HUBBLE SPACE TELESCOPE

       DAILY REPORT #3081

PERIOD COVERED:  0000Z (UTC) 03/26/02 - 0000Z (UTC) 03/27/02

Daily Status Report as of 086/0000Z

1.0 OBSERVATIONS SCHEDULED AND ACCOMPLISHED:

    1.1 Completed Thirteen Sets of NICMOS/1/2/3 8945 (Cooling System 
Monitoring)

        The Near Infrared Camera and Multi-Object Camera (NIC1, NIC2 and 
NIC3 was used 1}.to measure NICMOS detector performance during the 
cool-down and steady state operation of the NCS. 2}. to demonstrate 
stability {+/-0.1K} of the NICMOS detector temperature at the optimal 
science operating temperature. and 3}.to demonstrate repeatability {+/-0.1 
K} of NICMOS detector temperature following changes from the optimal 
science operating temperature.  No problems were encountered.

    1.2 Completed FGS/1 9234 (Calibrating the Mass-Luminosity Relation at 
the End of the Main Sequence)

        Fine Guidance Sensor #1 was used to calibrate the mass-luminosity 
relation for stars less massive than 0.2 Msun, with special emphasis on 
objects near the stellar/brown dwarf border.  The proposal completed with 
no reported errors.

    1.3 Completed WF/PC-2 8950 (SM3B Cool Down, Contamination Monitor, and 
Focus Check)

        The WF/PC-2 was used to monitor the planned cooldown to -88C, 
followed by UV monitors, focus checks, as well as decons and associated 
monitors.  No problems were noted.

    1.4 Completed WF/PC-2 9254 (Cycle 10 CTE Monitor)

        The WF/PC-2 was used to monitor CTE changes during cycle 10.  The 
proposal completed with no anomalous activity.

    1.5 Completed Two Sets of STIS/CCD 8963 (CCD Bias)

        The Space Telescope Imaging Spectrograph (CCD) was used to measure 
CCD read noise from multiple bias frames obtained in common science modes: 
amplifier D, gains 1 and 4 electrons/DN, and binning factors of 1x1, 1x2, 
2x1, and 2x2.  The read noise measurements before and after NCC turn-on are 
then compared, and standard calibration reference files for use in pipeline 
reduction of SMOV3B data are constructed.  The proposal had no reported 
problems.

    1.6 Completed Two Sets of STIS/CCD 8964 (CCD Darks)

        The Space Telescope Imaging Spectrograph (CCD) was used to obtain 
dark frames twice daily, as in a corresponding calibration 
program.  Standard calibration reference darks are constructed and hot 
pixel lists are updated for use in pipeline reduction of SMOV3B data.  All 
observations completed without incident.

    1.7 Completed WF/PC-2 9043 (Cepheid Distances to Early-type Galaxies)

        The WF/PC-2 was used to continue observations in the HST Key 
Project on the Extragalactic Distance Scale and the HST project on the 
"Calibration of Nearby Type Ia Supernovae'' that have greatly improved our 
knowledge of the Hubble Constant by providing a solid zero point for the 
Tully- Fisher {TF} relation and Type Ia Supernovae {SNIa}.  However, severe 
inconsistencies remain for distance estimators to early-type galaxies such 
as surface brightness fluctuations {SBF}, the planetary nebula luminosity 
function {PNLF}, the fundamental plane {FP}, and the globular cluster 
luminosity function {GCLF}.  As a result, the distance to the Virgo cluster 
core remains uncertain by as much as 20 determination is directly affected 
by a lingering 0.1 mag {5 uncertainty in the photometric calibration of the 
WFPC2.  Resolving these issues is essential not only to firm up the 
extragalactic distance scale, but also to understand the mass and velocity 
structure of the local universe. SBF in particular is emerging as the 
method of choice for mapping local velocity fields to 10, 000 kms because 
it offers an order of magnitude less Malmquist bias than TF, and SNIa are 
too rare to study large scale flows effectively.  This project will tighten 
the photometric calibration of the WFPC2, and provide a solid Cepheid 
calibration for SBF and PNLF.  The observations completed nominally.

    1.8 Completed Two Sets of ACS/WFC/HRC 9013 (Coarse Corrector Alignment)

        The Advanced Camera for Surveys (WFC and HRC) was used in an 
attempt to approximately optimize the ACS image quality over the fields of 
both the WFC and HRC channels by adjusting the IM1 and M1 corrector 
mechanisms in both tip/tilt {cylinder rotation} and focus.  These 
observations of a moderate density star field constitute the "first light" 
external images for the HST/ACS.  No anomalous activity occurred.

    1.9 Completed ACS/WFC/HRC 8947 (Weekly Test)

        The Advanced Camera for Surveys (WFC and HRC) was used to perform 
basic tests to monitor, the read noise, the development of hot pixels and 
test for any source of noise in ACS CCD detectors.  This program will be 
executed at least once a day for the entire lifetime of ACS.  There were no 
problems reported.

2.0 FLIGHT OPERATIONS SUMMARY:

    2.1 Guide Star Acquisitions:
       Scheduled Acquisitions:  7
    Successful:  7

  Scheduled Re-acquisitions:  7
    Successful:  7

    2.2 FHST Updates:
    Scheduled: 15
    Successful: 15

    2.3 Operations Notes:

        The NICMOS Cryo Cooler cooldown continues nominally.

        Using ROP SR-1A, the SSR-1 EDAC error counter was cleared twice.

        The following Operations Notes were executed during this 
operational day:
Turn On ACS HRC/SBC Corrector Status limit
Adjust ACS Error Count limit
Turn Off ACS HRC/SBC Corrector Status limit

        An SSR Command error was cleared at 085/1248Z per ROP SR-9A.

        Per an operations request, completed ACS Coarse Corrector 
Alignment, Part 2 at 085/1738Z.

        The NSSC-1 status buffer was dumped at 086/0007Z, using ROP NS-3.

        The Coarse Sun Sensor 3 Temperature (GCSS3T) broke the yellow limit 
at 086/043437Z and returned to normal bounds at 086/043443Z.  During this 
time the HST was in an SAA interval.  The temperature reached -45.0897 
degC: the yellow limit is set at -45.0000 degC.  HSTAR 8581 was written.

3.0 SIGNIFICANT FORTHCOMING EVENTS:

        Continuation of Servicing Mission Orbital Verification and the 
gradual resumption of normal science observations and calibrations.

/CAW