HUBBLE SPACE TELESCOPE

       DAILY REPORT #3094

PERIOD COVERED:  0000Z (UTC) 04/12/02 - 0000Z (UTC) 04/15/02

Daily Status Report as of 105/0000Z

1.0 OBSERVATIONS SCHEDULED AND ACCOMPLISHED:

    1.1 Completed ACS/HFC 9016 (Coronagraph Repeatability)

        The Advanced Cmaera for Surveys (HFC) was used to: {1} determine 
the relative positions of the coronagraph's occulting spots and the "Fastie 
Finger, " and {2} monitor the stability of the HRC coronagraph by 
repeatedly deploying the cal/coronagraph door mechanism and subsequently 
recording a quasi-flat field image.  All observations completed without 
incident.

    1.2 Completed Three Sets of STIS/CCD 8904 (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 in order to build up high-S/N superbiases and track the evolution 
of hot columns.  The proposal completed with no anomalous activity.

    1.3 Completed Ten Sets of ACS/WFC 8948 (CTE Test)

        The Advanced Camera for Surveys (WFC) was used to measure the 
baseline charge transfer efficiency {CTE} performance of the WFC detectors, 
emulating the CTE ground calibration testing.  Also, a  similar program 
will perform periodic measurements in order to track the change in the CTE 
as damage due to radiation exposure accumulates.   All observations were 
successful.

    1.4 Completed ACS/HRC 9020 (Preliminary ACS Sensitivity)

        The Advanced Camera for Surveys (HFC) was used to observe a 
spectrophotometric standard star through each filter of each camera to 
assess the sensitivity of the instrument.  The star is placed at the center 
of the aperture, and two images are taken through each filter.  There were 
no reported problems.

    1.5 Completed ACS/WFC 9032 (CCD Flash Calibration)

        The Advanced Camera for Surveys (WFC) was used to provide a 
preliminary baseline set of CCD FLASH exposure reference images for each 
current level/shutter-side/detector combination, for the pair of FLASH LEDs 
on the instrument side currently in use.  It also tested the short-term 
repeatability at the shortest FLASH exposure times that are expected to be 
used {1.0 sec}.  There were no reported problems.

    1.6 Completed Two Sets of STIS/CCD 8588 (Gamma-Ray Bursts and their 
Host Environments)

        The Space Telescope Imaging Spectrograph (CCD) was used to 
investigate the physics of gamma-ray bursts {GRBs} and the nature of their 
host galaxies.  The approach is three-pronged: 1} rapid HST ultraviolet 
spectroscopy and Chandra imaging obtained within two days of an outburst 
will allow probing the physics of the relativistic fireball and the nature 
of the ISM surrounding the GRB; 2} long-term optical monitoring of the 
optical transient {OT} will permit testing the hypothesis that GRBs are 
frequently highly collimated and to determine whether supernovae underlie 
GRBs; 3} Chandra and HST observations of "dark" GRBs will allow probing one 
of the greater mysteries surrounding GRBs, the nature of the bursts without 
optical counterparts.  There were no reported problems.

    1.7 Completed Eleven Sets of 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.

    1.8 Completed Ten Sets of ACS/HRC 9019 (Flat Field Stability)

        The Advanced Camera for Surveys (HRC) was used to assess the 
stability and uniformity of the low-frequency flat fields {L-flat} of all 
ACS detectors by using multiple pointing observations of the globular 
clusters NGC104 and NGC6681 - thus imaging moderately dense stellar 
fields.  By placing the same star over different portions of the detectors 
and measuring relative changes in its brightness it will be possible to 
determine local variations in the response of the detectors.  Based on 
previous experience with STIS, it is deemed that a total of nine different 
pointings will suffice to provide adequate characterization of the flat 
field stability in any given band.  For each filter to be tested, the 
baseline consists of 9 pointings with steps of ~20% of the FOV in a 
diagonal cross pattern.  No anomalous activity was reported.

    1.9 Completed Four Sets of STIS/CCD 8902 (Dark Monitor-Part 2)

        The Space Telescope Imaging Spectrograph (CCD) was used to monitor 
the darks.  No problems were reported.

    1.10 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.

