Operations CXO Status Report

Friday 2 May 2003 9.00am EDT

During the last week the observing schedule was replanned to include an observation of the galactic black hole H1743-322 that was accepted as a Target Of Opportunity (TOO) on 25 April. The observing schedule was interrupted a second time at 7:36pm on 30 April due to a high radiation event that activated the science instrument safing sequence (SCS 107). The high radiation is thought to be associated with the currently active coronal stream as Chandra approached the radiation belts, as was the case on April 17. The loads were restarted at 5:15pm on May 1 and included the TOO. Observations of 3C296, B3 1659+399 and HD 163296 were impacted by these events (total 53Ks science time) and will be rescheduled in a later load. The IRU-1 gyro-1 current remained at ~150mA (its yellow limit) with continued noisy behavior. Real-time procedures were completed on 29 April to re-enable dither and re-enable SCS 29 and on May 1 to re-enable SCS 107 and disable the Momentum Unload subfunction. The April 29 actions were corrective and procedures will be assessed and adjusted accordingly. The observing schedule for next week is shown below and includes an additional pad-time prior to radiation belt entry to mitigate the present elevated radiation conditions.

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RCW103                 ACIS-I       May 4
SDSS J222845-075755    ACIS-S
DOAR 21                ACIS-S/HETG  May 5
Radiation Belts                     May 6
PDS 456                ACIS-S/HETG
SCO X-1                ACIS-S/HETG  May 8
Radiation Belts
MXB 1659-298           ACIS-S       May 9
G11.2-0.3              ACIS-S
MRK 279                HRC-S/LETG   May 10
HD110073               ACIS-I
NGC 1800               ACIS-S

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All spacecraft subsystems, with the exception of the MUPS thruster A-1 under investigation, continued to operate nominally.

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