HUBBLE SPACE TELESCOPE

   DAILY REPORT #2877

PERIOD COVERED:  0000Z (UTC) 05/21/01 - 0000Z (UTC) 05/22/01

Daily Status Report as of 142/0000Z

1.0 OBSERVATIONS SCHEDULED AND ACCOMPLISHED:

    1.1 Completed 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.

    1.2 Completed WF/PC-2 9045 (The Relationship Between Radio Luminosity 
and Radio-Loud AGN Host Galaxy Properties)

        The Wf/PC-2 was used to determine the relationship between the 
properties of the host galaxies of radio-loud AGN and their radio 
luminosities.  Previous studies in this area with the HST have concentrated 
on the 3C sample which shows a tight correlation between luminosity and 
redshift, such that evolutionary effects cannot be distinguished from those 
depending upon radio luminosity.  Our sample of 46 radio galaxies at z ~ 
0.5 comes from four complete, low-frequency-selected samples of radio 
sources with differing flux limits.  Thus the total sample spans an 
unprecedented three orders of magnitude in radio luminosity at a fixed 
redshift interval.  The proposal completed with no reported problems.

    1.3 Completed Two Sets of WF/PC-2 8828 (Cycle 9 Supplemental Darks pt3/3)

        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 with no reported problems.

    1.4 Completed Six Sets of WF/PC-2 8811 (Cycle 9 Standard Darks)

        The WF/PC-2 was used to obtain dark frames every week in order to 
provide data for the ongoing calibration of the CCD dark current rate, and 
to monitor and characterize the evolution of hot pixels.  Over an extended 
period these data will also provide a monitor of radiation damage to the 
CCDs.  The proposal completed with no reported problems.

    1.5 Completed Six Sets of WF/PC-2 8699 (The Origin of Short-Period Comets)

        The WF/PC-2 was used to detect and characterize cometary nuclei in 
order to determine the basic physical properties of a large fraction of the 
population of short-period comets.  By acquiring statistically significant 
data, we can study the origin of this family of comets and test the 
hypothesis that they are collisional fragments from the Kuiper Belt 
Objects.  The observations completed with no reported problems.

    1.6 Completed WF/PC-2 9133 (Imaging of Gravitational Lenses)

        The WF/PC-2 was used to observe gravitational lenses that offer 
unique opportunities to study cosmology, galactic structure, galaxy 
evolution, quasar hosts and extinction.  They are also the only sample of 
galaxies selected on the basis of their mass rather than their luminosity 
or surface brightness.  While gravitational lenses can be discovered with 
ground-based optical and radio observatories, converting them from 
curiosities into scientific tools requires HST.  There were no reported 
anomalies.

    1.7 Completed WF/PC-2 8682 (A Snapshot Study of 0bservational Cosmology)

        The WF/PC-2 was used to examine the observational constraints on 
the cosmic star formation history that is currently among the most active 
fields in observational cosmology.  The most widely used tracer of the 
co-moving volume-averaged star formation rate {SFR} is the UV luminosity 
density, which early results found to peak at z~1- 2.  The apparent 
identification of the primary epoch of metal production and star formation 
in the Universe led to intense theoretical and observational 
interest.  Nevertheless, and remarkably for such a fundamental observation, 
little is known about the history of star formation in the Universe beyond 
its global average.  There were no reported anomalies.

    1.8 Completed WF/PC-2 8812 (Cycle 9 Internal Monitor)

        The WF/PC-2 was used to obtain routine internal monitors for WFPC2 
in order to monitor the health of the cameras.  A variety of internal 
exposures are obtained in order to provide a monitor of the integrity of 
the CCD camera electronics in both bays {gain 7 and gain 15}, a test for 
quantum efficiency in the CCDs, and a monitor for possible buildup of 
contaminants on the CCD windows.  There were no reported problems.

2.0 FLIGHT OPERATIONS SUMMARY:

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

  Scheduled Re-acquisitions:  6
Successful:  6

    2.2 FHST Updates:
Scheduled: 18
Successful: 18

    2.3 Operations Notes:

        The STIS instrument remains in safe.

        One three occasions, the CCS engineering status buffer limits were 
adjusted per ROP DF-18A.

        Using ROP SR-1A, the SSR EDAC error counter was cleared at 141/2248Z.

        The ephemeris table was uplinked at 142/0024Z as directed by ROP 
DF-07A.

3.0 SIGNIFICANT FORTHCOMING EVENTS:

        Continuation of normal science observations and calibrations.

/CAW