Hubble Space Telescope Daily Report #2868 – 9 May 2001

HUBBLE SPACE TELESCOPE

DAILY REPORT #2868

PERIOD COVERED: 0000Z (UTC) 05/08/01 – 0000Z (UTC) 05/09/01

Daily Status Report as of 129/0000Z

1.0 OBSERVATIONS SCHEDULED AND ACCOMPLISHED:

1.1 Completed WF/PC-2 8702 (The Most Elusive Nuclei of LMC Planetary
Nebulae)

The WF/PC-2 was used to carry out a SNAPSHOT survey of the faintest
nuclei of planetary nebulae {PNe} in the LMC. This program will be a
crucial follow-on to a Cycle 8 SNAPSHOT of LMC Pne. In thisa case the plan
is to observe the faintest or most obscured nuclei to determine their
evolutionary state to an accuracy not possible in the Galaxy. These
faintest central stars are predicted to be among the most massive nuclei,
and owing to the typically advanced age of the surrounding nebulae, are the
most sensitive discriminants for validating the post-AGB evolution
timescales predicted by theory. The observations completed with no
reported problems.

1.2 Completed Ten 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}. As
described in yesterday’s report and HSTAR 8207, the acquisition for the
fourth iteration of this proposal defaulted to fine lock backup on one FGS
only, possibly affecting two observations. Then, the loss-of-lock detailed
in 2.1 and HSTAR 8210 occurred during the ninth iteration of this proposal,
possibly affecting the observations in that iteration. Otherwise, the
observations completed nominally.

1.3 Completed Three 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 Two Sets of 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.

1.5 Completed Two Sets of STIS/CCD 8845 (Spectroscopic Flats C9)

The Space Telescope Imaging Spectrograph (CCD) was used to obtain
CCD flats in the spectroscopic mode. The observations completed with no
reported problems.

1.6 Completed Two Sets of WF/PC-2 8602 (A Snapshot Survey of the Sites
of Recent, Nearby Supernovae)

The WF/PC-2 was used to conduct a snapshot survey in V and I of the
sites of the nearby SNe, which have precisely known positions, to obtain
high-resolution information on their local environment. The proposal
completed with no reported problems.

1.7 Completed STIS/CCD 9246 (POMS Test Proposal: Non-scripted Parallel
Proposal Continuation IV)

The Space Telescope Imaging Spectrograph (CCD) was used to perform
a generic target version of the Archival Pure Parallel program. The
program will be used to take parallel images of random areas of the sky,
following the recommendations of the Parallels Working Group. The
observations completed with no anomalous activity.

1.8 Completed Five Sets of STIS/CCD 8836 (Performance Monitor {Cycle 9})

The Space Telescope Imaging Spectrograph (CCD) was used to measure
the baseline performance and commandability of the CCD subsystem. Only
primary amplifier D was used. Bias and Flat Field exposures were taken in
order to measure read noise, CTE, and gain. Numerous bias frames were
taken to permit construction of “superbias” frames in which the effects of
read noise have been rendered negligible. Full frame and binned
observations were made, with binning factors of 2 x 1, 1 x 2, 2 x 2, 4 x 1,
and 4 x 2. Dark images were taken in 2×2 binning mode; 1×1 binning darks
are being taken in the nominal CCD Dark Monitor. The exercise completed
nominally.

1.9 Completed WF/PC-2 8723 (A Snapshot Survey of Galactic Globular
Clusters)

The WF/PC-2 was used to observe the crowded centers of globular
clusters {GCs} that heretofore have produced intriguing discoveries of new
phenomena, most of which are not understood theoretically. The
observations completed with no reported problems.

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

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

1.11 Completed STIS/CCD 8572 (Identifying Normal Galaxies at 1.3 < z < 2.5)

The Space Telescope Imaging Spectrograph (CCD) was used to perform
studies of faint, distant galaxies. It is now possible to observe hundreds
of galaxies out to z=1 and in the range 3 < z < 4.5, yet the redshift range 1 < z <3 remains largely unexplored. No problems were noted.

1.12 Completed Two Sets of WF/PC-2 8585 (Cosmological Parameters from
Type Ia Supernovae at High Redshift)

The WF/PC-2 was used to measure the cosmological parameters, Omega,
Lambda, and thus the curvature, Omega_k, using Type Ia supernovae {SNe Ia}
as calibrated standard candles. As described in yesterday’s report and
HSTAR 8207, the acquisition for the first iteration of this proposal
defaulted to fine lock backup on one FGS only, possibly affecting two
observations. Otherwise, there were no other reported problems.

