Status Report

NASA Hubble Space Telescope Daily Report # 3670

By SpaceRef Editor
August 10, 2004
Filed under , ,

HUBBLE SPACE TELESCOPE – Continuing to collect World Class Science




S/C/NIC1/NIC3 9994

NICMOS Focus Stability

The purpose of this activity is to determine if the best focus
determined in SMOV is stable. This program will execute in
approximately one month intervals starting about 1 month after the
last execution of proposal 8980.

ACS/WFC 9847

The Structure and Physics of Extragalactic Jets

As part of an ongoing investigation into the physics of jets, we
propose to obtain ACS polarimetry of the jets of 3C 15, 3C 66B, 3C
346, 3C 371 and PKS 0521-36. This builds on our earlier HST work and
completes a sample of 9 jets that spans the range of jet luminosities
and morphological types. All of these jets have deep, multi-band HST
imaging, and radio polarimetry at matching resolution, and all but one
has Chandra data. Our goal is to investigate three fundamental issues,
brought to light by recent HST and Chandra observations. These are:
{1} What is the energetic and magnetic field structure of jets? {2}
What is the nature of particle acceleration in jets? {3} What is the
nature of the X-ray emission from jets, and what is its relationship
to lower energy emissions? Optical polarimetry provides unique
information about all of these issues. Because of their vastly
different radiative lifetimes {hundreds of years compared to
millions}, optical and radio polarimetry probe different electron
populations and emission regions. Comparison of radio and optical
polarimetry can therefore yield direct information about the
three-dimensional energetic and magnetic field structure of jets.
Optical polarimetry traces the magnetic field configuration in and
near electron acceleration regions, and when combined with optical and
X-ray spectral index maps, polarimetry can yield key constraints about
particle acceleration and the nature of the X-ray emission of jets.

NIC1/NIC2 9844

Brown dwarf atmospheric variability observations

We propose to use NIC1 and NIC2 to study brown dwarfs for atmospheric
variability. We will observe a sequence of early Ts, a detected
variable T2, a T3 and a T4.5. Atmospheric variability, that is
expected by some models for these objects, would constrain the
physical parameters of cloud vertical distribution, horizontal
homogeneity and the dynamics of the very cool atmospheres. The
existence and amplitude of the variations would reveal the size and
distribution of the cloud cover over the surface of the brown dwarf
and test a model explaining the rapidity of the L to T type
transition. The relative color changes would constrain the vertical
extent of dynamical process and the depth in the atmosphere at which
they take place. If a periodicity is measured, the rotational period
of the dwarf could be estimated.

ACS/HRC 9838

The Upper End of the Supermassive Black Hole Mass Function: Pushing
the 10 Billion Solar Mass Limit.

In 1994, HST provided the first secure detection of a supermassive
black hole {SBH} in a galactic nucleus. The galaxy was M87, the black
hole almost 4 billion solar masses. Since then, two dozen additional
SBH detections have been the outcome of the several hundred orbits of
HST time devoted to this cause. Yet, M87’s black hole is still the
most massive known, and in only two other galaxies have SBHs in excess
of a billion solar masses been detected. The aim of this proposal is
to characterize the high mass end of the local SBH mass function. Four
brightest cluster galaxies have been carefully selected. Their large
masses, luminosites and stellar velocity dispersions, as well as their
having a merging history which is unmatched by galaxies in less
crowded environments, make these galaxies the most promising hosts of
the most massive SBHs in the local Universe. It is in the high mass
regime that the unavoidable link between the evolution of supermassive
black holes and the hierarchical build-up of galaxies leaves its
clearest signature. It is these galaxies that are expected to be the
relicts of the most luminous high redshift quasars, those so
spectacularly targeted by the Sloan Digital Sky Survey. Expanding {and
extending} the high mass end of the local SBH mass function is the
next obligatory step we need to take to improve our understanding of
how SBHs, and their hosts, formed and evolved.


