preliminary design review presentation

Preliminary Design Review Presentation

NASA USLI 2021

November 3rd, 2020

2

Presentation Overview

Introduction - Christian Suray

Project Status


Project Management

● Established Standards and Procedures

● Composed a comprehensive list of derived

requirements

● Developed itemized budgets for subteams

● Holding weekly subteam and team meetings with

action item assignments

● Contacted schools to set up outreach opportunities

Technical Teams

● Opened trade studies:

○ Two payload designs

○ Recovery systems

○ Separation mechanisms

○ Electronics

● Created CAD models of payload and

rocket designs

● Ordered parts for subscale launch

3

2020-2021 UAH CRW Team Structure


CRW Management Team

4

“To learn more about high powered rocketry and the

NASA design process by meeting all USLI

requirements for the designing, building, and testing

of a rocket/payload system and to share our passion

for engineering with our community.”

Mission Statement

Introduction - Christian Suray 5

CRW Vehicle Team

Vehicle Overview - Stephen Ward 6

Vehicle Overview General Dimensions

● Overall length: 105in

● Upper Airframe Body Tube Length: 52 in

○ Payload: 24in and Main Parachute 18 in

● Aft Airframe Length: 44 in

○ Variable Drag System: 8 in and Drogue: 10 in

● Fin Dimensions (Span x Chord): 8x6

● Coupler Length: 14 in (1 in switch band)

General Materials

● Body Tube Material: Fiberglass

● Nose Cone Material: ABS

● Fin Material: ABS


Primary Vehicle Design

Payload Bay Main Parachute Drogue

Variable Drag System

MotorAv Bay

Elliptical Nose Cone CO2 Ejection Charges

BP EjectionEjection PistonElliptical

Fins

Separation

(600ft descent)

Apogee

Separation


Concept of Operations

4500

Alt

itu

de

AG

L(f

t.)

Vehicle Con-Ops

Jettison

Window

Ground Station

4000

1000

500

Apogee

Launch

Powered

Ascent

Burnout/VDS

Controlled Glide

Drogue

Deploy

Drogue

Opens

Vehicle

Landing

Payload Jettison

and Main Deploy

Payload Ops.

Time (sec.)0 11020 604.1


Vehicle Mission PerformanceCurrent Design Predictions (Based on L-850 motor)

● Target Apogee: 4000 ft

● Time to Apogee: 16.5 s

● Velocity Off Rail:

○ 8 ft. Launch Rod: 52.0 ft/s

○ 12 ft Launch Rod: 63.8 ft/s

● Stability Off Rail:

○ 8 ft. Launch Rod: 2.41

○ 12 ft Launch Rod: 2.67

● Ground Hit Velocity: 16.5 ft/s

● Max Ground KE: 52 ft-lbf

● Descent Time: 67.9 s

● Thrust-to-Weight ratio: 4.79

● Max Shock Force: 20 gs

● 20 mph crosswind drift: 2230 ft

● CP Location [Mach 0.3]: 83.3 in

● CG Location [Mach 0.3]: 62.3 in


Motor SelectionCurrent Design for Motor

● Aerotech L850:

○ 4280 ft apogee

○ 52.0 ft/s velocity off 8 ft rod

Alternatives Considered

● Aerotech L1520:

○ 4429 ft apogee

○ 65.4 ft/s velocity off 8 ft rod

● Aerotech L1150

○ 4006 ft apogee

○ 57.2 ft/s velocity off 8ft rod

● Aerotech K1000

○ 2579 ft apogee

○ 55.8 ft/s velocity off 8ft rodComparison of L-Class Motors Considered for Vehicle

Vehicle Components - Andrew Godwin 11

Motor Hardware and RetentionMotor Hardware Current Design

● All three considered L motors use the

same Aerotech RMS-75/3840 Motor

Casing

○ Allows more flexibility with motor

selection

○ Can change motors if design necessitates

● Mounting Hardware

○ Motor is housed inside of the motor

casing, which is attached to the body via

the rear centering ring and motor retainer.

