Daily 3736

HUBBLE SPACE TELESCOPE - Continuing to collect World Class Science

DAILY REPORT # 3736

PERIOD COVERED: DOYs 317-319

OBSERVATIONS SCHEDULED

ACS/WFC/NIC2/WFPC 9873 2 Main Sequence Turnoff Ages For Second
Parameter Clusters in M33

In cycle 5, we were granted 40 orbits to study the early formation
history of M33 by investigating the nature of the "second parameter"
phenomenon among its globular star clusters. Discovered among the
globular clusters of the Milky Way more than 30 years ago, the "second
parameter" effect describes the degeneracy in the behavior of
horizontal branch {HB} morphology with metal abundance. This
degeneracy implies the existence of a second parameter, which, in
addition to metal abundance, influences the morphology of the HB. We
constructed {V, V-I} color-magnitude diagrams for 10 M33 halo globular
clusters. From these diagrams, we measured the cluster metallicities
and HB morphologies. Surprisingly, 8 of the 10 clusters display
extremely red horizontal branches, with most of the HB stars lying
near or on top of the red giant branch, yet their metal abundances are
in the range -1.6 = [Fe/H] = -1.0. A likely explanation is that the
halo clusters in M33 are several Gyr younger than those in the Milky
Way. To test this hypothesis, we propose to obtain main sequence
turnoff photometry for two of our M33 clusters with similar
metallicities but vastly differing HBs - a so-called `second parameter
pair.' This will help to answer the question of whether age is the
second parameter among the M33 halo clusters and provide an important
clue to the overall nature of the second parameter effect.

NIC3 9846

The Origins of Sub-stellar Masses: Searching for the End of the IMF

Is there a preferred scale that defines the end of the IMF? We propose
to test this hypothesis by conducting a deep spectroscopic survey of
extremely low mass objects in the embedded young cluster associated
with NGC1333. At a distance of only 300pc, this cluster is one of the
nearest examples of a dense young cluster. We will be able to obtain
R=200 spectra and photometry for 40-60 cluster members with masses
between 5-40 Jupiter masses at an age of 1 Myr observed through
A{v}10 mag. This will enable us to estimate temperatures and
luminosities for all sources detected in the survey. We will compare
their positions in an H-R diagram to PMS evolutionary tracks in order
to estimate their ages and masses. For a solar metallicity cloud at a
temperature of 10 K, the minimum mass for fragmentation is thought to
be 10 Jupiter masses. A statistically significant sample of objects
detected below this limit would challenge the role of hierarchical
fragmentation in limiting substellar masses. The proximity of this
cluster combined with the unique sensitivity, wavelength coverage, and
multi-object spectroscopic capability of NICMOS on HST make this
experiment possible.

NIC1/NIC2/NIC3 8794

NICMOS Post-SAA calibration - CR Persistence Part 5

A new procedure proposed to alleviate the CR-persistence problem of
NICMOS. Dark frames will be obtained immediately upon exiting the SAA
contour 23, and every time a NICMOS exposure is scheduled within 50
minutes of coming out of the SAA. The darks will be obtained in
parallel in all three NICMOS Cameras. The POST- SAA darks will be
non-standard reference files available to users with a USEAFTER
date/time mark. The keyword 'USEAFTER=date/time' will also be added to
the header of each POST-SAA DARK frame. The keyword must be populated
with the time, in addition to the date, because HST crosses the SAA ~8
times per day so each POST- SAA DARK will need to have the appropriate
time specified, for users to identify the ones they need. Both the raw
and processed images will be archived as POST-SAA DARKSs. Generally we
expect that all NICMOS science/calibration observations started within
50 minutes of leaving an SAA will need such maps to remove the CR
persistence from the science images. Each observation will need its
own CRMAP, as different SAA passages leave different imprints on the
NICMOS detectors.

