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Дата изменения: Wed Oct 24 00:24:50 2007
Дата индексирования: Sat Mar 1 23:04:26 2014
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HST MOSES
July 30, 2003

CHAMP/MOSES SM4 SMOV Requirements
PCS TCS ASCS DMS

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HST MOSES

PCS L.10.4.8

J Wirzburger July 30, 2003

L.10.4.8 Pointing Control Subsystem Verification Requirements: PCS
L.10.4.8.1 Following release, the HST Pointing Control System will be returned to normal operations for SMOV with four gyros in the active control loop, (no shadow mode). A fine attitude reference will be uplinked to the spacecraft and the spacecraft will be maneuvered to point to the BEA attitude. The gyro biases will be determined and maintained to within 0.014 arc-seconds per second to allow successful guide star acquisition at the transition to the Science SMS. L.10.4.8.2 If any gyros are changed out, the gyro to FHST calibration shall be updated to an accuracy that reduces the attitude error following a vehicle maneuver to one arc-second per degree of slew or less. This calibration will be performed immediately after the end of the BEA period. Until then, history has shown slew miss-distances of about eight arc-seconds per degree of slew. L.10.4.8.3 The PCS shall acquire guide stars in fine lock.

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HST MOSES

PCS L.10.4.8

J Wirzburger July 30, 2003

Instrument or Subsystem : PCS (cont)
L.10.4.8.4 Once guide star acquisitions have begun, 2-FGS acquisitions will be scheduled such that the HST486 on-board gyro bias update algorithm will maintain the gyro drift rate bias to within 0.005 arc-seconds per second. L.10.4.8.5 The vehicle jitter during periods of gyro hold shall be measured. L.10.4.8.6 Perform a Vehicle Disturbance Test (VDT) to characterize HST line-ofsight jitter, structural dynamic responses, and disturbance sources. The VDT is a passive test (not a forced response test) using a low-bandwidth attitude control law during gyro-hold with the rate gyros in low mode. Obtain gyro -measured disturbance time responses due to SA-3, HGAs, RWAs, SSM thermal gradients, and COS and WFC3 mechanism articulation. The VDT shall consist of three separate tests that need not occur consecutively. The overall duration of the VDT is at least 12 orbits of spacecraft time including (1) at le ast 2 orbits at +V3 sunpoint while performing COS and WFC3 filter wheel articulation simulat ing routine flight operations, (2) at least 5 orbits at +V3 sunpoint after achieving thermal equilibrium (at least 36-hours at +V3 sunpoint), and (3) at least 5 orbits at V1 sunpoint.

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HST MOSES

PCS L.10.4.8

J Wirzburger July 30, 2003

Instrument or Subsystem : PCS (cont)
L.10.4.8.7 All gyros will be left in a powered on state through the gyro to FHST alignment calibration, if it is to be performed. Following the completion of the gyro to FHST alignment calibration, the two gyros not in the active control loop will be configured off. Following the VDT or the gyro to FHST calibration, which ever occurs last, one of the four gyros will be removed from the control loop and powered off. L.10.4.8.8 The maximum FHST Update attitude correction thresho ld will be managed to aid in attitude maintenance until the slew miss-distances and gyro biases are reduced to a sufficient level to permit successful FGS acquisitions. The threshold will be increased from the nominal 300 arc-seconds up to 760 arcseconds per axis if large attitude errors are anticipated prior to FGS acquisitions.

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HST MOSES

DMS L.10.4.9

S. Sands July 30, 2003

L.10.4.9 Data Management Subsystem Verification Requirements - DMS

L.10.4.9.1 The DMU-to-SI C&DH Cross-Strap (DSC) shall provide nominal spacecraft operations in the Aa cross-strap configuration "A" side DMU module to "a" side CU/SDF.

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HST MOSES

TCS L.10.4.13

C. Cottingham July 30, 2003

L.10.4.13 Thermal Control Subsystem Verification Requirements - TCS
L.10.4.13.1 Verify predicted temperature changes due to NOBL installation on SSM Bays 5, 7 and 8. Bay 7 components are predicted to drop 3-4 °C with the installation of NOBLs. Bay 8 components are predicted to drop 2°C with the installation of NOBLs. Bay 5 components are predicted to drop 8-10°C (TBD) with the installation of NOBLs and removal of external MLI.

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HST MOSES

ASCS L.10.4.15.

C. Cottingham July 30, 2003

L.10.4.15 Aft Shroud Cooling Subsystem Verification Requirements - ASCS
L.10.4.15.1 Verify the ASCS ACS CPL shall be able to maintain the ACS Interface Plate temperature at -2 °C (+/- 0.5 over 98 minutes) when ACS is in WFHROper or WFMAHVon. L.10.4.15.2 Verify the ASCS COS CPL shall be able to maintain the COS I/F plate temperature at 10°C (+/ - 0.5 over 98 minutes) when COS CS is in Operate mode, the NUV Low Voltage is enabled and the FUV is in Boot mode or above. L.10.4.15.3 Verify the ASCS STIS/STIK CPL shall be able to maintain the STIS/STIK evaporator at -11°C (+/- 0.5 over 98 minutes)with the CS in Operate, the TECs set to 3 amps and both Band 1 and Band 2 MAMA LVPSs are enabled.

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