HUBBLE SPACE TELESCOPE

   DAILY REPORT #2510

PERIOD COVERED:  0000Z (UTC) 11/30/99 - 0000Z (UTC) 12/01/99

Daily Status Report as of 335/0000Z

1.0 OBSERVATIONS SCHEDULED AND ACCOMPLISHED:

Since HST remains in Zero Gyro Sun Point (ZGSP), no science observations 
were performed.

2.0 FLIGHT OPERATIONS SUMMARY:

    2.1 Guide Star Acquisitions:

                                         No activity

    2.2 FHST Updates:

                                         No activity

    2.3 Operations Notes:

        The HST continues in ZGSP.  For much of the day, operations and 
engineering personnel participated in the PSEA/RMGA On-Orbit Test.  The 
following events were a part of that test.  At approximately 334/1200Z, the 
aperture door (AD) was closed.  Then the SI C&DH was safed and the FGEs 
were powered off in preparation for the PSEA test mode.  The RMGA unit was 
powered on.  Its three gyros were observed in the test mode for 
approximately one orbit.  Initial reports are that the RMGA data passed the 
acceptance criteria for continuing to initiate the PSEA.  The thermal data 
was acceptable.  However, a decision was made to not to proceed with the 
entry into PSEA control, but to continue in the test mode for an additional 
three orbits.  During this period, it was noticed that the AD had drifted 
open first to about 3 degrees and then to 5 degrees (at 334/1958Z).  It was 
later determined that the AD movement coincided with MCU operate commands 
from the PSEA.  The PSEA commands the AD with every test mode initiate 
command while in orbit night.  The MCU register was zeroed, which was 
expected to inhibit further AD movement.  Later, it was discovered that 
there remains a small signal in PSEA which can lead to further door 
movement.  HSTAR 7390 was written to document the AD occurrences.

        Following the test, the FGE units were re-powered at 334/2030Z, the 
NSSC-1 was recovered at 334/2050Z, and the WF/PC-2 heat pipe heater was 
enabled at the same time.  The RMGA was commanded off at 
334/334/2120Z.  Finally, the aperture door was commanded to a closed 
position at 334/2252Z.

        It is anticipated that the PSEA/RMGA On-Orbit Test will pick up 
again on Friday.

3.0 SIGNIFICANT FORTHCOMING EVENTS:

        Servicing Mission 3A, currently scheduled for December 9, 1999.

/CAW