Sunday, April 19, 2009

Day 25, 4/19/09 -- One step back, six steps forward.

Last night, I stayed late to cycle the helium adsorption refrigerators in our cryostat while Daniel and Joy did scan tests. When I was nearly done, we noticed that the gondola started making a horrific noise when moving in elevation. We decided that we would cease any tests involving elevation motion until Michele and Britt had a chance to give it a listen in the morning. I went home at 3 AM or so; the other two stayed until about 7:30 AM(!).

In the morning, Michele and Britt checked and found it was making the same kinds of noises as it did once before when there was some wear and debris in the trunnion bearing. with it's head! The inner frame had to be removed so the bearings could be inspected and repairs effected.

In the meantime, we were able to get a lot of work done on the gondola. Jeff, Michele, and Britt finished the last bit of drilling and bolting for the primary mirror rollbar. I started Jeff off on making a mount for our sun sensor while I started work on the GPS mount -- first, a slight redesign of the geometry to give more clearance for the launch vehicle and then drilling of some more holes. I had Jeff cut the carbon-fiber tubes to length while I -- yep, you guessed it, drilled some more holes (in the antenna backplanes). We were able to get the entire GPS mount assembly mocked up and basically ready for gluing.

Michele and Britt found a small chip of aluminum in one of the trunnion bearings, most likely from all of the drilling we've been doing on the inner frame. They removed it and smoothed out the damage and the inner frame went back on by the end of the day.

On the detector front, the detector team was working on getting the system back up to speed after the fridge cycle. Hannes reports that Fran├žois was able to tune all of the SQUIDs in the system with a single command from his computer. Neat! While that was happening, Dan kept plugging away at setting up all of our calibration experiments.

Around the base, there's been some changes. The FIREBall team is basically all set up and ready for flight -- the personnel have tucked everything out of the way until their flight, and have left the premises seemingly until then. And another experiment showed up today: CREST, a cosmic ray telescope. I think they're planning to be flight-ready in about 2 weeks!

Jeff and I left the high bay early tonight -- 9PM. Jeff points out that it is indeed a sad state of affairs when 9PM qualifies as an "early night".


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