Young Massive Clusters in Spiral Galaxies and the Connection with Open

We propose to carry out a census of star clusters in the disks of the
nearby spiral galaxies NGC 45, NGC 1313, NGC 4395, NGC 5236 and NGC
7793. Using ACS, we will identify much fainter and older star clusters
than possible in previous ground-based surveys, or even in HST imaging
of more distant galaxies. For the first time, we will directly explore
the connection between young "massive” {or "super”} star clusters
{YMCs} and lower-mass "open” clusters in different star forming
environments. We will test the universality of the luminosity- and
mass functions of stellar clusters and establish whether the presence
of YMCs is a result of a top-heavy cluster luminosity function, or
follows from generally richer cluster systems. Our target galaxies
span a range of morphological properties, surface brightness and star
formation rate. Some of them are known from ground-based studies to
host large numbers of YMCs while others have more modest cluster
populations. However, previous ground-based data were restricted to
luminous clusters younger than about 500 Myr. Here we will extend the
search to clusters formed throughout the entire lifetime of each
galaxy and reach clusters with properties typical of the Milky Way
open clusters. This will allow us to close the gap between studies of
extragalactic and Galactic disk clusters.

ACS/WFC 9727

Exploration of the SN Ia Hubble Diagram at z > 1.2

In the spirit of a Treasury proposal, we propose to organize, and
deliver to the astronomical community, non-proprietary follow-up
observations of ~10 Type Ia supernovae at 1<z<1.7 that are expected to
be discovered in a Cycle 12 Treasury proposal. Together with the
currently available sample, this would provide a Hubble diagram with
over 20 SNe Ia in this redshift range, where it is possible to test
the current cosmological model in the epoch of deceleration: If z ~
0.5 SNe Ia are fainter due to evolution rather than an accelerating
expansion, they should continue to get fainter at even higher
redshifts. This size sample will show trends and outliers, and permit
a more rigorous treatment of the asymmetric amplification distribution
from gravitational lensing. This is a key redshift range for the
studies of dark energy that will be done with future surveys {and
future instruments now being designed}; this dataset will lay the
ground-work for these studies by establishing the simple properties of
the supernovae in this redshift range, including magnitudes, colors,
and timescales. If considered more appropriate, this proposal could be
treated as a part of a Treasury or Director’s Discretionary program,
since the data would be available to everybody immediately, and we
would welcome others who would want to work with us on it.

ACS/HRC 9703

Coronagraphic Search for Planets around Nearby Stars

We will use the HRC coronagraph to search for planets, disks, and
exo-zodiacal dust around nearby stars. We have selected the following
stars: alpha Cen A and B, tau Ceti, and epsilon Eridani. The
observations of each star will be taken at two or more epochs. The
observations will be broken into a sequence of short exposures and
taken at different roll angles to compensate for "telescope breathing"
during the orbit. As a further precaution, the observations will be
scheduled after the closest possible nearby pointing in order to
minimize thermal changes in the OTA during the first orbit of
observations. After matching phases, the PSFs from one star will be
subtracted from the other star.

NIC1/NIC2/NIC3 8793

NICMOS Post-SAA calibration – CR Persistence Part 4

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.

