Friday, November 30, 2012

Day 37, November 30, 2012 -- Cacophony!

The high bay can be an incredibly noisy place. Not in the 'hurts your ears to be inside' sense, but the kind of din that gradually creeps up on you and envelops you and you don't notice until it's gone. Besides the constant hum of power supply cooling fans and the incessant dull scream of the liquid cooling pumps running at full blast, there's often various groups of people shouting instructions from downstairs to the mezzanine and vice-versa, drills whining, and the unmistakable sound of the elevation actuator buzzing as it points the telescope up and down and people freak out as they ask "Is the gondola supposed to be moving?!?!" (which it usually is).

Even in this environment, we get work done. Today, as in many days, we weren't dedicated to a specific test so the various sub-teams made progress on their individual priorities as best they could given whatever other constraints the gondola had. The liquid cooling system is now leak-free and filled with the flight coolant, Dynalene HC. Jeff and Kyle spent much of the day testing the HWP system after the control crate heatsinking had been redone. In addition, Kyle and Seth debugged a nagging issue with our heater board commanding that caused some commands to not execute as desired. They think they have found the solution, but further testing is required, and Kyle is overseeing a fridge cycle this evening to check its robustness.

Elsewhere, Britt, Michele, Matt, and Shaul came up with a solution to our battery temperature issue. Our batteries are fancy lithium ion jobs with sophisticated control electronics and a relatively narrow temperature range of 0 to 45 degrees C. Our system was designed for float altitudes, but in our outdoor test a few days back we found that the batteries were getting too cold even with their heaters on. Britt and Michele started the task of cutting foam insulation panels for the batteries to keep them warm during the pre-flight, launch, and ascent phases of the mission.

Other smaller items: I connected up the cables for the bolo power supply filter boxes (harder than it sounds, trust me) and mylarized some foam, KyleH cut some foam panels to close out the top of the BTS, and part of the high bay was cleaned up to make room for the assembly of our massive solar arrays.

Pictures (only a couple today):
https://picasaweb.google.com/104253244018605213307/EBEXInAntarctica20121130

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