HUBBLE SPACE TELESCOPE

       DAILY REPORT #2501

PERIOD COVERED:  0000Z (UTC) 11/15/99 - 0000Z (UTC) 11/16/99

Daily Status Report as of 320/0000Z

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:
       Scheduled Acquisitions: 0
     Successful: 0

  Scheduled Re-acquisitions: 0
     Successful: 0

    2.2 FHST Updates:
     Scheduled: 0
     Successful: 0

    2.3 Operations Notes:

        HST remains in the Zero Gyro Sun Point (ZGSP).

        Using ROP SR-1, the SSR EDAC error counter was cleared six times.

        A TTR was written for a GSTDN Canberra command test support which 
failed at 319/1401Z, due to a cable problem.

        A spacecraft emergency was declared, giving HST a higher priority 
in scheduling network resources to support analysis efforts.  Special GSTDN 
requests were made for the support periods at 319/1411Z, 319/1544Z, and 
319/2315Z.

        At 319/175147Z, safing limits indicated that the battery rate of 
charge test had failed resulting in the autonomous execution of 
SMAC14.  This macro initiated load shedding by powering off all FGEs and 
FHSTs.  The rate of charge test failed because the rate of charge threshold 
(14 amps) for daylight was not reached for 800 consecutive seconds after 
entry into day.  Full state of charge was still reached in the orbit.  This 
failure was similar in signature to the failure at 318/1908Z.  HSTAR 7359 
documents this event.

        Analysis indicated that the failure occurred while the vehicle was 
attempting sun capture after entering orbit day at 319/173106Z with a sun 
point attitude error greater than 60 degrees.  This error was large enough 
to trip the Bright Object Detection test at 319/175404Z.  All preceding and 
subsequent orbits on day 319 had nominal rate of charge profiles and 
initial attitude errors.

        The FGE was powered on at 319/2033Z.  A procedure was executed to 
clear error flags and re-enable the rate of charge test and SMAC14.  In 
addition, the trickle charge timer was modified from 3 orbits to 2 orbits, 
the rate of charge error limit increased from 800 seconds to 2100 seconds, 
and the 2nd RWA momentum safemode test disabled.

        SE Briefing is scheduled at 3pm to status each of the subsystems. 
Analysis is continuing on determining the cause of the large unexpected sun 
point attitude errors at the enter orbit day event on days 318 and 319.

        At 320/085030Z, the NICMOS thermal bottom temperature 1 (NBSHLTMP) 
monitor flagged out-of-limits high at 16.07degC, and continues to toggle 
in- and out-of-limits.  The limits for this parameter are 16.0 degC and 
15.0 degC.  HSTAR 7360 was written.

3.0 SIGNIFICANT FORTHCOMING EVENTS:

        Servicing Mission 3A, currently scheduled for December 6, 1999.

/CAW