S/C 10358

Guide Star Test for program 10265


Stars in Extended HI Disk Galaxies

Half of gas rich galaxies have HI disks extending well beyond their
optical extents. This gas is a significant potential fuel repository
for future star formation. How can galaxies can store such quantities
of ISM without any apparent star formation? These extended gas disks
have well maintained velocity dispersions and dynamical structure.
What is keeping them warm? Perhaps there is star formation, but at
such low levels it is not readily apparent. We have begun
investigating this problem by looking for low-level star formation in
extended HI disk galaxies. Our first target was the spectacularly dark
matter dominated galaxy NGC2915. In this case our hypothesis was
proven to be correct. We found indications for low level star
formation in two ways. {1} Our ACS WFC images show a noticeable blue
plume of stars in the g vs g-V as well as the V vs V-I color magnitude
diagrams. The blues stars extend over the full area of the WFC and are
highly clumped. {2} Previous deep Halpha images shows a few very faint
HII regions near the Holmberg radius. The weakness of the HII regions
and the large numbers of blue {B} stars suggests that the IMF is
truncated at the upper end compared to typical IMF parameterizations.
This could imply that H-alpha surveys underestimate the true star
formation rate. Another surprising result of the ACS observations is
that the old population also extends well passed the Holmberg radius
and includes globular clusters. We propose to observe a second galaxy
for this program – NGC4789A {DDO154}. Like NGC2915, it also has HI
extending more than five times the Holmberg radius in a fairly well
ordered disk. In this case the old stellar population is comparatively
weak, and the foreground reddening is much less. This second set of
observations will give us a check on the generality of the NGC2915
results. In particular an IMF that does not extend up to O star
formation could have major implications for metal production, kinetic
energy release and ionization of the intergalactic medium.

ACS/HRC 10255

A Never Before Explored Phase Space: Resolving Close White Dwarf / Red
Dwarf Binaries

We propose an ACS Snapshot imaging survey to resolve a well-defined
sample of highly probable white dwarf plus red dwarf close binaries.
These candidates were selected from a search for white dwarfs with
infrared excess from the 2MASS database. They represent unresolved
systems {separations less than approximately 2" in the 2MASS images}
and are distributed over the whole sky. Our HST+ACS observations will
be sensitive to a separation range {1-20 AU} never before probed by
any means. The proposed study will be the first empirical test of
binary star parameters in the post-AGB phase. By resolving as few as
20 of our ~100 targets with HST, we will be able to characterize the
distribution of orbital semi-major axes and secondary star masses.

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
0.7<z<1.9, 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 10210

Groups of Dwarf Galaxies: Pools of Mostly Dark Matter?

Within 5 Mpc, there are 6 groups with well-known luminous galaxies but
there also appears to be a comparable number of groups containing only
dwarfs. If these dwarf entities are truly bound then M/L values are an
order of magnitude higher than values found for groups with luminous
spiral galaxies. There are theoretical reasons to anticipate that low
mass halos may frequently be mostly dark. The dynamical influence of
low mass halos is negligible in familiar groups with luminous members.
By contrast, a study of the dynamics of `groups of dwarfs’ may provide
direct evidence of the existence of dark matter potential wells with
few baryons. The goal of the present study is to gather detailed
information on the 3-D distribution of dwarf galaxies suspected to lie
within 7 groups of dwarfs within 5 Mpc. Distances with 7% relative
accuracy can be measured with the Tip of the Giant Branch method with
ACS and integrations within 1 orbit per target.

ACS/HRC 10205

ACS Imagery at the Top of the IMF

We shall observe two key massive hot stars to investigate the effects
of multiplicity and rotational mixing on their parameters and
evolution. {1} The prototype O2 If* star HD 93129A dominates the
compact cluster Trumpler 14, one of the ionizing clusters of the
Carina Nebula. It has been an anchor point for analyses of the most
massive stars. Unexpectedly, it has been resolved as a 55 mas binary
by FGS. The derived delta m of 0.9 implies that the companion may be
similar to the O3 dwarfs HD 93128 and HD 93129B {3" from A} in Tr 14.
Recent radio and X-ray data suggest that the HD 93129A system is a
colliding-wind binary. We plan an orbit of very short ACS exposures on
this key cluster to obtain resolved multicolor photometry of its
crowded inner members for the first time. {2} The recent discovery of
a CNO dichotomy among five O2 giants in the Magellanic Clouds provides
a new evolutionary diagnostic for the most massive stars, which is
related to their initial rotational velocities. The abundance
anomalies are seen in the UV wind spectra as well as optical lines.

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.