1.13 Completed WF/PC-2 8815 (Cycle 9 Earth Flats)

The WF/PC-2 was used to monitor flatfield stability. This proposal
obtains sequences of Earth streak flats to construct high quality flat
fields for the WF/PC-2 filter set. These flat fields will allow mapping of
the OTA illumination pattern and will be used in conjunction with previous
internal and external flats to generate new pipeline superflats. The
proposal completed nominally.

1.14 Completed STIS/CCD/MA2 8569 (A New Survey for Low-Redshift Damped
Lyman-Alpha Lines in QSO MgII Systems)

The Space Telescope Imaging Spectrograph (CCD and MA2) was used to
support studies which have shown that most of the observable neutral gas
mass in the Universe resides in QSO damped LyAlpha {DLA} systems. However,
at low redshift, DLA can only be found by searching in the UV with HST. By
boot-strapping from the MgII statistics, we will be able to further improve
the determination of the low- redshift statistical properties of DLA {their
incidence and cosmological mass density} and open up new opportunities for
studies at low redshift. The observations completed nominally.

1.15 Completed STIS/MA1 8843 (Cycle 9 MAMA Dark Measurements)

The Space Telescope Imaging Spectrograph (MA1) was used to perform
the routine monitoring of the MAMA detector dark noise. The proposal
completed nominally.

1.16 Completed STIS/CCD 8611 (Observations of Nearby Type Ia Supernovae)

The Space Telescope Imaging Spectrograph (CCD) was used to obtain
UV spectra of five nearby {0.02 < z < 0.08} SNe Ia in the Hubble Flow. The spectra will be taken at weekly intervals over a range in time starting slightly before maximum light and extending to +30 days. These observations will accomplish the following three goals: {1} calibration of the rest frame UV light curves of SNe Ia and an assessment of their potential use as distance indicators through UV light curve shape analyses. {2} improvement in our understanding of the physics of SNe Ia, metallicity/evolutionary effects and correlations between peak brightness and UV spectral features. {3} calibration of the SNe Ia previously observed by HST at high-redshift. This data is crucial for proper cross-filter k-corrections and calibration of the supernova photometry. The observations completed with no reported anomalous activity.

1.17 Completed Two Sets of WF/PC-2 8604 (Stellar Populations Across the
Small Magellanic Cloud (SMC) : History and Structure)

The WF/PC-2 was used to investigate the structure and evolutionary
history of the SMC by obtaining a series of 50 three-color snapshots of
selected SMC regions. With this polling of SMC field star properties, we
will produce color-magnitude diagrams in the U, V and I bands which will
reach V~23.5 in regions too crowded to be observed accurately from the
ground. The observations completed nominally.

1.18 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. The loss-of-lock detailed in 2.1 and HSTAR 8210
occurred during this proposal, possibly affecting the
observations. Otherwise, there were no other reported anomalies.

2.0 FLIGHT OPERATIONS SUMMARY:

2.1 Guide Star Acquisitions:

Scheduled Acquisitions: 12

Successful: 12

As described in HSTAR 8210, there was a loss-of-lock on FGS-3 at
128/223631Z after a successful acquisition at 128/222954Z. The proposals
presented in 1.2 and 1.18 may have been affected.

Scheduled Re-acquisitions: 4

Successful: 4

2.2 FHST Updates:

Scheduled: 23

Successful: 23

2.3 Operations Notes:

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

Per an operations request, gyro #5 was successfully turned on at
128/1210Z. The initial motor signature current and rate output were as
expected. The motor current displayed an itial spike and then settled to a
nominal value of 140 mAmps. At 128/1515Z, the motor current began an
upward climb, necessitating several modifications of the limits for that
parameter. Then, at 129/041654Z, the motor current rose to 250 mAmps, and
over a period of a minute continued to rise to the stall current of 320
mAmps. Shortly after a forward service was acquired, flight operations
personnel powered off gyro #5 at 129/042056Z per an operations
request. The spinning restart was not executed since the gyro has already
been above the 320 mAmps level for three minutes by the time that the
forward service occurred.

The CCS status buffer was dumped and cleared at 128/1538Z per ROP
DF-18A. Using the same ROP, the CCS status buffer limits were adjusted at
1282315Z.

The NSSC-1 status buffer was dumped and reset at 128/2323Z per ROP
NS-3.

A TTR was written for a required re-transmit during a NSSC-1 load
uplink at 129/0330Z.

The NSSC-1 engineering report #0 was reset at 129/0341Z as directed
by ROP NS-5.

3.0 SIGNIFICANT FORTHCOMING EVENTS:

Continuation of normal science observations and calibrations.