○ Force from the motor during firing is

transmitted to the body tube through

theaft centering ring. Aerotech RMS-75/3840 75mm Reloadable Motor Assembly

12Vehicle Components - Andrew Godwin

Motor Hardware and Retention (cont.)Motor Retainer Current Design

● Aeropack RA75 Flanged Retainer

○ Allows quick motor change after flight

○ Simple and strong connection to vehicle

○ Retainer is attached to the back of the aft

centering ring via 12 screws

○ Keeps the motor from falling out the rear

of the vehicle during descent

Centering Ring Current Design

● Aluminum (likely 6061-T6)

● Machined in house

● More allowances for other vehicle design considerations

● Attaches to the vehicle using 4 screws through the wall of the body

tube

Aeropack RA75 Retainer13Vehicle Components - Andrew Godwin

BulkheadsDesign Process

● Leading Material: Aluminum 6061-T6

● Machined in-house

● Designed individually based on expected loads

○ Expected load based on main parachute

deployment deceleration (≅ 20 g’s)

● Design analysis performed using Solid Edge

and Nastran NX

Nose Cone Bulkhead FEA


● Madcow Fiberglass

● 3D-Printed ABS

● Outsourced machining

● FEA performed using 141

lbf tensile load.

● Load calculated using

nose cone mass and

estimated main chute

deployment force

● FEA shows that FOS ≅1.5

Nose Cone Bulkhead

● Pockets machined to

save weight

● Exact dimensions

determined through

repeated FEA tests


Nose ConeCurrent Design

● Elliptical 8” Tall, 6.17” Max OD, 3” Shoulder

○ 3D Printed, ABS, 40% infill

■ 3D Printing simplifies manufacturing

● Tracker housed inside

○ Mounted on printed ABS sled

○ External key switch

● Payload Retention

● Removable tip

● U-bolt recovery harness attachment

● Aluminum 6061-T6 Bulkheads

● Considering Mounted Camera


● Nose Cone - Madcow 5:1 Ogive

● Nose Cone Design - ABS, Shear Configuration

● Nose Cone Material - POM, PLA, PLA+

● Bulkhead Material - ABS, Fiberglass

Tracker Sled

Nose Cone Detail Views

Payload Retention


Body Tube● Leading Design

○ 6” Madcow Fiberglass Body Tube

○ Current Rocket design is 105 in long

● Alternative Materials

○ Carbon Fiber

○ Cardboard

● Considered Parameters

○ Strength- Sufficient enough to support

the rocket under expected flight loads

○ Customizability- Sections for fins and

VDS can easily be cut into the tube

○ Availability- Reasonable shipping

times from manufacturer

○ Cost - Not an inefficient expense

○ Weight- Does not require an

unacceptable propulsion system to

reach desired apogee 16Vehicle Components - Andrew Godwin

FinsCurrent Fin Design

● Combined fins and fin bracket

● Dimensions

○ Elliptical shape, NACA-0008 cross-section

○ 6 inch body chord, 8 inch span

○ NACA-0008 compromise between drag and strength

○ Elliptical shape gives better stability per fin area

● Material: 3D-Printed ABS

○ Allows iteration and rapid changes if needed

○ More complex/combined geometries possible

○ More consistent in production

○ Rapid replacement if one fails

● Possible challenge: mounting fins to airframe

○ Current design uses nut plates

● Pitot tube installed on two opposite fins

Alternatives considered

● Non-mechanical attachment (glue, epoxy): less reliable

● Fiberglass material: more difficult to work with and less consistent

● Non-airfoil cross-section: higher drag and larger area

Fin CAD Model Internal CAD of Pitot Probe


Recovery SystemDrogue parachute

● Deploys at apogee

● Fruity Chutes CFC-18

● Descent rate of 105 ft/s

Main Parachute

● Deploys at altitude of 600 ft

● Iris Ultra IFC-96

● Descent rate of 16.4 ft/s

● Total Descent time is 67.7 seconds

● Piston will be used to deploy main parachute

● Slider being considered to lower main chute deployment

impulse by extending chute opening time


● Main Parachute

○ Iris Ultra IFC-144

○ Chute opening force would be too great and fall time would be too long

Recovery

Harness/Layout


Avionics BayCurrent Design

● 14” coupler with 1” switch band

● Electronic Sled in horizontal configuration

○ 3D printed (ABS)

