OCULUS - ASR M ICHIGAN T ECHNOLOGICAL U NIVERSITY Andrew Mauragis Joshua Ehlert Lars Ramseyer SHOT II P OST- L AUNCH J UNE 13, 2010

E XPECTED R ESULTS: -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).

A CTUAL R ESULTS: Mean ΔT: 4.75 °C

O UTCOME: 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

A NALYSIS AND C ONCLUSION: 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