Critical Design ReviewTeam SkyHawk

Fort Lewis CollegeChristopher Hardrick, Peter Samuelson, Travis Lange

June 24, 2010

1

Mission Overview

Primary Objectives

Collect atmospheric radiation levels This collection will help us learn about the quantity of

radiation in varying layers of atmosphere

Perform visible and ultraviolet spectrum analysis of the atmosphere

From the collection of UV data we plan to analyze the amount of ozone present above eastern Colorado

2

Theory Behind Objectives

• Radiation• The atmosphere does a great job at scattering radioactive particles

that enter from the sun, celestial bodies and space in general. With the increase in altitude, there is less atmosphere to scatter this radiation and is why we expect to see a more dense concentration in radioactive particles.

• Ozone• Ozone in the atmosphere are particulates that absorb harmful UV

rays from the sun, most strongly absorbing UV-B and UV-C. In the wavelength spectrum this equates to 100 to 320 nanometers.

3

Mission Requirements

4

Requirement Method Status

The battery must supply a minimum of 10 Watts for 3 hours.

Design, Analysis, Test

Camera software must be capable of operating two cameras.

Design, Test

The ITX must be accessed remotely. Design, Test

Sensors must be exposed to atmosphere. Design

ITX must be able to run Windows XP. Analysis, Test

The USB DAQ must be able to process and deliver data from the sensors to the ITX for storage.

Design, Analysis, Test

Memory usage must not exceed 16 GB. Test, Analysis

Mission Requirements

5

Requirement Method Status

The spacecraft must not exceed a weight of 1.5 kg. Design, Test

Structurally integrated center tube for flight string. Design, Test

The spacecraft’s center of gravity (CG) shall be within 0.25” of the geometric central axis of the ICU.

Design, Analysis

All parts of the payload must remain attached to the flight string during flight.

Design

The spacecraft’s CG shall not lie more than 12” above the satellite interface plane (SIP) .

Design, Analysis

The payload must survive environmental stresses at 100,000 feet.

Design, Analysis

The payload must survive an accelerative load up to 15 g’s.

Design, Test

Operation

• Prior to Launch (On Site)• Assure full battery charge and connect in payload• Activate power switch• Close Payload• Remote access ITX• Begin script file

• Script file activates camera software• Initiates both cameras

• Initiates terminal for Geiger Counter data acquisition• Activates USB DAQ

• DAQ begins to take in data from sensors and sends data to file saved to flash drive

• Attach to flight string

6

Operation

• Post Launch (On Site)• Open payload hatch• Turn power switch to off

• Post Launch (Off Site)• Prepare battery for storage• Analyze data from USB flash memory• Get ready for LA!!

7

8

9

Pressure Sensor

Battery

XYZ Accelerometer

Geiger Counter

DAQ

Ports for Photodiodes and Thermisters

USB hub

PSU

Wi-Fi

Port For Flash Memory

Cameras

ITX

Structural Overview

• Structure• 3K 2x2 Twill Weave Black Carbon Fabric• Bubble aluminum sheeted insulation

• Flight String• 160 PSI plastic tubing• Inner Diameter: 8 mm• Successfully used in previous launches

10

Structural Drawings

11

Structural Drawings

12

Structural Drawings

13

Subsystems Overview

• Power• System has a cut off voltage of 11.5 V• Battery supplies all power to PSU

• PSU supplies correct power to ITX, 13.5 V to pressure sensor and 5 V to accelerometer (all else is 5 V USB supplied)

• Data Acquisition (DAQ)• USB DAQ collects voltages from 8 channels of sensors• DAQ streams data to ITX to save on flash memory

• Channel 0: Pressure Sensor• Channel 1: Accelerometer X• Channel 2: Accelerometer Y• Channel 3: Accelerometer Z• Channel 4: Photodiode (VIS)• Channel 5: Photodiode (UV)• Channel 6: External Temperature• Channel 7: Internal Temperature

14

Subsystems Overview

• Thermal• Insulation maintains temperature above -10 degrees C with heat

generation from ITX radiative cooling fins• Battery must remain above 10 degrees C to supply power