    1.11 Completed Five Sets of WF/PC-2 8937 (Cycle 9 Supplemental Darks pt2/3)

        The WF/PC-2 was used obtain three dark frames every day to provide 
data for monitoring and characterizing the evolution of hot pixels.  No 
problems were encountered.

    1.12 Completed STIS/CCD 8908 (CCD Imaging Flats C10)

        The Space Telescope Imaging Spectrograph (CCD) was used to 
investigate flat-field stability over a monthly period.  The proposal 
completed with no reported problems.

    1.13 Completed STIS/CCD 9077 (Survey of the LMC Planetary Nebulae)

        The Space Telescope Imaging Spectrograph (CCD) was used to perform 
a snapshot survey of all known LMC planetary nebulae {PNe} in order to 
study the co-evolution of the nebulae and their central stars, and to probe 
the chemical enrichment history of the LMC.  There were no reported problems.

    1.14 Completed STIS/CCD 9176 (LMC Eclipsing Binaries with Cepheid 
Components: The Key to the Extragalactic Distance Scale)

        The Space Telescope Imaging Spectrograph (CCD) was used to 
determine the distance to the LMC and to observe the Cepheid P-L that form 
the backbone of the Cosmic Distance Scale and the determination of 
H_degrees.  Unfortunately, in spite of concerted efforts of many 
investigators, the zero point of the Cepheid P-L law and the LMC distance 
remain controversial and uncertain to ~10-15, using eclipsing binaries 
{EBs} as "standard candles'' to include two recently discovered LMC 
eclipsing binaries {EBs} with Cepheid components.  These observations of 
these extraordinary systems hold the key to determining simultaneously the 
Cepheid P-L zero point and the LMC distance, and to provide a direct test 
of the Baade-Wesselink parallax method.  There were no reported problems.

    1.15 Completed STIS/CCD 9110 (A Search for Kuiper Belt Object Satellites)

        The Space Telescope Imaging Spectrograph (CCD) was used to 
investigate whether the large number of collisions thought to have taken 
place in the primordial Kuiper belt suggest that many Kuiper belt objects 
{KBOs} could have suffered binary-forming collisions similar to that which 
formed the Pluto -- Charon binary.  Detection of such KBO satellites would 
allow measurement of  KBO masses, would help to understand the past 
collisional environment of the Kuiper belt, and would give a context to the 
otherwise unique-seeming formation of the Pluto -- Charon binary.  The 
proposal completed with no reported problems

    1.16 Completed STIS/CCD/MA1 8962 (Contamination Monitor)

        The Space Telescope Imaging Spectrograph (CCD and MA1) was used to 
observe the flux standard GRW +70 5824 to assess whether FUV sensitivity is 
significantly below performance obtained during execution of 8961 {End of 
BEA Test} and prior to SM3B.  Significantly degraded sensitivity will 
trigger additional observations of flux standards to validate the initial 
result and/or track subsequent {de}contamination.  GRW +70 5824 is observed 
bimonthly in the same mode as part of the regular STIS monitoring 
program.  Measurement accuracy will be limited global sensitivity 
fluctuations {less than 5%}, rather than photon counting statistics.  No 
anomalous activity was observed.

    1.17 Completed Two Sets of FGS/1 8898 (Calibrating FGS1r's 
Interferometric Response as a Function of Spectral Color)

        Fine Guidance Sensor #1 was used to obtain reference point source 
Transfer Functions {S-Curves} through the F583W filter and the F5ND 
attenuator at the center position of the FGS1r FOV for a variety of stellar 
spectral colors.  The data will be added to the library of point source 
interferograms that was assembled from the Cycles 8 and 9 calibration 
program.  These Transfer Functions are needed to support the analysis of GO 
science data for the study of close and wide binary star systems and for 
determining the angular diameter of extended sources.  The proposal 
completed with no reported problems.

