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ROSAT Guest Observer Facility

ROSAT Status Report #82:

Jan. 27, 1994

ROSAT is Safe-hold Mode

Due to difficulties with its attitude control system, ROSAT has been in safe-hold mode almost continually since the end of last year. Any attempt to restart pointing operations has led to a return to safe mode after a short time. The primary symptom of the problem is that the satellite drifts off-target during orbit night, when the attitude solution is based exclusively on input from the magnetometer and the S-gyro. In the most recent instance, the satellite drifted 100 degrees off the nominal pointing position. The cause of this drift is still being investigated; it is hoped that a solution involving an attitude control software update can be found. Given the potential danger to the satellite, ROSAT will remain in safe mode while the problem is investigated, which is expected to take a few weeks. Contingency plans are also being developed in the event it is necessary to return to a one-target-per-day mode reminiscent of the "reduced pointing mode" after the first gyro failure.

Note Please send ROSAT questions, requests for documentation, etc. to rosat@rosserv *NOT* ROSAT::REQUEST.

Thank you

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Curator: Michael Arida (ADNET);
HEASARC Guest Observer Facility

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This file was last modified on Tuesday, 14-Sep-1999 11:47:04 EDT

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