FGS 10386

Long Term Monitoring of FGS1r in Position Mode

It is known from our experience with FGS3, and later with FGS1r, that
an FGS on orbit experiences long term evolution, presumably due to
disorption of water from the instrument's graphite epoxy composits.
This manifests principally as a change in the plate scale and
secondarily as a change in the geometric distortions. These effects
are well modeled by adjustments to the rhoA and kA parameters which
are used to transform the star selector servo angles into FGS {x, y}
detector space coordinates. By observing the relative positions of
selected stars in a standard cluster at a fixed telescope pointing and
orientation, the evolution of rhoA and kA can be monitored and
calibrated to preserve the astrometric performance of FGS1r.

ACS/HRC/WFC 10367

ACS CCDs daily monitor- cycle 13 - part 1

This program consists of a set of basic tests to monitor, the read
noise, the development of hot pixels and test for any source of noise
in ACS CCD detectors. The files, biases and dark will be used to
create reference files for science calibration. This programme will be
for the entire lifetime of ACS.

ACS/HRC 10272

A Snapshot Survey of the Sites of Recent, Nearby Supernovae

During the past few years, robotic {or nearly robotic} searches for
supernovae {SNe}, most notably our Lick Observatory Supernova Search
{LOSS}, have found hundreds of SNe, many of them in quite nearby
galaxies {cz 4000 km/s}. Most of the objects were discovered before
maximum brightness, and have follow-up photometry and spectroscopy;
they include some of the best-studied SNe to date. We propose to
conduct a snapshot imaging survey of the sites of some of these nearby
objects, to obtain late-time photometry that {through the shape of the
light and color curves} will help reveal the origin of their lingering
energy. The images will also provide high- resolution information on
the local environment of SNe that are far superior to what we can
procure from the ground. For example, we will obtain color-color and
color- magnitude diagrams of stars in these SN sites, to determine
their progenitor masses and constraints on the reddening. Recovery of
the SNe in the new HST images will also allow us to actually pinpoint
their progenitor stars in cases where pre-explosion images exist in
the HST archive. Use of ACS rather than WFPC2 will make our snapshot
survey even more valuable than our Cycle 9 survey. This Proposal is
complementary to our Cycle 13 archival proposal, in which we outline a
plan for using existing HST images to glean information about SN
environments.

ACS/WFC 10235

Dark vs. luminous matter in the CenA/M83 galaxy complex

The distribution of dark vs. luminous matter on scales of 0.1-1.0 Mpc
remains poorly understood. For a nearby group, the total mass can be
determined from the radius of "the zero-velocity surface", which
separates the group from the general Hubble flow. This new method
requires the measurement of accurate distances and radial velocities
of galaxies around the group, but gives total mass estimates
independent of assumptions about the state of relaxation or orbital
characteristics. The mass pertains to the group at the full scale to
which it is bound. Upon application in several nearest groups, the
method yields mass estimates in agreement with the sum of the virial
masses of subcomponents. However, the typical total M/L ratio for the
nearby groups of ~30 Mo/Lo implies a local mean density of matter
which is only 1/7 the canonical global density . The nearby complex of
galaxies around Cen A and M83 resembles our Local Group by the
dumb-bell concentration of objects around a pair of dominant galaxies.
Accurate distances have been acquired recently for ~20 group members
by the TRGB method using HST. We will measure TRGB distances to the 17
remaining galaxies in the region. These observations will constrain
the dynamical state of the halo surrounding the nearest giant E-galaxy
Cen A, providing a comparison with the halos of the nearest spirals.