    1.18 Completed ACS/HRC/WFC 9292 (The Nature of Galaxies at z > 4)

        The Advanced Camera for Surveys (HRC and WFC) was used to further 
look into recent discoveries of a number of galaxies and quasars at 
redshifts greater than 5 that has identified the z>5-6 epoch as key to 
understanding the earliest formation phases for galaxies.  However, 
establishing the characteristics and properties of these earliest galaxies 
is proving to be a particularly difficult.  They are faint, with I{AB} 
magnitudes around 26-27.  Thus, substantial investments of time are needed 
to obtain high S/N images, while ground-based spectroscopy, even with 8-10 
m class telescopes, has provided little more than redshifts.  Establishing 
the physical properties of these galaxies will be a challenge for the 
foreseeable future.  However, there is a subset of this high redshift 
population that is amenable to more detailed study.  These are sources that 
have been strongly lensed by low redshift clusters.  No problems were reported.

    1.19 Completed WF/PC-2 9145 (A Snapshot Survey of the Optically 
Selected Type-2 Quasars)

        The WF/PC-2 was used to observe an identified population of 
emission-line objects in DPOSS, which can be plausibly interpreted as the 
long-sought type-2 quasars.  They have high-ionization Seyfert-2 like 
spectra, but with narrow-line luminosities comparable to those of the 
luminous type-1 quasars in the same redshift range.  This population may be 
a major contributor to the cosmic hard x-ray background.  It is proposed to 
obtain multi-color images of a representative sample of these objects, in 
order to examine their morphology.  We may be able to detect point-like 
nuclei which are not detectable in ground-based images, the dust lanes 
hiding them from our view, possible evidence for tidal interactions and the 
overall morphology of their hosts, etc.  The proposal completed with no 
reported problems.

    1.20 Completed STIS/CCD 9131 (Imaging the Host Galaxies of High 
Redshift Type Ia Supernovae)

        The Space Telescope Imaging Spectrograph (CCD) was used to complete 
the snapshot survey of distant galaxies of known redshift which hosted 
supernovae {SNe} of Type Ia found via the Supernova Cosmology Project 
{SCP}.  No problems were seen.

2.0 FLIGHT OPERATIONS SUMMARY:

    2.1 Guide Star Acquisitions:
       Scheduled Acquisitions: 25
    Successful: 25

        The acquisition at 105/063254Z defaulted to fine lock back-up on 
FGS-1 only when FGS-3 failed to achieve lock.  HSTAR 8607 was written.  Two 
proposals (ACS 8947 and STIS 9846), each occurring during the period of the 
next report may have been affected.
  Scheduled Re-acquisitions: 29
    Successful: 29

    2.2 FHST Updates:
    Scheduled: 39
    Successful: 38

        The roll delay update at 103/070750Z failed due to tracker 2.  The 
subsequent acquisition, however, was successful.  HSTAR 8604 was written.

    2.3 Operations Notes:

        The NICMOS Cryo Cooler has achieved its predicted endpoints, 
allowing some delayed portions of the Servicing Mission Orbital 
Verification (SMOV) to proceed.

       During the weekend, the following operations notes were executed:
Adjust ACS Error Count Limit
ACS STB 935
Change Limits MAMA Threshold Voltage
Change Limits MCE-2 Reset Det
Change Limits MAMA Threshold
Tabulation of Slew Attitude Error (Miss-distance)
COMMAND PROBLEM

        The CCS engineering status buffer limit for SESBSLD was adjusted 
twice per ROP DF-18A.

        Using ROP SR-1A, the SSR-1 EDAC error counter was cleared at 102/1107Z.

        An operations request was executed at 102/1331Z to allow future ACS 
SBC MAMA high voltage turn-ons.

        A TTR was written for a required re-transmit at 103/034017Z during 
a NSSC-1 load.  SI C&DH errors were reset at 103/0345Z as directed by ROP 
NS-05.

        The SSR-3 EDAC error counter was cleared at 103/0347Z and at 
103/0755Z per ROP SR-9A.

        Per HSTAR 8606, at 104/231851Z, HGA2XPOS flagged out-of-limits with 
a value of 86.6051 for 10 seconds.  It flagged twice more for 10 seconds at 
104/233951Z and at 104/234141Z.

        Systems Engineering personnel observed the nominal ACS SBC MAMA low 
voltage turn-on at 105/0425Z.

3.0 SIGNIFICANT FORTHCOMING EVENTS:

        Continuation of SMOV and the gradual resumption of normal science 
observations and calibrations.

/CAW