1. Team DSRO Critical Design Review Taylor Boe Andrew Buckner Andrew Gilbert Emily Howard Grace Harsha Bobby Stillwell October 14, 2008

2. Mission Overview The primary mission of Operation H.A.L.O. is to find the optimal altitude at which one can take quality telescopic images of celestial bodies from a high altitude observatory. By taking light readings of ambient light intensity (all wavelengths) at various altitudes up to 30,000 meters using a photometer, and comparing this to past data we shall achieve an understanding of where ambient light remains constant above our stratosphere, no longer interfering with telescopic imagery, so that future missions can attempt to obtain quality images of celestial bodies at a lower cost compared to current ground based or orbiting telescopes.

3. Requirement Flow Down 1.0 Mission requirements: The H.A.L.O. payload shall provide evidence that it is feasible to capture high quality images of celestial bodies from a near space environment. The payload will be functioning no later than November 15, 2008 and will follow all proposal requirements concerning the weight (1000g) and price ($150) budgets. 2.0 Objective Requirements: 2.1 Operation H.A.L.O. will take light intensity readings throughout the ascent to an altitude of 30 km. 2.2 The payload will be logging the internal and external temperature for the duration of the flight as well as humidity to ensure that the environment is not to extreme for a high altitude observatory. 3.0 System Requirements: 3.1 The payload will gather light intensity readings through a photometer, and store the voltage data onboard the payload via a microcontroller. 3.2 The photometer shall be calibrated and tested prior to November 15, 2008, to ensure its proper functionality. 3.3 We shall use an internal heating device to keep our power source at an optimum level. 3.4 A “cold finger” will be implemented into our photometer design to conduct heat away from our photometer circuit to ensure that the photodiode stays cool and does not record false data due to excess energy in the form of heat.

4. How We plan to build a photometer to take light readings, via a photodiode, that shall provide data about sky brightness at different altitudes up to 30 kilometers. The data shall be stored on a microcontroller. The photometer is Kyle Kemble’s design which is based upon the design of Dr. Yorke Brown. The altitude, at which we took our readings, shall be obtained using math and our understanding of the rate of ascent after the balloon flight.

5. Given Parts Camera HOBO Data Logger Temp Probes 9V Batteries x 3 Heater Tube Foam Core Aluminum Tape Switches x 3 American Flag

6. Photometer Parts Microcontroller (Arduino Pro Mini, Logomatic v2 Serial SD Datalogger, FTDI Basic Breakout) Lens Black Felt 1.25 inch PVC Pipe 1 inch PVC pipe Photodiode Op-Amps Reed Relay Capacitor (1000 pf) Voltage Divider Decoupling Capacitors (.1 uf) 910 Ohm Resistor 750 Ohm Resistor LED Circuit Board 12V Batteries x 2

9. Photometer Schematic

11. Mass Contingency Item Camera HOBO Data Logger Temp Probes 9V Batteries x 3 Heater Tube Foam Core Aluminum Tape Switches x 3 American Flag Photometer Item Mass (grams) 220 29 30 135 32.5 50 155 30 21 1 200 Mass Remaining (grams) 780 751 721 586 553.5 503.5 348.5 318.5 297.5 296.5 96.5

12. Price Budget Item Camera HOBO Data Logger Temp Probes 9V Batteries x 3 Heater Tube Foam Core Aluminum Tape Switches x 3 American Flag Photometer Total: Price (in Dollars) 0 0 0 0 0 0 0 0 0 0 100.35 _______ 100.35

13. Functional Block Diagram 2 12V Battery SwitchCircuit BoardPhotodiode Microcontroller/ Memory Internal 3V Lithium Battery Hobo Data Logger External Temperature Internal TemperatureHumidity3 9V BatteriesSwitchHeater Internal Lithium Battery Switch CameraInternal SD Memory Card

14. Schedule October 1: Start work on the first test shell of the satellite. October 4: First test of Satellite shell (drop test, whip test, and stair test). October 13: Start Work on our photometer. October 20: Start construction of final satellite shell. October 22: Final shell of satellite shall be finished. October 25: First cold test of working components in test box with heater. October 29- November 8: Component Testing (photometer tests and more cold tests). November 4: In class mission simulation. November 6: In class mission simulation. November 12: Design shall be finished. All tests shall have been performed. November 15: Launch Day November 17: Gather raw flight data. Begin work of final presentation. November 18: In-Class Launch Recap November 19- 29: Repair satellite. November 29: Team Video shall be finished. December 2: Final team Presentation

15. Testing Drop test Stair test Whip test Cold Test of basic electronics Cold/Light test of Photometer Functionality tests Memory/Data test Capacitor/Electronics test (final) Imaging test

16. Expected Results We expect to prove that there is in fact an altitude above which ambient light (light from the atmosphere) stabilizes enough to image stars. The data collected will provide evidence that it is possible to take high quality telescopic images of celestial bodies from near space.

17. Biggest Worries Photometer working Photometer pointing at the sun Thermal Time