NIC/NIC3 10226

The NICMOS Grism Parallel Survey

We propose to continue managing the NICMOS pure parallel program.
Based on our experience, we are well prepared to make optimal use of
the parallel opportunities. The improved sensitivity and efficiency of
our observations will substantially increase the number of
line-emitting galaxies detected. As our previous work has
demonstrated, the most frequently detected line is Halpha at
0.7z1.9, which provides an excellent measure of current star
formation rate. We will also detect star- forming and active galaxies
in other redshift ranges using other emission lines. The grism
observations will produce by far the best available Halpha luminosity
functions over the crucial--but poorly observed--redshift range where
galaxies appear to have assembled most of their stellar mass. This key
process of galaxy evolution needs to be studied with IR data; we found
that observations at shorter wavelengths appear to have missed a large
fraction of the star-formation in galaxies, due to dust reddening. We
will also obtain deep F110W and F160W images, to examine the space
densities and morphologies of faint red galaxies. In addition to
carrying out the public parallels, we will make the fully reduced and
calibrated images and spectra available on-line, with some
ground-based data for the deepest parallel fields included.

ACS/WFC 10217

The ACS Fornax Cluster Survey

The two rich clusters nearest to the Milky Way, and the only large
collections of early- type galaxies within ~ 25 Mpc, are the Virgo and
Fornax Clusters. We propose to exploit the exceptional imaging
capabilities of the ACS/WFC to carry out the most comprehensive
imaging survey to date of early-type galaxies in Fornax: the ACS
Fornax Cluster Survey. Deep ACS/WFC images -- in the F475W {g'} and
F850LP {z'} bands -- will be acquired for 44 E, S0, dE, dE, N and dS0
cluster members. In Cycle 11, we initiated a similar program targeting
early-type galaxies in the Virgo Cluster {the ACS Virgo Cluster
Survey; GO-9401}. Our proposed survey of Fornax would yield an
extraordinary dataset which would complement that already in hand for
Virgo, and allow a definitive study of the role played by environment
in the structure, formation and evolution of early-type galaxies and
their globular cluster systems, nuclei, stellar populations, dust
content, nuclear morphologies and merger histories. It would also be a
community resource for years to come and, together with the ACS Virgo
Cluster Survey, constitute one of the lasting legacies of HST.

FGS 10202

Resolving OB Binaries in the Carina Nebula, Resuming the Survey

In March 2002 we carried out a small, high-angular resolution survey
of some of the brightest OB stars in the Carina Nebula with FGS1r in
an attempt to resolve binary systems which had thus far evaded
detection by other techniques. Of 23 stars observed, 5 new OB binaries
were discovered with component separations ranging from 0.015"
to0.325". This yield over the spatial domain of FGS1r's angular
resolution, coupled with published statistics of the incidence of OB
stars in short-period spectroscopic, and long-period visual binaries
suggests that the fraction of binarity or multiplicity among OB stars
is near unity. Our unexpected resolution of the prototype O2 If* star
HD 93129A as a 55 milli-arcsecond double is a case in point that great
care must be exercised when one attempts to establish the IMF and
upper-mass cuttoff at the high-mass end of the HR diagram. We propose
to resume the survey to observe a larger, statistically meaningful
sample of OB stars to establish a firm assessment of multiplicity at
the high-mass end of the IMF in these clusters. We will also
investigate the single-star/binary-star status of several
astrophysically important, individual stars in order to enable a
better understanding of the evolution of high- mass stars.

ACS/HRC 10199

The Most Massive Galaxies in the Universe: Double Trouble?

We are proposing an HST snapshot survey of 70 objects with velocity
dispersion larger than 350 km/s, selected from the Sloan Digital Sky
Survey. Potentially this sample contains the most massive galaxies in
the Universe. Some of these objects may be superpositions; HST imaging
is the key to determining if they are single and massive or if they
are two objects in projection. The objects which HST imaging shows to
be single objects are interesting because they potentially harbor the
most massive black holes, and because their existence places strong
constraints on galaxy formation models. When combined with ground
based data already in hand, the objects which HST imaging shows are
superpositions provide valuable information about interaction rates of
early-type galaxies as well as their dust content. They also constrain
the allowed parameter space for models of binary gravitational lenses
{such models are currently invoked to explain discrepancies in the
distribution of lensed image flux ratios and separations}.

