CSU DemoSAT -B 2010 Critical Design Review

1. CSU DemoSAT-B 2010Critical Design Review Colorado State University Paul Scholz, Tyler Faucett, Abby Wilbourn, Michael Somers June 14 2010

2. Mission Overview • Objective: to study alternative energy collection at different altitudes • Find the ideal altitude for alternative (wind & solar) energy collection. • Is high altitude energy collection worthwhile? • Can the added cost of high altitude energy collection be made up for with increases in efficiency?

3. Current Products“MARS” – Maggen Air Rotor System

4. CoolEarth Solar Balloon MARS turbine

5. How we can help • Our test could provide useful data to someone wishing to put up a similar system on Earth or Mars • An airborne solar/wind power farm could be very useful for remote area power generation • Our test vehicle will provide data to give an altitude of maximum power generation.

6. Mission Requirements

7. Concept of Operations • Just before launch power to the heaters and microcontroller will be turned on via switches on the top of the payload • The microcontroller will run its program which includes taking input from 5 different sources and transmit the data serially back to the SD card at a rate which we will specify for each sensor • After the program has run for 150 minutes, the program will end so that we do not write over our flight information with data collected on the ground

8. Subsystems • Structural • Thermal • Data • Storage • Processing • Electrical • Sensing

9. Subsystem – Structural • Must have cylindrical shape • Allows for even and constant sun exposure to solar faces • Must have center core flight string pass through • Pass through design must comply with all DemoSAT-B regulations • Pressure differences inside and outside the payload must not exceed 10 psid

10. Subsystem - Thermal • The internals of the payload must remain above 0C to prevent failures of electrical components • The internal electrical components must be placed as close to the center of the payload as possible • Internal flexible heaters will be installed to maintain required internal temps. • Flexible heaters allow for easy placement near critical components (battery) Temp. Distribution Flux

11. Subsystem - Data • Processing • All sensor data shall be processed on a PIC 16F884 microcontroller • Storage • The PIC shall send data from the sensors to the data storage unit every 5 seconds • The data storage device shall be removable and portable and must allow for computer interface

12. Subsystem - Electrical • All electrical components must be powered by a 5V source • The power supply must be able to produce 4.8V to 6V for at least 2 hours • Switches for electrical components must be mounted on the external of the payload

13. Subsystem – Sensing • Wind Speed Sensing • Anemometer must be at least 2in from the flight cord • At least 2 axis of acceleration must be sensed to accurately measure wind speed • Altitude Sensing • Payload must contain at least 1 pressure sensor and 1 temperature sensor • Pressure and Temp must be measured externally for accurate data • Solar Panels • Solar panels must cover at least 90% of the rounded faces of the payload • All external sensors must be able to operate at temperatures ranging from -80C to 30C

14. Subsystems Block Diagram

15. Schematics/Drawings/Analysis

20. 100mph winds at -80C • 5W internal heat generation • Steady state.

21. 100mph winds at -80C • 5W internal heat generation • Steady state.

22. Commands and Sensors Data transferred serially from PIC microcontroller to SD card mounted in SD card reader.

24. Sensor Specifications

25. Accelerometer Math • X and Y out were generated randomly • Samples were taken every second for this example

26. Test Plans • Testing Types • Structural Test • Whip test • Drop test • Stair pitch test • Environmental Test • Cooler Test • Functional Tests • Bench Test

27. Structural Tests Test Structure • Made in the same fashion as actual structure with minor differences • Heavier outer shell with no carbon fiber around the foam • Thicker (2x) mounting plate • Ballast taped to mounting plate on inside • Accelerometer bracket attached • Aluminum square screwed to top to simulate the anemometer. • Total weight was 3.25 lbs

28. Test Structure Photos Removable Frame Pieces of ballast used Assembled test structure

29. Whip Test • Performed 5 whip tests and took video of all of them. • Payload was spun overhead as fast as possible • After being at speed for several revolutions the experimenter pulled in on the string as hard as possible to simulate a high g-load. • The length of rope from the hand of the experimenter to the payload cg was 80 inches • From the video the calculated angular velocity was 60 RPM • The calculated g load at these conditions was 8.2g with the peak during the pull being higher

30. Potenial Damage/Assessment • Top plate could have been bent • Epoxy interface between the tube and fitting could fail • Acrylic posts imbedded in the foam could pull out or break • No damage was observed during this test

31. Whip Test Video

32. Stair Pitch Test • Structure was kicked down a flight of 13 concrete steps • Step profile was 7.25 inches tall and 10.5 inches long

33. Potential Damage/ Assessment • CF tube could break • Foam could fracture • Acrylic posts breaking or pulling out • Top plate bending • One Acrylic post was broken during the tumble at the base of the nut • All other parts were unharmed • Possible fix would be to shorten the posts to be only as tall as the nuts to lessen the moment on impact

34. Drop Test • Structure was thrown off a balcony from a height of 22.63 ft. above the concrete ground • It landed almost sideways but angled enough that the top plate took the initial impact

35. Potential Damage/ Assessment • Broken CF tube • Acrylic posts breaking or pulling out • Foam breakage • Top plate bending • The top plate was bent from impact • The foam fractured and broke from impact • The foam layers separated near the region of impact • The fix for the foam is that it will be encased in a carbon fiber outer shell

36. Structural Test Summary • No repairs were made during testing • Weak points were discovered to be the acrylic posts and the top aluminum plate • Of the five pieces of ballast originally taped to the mounting plate before the tests 3 were still attached • The plate may have bent less from the drop test if the third post had still been there • From the tests we are confident that the electronics on our payload will survive the extreme conditions they may encounter and our data will be recoverable

37. Secondary Whip Test • This test was added after the other tests had been completed and analyzed • In this version of the whip test, we dropped the payload attached to a 10 foot rope • The sudden stop the payload experienced as the rope came to its full length was a better way to impart a sudden directional change in order to determine if the posts would hold, and if the internal electronics would stay secure • All other tests had been performed previously, and the damage was repaired

38. Potential Damage/Assessment • The post that previously broke and was re-glued broke again • Minor foam fractures around the posts • No internal ballast pieces separated from the mounting plate • Overall, there was no significant additional damage to the structure. We are still confident that the top plate will remain secure, as well as the internal electronics • Vibration testing may be analyzed when all electronics are in place to verify that our data will be retrievable

39. Secondary Whip Test Video

40. Environmental Tests • Cooler Test • Must purchase Dry Ice and Cooler • Potential Point of Failure: • Payload: Insulation design may be flawed and low internal temps may cause freezing/condensation on electrical components. • Adjustments may need to be made to heater placement and insulation

41. Solar Panel Cold Test • The solar panel output will be tested for variations in temperature • The panel, a 90 W light source above the panel, and a thermocouple will be placed inside a refrigerator originally at room temperature • The refrigerator will then be turned on to its highest setting • The solar panel output and temperature will be recorded at a constant temperature interval of 2 degrees Celsius

42. Setup

43. Results • The starting temperature was 22 ˚C • Final temperature was -18 ˚C • Voltage readings were taken with a multimeter every two degrees • The voltage readings combined with known resistance values yielded current and power • Dry ice was added to the refrigerator to reach the lowest temperature

44. Temperature Relationships

45. Functional Test • Bench Test • Potential Points of Failure: • Overheating of internal electrical components • No data transmission to SD Card • No data transmission from sensors • Wiring failure

46. Parts List

47. Schedule

49. Monetary Budget Mass Budget

50. Questions?