○ Standoffs and battery retention integrated into print

○ Heat-Set Threaded Inserts

● 6061-T6 Aluminum Bulkheads

○ Machined to house CO2 cartridges for main deployment

Potential Concerns

● Heat-Set inserts pull out

○ No documentation on pull-out strength so will perform tensile

tests

● Hinges or latch fail on battery retention

○ Will test hinge strength to failure in tensile test


CO2 EjectionCurrent Plan and Design

● CO2 used for main deployment and black powder used for

drogue○ Provides clean burn and increases safety

● CO2 kit is ordered from Tinder Rocketry○ Provides cartridges and mounting system

● CO2 cartridge size is being determined○ Piston is needed to help deployment

○ Depends on piston travel distance and separation force

required

Potential Concerns

● Increased main recovery volume leads to heavy CO2

system○ Can be tested further to ensure separation capability

● Can revert to BP if CO2 continues to fail


Variable Drag System (VDS) Overview

● Objective: Narrow the uncertainty interval for target apogee

● Active controls account for anomalies during flight

○ Crosswinds

● Main Advantage: Superior apogee control

● Disadvantages: Weight, complexity, modes of failure

● Located behind center of gravity for stability

Variable Drag System

VDS Bay

Variable Drag System - Fred Schulze 21

VDS Deployment MechanismBoth Designs

● Located at bottom of VDS bay to maximize rocket stability

Linear Translating Plate Design

● Main Advantages: Weight, Simplicity

● Main Disadvantage: Low Drag

Gear Design

● Main Advantage: Exposed Area

● Main Disadvantage: Amount of body tube removed

Linear Translating Plate Design Swivel Design

Mechanism

22Variable Drag System - Fred Schulze

Variable Drag System Control● Rocket motor designed to overshoot target apogee

○ Control scheme aims to methodically reduce this

overshoot as apogee is approached

○ Up to 230 ft of apogee reduction (main design)

● VDS only activates after burnout and deactivates at apogee

● Parameters needed: Vehicle velocity, altitude, flight angle

● Sensors needed: Altimeter, pitot probe, accelerometer

● Velocity error controlled with PID

○ Stepper motor allows drag plates to be precisely

deployed to create the necessary drag

● VDS drag vs deployment needs to be tested

○ Wind tunnel testing for drag vs area

○ Testing Cd with subscale (non-active control)

23Variable Drag System - Fred Schulze

CRW Payload Team

Payload Overview - Joseph Barragree 24

Primary Design - Isopedotus

● Autogyro for descent

● Active roll-stabilization fins

● Extending legs for leveling

● Horizontal landing legs

● Multiple fish-eye cameras and image stitching

Alternate Design - Ophanim

● Drogue-chute for descent

● Allowed to land in any orientation

● Levels by balancing the entire body via reaction wheels

● Rotates the body to produce panorama with single camera

● No external mechanisms or legs

Payload High-Level Designs

Payload Overview - Joseph Barragree 25

Isopedotís Payload Overview

Isopedotís Design - Joseph Barragree

● Cylindrical Profile

○ Spring Loaded mechanically locking legs

○ Extending all-thread

○ Three fish-eye cameras

● Jettisoned at main deploy

● Autogyro Descent

● Low CG for stability on ground impact

● Capable of correcting a 45 degree landing

orientation

● Transmits panorama to ground station

26

● Spring Loaded Leg locking mechanism

○ Legs slide into lander to decrease impact on pin

● All-Thread Leveling mechanics

○ All-thread is vertically extended through the base to level the

payload body

○ Designed to correct for a maximum 45 deg tilt

Isopedotís Landing System

Isopedotís Design - Joseph Barragree 27

● Two Options were Considered

○ Parachute

■ Increases Drag

● Simple

● Effective

● Reliable

○ Autogyro

■ Rotation increases

drag and converts

potential to rotational

Kinetic energy.