ACS/HRC 10185

When does Bipolarity Impose itself on the Extreme Mass Outflows from
AGB Stars? An ACS SNAPshot Survey

Essentially all well-characterized preplanetary nebulae {PPNe} --
objects in transition between the AGB and planetary nebula
evolutionary phases - are bipolar, whereas the mass-loss envelopes of
AGB stars are strikingly spherical. In order to understand the
processes leading to bipolar mass-ejection, we need to know at what
stage of stellar evolution does bipolarity in the mass-loss first
manifest itself? Our previous SNAPshot surveys of a PPNe sample {with
ACS & NICMOS} show that roughly half our targets observed are
resolved, with well-defined bipolar or multipolar morphologies.
Spectroscopic surveys of our sample confirm that these objects have
not yet evolved into planetary nebulae. Thus, the transformation from
spherical to aspherical geometries has already fully developed by the
time these dying stars have become preplanetary nebulae. From this new
and surprising result, we hypothesize that the transformation to
bipolarity begins during the very late AGB phase, and happens very
quickly, just before, or as the stars are evolving off the AGB. We
propose to test this hypothesis quantitatively, through a SNAPshot
imaging survey of very evolved AGB stars which we believe are nascent
preplanetary nebulae; with our target list being drawn from published
lists of AGB stars with detected heavy mass-loss {from millimeter-wave
observations}. This survey is crucial for determining how and when the
bipolar geometry asserts itself. Supporting kinematic observations
using long-slit optical spectroscopy {with the Keck}, millimeter and
radio interferometric observations {with OVRO, VLA & VLBA} are being
undertaken. The results from this survey {together with our previous
work} will allow us to draw general conclusions about the onset of
bipolar mass-ejection during late stellar evolution, and will provide
crucial input for theories of post-AGB stellar evolution. Our survey
will produce an archival legacy of long-standing value for future
studies of dying stars.

ACS/HRC 10180

Ultracompact Blue Dwarfs: Galaxy Formation in the Local Universe?

Recent observations suggest that very low-mass galaxies in the local
universe are still in the process of formation. To investigate this
issue we propose to obtain deep ACS HRC images in the U, V and I bands
of a sample of 11 "ultracompact" blue dwarf galaxies {UCBDs}
identified in the Sloan Digital Sky Survey. These objects are nearby
{z 0.009}, actively star-forming, and have extremely small angular
and physical sizes {d 6" and D 1 kpc}. They also tend to reside in
voids. Our WFPC2 images of the prototype object of this class, POX
186, reveal this tiny object to have a highly disturbed morphlogy
indicative of a recent {within 10^8 yr} collision between two small {~
100 pc} clumps of stars that could represent the long-sought building
blocks predicted by the Press-Schechter model of hierarchical galaxy
formation. This collision has also triggered the formation of a
"super" star cluster {SSC} at the object's core that may be the
progenitor of a globular cluster. POX 186 thus appears to be a very
small dwarf galaxy in the process of formation. This exciting
discovery strongly motivates HST imaging of a full sample of UCBDs in
order to determine if they have morphologies similar to POX 186. HST
images are essential for resolving the structure of these objects,
including establishing the presence of SSCs. HST also offers the only
way to determine their morphologies in the near UV. The spectra of the
objects available from the SDSS will also allow us to measure their
star formation rates, dust content and metallicities. In addition to
potentially providing the first direct evidence of Press-Schechter
building blocks, these data could yield insight into the relationship
between galaxy and globular cluster formation, and will serve as a
test of the recent "downsizing" model of galaxy formation in which the
least massive objects are the last to form.

