HUBBLE SPACE TELESCOPE - Continuing to collect World Class Science

DAILY REPORT      # 4538

PERIOD COVERED: UT January 31, 2008 (DOY 031)

OBSERVATIONS SCHEDULED

FGS 11078

HST/FGS 1-Gyro On-Orbit Checkout

This proposal uses an FGS as an astrometer to observe bright stars

(V<12) in Position mode, with the two other FGSs operating as guiders.

The data obtained by the astrometer will be used to "witness" the

pointing performance of the Observatory in FineLock under 1-gyro

operations. Each visit of this proposal will have a single Pos mode

exposure, the duration of which is to be set by target visibility or by

other tests being conducted in parallel or in sequence with this

proposal. For planning purposes this proposal specifies an exposure time

of 40 minutes, but this can be adjusted as needed.

S/C 11345

HST/PCS 1-Gyro On-orbit Checkout

This proposal contains the part of the on-orbit test that cannot be

satisfied by the science proposals. This includes testing certain M1G,

T1G and F1G capabilities that could potentially compromise any science

data collection, but are needed to validate the robustness of 1-gyro

science mode.

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:

18191-2 - TMDIAG for CSS/MSS Rate

18194-0 - TMDIAG for CSS/MSS Rate

18193-1 - Execute S/M Recovery SPC Load to Clear SA Position Test

18192-1 - Power On SADE 2: OGS On-Orbit Test

18195-0 - Re-instate TMDIAGs @ 031/22:22z

18196-0 - Reconfigure MAT RF Switches at end of KFSP LGA Operations

18187-0 - Uplink N02Z1100g and set ATP pointer after completion of OGS/KFSP OOT

18197-0 - OBADs for post-OGS OOT LBBIAS

18198-0 - OBADs for post-OGS OOT LBBIAS

18199-0 - Update the Gyro Drift Rate Bias for post-OGS OOT operations

COMPLETED OPS NOTES: (None)

                       SCHEDULED      SUCCESSFUL 

FGS GSacq               02                  02                  

FGS REacq                0                   0                   

OBAD with Maneuver 07                  07

SIGNIFICANT EVENTS:

Flash Report - Day 3 One Gyro Science (OGS)/Kalman Filter Sun Point

(KFSP) OOT

The OGS portion of the OGS/KFSP OOT concluded successfully at 031/11:45.

All test objectives were met and UKF and control performance was nominal

throughout. All FGS guide star acquisitions succeeded and fine guidance

continued until terminated nominally. All OBAD corrections for which

data is currently available succeeded, with a maximum OBAD attitude

correction maneuver of 2.44 degrees. The T1G PRT slews and other

activities conducted by ground command also succeeded nominally.

Preliminary mean jitter estimates during F1G fine lock periods are

within 7 masecs RMS and were as predicted.

The KFSP mode was entered at 031/12:42 with a nominal -V1 sunline

capture from the initial 15 degree offset attitude. Once the sun-line

was captured at -V1, the RWA bias started to build and was fully

established within 45 minutes. All KFSP OOT testing was successful. All

of the test steps executed as planned and the KFSP performance met all

requirements. The 45 degree offset captures in -V1 and +V3 and the KFSP

Bypass -V1 and +V3 Captures were successful with minimal overshoots. The

slews to the sun-line appeared to be pure eigenvector maneuvers and

there were no noticeable rates about the sun-line after capture.

Recovery from KFSP to M1G began at 031.23:57. The OOT will complete

tonight with SMS commanding beginning at 32/06:00. Science will resume

at 32/07:30.