01

Plate Clearance = 19

Hollow Plate Thickness = 03

Inner Control Area = 11x11 Hollow Central Stabilizer 4x4x20(tall)

Appendix

Thin-set Bearing

bull Minimal friction with plate rotation I comparison to other methods

bull COTS Available size range of 12 -14 cm any of which will fit the Hollow Plate

wwwfrb-bearingscom afkthinbearingcom

71

Appendix

Brush vs Brushless DC Motors

bull Pros bull Inexpensive and reliable bull Simple two-wire control bull Extended operational life

bull Cons bull Increased speed rarr increased friction bull Inadequate heat dissipation bull Low speed range bull Electromagnetic interference

bull Pros bull Accurate positioning bull No power loss across brushes rarr efficient bull Small size bull Good heat dissipation bull Higher speed ranges

bull Cons bull Higher cost bull Require more complex control strategies

67

Appendix

Needed Torque for Pitching

68

Assume axle weight and plate are aluminum

Axle

(Rod)

Rolled Blade

(Hollow Cylinder)

Tip Mass

(Rod)

Plate

(Two Hollow

Cylinders)

Dimensions Diameter = 0005 m

Length = 0105 m

Width = 010 m

Length = 220264 m

Thickness = 25

10-6 m

Mass = 0036 kg

Diameter 1 = 014 m

Length 1 = 003 m

Diameter 2 = 0125 m

Length 2 = 0015 m

Thickness = 0003 m

Inertia (I) IA = 0051

IB = 0562

ITM = 0306

IP = 2116

Total Inertia (

)

Angular Acceleration (

)

Torque (τ)

Volume and mass of each part were found in order to determine inertia

Torque needed to pitch a single blade was found from inertia and angular acceleration

Appendix

Reducing Vibration in Motor Torque

Torque

Rotor

Position

Incremental Rotary Optical Encoder

-transparent disk with equally spaced opaque sections

-light emitting diode detected by photo detector

-causes light pulses used to determine position

-outputs signal before digitization two quadrature sine waves

bull Dimensions all in cm

70

Appendix

Baseline Design Dimensions

20

14

10

Deployment Motor Area lt 2x3

Pitching Motor Area lt 3x4

Outset Blade Stabilizers = 01x01

Plate Clearance = 19

Hollow Plate Thickness = 03

Inner Control Area = 11x11 Hollow Central Stabilizer 4x4x20(tall)

Appendix

Thin-set Bearing

bull Minimal friction with plate rotation I comparison to other methods

bull COTS Available size range of 12 -14 cm any of which will fit the Hollow Plate

wwwfrb-bearingscom afkthinbearingcom

71

Appendix

Needed Torque for Pitching

68

Assume axle weight and plate are aluminum

Axle

(Rod)

Rolled Blade

(Hollow Cylinder)

Tip Mass

(Rod)

Plate

(Two Hollow

Cylinders)

Dimensions Diameter = 0005 m

Length = 0105 m

Width = 010 m

Length = 220264 m

Thickness = 25

10-6 m

Mass = 0036 kg

Diameter 1 = 014 m

Length 1 = 003 m

Diameter 2 = 0125 m

Length 2 = 0015 m

Thickness = 0003 m

Inertia (I) IA = 0051

IB = 0562

ITM = 0306

IP = 2116

Total Inertia (

)

Angular Acceleration (

)

Torque (τ)

Volume and mass of each part were found in order to determine inertia

Torque needed to pitch a single blade was found from inertia and angular acceleration

Appendix

Reducing Vibration in Motor Torque

Torque

Rotor

Position

Incremental Rotary Optical Encoder

-transparent disk with equally spaced opaque sections

-light emitting diode detected by photo detector

-causes light pulses used to determine position

-outputs signal before digitization two quadrature sine waves

bull Dimensions all in cm

70

Appendix

Baseline Design Dimensions

20

14

10

Deployment Motor Area lt 2x3

Pitching Motor Area lt 3x4

Outset Blade Stabilizers = 01x01

Plate Clearance = 19

Hollow Plate Thickness = 03

Inner Control Area = 11x11 Hollow Central Stabilizer 4x4x20(tall)

Appendix

Thin-set Bearing

bull Minimal friction with plate rotation I comparison to other methods

bull COTS Available size range of 12 -14 cm any of which will fit the Hollow Plate

wwwfrb-bearingscom afkthinbearingcom

71

Appendix

Reducing Vibration in Motor Torque

Torque

Rotor

Position

Incremental Rotary Optical Encoder

-transparent disk with equally spaced opaque sections

-light emitting diode detected by photo detector

-causes light pulses used to determine position

-outputs signal before digitization two quadrature sine waves

bull Dimensions all in cm

70

Appendix

Baseline Design Dimensions

20

14

10

Deployment Motor Area lt 2x3

Pitching Motor Area lt 3x4

Outset Blade Stabilizers = 01x01

Plate Clearance = 19

Hollow Plate Thickness = 03

Inner Control Area = 11x11 Hollow Central Stabilizer 4x4x20(tall)

Appendix

Thin-set Bearing

bull Minimal friction with plate rotation I comparison to other methods

bull COTS Available size range of 12 -14 cm any of which will fit the Hollow Plate

wwwfrb-bearingscom afkthinbearingcom

71

bull Dimensions all in cm

70

Appendix

Baseline Design Dimensions

20

14

10

Deployment Motor Area lt 2x3

Pitching Motor Area lt 3x4

Outset Blade Stabilizers = 01x01

Plate Clearance = 19

Hollow Plate Thickness = 03

Inner Control Area = 11x11 Hollow Central Stabilizer 4x4x20(tall)

Appendix

Thin-set Bearing

bull Minimal friction with plate rotation I comparison to other methods

bull COTS Available size range of 12 -14 cm any of which will fit the Hollow Plate

wwwfrb-bearingscom afkthinbearingcom

71

Appendix

Thin-set Bearing

bull Minimal friction with plate rotation I comparison to other methods

bull COTS Available size range of 12 -14 cm any of which will fit the Hollow Plate

wwwfrb-bearingscom afkthinbearingcom

71