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 z<0.3 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/WFC 10146

Solving the problem of the White Dwarf Cooling Sequence End in M4: an
efficient approach

The end of the white dwarf {WD} cooling sequence {WDCS} has never been
observed, despite the importance that it has in providing an age
estimate of old stellar systems, independent from the standard method
of the main sequence turn off. The best targets for this investigation
are the closest stellar clusters, and, among them, globular clusters
are the most interesting ones. Being the oldest stellar aggregates,
they allow to probe the advanced WD cooling phases, and the
independent age estimate coming from the end of their WDCS has an
important cosmological impact. M4 is the best target for this
investigation. Despite huge observational efforts, we still miss the
end of its WDCS. The ACS camera offers a unique opportunity to
identify it. Coupled with already existing observations, we here prove
that we can finally reach it with only 10 HST orbits. This is probably
the last opportunity we have for a large number of years. The data we
are requesting here, will also be used to complete other two programs
of great astrophysical impact: the observational detection of the main
sequence hydrogen burning limit, and the measurement of the
geometrical distance of M4.

ACS/WFC 10135

Unveiling the Progenitors and Physics of Cosmic Explosions

GRBs and XRFs are clearly highly asymmetric explosions and require a
long-lived power source {central engine}. In contrast, nearby
core-collapse events are essentially spherical explosions. However,
the failure of spherical neutrino driven collapses has led to the idea
that asymmetric energy release is essential for the explosion. The
recent finding of a Type Ic SN in GRB 030329, the association of the
low energy event GRB 980425 with SN 1998bw, the theoretical
development discussed above and the rise of collapsar models make it
timely to consider whether all these explosions contain engines. Given
the uncertainties in theoretical modeling it is clear that
observations are needed to guide models. A priori there is little
reason to expect connection between the ultra-relativistic jet that
powers the GRB and the explosive nucleosynthesis of the ~0.5 solar
masses of Nickel-56 that powers the accompanying supernova. We propose
a comprehensive program of ACS photometric searches {and measurements}
for SNe associated with GRBs and XRFs. In concert, we will undertake
ground-based spectroscopy to determine velocity widths, and measure
engine parameters from pan-chromatic afterglow observations. Our goal
is to produce a comprehensive database of engine and SN physical
parameters against which theoretical modeling will be guided.

ACS/WFC 10120

The Formation Histories and Dynamical Roles of X-ray Binaries in
Globular Clusters

Close binaries are fundamental to the dynamical stability and
evolution of globular clusters, but large populations have been
extremely difficult to identify. Chandra X-ray images provide a
revolutionary resource, revealing a few to dozens of low-luminosity
X-ray sources in every cluster deeply examined; our own Chandra
programs uniformly study these ubiquitous X-ray sources {close
binaries and their progeny} in 11 clusters. However, definitive
understanding of the nature of the various X-ray subpopulations
requires the identification of optical counterparts, and HST is the
demonstrated key in these crowded environments. We thus propose a
proven, efficient, and uniform, HST multicolor imaging program for
optical identifications in 6 of our clusters with Chandra data
on-hand, but which lack adequate optical images in the HST archive.
The proposed ACS images will permit statistical classifications into
the various subtypes: CVs, qLMXBs, BY Dra’s/RS CVn’s {and MSPs}. A
unique aspect of our program is that our clusters span a range of
physical properties such as central concentration, cluster size, and
mass–essential ingredients in the formation, evolution, and dynamical
roles of cluster binaries. Exploiting this range of properties, we
have identified a relation that provides the first compelling link
between the number of X-ray sources and the predicted stellar
encounter frequency in globular cluster cores. But further progress in
understanding the details implicit in this relationship {e.g., whether
CVs and qLMXBs formed primarily via stellar encounters, while BY
Dra’s/RS CVn’s are mainly primordial binaries} demands uniform optical
identifications for multiple clusters, spanning the full range
physical properties.

