HUBBLE SPACE TELESCOPE - Continuing to collect World Class
Science
DAILY REPORT #4876
PERIOD COVERED: 5am June 26 - 5am June 29, 2009 (DOY
177/0900z-180/0900z)
OBSERVATIONS SCHEDULED
WFC3/UV 11808
WFC3 UVIS Bowtie Monitor
The UVIS detector was observed during ground testing to
occasionally
exhibit flat field and dark variations with a bowtie pattern. These
variations are most significant as ~1% flat field (gain) variations
across the field of view. It is believed that this represents a state or
condition into which the detector can transition for reasons and under
circumstances which are not currently understood. It is also very
unlikely that most science observations will determine the state (bowtie
or no-bowtie) of the detector. Ground test data indicates that this
state is long lived (many hours to ~one day). Hysteresis or memory of
past light exposure is also associated with this state.
Recent evidence suggests that exposing the detector to
~200k to 500k
electrons may quench this state. This proposal obtains an internal flat
field sequence of three exposures: one at 10x full well with two at 0.5x
full well immediately before and after. Each exposure is 3x3 binned to
reduce the data volume required.
These visits should be scheduled 2x per day until further
direction is
provided.
COS/FUV 11483
FUV Detector Internal Functionality and Operation
The functionality and operation of the COS FUV detector
will be tested
using internal sources. Several science exposures will be taken in
TIME-TAG using both the DEUTERIUM and Pt/Ne lamps.
This is SMOV Activity COS-25.
COS/FUV 11482
FUV Detector Dark
Measure the FUV detector dark rate by taking long science
exposures with
no light on the detector. The detector dark rate and spatial
distribution of counts will be compared to pre-launch data in order to
verify the nominal operation of the detector, and for use in the CalCOS
calibration pipeline. Variations of count rate as a function of orbital
position will be analyzed to find dependence of dark rate on proximity
to the SAA.
This is SMOV Activity COS-24.
WFC3/IR 11449
IR SAA Passage Behavior
In this program, the behavior of the WFC3 IR FPA through
the Southern
Atlantic Anomaly (SAA) as well as following the SAA crossing will be
characterized. Short and long term residual effects may consist of high
cosmic ray (CR) hit rates, high dark and background levels, residual
glow and count rates, flip memory bits, etc.... The data will help
refine the shape of the SAA contours for WFC3 (the initial SAA model for
WFC3 IR is 30 which is the same as the ACS CCDs and WFPC2, as well as
WFC3 UVIS (but labeled 29)). This proposal corresponds to activity ID
WFC3-36.
WFC3/IR 11447
WFC3 IR Dark Current, Readnoise, and Background
This proposal obtains full-frame, four-amp readout images.
Un-illuminated internals are taken at regularly spaced intervals
throughout SMOV in order to assess and monitor readnoise and dark
current (of both light-sensitive pixels and reference pixels), and bad
(warm, hot, dead, variable) pixels. In addition, externals aimed at
fields with sparse stellar density are taken to measure diffuse
background light.
This program corresponds to WFC3-34.
WFC3/UV 11446
WFC3 UVIS Dark Current, Readnoise, and CTE
This proposal obtains full-frame, four-amp readout bias
and dark frames
at regularly-spaced intervals throughout SMOV in order to assess and
monitor dark current, bad (warm, hot, dead) pixels, and readnoise. In
addition, a set of internals using the WFC3 calsystem are taken to
provide a baseline CTE measurement.
WFC3-33
WFC3/UV 11426
UVIS SMOV Contamination Monitor
The UV throughput of WFC3 during SMOV is monitored via
weekly standard
star observations in a subset of key filters (as many as will fit into a
single orbit but to include at a minimum F218W, F225W, F275W, and
F606W). The data will provide a measure of throughput levels as a
function of time and wavelength, allowing for detection of the presence
of possible contaminants. In addition, a small set of internal exposures
are included with the externals, to provide verification of detector
stability.
This proposal corresponds to activity WFC3-13.
WFC3/IR/UP 11425
WFC3 IR Initial Alignment
The corrector mechanism will be used to iteratively bring
the IR channel
of WFC3 into alignment with the OTA using phase retrieval of focus
diverse star images over the field. Three visits are required; corrector
offsets will be uplinked after each visit via realtime command.