ACS/WFC 10178

Imaging Polarimetry of Young Stellar Objects with ACS and NICMOS: A
study in dust grain evolution

The formation of planetary systems is intimately linked to the dust
population in circumstellar disks, thus understanding dust grain
evolution is essential to advancing our understanding of how planets
form. By combining {1} the high resolution polarimetric capabilities
of ACS and NICMOS, {2} powerful 3-D radiative transfer codes, and {3}
observations of objects known to span the earliest stellar
evolutionary phases, we will gain crucial insight into the initial
phases of dust grain growth: evolution away from an ISM distribution.
Fractional polarization is a strong function of wavelength, therefore
by comparing polarimetric images in the optical and infrared, we can
sensitively constrain not only the geometry and optical depth of the
scattering medium, but also the grain size distribution. By observing
objects representative of the earliest evolutionary sequence of YSOs,
we will be able to investigate how the dust population evolves in size
and distribution during the crucial transition from a disk+envelope
system to a disk+star system. The proposed study will help to
establish the fundamental time scales for the initial depletion of
ISM-like grains: the first step in understanding the transformation
from small submicron sized dust grains, to large millimeter sized
grains, and untimely to planetary bodies.

NIC2 10176

Coronagraphic Survey for Giant Planets Around Nearby Young Stars

A systematic imaging search for extra-solar Jovian planets is now
possible thanks to recent progress in identifying "young stars near
Earth". For most of the proposed young {~ 30 Myrs} and nearby {~ 60
pc} targets, we can detect a few Jupiter-mass planets as close as a
few tens of AUs from the primary stars. This represents the first time
that potential analogs of our solar system - that is planetary systems
with giant planets having semi-major axes comparable to those of the
four giant planets of the Solar System - come within the grasp of
existing instrumentation. Our proposed targets have not been observed
for planets with the Hubble Space Telescope previously. Considering
the very successful earlier NICMOS observations of low mass brown
dwarfs and planetary disks among members of the TW Hydrae Association,
a fair fraction of our targets should also turn out to posses low mass
brown dwarfs, giant planets, or dusty planetary disks because our
targets are similar to {or even better than} the TW Hydrae stars in
terms of youth and proximity to Earth. Should HST time be awarded and
planetary mass candidates be found, proper motion follow-up of
candidate planets will be done with ground-based AOs.

ACS/WFC 10174

Dark-matter halos and evolution of high-z early-type galaxies

Gravitational lensing and stellar dynamics provide two complementary
methods to determine the mass distribution and evolution of luminous
and dark-matter in early- type {E/S0} galaxies. The combined study of
stellar dynamics and gravitational lensing allows one to break
degeneracies inherent to each method separately, providing a clean
probe of the internal structure of massive galaxies. Since most lens
galaxies are at redshifts z=0.1-1.0, they also provide the required
look-back time to study their structural and stellar-population
evolution. We recently analyzed 5 E/S0 lens galaxies between z=0.5 and
1.0, combining exquisite Hubble Space Telescope imaging data with
kinematic data from ground-based Keck spectroscopy, placing the first
precise constraints on the dark-matter mass fraction and its inner
slope beyond the local Universe. To expand the sample to ~30 systems
-- required to study potential trends and evolution in the E/S0 mass
profiles -- we propose to target the 49 E/S0 lens-galaxy candidates
discovered by Bolton et al. {2004} from the Sloan Digital Sky Survey
{SDSS}. With the average lens rate being 40% and some systems having a
lensing probability close to unity, we expect to discover ~20 strong
gravitational lenses from the sample. This will triple the current
sample of 9 E/S0 systems, with data in hand. With the sample of 30
systems, we will be able to determine the average slope of the
dark-matter and total mass profile of E/S0 galaxies to 10% and 4%
accuracy, respectively. If present, we can simultaneously detect 10%
evolution in the total mass slope with 95% confidence. This will
provide unprecedented constraints on E/S0 galaxies beyond the local
Universe and allow a stringent test of their formation scenarios and
the standard cosmological model.

