SOHO back out of ESR
1 December 1999As of Thursday 2 December, 19:42 UT, SOHO is no longer in Emergency Sun Reacquisition (ESR) mode, after a successful transition to CoarseRoll Pointing (CRP) mode.
The CRP mode now appears to function correctly, after the Gyroless patch of the onboard software was uploaded, verified and tested earlier today. No indications of failure on the primary Attitude Control Unit (ACU A) have been found.
Manual braking of the roll rate in CRP mode left SOHO in a stable roll position at -76 degrees. The High Gain Antenna (HGA) will be repointed towards earth, allowing acquisition of medium rate telemetry through the HGA instead of the current low rate telemetry received through the Low Gain Antenna (LGA).
The spacecraft will be left in CRP mode for the night. Plans for tomorrow include momentum management and stationkeeping (orbit trim) maneuvres to compensate for the two ESR episodes during the last few days.
Detailed technical updates and reports throughout the day are available on the SOHO homepage.