● Stable

● Innovative

● Controllable

Isopedotís Recovery

Isopedotís Design - Joseph Barragree

● Results:

○ Isopedotís - Autogyro is applicable

28

Payload/Autogyro Detachment Mechanism

Descent Control Design - Joseph Baragree

● Solenoid and a thin cylindrical rod to constrain movement

● Activation of solenoid will allow for movement

● Compressed spring will push rod and allow detachment

● Tether of approximately 8 feet will connect autogyro and payload after detachment

29

● Jettison at main deploy

● Payload parachute descent

● Initial landing/chute detach

● Levels the body with reaction wheel control

● Capture and process panorama while rotating

body around vertical axis

● Transmit panorama to ground station

Ophanim Payload Design - Joseph Barragree

Ophanim Payload Operations

30

Ophanim Payload Details● Maximum diameter of 5.8”

● Body Material:

○ Panels of ⅛” thick acrylic

○ Screwed and epoxied together

○ Top panel screwed only to allow access

● Payload Parachute attachment options:

○ Autogyro detachment mechanism with parachute

attached instead

○ Eye bolt screwed into top triangular panel for non-

detaching parachute option

● Single Camera placed on outer edge

○ Prevents internal structure from blocking image

● Electronics placed to balance CG

● Quick release bay for battery access

○ Latched and unlatched by hand

○ Constrain batteries to ensure connection

Ophanim Payload Design - Joseph Barragree

Eye bolt Detachment

Mechanism

Autogyro Detachment

Mechanism

31

● Lands naturally on any side and detaches parachute with Tender Descender

● Levels by transferring angular momentum between reaction wheels and the payload body

● Governing dynamics can be modeled like a 3D inverted pendulum

● Active leveling will use LQR or PID control to maintain level balance

o LQR requires a complex analytical model and linearization, though the 3D inverted pendulum is solved in the literature

o PID control is simpler in design, but less precise

Ophanim Landing System

Ophanim Payload Design - Joseph Barragree 32

Payload Retention

Retention Design - Nathan Ulmer

● Applicable Subsystem Requirements

○ The retention system fully retains the payload until jettison event

○ After jettison, the payload is completely free from the rocket

○ Does not prevent the main parachute from deploying properly

● Interface With Vehicle

○ Mounted in the nose cone between two bulk plates connected

with threaded rods.

○ Retained vertically with a claw mechanism

○ Retained horizontally with sabot

● Deployment Operations

○ Nose cone pushed out with main deploy

○ Sabot falls away but remains tethered to nose cone U-bolt

○ Claw releases close to 500 feet, and allows payload to fall out

○ Payload opens autogyro and legs

● Claw mechanism Details

○ Attaches to eyebolt on payload body

○ Controlled by altimeter in nose cone body

○ Claw is closed by default due to a torsion spring

○ Servo moment arm and sabot shape resist accidental opening

○ Two servos control opening and closing of the claw33

Retention Design Trade Study

Retention Design - Nathan Ulmer

● High Level Retention Designs Considered

○ Cage - Underneath main deployment charges, opens body tube to release payload

○ Container - Acts as piston just below main parachute, actively retained to vehicle body,

drops payload using claw mechanism after main deployment

○ Nose Cone - Extension to nose cone, deployed with main parachute, releases payload

from claw mechanism after main deployment

● Selected Option - Nose Cone Retention

○ Does not interfere with main parachute deployment, unlike the container

○ Jettison does not depend on rocket body orientation, unlike the cage

○ Highest possible center of mass increases vehicle stability

Cage Container Nose Cone

34

Electrical Subsystem Design - Mason Barrow

● Payload Controlled by Teensy 4.1

○ Reads Data from Sensors

○ Operates Cameras and Motors

● Electronics will be mounted on custom PCB

○ Compact

○ Lightweight

● Batteries

○ Powered by two Samsung 18650 Batteries (3.7V, 3000mAh)

○ In series, power payload for 300+ minutes

18650 Batteries

Electrical Overview

35

Selection: Teensy 4.1

● Accessibility○ Arduino Libraries

○ Prior Experience

○ Self-Contained Unit

● Specifications○ 600 MHz

○ 3 SPI, 3 I2C, 7 Serial, 31 PWM, 2 ADCs

○ On-board RTC and MicroSD Card Slot

○ Pixel Processing Pipeline

Microcontroller Selection

Electrical Subsystem Design - Mason Barrow 36

Sensor Selection


Cameras

Selection: OV5642

● Accessibility○ Made for Arduino

○ Extensive Documentation

● Specifications○ 240p, 480p, 720p, 1080p, 5MP Options

○ Compressible

○ Multiple Output Formats

● 3 Cameras 120° apart, each with 180° Fisheye Lens

Camera Selection


Link Budget Calculations:

Where

● PT (Transmit Power) = 24 dBm

● GT (Transmit Gain) = 1.9 dBi

● LM (Link Margin) = 30 dB

● GR (Receiver Gain) = 10.65 dBi

● PR (Receiver Power) = -110 dBm

● Freq (Frequency) = 900 MHz

Estimated Range = 11.04 Miles

Ground Control Station Overview


● Assuming max power consumption when active

Power Budget


● Superloop Design

● C++ on Arduino IDE

● Software Tasks:

○ Communicate with Sensors

○ Transmit Telemetry

○ Self Level

○ Take and Transmit Multiple Pictures

Software Overview


CRW Safety Team

Safety - Jason Kuhn 42

Safety Officer: Colin Boggs

Responsibilities:

● Management of Risk and Hazard Analysis

● Failure Modes and Effects Analysis

● Application of Safety Requirements from NAR, NASA, PRC,

etc.

● Creation of Major Standard Operating Procedures

○ Review and Approval of Minor SOP’s

● Coordinate Safety Efforts at All Major Testing

● Management of Fabrication and Testing Plans

○ Includes scheduling time for the usage of the PRC

● Management of Team Certifications

○ PRC and CRW Safety Quiz

○ CPR, AED, and First Aid Certification

● Major Safety Briefings

Safety Leads: Jason Kuhn (Vehicle) and Sam Mosley (Payload)

Responsibilities:

● Interface between Sub-Teams and the Safety Officer

● Collection and Management of Component Data Sheets and

Material Safety Data Sheets

● Creation of Minor Standard Operating Procedures

● Coordinate Safety Efforts at All Minor Testing

● Minor Safety Briefings

Safety Officer

Colin Boggs

Payload Safety Lead

Sam MosleyVehicle Safety Lead

Jason Kuhn

Vehicle TeamPayload Team

Safety Organization


General Protocols:

● All project meetings, including general meetings and sub-team meetings, have been and will continue to be held online via Zoom or Discord

● All members are required to comply with UAH COVID-19 regulations

○ Completing Charger Healthcheck at least once every three days

○ Compliance with random COVID screenings

● Team members who experience symptoms or are traced to someone who has recently tested positive are encouraged to undergo a COVID-19

test

○ Team members who test positive will be required to isolate until they receive clearance from a medical professional

In-Person Operations:

● All team members are required to wear cloth face coverings when meeting in-person

● Social distancing measures will be put in place wherever possible

● Use of the UAH Machine Shop and PRC Fabrication Shop must be scheduled through the Safety Officer

COVID-19 Precautions


Personnel Hazard Analysis

Safety - Jason Kuhn

Identification:

● Derived from safety requirements, equipment usage manuals, and SDS’s

● What characteristics of this material/equipment could cause harm to our personnel?

● What kind of accidents could happen because of improper use of this material/equipment?

● Consultation of the team mentor and faculty advisor

Causes and Effects:

● Determine the safety measure that would be insufficient or unfollowed for the hazardous

situation to happen

● How badly could this hazard harm an individual?

○ Leads to a range of effects from minor to severe

○ Effects remain the same both before and after mitigations, quantified by a

severity score

Probability:

● Quantified via Risk Assessment Matrices, both before and after mitigations are put in

place

● Will tend to be high before mitigations and significantly lower after mitigations are put in

place

45

Example Hazard Analysis Table:

● Hazard analysis for the handling of fiberglass

● Individually identifies the hazards associated

with the material

○ Skin Exposure

○ Eye Contact

○ Inhalation

● Lists the determined cause(s) and effects of

each hazard

● The mitigation put in place for each hazard is

recorded, as well as any effects of that

mitigation on the project as a whole.

● A risk level is determined both before and after

any mitigations are put in place.

Personnel Hazard Analysis


Identification:

● Derived from manufacturer information and/or known material limits

● Documented by component designers in Component Data Sheets (CDS’s)

● How could this component fail?

● Consultation of the team mentor and faculty advisor

Probability:

● Quantified via Risk Assessment Matrices, both before and after mitigations are put in place

● Valuable resource - “Launching Safely in the 21st Century”

○ Published by NAR

○ Information on common failure modes and the statistics associated with them

Failure Modes and Effects Analysis

Safety - Jason Kuhn

Causes and Effects:

● Causes of failures identified through research

○ How is the part/component manufactured?