NIC2 10173

Infrared Snapshots of 3CR Radio Galaxies

Radio galaxies are an important class of extragalactic objects: they
are one of the most energetic astrophysical phenomena and they provide
an exceptional probe of the evolving Universe, lying typically in high
density regions but well-represented across a wide redshift range. In
earlier Cycles we carried out extensive HST observations of the 3CR
sources in order to acquire a complete and quantitative inventory of
the structure, contents and evolution of these important objects.
Amongst the results, we discovered new optical jets, dust lanes,
face-on disks with optical jets, and revealed point-like nuclei whose
properties support FR-I/BL Lac unified schemes. Here, we propose to
obtain NICMOS infrared images of 3CR sources with z0.3 as a major
enhancement to an already superb dataset. We aim to deshroud dusty
galaxies, study the underlying host galaxy free from the distorting
effects of dust, locate hidden regions of star formation and establish
the physical characteristics of the dust itself. We will measure
frequency and spectral energy distributions of point- like nuclei,
expected to be stronger and more prevalent in the IR, seek spectral
turnovers in known synchrotron jets and find new jets. We will
strongly test unified AGN schemes and merge these data with existing
X-ray to radio observations. The resulting database will be an
incredibly valuable resource to the astronomical community for years
to come.

ACS/HRC 10165

Determination of orbits and colors for two new binaries in the Koronis
asteroid family

We propose to measure color and orbital properties of two asteroid
binaries in the Koronis family discovered in our SNAP-9747 survey. The
best previously studied asteroid binary system, Ida/Dactyl, is also in
the Koronis family. Differential space weathering measured on the Ida
and Dactyl surfaces has been a powerful constraint on models of
satellite formation mechanisms and satellite survivability. HST offers
the unique opportunity for similar measurements of these much smaller,
main-belt binaries. The new satellites are believed to have formed
through different collisional mechanisms than Ida/Dactyl. Further,
with a set of 4 relative position measurements for each of the two
systems, added to the discovery snapshots, we will determine and
compare the densities of the primaries with Ida {a large, 31.5 km,
asteroid with density 2.6+-0.5 g/cm^3, measured by the Galileo flyby}.
In contrast, {17246} and {22899} are 4.5 km bodies that are likely to
have been restructured since the family- forming event by subsequent
collisions. As all are members of the same family, differences in
density would constrain bulk composition and internal structure {e.g.
shard vs. rubble-pile}. Hence, these measurements are likely to
further elucidate the mechanisms for formation of satellites.

ACS/WFC 10154

Morphology of z ~ 7-10 galaxies viewed through gravitational
telescopes

The aim of these observations is to obtain deep z/ACS and H/NICMOS
images in the core of two lensing clusters, A1835 and AC114, where a
few z ~ 7-10 galaxy candidates have been selected from our ultra-deep
JHK imaging program with Isaac/VLT. Spectroscopic observations have
allowed to confirm 2 of these candidates thanks to the detection of
faint emission lines identified as Lyman alpha at z=7.2 and 10. Our
HST project is focused on two main goals: {1} the morphological
confirmation of galaxy candidates lying near critical lines, and {2}
the determination of the physical scales involved in star-forming
regions at z ~ 7-10. These goals should have important implications on
our present knowledge of the galaxy formation process in the early
Universe.

ACS/WFC 10126

The 3-D Shape of the SMC: Is It Tidally Distorted?

We propose to exploit the exceptional spatial resolution of HST to
definitively show whether the SMC is tidally elongated along the
line-of-sight, and therefore the status of the Milky Way's
interaction/destruction of the Magellanic Clouds. We use BVI ACS
images of several crowded SMC fields in the region predicted by models
of the orbit and tidal evolution of the Magellanic Clouds {and by
observations of Cepheids} to have a large depth. We exploit the red
clump feature {and the rarer true horizontal branch} to derive the
depth. Specifically, we will observe six fields along the predicted
region of maximum distance gradient of the SMC, along with two ACS
fields and several WFPC2 fields in the archives, to map out the depth
of the SMC in this region. We are searching for substructure, such as
a tidal tail, that may be present. Crowding in this region of the SMC
is so severe that this project cannot be done from the ground.

