Satellite Status

Report #6
Star Date: Dec. 2, 1998

Much has happened in the month since the last report. FUSE is in a huge thermal vacuum tank at NASA/Goddard Space Flight Center undergoing what is called "Thermal Vac testing." The satellite has been under vacuum since Sunday, Nov. 15th. The process of "outgassing", whereby trapped air and water vapor within the structure is released into the surrounding vacuum tank and removed, took considerably longer than expected, delaying some tests and causing a lot of schedule reshuffling. However, the Integration and Test team, led by Dan Mark and Steve Conard, have done a great job in prioritizing test activities and using the precious vacuum test time to best advantage.

We are currently running a round-the-clock "End-to-End" test, where UV light from a collimator is fed into each of the four telescope channels in order to allow focussing and alignment to take place. Except for minor glitches, this activity is proceeding as planned. This test was the first time since February 1998 that UV light has been seen with the flight detectors, and to everyone's delight, everything looks nominal.

Vacuum testing continues through December, with the satellite being alternated between "hot" and "cold" cycles to make sure everything behaves properly and to characterize the thermal profile of the satellite. The new year begins with one last week of testing, prior to buttoning up the satellite for shipment to Cape Canaveral. Launch is still scheduled for March 18, 1999!

Reported by: Bill Blair

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