HUBBLE SPACE TELESCOPE - Continuing to collect World Class Science



DAILY REPORT #4852



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



OBSERVATIONS SCHEDULED



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





FLIGHT OPERATIONS SUMMARY:



Significant Spacecraft Anomalies: (The following are preliminary reports

of potential non-nominal performance that will be investigated.)



HSTARS:

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





COMPLETED OPS REQUEST:

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 @ 144/01:34z

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





COMPLETED OPS NOTES: (None)



SCHEDULED SUCCESSFUL

FGS GSAcq 19 19

FGS REAcq 00 00

OBAD with Maneuver 22 22





SIGNIFICANT EVENTS:



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 3.5x10-6 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.