FGS 10106

An Astrometric Calibration of the Cepheid Period-Luminosity Relation

We propose to measure the parallaxes of 10 Galactic Cepheid variables.
When these parallaxes {with 1-sigma precisions of 10% or better} are
added to our recent HST FGS parallax determination of delta Cep
{Benedict et al 2002}, we anticipate determining the Period-Luminosity
relation zero point with a 0.03 mag precision. In addition to
permitting the test of assumptions that enter into other Cepheid
distance determination techniques, this calibration will reintroduce
Galactic Cepheids as a fundamental step in the extragalactic distance
scale ladder. A Period-Luminosity relation derived from solar
metallicity Cepheids can be applied directly to extragalactic solar
metallicity Cepheids, removing the need to bridge with the Large
Magellanic Cloud and its associated metallicity complications.

WFPC2 10078

WFPC2 Cycle 12 Close-Out Photometric Cross-Calibration

This proposal is aimed at providing photometric zeropoint
cross-calibration between the commonly used WFPC2 photometric filter
sets and those that will be used for ACS and WFC3. The proposal
consists of observations of a set of standard stars, including the
SDSS primary standard BD+17D4708 {F5} and two red standard stars, VB8
{an M7-dwarf} and 2M0036+18 {L3.5 dwarf}. For the red stars, medium
and broad-band filters redward of F606W are calibrated, while for
BD+17D4708 an extensive set of 22 medium and broad-band filters is
used {from F185W to F1042M}. The intent is to observe these stars with
as many filters as possible, to eventually allow cross-calibration of
archival WFPC2 data with data from ACS, WFC3, SDSS and 2MASS.

FLIGHT OPERATIONS SUMMARY:

Significant Spacecraft Anomalies: (The following are preliminary
reports of potential non-nominal performance that will be
investigated.)

HSTAR 9602: FHST Full Maneuvers (U1,3FM) @ 319/19:17:55Z and
19:20:40Z failed with Error Box results (QEBSTFG0, QEBSTFG1, and
QEBSTFG2) indicating "3FAIL". Following GS Acquisition resulted in FL
backup (2,0,2). Under investigation.

HSTAR 9603: GS Acquisition (2,1,2) @ 319/19:44:42Z resulted in FL
backup (2,0,2) during LOS. No flags were indicated at AOS. FHST FM
Updates @ 319/19:17:55Z and 19:20:40Z failed, see HSTAR 9602. Under
investigation.

HSTAR 9604: GS Acquisition (1,3,1) @ 319/21:02:32Z took two attempts
to successfully achieve FL. GS Acquisition locked up on both FGSs and
reached Sci Init @ 319/21:02:28Z. FGSs returned to SSM Control @
319/21:02:32Z. GS Acquisition was successful @ 319/21:04:30Z. Under
investigation.

COMPLETED OPS REQs:
17305-0 Update EEPROM Bank 0 Star Catalog @ 317/14:00z
17302-0 FSW 2.6C OBADs (3-Gyro) @ 317/16:30z

OPS NOTES EXECUTED: None

SCHEDULED SUCCESSFUL FAILURE TIMES
FGS Gsacq 27 27
FGS Reacq 20 20
FHST Update 44 42 See Hstar
# 9602
LOSS of LOCK


SIGNIFICANT EVENTS:

Successfully completed modification of Command Generator parameters @
319/23:08:36Z to ensure torque margins are maintained during Two Gyro
Science on-orbit testing over the next several weeks (OR 17306). The
first large vehicle maneuver (92.3 degrees), using the modified
Command Generator completed successfully @ 321/01:32Z. The maneuver
was monitored by both FSW and PCS engineers. Subsequent attitude
corrections were normal. The first GS acquisition was successfully
completed at ~ 320/01:44Z.