WFPC2 10112

HST Observations of Astrophysically Important Visual Binaries

This is a continuation of a project begun in Cycle 7 and continued up
through Cycle 11. The program consists of annual or biannual WFPC2 or
FGS observations of three visual binary stars that will ultimately
yield fundamental astrophysical results, once their orbits and masses
are determined. Our targets are the following: {1} Procyon {P = 41
yr}, for which our first WFPC2 images yielded an extremely accurate
angular separation of the bright F star and its much fainter
white-dwarf companion. Combined with ground-based astrometry of the
bright star, our observation significantly revised downward the
derived masses, and brought Procyon A into excellent agreement with
theoretical evolutionary tracks for the first time. With the continued
monitoring proposed here, we will obtain masses to an accuracy of
better than 1%, providing a testbed for theories of both Sun-like
stars and white dwarfs. {2} G 107-70, a close double white dwarf {P =
19 yr} that promises to add two accurate masses to the tiny handful of
white-dwarf masses that are directly known from dynamical
measurements. {3} Mu Cas {P = 21 yr}, a famous metal-deficient G dwarf
for which accurate masses will lead to the stars’ helium contents,
with cosmological implications.

WFPC2 10080

Wavelength Stability of Narrow Band and Linear Ramp Filters

Verify the mapping of wavelength as a function of CCD position on
LRFs; check for changes in central wavelengths of narrow band filters.

WFPC2 10072


This calibration proposal is the Cycle 12 routine internal monitor for
WFPC2, to be run weekly 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.

WFPC2 10071

WFPC2 CYCLE 12 Supplemental Darks Part 3/3

This dark calibration program obtains 3 dark frames every day to
provide data for monitoring and characterizing the evolution of hot

WFPC2 10068

WFPC2 CYCLE 12 Standard Darks

This dark calibration program obtains 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.


CCD Daily Monitor

This program consists of basic tests to monitor, the read noise, the
development of hot pixels and test for any source of noise in ACS CCD
detectors. This programme will be executed once a day for the entire
lifetime of ACS.


ACS internal CTE monitor

The charge transfer efficiency {CTE} of the ACS CCD detectors will
decline as damage due to on-orbit radiation exposure accumulates. This
degradation will be closely monitored at regular intervals, because it
is likely to determine the useful lifetime of the CCDs. All the data
for this program is acquired using internal targets {lamps} only, so
all of the exposures should be taken during Earth occultation time
{but not during SAA passages}. This program emulates the ACS
pre-flight ground calibration and post-launch SMOV testing {program
8948}, so that results from each epoch can be directly compared.
Extended Pixel Edge Response {EPER} and First Pixel Response {FPR}
data will be obtained over a range of signal levels for both the Wide
Field Channel {WFC}, and the High Resolution Channel {HRC}.


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

HSTAR 9507: GS Acquisition (1,2,1) @ 221/02:15:59Z resulted in FL
backup (1,0,1) due to SSLE on FGS 2. There were no FHST FM Updates
scheduled prior to the acquisition. FHST Map scheduled @ 221/02:53Z
showed attitude errors of -12.00, -3.192, and -3.757 arcsec. Under


  • 17244-1 – SAFE STIS @ 219/1926z


  • 1257-1 – Adjust ACS Error Count Limit @ 220/1639z
  • 1257-1 – Adjust ACS Error Count Limit (closed) @ 222/1641z

                         SCHEDULED     SUCCESSFUL    FAILURE TIMES
FGS GSacq             34                        34
FGS REacq             21                         21
FHST Update           52                         52


At Project direction, STIS was commanded from Suspend to Safe Mode @
219/19:25:48Z (OR 17244-1). Signature appears nominal. EPS SE
monitored the expected power reduction, load, and structure currents.
Since STIS was safed, input power and temperatures within the
instrument have reached their nominal safe mode ranges and have
stabilized. SI SEs continue to monitor all available temperatures and
Voltages while STIS remains in Safe Mode.

Battery 1 Capacity Test scheduled to start 223/10:11Z (OR 17245-2 with
attached Battery 1 Capacity test script). Three opportunities to
connect SA, Section 1 to Diode Bus B are scheduled to ensure no large
trickle discharge in the orbit prior to the capacity test. First
opportunity 223/11:04Z, second 223/12:39Z, and third 223/14:16Z.

SpaceRef staff editor.