○ Has this part/component been used in the past? If so, has it failed and why?

● Determine the consequences of failure, focus on mission performance and human safety

○ Effects remain the same before and after mitigations, quantified by severity score

47

A picture or 3D rendering is included

as a reference for those unfamiliar with

the component.

A table of failure modes and effects is

included for each component, as well

as alternative options for the

component.

● General Information

○ Identifies a point of contact

○ Sub-Group

○ Designer

● Technical Information

○ Included in case the part needs

to be reproduced

○ Material

○ Dimensions

○ Weight

● Business Information

○ For reference by team

management

○ Vendor

○ Cost

○ Delivery Time

Component Data Sheet


Probability:


place

● The effect of mitigations for environmental hazards are often the harshest

Causes and Effects:

● Causes of hazards identified through research

○ Environmental operation limits of components

○ Proper handling and disposal of materials

● How could this hazard effect either mission performance or the launch/testing

environment?

Identification:

● Determine risks to the vehicle or personnel posed by environmental factors

○ Non-ideal weather conditions (rain, hail, high winds)

○ Excessive heat or cold

● Determine risks the project poses to the environment

○ Pollution

○ Damage to plants and wildlife

Environmental Hazards


General Project Risks

Safety - Jason Kuhn

Probability:


place

● Unlike other risks and hazards, both the probability and severity of these risks can be

mitigated

Causes and Effects:

● What managerial issues could cause major problems for the project?

○ Poor budgeting and/or scheduling

○ Poor scheduling

● How could these issues harm the project?

Identification:

● Determine risks associated with scheduling, budget, and resource allocation

50

● Total Identified Risks per Risk Level

● Does not Include Component Level Failure Modes

Risk Level Totals

Safety - Jason Kuhn

● Risk Levels Decrease After Mitigation

● High Risks After Mitigation are not Acceptable

51

0

5

10

15

20

25

30

35

40

No Risk Low Risk Moderate Risk High Risk

1

10

26

38

13

38

24

0

Before Mitigation After Mitigation

SOP’s:

● Provide a clear procedure of what to do during a test or launch, and how to do those things safely

● Require signed verifications for steps that mitigate major risks, hazards, or failure modes

● Safety briefings will be held either the night before or the morning of each test or launch

Caution Statements:

DO NOT…

● Bold red text indicates an emphasis on a certain step in the procedure or an aspect of that step

CAUTION: CHECK FOR PPE USAGE OF ALL PARTICIPANTS

● This formatting indicates required PPE usage during testing or fabrication

CAUTION: DANGEROUS MATERIAL; REVIEW SDS BEFORE HANDLING

● This formatting indicates the impending use of a hazardous material, such as black powder.

CAUTION: CRITICAL HAZARD PRESENT; USE EXTREME CAUTION

● This formatting indicates the presence of a critical hazard in the SOP.

● These hazards require the utmost caution, and tasks with this level of caution will only be carried out by a Red Team.

SOP’s and Caution Statement Methodology


CRW Project Management

53

Project Schedule Overview

Management - Christian Suray

NASA PDR Presentation

54

● Residual funds from previous CRW USLI teams

● Alabama Space Grant Consortium (ASGC)

● NASA USLI 2019-2020 Safety Award

Budget Breakdown: Funding

Management - Christian Suray 55

Budget Breakdown: By Subteam


Requirement Tracking System

Management - Christian Suray

5.9%

57

● Outreach activities will be conducted virtually for high schools

previously attended by CRW members

● Hands-on experiments and in-person demonstrations will be held at

schools in Madison City, Madison County, and Morgan County

● There are 37 prospective schools open to outreach

School Outreach


● Presentation material will be tailored to education level.

● Examples of activities that will be conducted are as follows:

Balloon Thrust Experiment Water Bottle Rocket

School Outreach


● Facebook, Instagram, and Twitter will be used to share weekly project

updates and CRW member highlights.

