Status Report

NASA Hubble Space Telescope Daily Report #4852

By SpaceRef Editor
May 26, 2009
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HUBBLE SPACE TELESCOPE – Continuing to collect World Class Science


PERIOD COVERED: 5am May 22 – 5am May 26, 2009 (DOY 142/0900z-146/0900z)


S/C/FGS 11457
Verify Guide Star Acquisition with Continuing FGSs

After the shuttle deploys HST at the end of SM4 and at the beginning
of SMOV4, it will be necessary to test and demonstrate HST’s ability
to acquire guide stars with the FGSs. This is a major pre-requisite
for all observations by HST’s SIs when precision pointing under guide
star control is needed. This proposal will test the ability of each of
the unreplaced FGSs to acquire a primary guide star while another FGS
acquires a secondary guide star. After acquiring the guide star pair,
HST will track these stars in finelock for approximately 10 minutes.
When possible, use guide stars that have been successfully acquired
and tracked in the past.

S/C/ACS 11365
Load and Dump Onboard Memory

This proposal is a test and verification of the ACS dump of memory
capability. Areas of Control Section (CS) to dump include: EDAC RAM,
EEPROM, and CS PROM (with the CS in Operate). Areas of MIE memory to
dump include: MIE RAM and MIE PROM (with the MIE in Operate). Note
that the MIE memory must first be copied to CS buffer RAM as images,
which are then dumped.

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.

S/C/COS 11353
COS Dump Test and Verification of COS Memory Loads

This proposal is a test and verification of the COS dump of memory
capability. Areas of Control Section (CS) to dump include: EXEC RAM,
EEPROM, and CS PROM (with the CS in Operate). Areas of DIB memory to
dump include: DIB RAM and DIB PROM (with the DIB in Operate). Areas of
DCE memory to dump include: the DCE code image. Note that the DIB and
DCE memory must first be copied to CS buffer RAM as images, which are
then dumped. Supports Activity COS-02


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


11845 – During FGS-2 ITS test at 142/11:48 – Trans mode failed with no
S-curve detected in y-axis. FGS-2 did achieve Fine Lock and LOS scan
was also successful.

11847 – WFC3 safed on IMEB1ST @ 145/13:02z


18436-2 – Open COS FUV DVA door @ 142/15:26z
18441-0 – VDT Macro Installation – IP-170 @ 143:10:50z
18442-0 – Execute Vehicle Disturbance Test – IP-170 Section B and C @
18451 0 – Recover WFC3 to Boot @ 145/13:50z
18444-1 – Reset WFC3 setpoints after recovery @ 145/14:04z
18452-4 – Recover WFC3 from Boot to Operate @ 145/16:16z
18448-0 – ACS CEB-R ASIC FSW Timing Pattern Update @ 146/16:22z
18446-1 – Clear ACS WFC TEC Event Flag 8 @ 145/17:22z



FGS GSAcq 19 19
FGS REAcq 00 00
OBAD with Maneuver 22 22


Flash Reports:

-COS successfully transition to operate at ~ 142/10:32. The FUV DCE
successfully transition to operate at 142/10:52. No limit violation
observed and the instrument is performing nominally.
COS internal pressure is currently at 3.5×10-6 torr, we are on
schedule for opening the FUV DVA door at 11:00am EST Friday morning.

-The COS and ACS memory that was collected was dumped from the SSR at
142/13:40z, these dumps were analyzed and report to be as expected.

-The COS FUV door was successfully opened at 142/15:22. All power and
position telemetry was as expected. A small increase in pressure was
measured by the COS internal and ESM ion gauges.

-VDT data collection successful. The Vehicle Disturbance Test at the
+V3 sunpoint attitude was successfully completed at 2009/144/01:34
with the nominal gains restored to the vehicle control law. An LBBIAS
was uplinked to the vehicle to ensure minimal bias errors at the
following Guide Star Acquisition. That subsequent acquisition at
144/03:45 succeeded.

-At 145/1100 WFC3 recovery from Protect Safe mode began via stored
commanding. At 145/1302 during the transition to Protect Operate, the
instrument safed as a result of a limit check violation of an
SES-collected thermistor on the unpowered MEB.

-WFC3 was recovered to Protect Operate. At 145/1631 WFC3 successfully
intercepted the SMS timeline to dump EEPROM, Exec RAM, and PROM
memory. SSR playback is currently in progress and the memory dumps
will be analyzed by the Payload FSW team.

-WFC3 EEPROM, Exec RAM, and PROM memory dumps were collected via SMS
starting at 145/1631. The SSR playback of these dumps began at
145/1651. The Payload FSW team has verified the contents of the memory
dumps are as expected.

WFC3 remains in Protect Operate.

-The FSW team completed the COS analysis of the zero-filled pattern
loaded to and dumped from CS Buffer memory at 145/1700. In summary, no
bit flips in CS Buffer memory were observed.

SpaceRef staff editor.