oculus - asr m ichigan t echnological u niversity andrew mauragis joshua ehlert lars ramseyer shot...
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OCULUS - ASRMICHIGAN TECHNOLOGICAL
UNIVERSITY
Andrew MauragisJoshua EhlertLars Ramseyer
SHOT II POST-LAUNCHJUNE 13, 2010
EXPECTED RESULTS:
- H-bridge temperature increased rapidly during vacuum tests. This mission will test the thermal properties of the H-bridge in low pressure combined with low temperatures (-80 °C).
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Magnetic Torquer Vacuum Test
H-Bridge 2
H-Bridge 1
Torque Rod
Picaxe 1
Resistor 3
Time of Day
Temperature (°C)
ACTUAL RESULTS:
Mean ΔT: 4.75 °C
OUTCOME:
• Partial failure of logging payload• Temperature?• Loose Connection?• Batteries?
• Data acquired does not match expected results• In vacuum chamber, component did not reach a
steady-state ΔT after 30 minutes• In payload, ΔT established almost
instantaneously, at 5 C
ANALYSIS AND CONCLUSION:
• Cause for discrepancy?• Different vessel size (small insulated box vs
open board)• Ambient temperatures vs Box temperature
• Requires additional testing:• Consistent ΔT on SHOT payload, but varying
on initial vacuum test• Short in actual test magtorquer (not in our
simulated one)• Likely heatsink h-bridges to Oculus-ASR
structure