WFC3/UP/UV 11424
WFC3 UVIS Initial Alignment
The corrector mechanism will be used to iteratively bring
the UVIS
channel of WFC3 into alignment with the OTA using phase retrieval of
focus diverse star images over the field. Three visits are required;
corrector offsets will be uplinked after each visit via realtime
command.
This proposal is activity id WFC3-11
STIS07/CCD 11404
CCD Dark and Bias Monitor for SMOV4/Cycle 17 Activity
STIS-07
Monitor the darks for the STIS CCD. Monitor the bias in
the 1x1, 1x2,
2x1, and 2x2 bin settings at gain=1, and 1x1 at gain = 4, to build up
high-S/N superbiases and track the evolution of hot columns.
ACS/WFC 11379
ACS CCD Image Quality Verification
This program will obtain a series of images to evaluate
the point source
image quality over the fields of view of the ACS HRC and WFC channels in
normal imaging (non-coronagraphic) mode, after the corrector mechanisms
have been used to optimize the image focus and symmetry. A moderate
density open cluster, NGC-188, will be the target, since it is available
year-round and has suitable density and magnitude distribution. Images
will be obtained in the F502N and F625W filters, with 0.5 px dithers in
each axis of the WFC to improve PSF sampling. Larger (~10 arcsec)
POS-TARG offsets will be used to improve the sampling over the HRC
field, while maintaining mean star separation (>5 arcsec) adequate for
PSF evaluation to a reasonable radius. This corresponds to activity
ACS17
ACS/WFC 11374
CCD Flat Field Stability (Internal Tungsten Lamps)
The stability of the CCD flat fields will be investigated
using the
internal tungsten calibration lamps and the standard filter subset
(F435W, F625W, F814W, and F850LP). High signal observations will be used
to assess the stability of the pixel-to-pixel flat field structure
(P-flat) and to verify the position of the dust motes. The stability of
the low-frequency flat fields (L-flats) will be assessed by comparing
internal exposures obtained just prior to the ACS failure in January
2007 and immediately following the ACS repair in August 2008. This is
activity number ACS-11.
ACS/WFC 11369
ACS CCD functional test for WFC
During the ACS Repair (ACS-R) conducted during Hubble
Servicing Mission
4 (SM4), astronauts will install a CCD Electronics Box Replacement
(CEB-R) and Low-Voltage Power Supply Replacement (LVPS-R). A rudimentary
aliveness/functional test (AT/FT) will be conducted on-orbit during SM4.
Shortly after SM4, the more comprehensive CCD function test (FT) defined
in this program will be conducted as part of SMOV. This program is
modeled after the original CCD functional test (HST program 9005, PI
Mark Clampin) conducted following the initial installation of ACS during
Hubble Servicing
proposal 11396.
ACS/WFC 11367
CCD Hot Pixel Annealing
Hot pixel annealing will be performed during SMOV4 before
the CCDs are
used for observations. The CCD TECs will be turned off and heaters will
be activated to bring the detector temperatures to about +20C. This
state will be held for approximately 12 hours, after which the heaters
are turned off, the TECs turned on, and the CCDs returned to normal
operating condition. To assess the effectiveness of the annealing, a
bias and four dark images will be taken before and after the annealing
procedure for both WFC and HRC. All the data for this program are
acquired using internal targets. The initial annealing occupied 5
visits. A copy of these visits to be run 4 to 5 weeks later has been
added to support proposals 11465, 11510 and 11511. The latter proposal
was too long.
S/C 11364
Vehicle Disturbance Test
The purpose of the VDT is to measure and characterize
uncompensated
environmental disturbances acting upon the HST during normal operation.
The VDT is a passive test (not a forced-response test) used to obtain
signatures for both externally induced (e.g. SCM, SA-3, SSM thermal
gradients) and internally induced (e.g. HGA, RWA, COS and WFC3
mechanisms) disturbances affecting HST LOS pointing. The disturbances
observed will be used as the nominal on-orbit disturbances in pointing
control simulations until the next VDT is run.