• Video Capture• Software maintains two cameras• Video capture is alternated between two cameras• Frame rate memory usage cannot exceed 10 GB of flash memory

capacity

• Memory• 16 GB Flash drive memory

15

Subsystems Design Drivers

Thermal

Power

Memory

16

Parts List

Part Company Status

Battery Thunder Power RC Just Arrived

280 nm Optical Filter Edmunds Optics Just Arrived

USB DAQ Measurement Computing Just Arrived

Pressure Sensor ICSensors Acquired

XYZ Accelerometer Analog Devices Acquired

Pico ITX EPIA Acquired

Web Cam Microsoft Acquired

PSU EPIA Acquired

USB Wi-Fi Nfiniti Acquired

Geiger Counter Sparkfun Acquired

Carbon Fiber Infinity Composites Acquired

Compact Flash (OS) Transcend Acquired

Flash Drive Unknown Acquired 17

Parts List

Part Company Status

UV Photodiode Ordered

VIS Photodiode Ordered

18

Special Requirements / Requests

Would prefer to be at the top of the payload flight string in order to capture balloon burst

How non-aerodynamic does a payload need to be to designate the top position?

19

Management

20

Management

21

Management

• Current concentration on finishing all ITX interfacing and structure molding

• Moving concentration towards sensors

22

Management - MassItem Predicted Mass Actual Mass

Battery 325

ITX (Board Only) 137

PSU 74

Flash (OS) 40

Flash (storage) 8

Wi-Fi 4

USB Connections 89

Geiger Counter 51

Pressure Sensor (Entire Circuit) 17

Accelerometer (Entire Circuit) 11

Two Cameras 35

UV Filter 2

UV Photodiode 15

VIS Photodiode 15

USB DAQ 45

Thermisters 1

Switches & Wires 25

Predicted Total

Total 55 839 894

Structure g/sq.in. sq. in. Predicted Mass Actual Mass

Carbon Fiber 1.1 250.5 275.55

Flight String Tube 10

Insulation 0.19 250.5 47.71428571

Total 333.2642857

Grand Total Mass 1227.26 Grams 23

Management - Budget

Part Cost

Battery $90

USB DAQ $150

Geiger Counter $165

Carbon Fiber Supplies $95

USB Hub x2 $20

UV Filter $120

Molding Foam $30

Misc. $100

Photodiodes $50

24

Current Total $820

Test Plans

• Planned Testing• Endurance Test

• Battery testing• Run entire payload for a minimum of 2.5 hours

• Drop Test• Already tested Carbon layers• Payload will be dropped from 21 foot balcony on to concrete patio

• Whip test• 30 foot drop while attached to actual flight string sample

• Cold Test• Run entire payload for a minimum of 2.5 hours at -20 C environment• Then at -40 C environment• Then at -80 C environment

• Vacuum Test• Run payload, excluding structure, while in vacuum

25

Test Plans

• Testing procedures• All our tests have been written out, for example:

• Tests are written for each individual component in the payload as well as the five main tests present on the previous slide

• Testing is scheduled for July 8th through the 16th, result analysis and repair is scheduled for July 17th through the 28th

26

Test SubjectStep ID NumberProcedure Expected Results Actual Results

Pass/Fail/Partial Comments

ITX Boards 1 Get the ITX Boards and all the components Find all of them Found all of them Pass Componets: Power, USB, and VGA cables, compact flash and reader, and a monitor

2 Hook the USB cables to oneof the ITX Boards Hook up fine Hooked up Pass

3 Put the compact flash reader on a ITX Board Hook up fine Hooked up Pass

4A Turn on one ITX Board Turns on Doesn't work Fail Turns on sometimes but then shuts down

4B Turn on the other ITX Board Turns on Turned on Pass Short the fifth and sixth pin

Cameras 1 Get the cameras Find all of them Found all of them Pass

2 Make sure the wires are still connected Connected Connected Pass

3 Plug the cameras into the USB ports

4 Find cameras on the ITX Board Find all of them Found all of them Pass Needed to get drivers from Microsoft website

Conclusions

• Our Concerns• At the present moment we are unsure if the ITX and USB hub can power all of

the usb devices• If not we are prepared to power each USB device externally

• We have little experience writing script files

• Typical Web Cams do not span a spectrum that dips deep in to UV• Our back up plan if the web cam cannot “see” through the 280 nm filter is to use a standard

UVenus filter to capture the upper bounds of UV and use the narrow band filter over the UV Photodiode to better pin point the spectrum band we are interested in.

• So far operations are moving smoothly and roughly on schedule.

27

Questions or Suggestions?

28