1. Team Zephyr Critical Design Review Joseph Sheehey, Huy Le, Andrew Zizzi, Alex Morrow, Sam Evans, Logan Wright October 14, 2008

2. Mission Overview The BalloonSat Zephyr shall ascend to an altitude of approximately 31,000 meters and perform measurements on internal and external temperature, relative humidity, and ambient sky brightness between the ranges of 380 nm to 740 nm and 875 nm to 980 nm. The science of this mission exists to better understand the optimal wavelength range high altitude observatories should utilize. Hypothesis –Infrared and UV ambient light will increase with altitude –Visible spectrum light will decrease with altitude

3. Objective Requirements BalloonSat Zephyr shall not exceed one kilogram in mass and shall be completed by October 30, 2008. The cost of materials not including those provided by Space Grant shall not exceed $150. The BalloonSat shall measure ambient sky brightness in watts/meter2 using LED photometers throughout the ascent of the flight and record this data on HOBO dataloggers. The BalloonSat shall fly a powered resistance heater during the entire flight. The Canon A570IS shall be programmed to take images every ten seconds during the ascent of the balloon. BalloonSat Zephyr shall fly a HOBO with an internal relative humidity and internal temperature probe as well as an external temperature probe that shall protrude from the foamcore structure to provide an accurate reading. Team Zephyr shall approximate ascent and descent rates during the flight by comparing recorded external temperature data to known atmospheric temperature profiles.

4. System Requirements BalloonSat Zephyr shall be constructed from lightweight foam composite material and shall be manufactured in a simple process that is capable of withstanding the forces experienced during flight so that it can fly again. The BalloonSat shall fly ten different colors of LEDs covering the aforementioned wavelength ranges. There shall be five LEDs of each color that are wired in series with a known resistance and connected to a HOBO data logger voltage input channel. The three four-channel HOBOs shall be programmed to record voltage levels for each LED string at simultaneous ten second intervals. The heater shall be powered by three nine-volt batteries from immediately before takeoff until retrieval. All images from the Canon A570IS shall be stored on a two GB SD memory card. The firmware of the camera shall be programmed to take an image every ten seconds after the camera has been turned on until the memory card is full. The temperature and relative humidity HOBO shall be programmed to take and record data readings every ten seconds from launch until retrieval. Team Zephyr shall compare temperature data from the HOBO to recorded atmospheric temperature profiles with respect to time to determine the average ascent and descent rates of the BalloonSat.

5. Design One-directional diode in LED produces a current when hit by a photon of correct wavelength Power = V 2 /R Area = 5(A LED ) = 98.2 mm 2 Intensity = P/A = Watts/meter 2 Voltage varies with intensity and resistance varies with temperature

6. Experiment Hardware Parts Ten to fifteen LEDs of each color (spares included for testing and backup) Electrical wire Straws Four 4-channel HOBOs Temperature independent resistors

7. Design Drawings

9. Functional Block Diagram

10. Budget ComponentMassPricePart NumberVendor Name Structure145g$0.00-Space Grant Camera222g$0.00Canon A570 ISSpace Grant HOBO29g$0.00H08-007-02Space Grant HOBO (3)90g (~29g ea.)$0.00H08-006-04Space Grant Heater15g$0.00-Space Grant 9V Batteries (3)140g (~46g ea)$0.00-Space Grant Camera Filter15g$11.40MISL40.5B&H Photo Video Wiring100g--- LED's (5 of each color are flight, the rest are backup,) Mass is for Flight Hardware only IR (10)1.5g (~.3g ea)$12.40RL5-IR2730SuperBrightLEDs Red (15)1.5g (~.3g ea)$7.85RL5-R12120SuperBrightLEDs Orange (15)1.5g (~.3g ea)$4.10RL5-O4030SuperBrightLEDs Yellow (15)1.5g (~.3g ea)$7.85RL5-Y12120SuperBrightLEDs Green (15)1.5g (~.3g ea)$8.60RL5-G16120SuperBrightLEDs Aqua (15)1.5g (~.3g ea)$7.85RL5-A7032SuperBrightLEDs Blue (15)1.5g (~.3g ea)$8.60RL5-B12120SuperBrightLEDs Violet (15)1.5g (~.3g ea)$13.40RL5-V1015SuperBrightLEDs Ultraviolet (15)1.5g (~.3g ea)$14.40RL5-UV1230SuperBrightLEDs White (15)1.5g (~.3g ea)$10.20RL5-W15120SuperBrightLEDs Totals771g$106.65

11. Schedule Major Deadlines –October 18 th Whip Test –October 25 th and 26 th Final Construction and Experiment Integration –October 30 th - Cold Test –November 4 th – Mission Simulation –November 14 th – Final Weigh-in and BalloonSat Turn-in –November 15 th - Launch

12. Test Plan Drop Test – October 9th –Completed Stair Test – October 9th –Completed Whip Test – October 18th Light Intensity Test – October 30th –To calibrate LEDs Cold Test – October 30th –Examine change in resistance with respect to temperature –Determine timing interval for camera measurements –Test thermal subsystem

13. Biggest Worries Finishing Integration on Time Wiring of LED Photometers surviving flight Forces