Social Media


● Working to establish test procedures for the following:

○ 3D printed nose cone and fins, CO2 deployment, VDS

● Trading two payloads in parallel

○ Design will be down-selected as testing progresses

● Purchasing subscale rocket parts for launch in late November

● Virtual outreach starting in Mid-November. In person outreach

starting in December

● Developing and assigning CDR action items

Conclusion


Q&A

62

Back Up Slides

TrackerLeading Choice

● 2014 CRW XBee Pro S3B/Antenova GPS Tracker

○ XBee Pro S3B Ground Station

○ Transmits up to 6 miles, realistically roughly 2 miles

○ Driven by CR123A 3V Lithium Ion Battery

○ Transmits between 902 and 928 MHz

○ 250 mW Transmission Power

○ Uses RP-SMA antennas

○ Tested, currently transmits accurate location data


● Apogee Simple GPS Tracker

○ $431.58, 6-8 mile range, all in one

● Raspberry Pi, XBee Pro S3B, Adafruit GPS

○ Similar performance as current choice, bulky

Basic CAD Model of Leading Choice - Tracker Layout of Leading Choice


● Cylindrical profile

○ Mechanically locking legs

○ Extending all-thread

○ Three cameras

● Total mass, including a 20% growth factor, is 3lb

● Low CG for stability

Isopedotís Payload Details


● Operational overview

● Design considerations

Isopedotís Recovery Operation


● Parachute:

○ Uses drag of larger area to slow down

system

○ Pros:

■ Simple

■ Effective

■ Reliable

Payload Recovery

Descent Control Design - Nathan Ulmer

● Autogyro

○ Uses aerodynamic forces of spinning

blades to reduce velocity

○ Pros:

■ Stable

■ Innovative

■ Controllable

67

Payload Descent

● Autogyro

● Detach mechanism

● High level CAD render

Payload Descent - Joseph Barragree

● “1st Order” Analysis Completed

○ Assumes:

■ Thin-Airfoil Theory

■ Totally Laminar Flow

○ Results:

■ Terminal Velocity: 7[m/s]

■ Angular Velocity: 12[rev/s] = 725 [rpm]

○ Sensitivities:

■ Bearing Damping Equation

● Fb = I μ ω^2

■ Losely- Width and Length of Blades

● Higher Order Methods in Consideration

○ CFD simulation of Autogyro alone

○ CFD simulation of Whole Payload (Much more

complex)

○ Reservations

■ Limited Skill and Mastery of Tools

■ Costly in time

■ Cost is proportional to accuracy

Autogyro Calculations

Descent Control Design - Nathan Ulmer

A

B

C

A: Conversion of actual flow to Effective conditions for simulation.

B: Velocity time dynamics (positive downwards)

C: Rotation time dynamics

Note: Values subject to change

Comparison of Descent Devices

Autogyro Only Parachute Only

Drogue chute On

Autogyro

Importance

Criteria

Rating

Weighted

Score

Criteria

Rating

Weighted

Score

Criteria

Rating

Weighted

ScoreCriteria

Obfuscation 10 8 80 3 30 7 70

Reliability 9 5 45 9 81 6 54

Stability 8 10 80 4 32 10 80

Innovation 3 8 24 3 9 10 30

Complexity 3 4 12 10 30 4 12

Cost 3 4 12 4 12 4 12

0 0 0

Total Weighted Score 253 194 258

● Obfuscation

○ The descent mechanism should be unlikely to impede

the function of the payload via collision or

obfuscation of the camera

● Reliability

○ The descent mechanism should be unlikely to fail or

break during its launch or descent

● Stability

○ The descent mechanism should not oscillate the

payload such that the leveling device is unable to

perform its task. Less oscillation is prefered

● Innovation

○ New, innovative, or interesting designs are likely to

improve our chances during competition if

implemented properly

● Complexity

○ The intricacy of the systems is directly proportional

to construction or reliability concerns which need to

be evaluated.

● Cost

○ Weight and monetary costs. Have not yet been

assessed but parachute is likely to be more expensive

in monetary cost.

Note: Higher is better

Both autogyro solutions are roughly equivalent as such we will continue

with these approaches. The reliability and ease of a parachute make it an

ideal backup candidate.

70Descent Control Design - Nathan Ulmer

Subscale Gantt Chart


Full-Scale Gantt Chart


CRW Weekly Schedule


Other Possible Launch Dates


preliminary design review presentation

Documents