The test occurs after release, and most of the VDT can be
run during the
BEA period. The -V1 sunpoint portion of the VDT usually occurs after the
BEA period is complete. The VDT shall consist of two separate tests that
need not occur consecutively. The overall duration of the VDT is at
least 13 orbits of spacecraft time including (1) at least 8 orbits at
+V3 sunpoint after achieving thermal equilibrium (at least 36-hours at
+V3 sunpoint) and three out of 8-orbits have RWA Friction Compensation
turned Off, and (2) at least 5 orbits at -V1 sunpoint (all or part of
this segment have RWA Friction Compensation turned Off). At the
beginning of each test, the attitude control law gains are switched to
maneuver gains, and the gyros are commanded to low mode. The nominal
attitude control law configuration will be restored at the end of each
test.
Each test is initiated via SMS execution of stored program
macros in the
HST flight computer to switch the attitude control law gains to
low-bandwidth maneuver gains, command the gyros into low mode, terminate
Velocity aberration and parallax (VAP) processing, and manage the status
of on-board RWA Friction Compensation. The nominal attitude control law
configuration will be restored at the end of each test via SMS execution
of stored program macros. The stored program command macros are
developed specifically for the VDT by the Flight Software and Pointing
Control System groups.
COS23/FUV/S/C/ 11356
COS FUV Initial On-Orbit Turn-On
This proposal specifies the procedure for SMOV initial HV
turn-on and
ramp-up of the COS FUV detector. (The FUV will have been commanded to
its Operate state to support execution of proposal 11353.) The procedure
is detailed in the Observing Description, but in summary, the following
is done: The initial transition from FUV Operate to HVLow is broken into
two parts, with a gap of 4 hours between turning on the HV and ramping
to the HVLow (SAA) voltage. This will be followed by 5 cycles of HV
ramp-up and return to HVLow. Cycles will ramp up to successively higher
(magnitude) voltage, with the fifth cycle going to the nominal operating
values. There will be a gap of at least 4 hours between cycles. All HV
ramp-up will be done at 10 sec per HV "step". The step rate and cycle
voltage values (for Segments A and B) must be patched in FSW in each
cycle prior to the HV ramp commanding. Memory monitors will be set on
the patched memory locations. Immediately after any HV commanding, and 4
hours after ramp-up commanding, the DCE memory will be dumped.
Immediately after HV ramp-up commanding higher than HVLow, short DARK &
WAVE exposures will be obtained. Visits 01 and 02, and all the
subsequent even numbered visits (the ones 4 hours after HV ramp-ups),
end with NSSC-1 COS event flag 3 being set. If the flag remains set,
subsequent FUV commanding will be skipped. Thus, Operations Requests
must be in place to clear the flag prior to those subsequent visits.
Real-time monitoring of the telemetry will be used to guide the
decisions whether or not to clear the flag. The final visit (13)
provides a scheduled final opportunity to clear flag 3, and if the flag
is cleared, initiates nominal FUV HV commanding and requests a DARK
exposure.
FLIGHT OPERATIONS SUMMARY:
Significant Spacecraft Anomalies: (The following are
preliminary reports
of potential non-nominal performance that will be investigated.)
HSTARS: (None)
COMPLETED OPS REQUEST:
18559-0 - Power off COS ion gauge @ 177/1306z
18566-1 - Post-VDT Gyro 345 Configuration & Gyro 6 Power Off @ 177/1753z
18563-1 - WFC3 UVIS Corrector Adjustment (Visit 1) @ 177/1757z
18565-1 - OBAD Maps for LBBIAS for Gyro 345 Reconfiguration @177/1928z
18567-0 - LBBIAS Uplink for post-345 gyro reconfiguration @ 177/2038z
18568-0 - LBBIAS Updates for Extended Gyro Guiding Intervals (Generic) @
177/2359z, 178/0130z, 178/2215z, 179/0440z, 180/0250z
18569-2 - WFC3 UVIS Corrector Adjustment (Visit 2) @ 179/0309z
COMPLETED
OPS NOTES: (None)
SCHEDULED SUCCESSFUL
FGS
GSAcq
13
13
FGS REAcq
03
03
OBAD with Maneuver
12
12
SIGNIFICANT EVENTS:
Flash Reports:
-At 177/1745z the gyro configuration was successfully changed from a 456
configuration, which was used to support the Vehicle Disturbance Test,
to a 345 configuration. Gyro 6 was subsequently powered off
at 177/1752z.
Subsequent pointing control system performance was nominal.
-COS ion
gauge was disabled at 177/1303z.