HUBBLE SPACE TELESCOPE

   DAILY REPORT #2845

PERIOD COVERED:  0000Z (UTC) 04/05/01 - 0000Z (UTC) 04/06/01

Daily Status Report as of 096/0000Z

1.0 OBSERVATIONS SCHEDULED AND ACCOMPLISHED:

    1.1 Completed Two Sets of WF/PC-2/STIS/CCD 8679 (Constraining the Age 
of the Oldest Stars from the White Dwarf Cooling Sequence in M4)

        The WF/PC-2 and the Space Telescope Imaging Spectrograph (CCD) were 
used to search for the oldest and hence coolest white dwarfs {WDs} in M4, 
the nearest Galactic globular cluster to the Sun.  New models for cooling 
hydrogen white dwarfs predict that their colors should become bluer, rather 
than redder, with increasing age. The goal is to test these models and at 
the same time constrain the age of M4.  The proposal completed with no 
problems.

    1.2 Completed Two Sets of WF/PC-2 8827 (Cycle 9 Supplemental Darks pt2/3)

        The WF/PC-2 was used to obtain three dark frames every day to 
provide data for monitoring and characterizing the evolution of hot 
pixels.  The proposal completed nominally.

    1.3 Completed STIS/CCD 8864 (CCD Dark Monitor-Part 2)

        The Space Telescope Imaging Spectrograph (CCD) was used to monitor 
the darks for the CCD.  The proposal completed nominally.

    1.4 Completed Two Sets of WF/PC-2 8867 (Gamma-Ray Bursts: Discovering 
The Progenitors And Understanding The Explosion - Visits A0-R0)

        The WF/PC-2 was used to observe a gamma-ray burster, 
GRB010222.  Gamma-ray burst astronomy, one of the most active and exciting 
frontiers in astrophysics, is now entering a critical stage -- with 
dramatic leaps in understanding of these events, as well as new 
discoveries.  Improvements in triggering and positioning accuracy provided 
by the SAX and HETE-2 gamma-ray satellites will allow entirely new classes 
of events to be studied.  Given the recent progress in this field, the 
proposers are now in a position to design precision, broadband measurements 
that can provide quantitative information on the as-yet unknown energy 
sources, the explosion geometry, and the surrounding medium.  In 
particular, the growing evidence of an intimate connection between SNe and 
GRBs can be definitively tested.  The proposal completed with no reported 
problems.

    1.5 Completed Four Sets of STIS/CCD 9248 (Probing the Large Scale 
Structure: Cosmic Shear Observations)

        The Space Telescope Imaging Spectrograph (CCD) was used to measure 
the distortion of light bundles from distant galaxies that probe the 
statistical properties of the intervening inhomogeneous {dark} matter 
distribution.  Its tidal gravitational field distorts the observable image 
shapes thereby causing a coherent ellipticity pattern {Cosmic Shear}.  The 
observations completed nominally.

    1.6 Completed WF/PC-2 8816 (Cycle 9 UV Earthflats)

        The WF/PC-2 was used to obtain sequences of Earth streak flats to 
improve the quality of pipeline flat fields for the WFPC2 UV filter set and 
in order to monitor flat field stability.  There were no reported problems.

    1.7 Completed WF/PC-2 8720 (Masses and Multiplicity of Nearby Free- 
floating Methane and L Dwarfs)

        The WF/PC-2 was used to observe 50 very-low-mass objects in the 
solar neighborhood with spectral types of L0 and later {including several 
dwarfs with Methane absorption bands in their atmospheres}.  These objects 
will be observed in two filter bands with the aim to identify close 
companions, measure their colors, and to obtain first epoch data of the 
newly discovered binaries.  The observations completed nominally.

    1.8 Completed STIS/CCD 8851 (Sparse Field CTE test {Cycle 9})

        The Space Telescope Imaging Spectrograph (CCD) was used to perform 
CTE measurements that are made using the "sparse field test", along both 
the serial and parallel axes.  The proposal completed with no reported 
anomalies.

    1.9 Completed STIS/CCD 8865 (Bias Monitor-Part 2)

        The Space Telescope Imaging Spectrograph (CCD) was used to monitor 
the bias in the 1x1, 1x2, 2x1, and 2x2 bin settings at gain=1, and 1x1 at 
gain = 4, to build up high-S/N superbiases and track the evolution of hot 
columns.  The proposal completed with no anomalous activity.

2.0 FLIGHT OPERATIONS SUMMARY:

    2.1 Guide Star Acquisitions:
       Scheduled Acquisitions:  9
Successful:  9

  Scheduled Re-acquisitions:  7
Successful:  7

    2.2 FHST Updates:
Scheduled: 18
Successful: 18

    2.3 Operations Notes:

        The SSR EDAC error counter was reset three times, using ROP SR-1A.

        The STIS MCE-1 reset at 095/113938Z while the low voltage was on 
and while inside an SAA interval.  The STIS flight software error counter 
was cleared per ROP NS-12.  MAMA-2 was recovered at 095/2353Z via normal 
SMS commanding.

        The CCS engineering status buffer limits were adjusted at 
096/0727Z, per ROP DF-1A.

        A TTR was written when a re-transmit was required at 096/0713Z 
during a 486 command load uplink.

3.0 SIGNIFICANT FORTHCOMING EVENTS:

        Continuation of normal science observations and calibrations.

/CAW