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Friday 6 April 2001 6.30pm EST
Last week the observing schedule was interrupted following a high radiation event at 10:22pm EDT on Apr 2 that stopped the daily load and activated the science instrument safing sequence (SCS 107). The radiation event followed the largest solar flare in 25 years.
All actions were nominal and assessment of the dump data confirmed that the trigger was due to high proton counts in the EPHIN E1300 channel exceeding the pre-defined threshold of 10 counts/cm^2/s/sr. The solar levels subsided to an acceptable level over the next 72 hours and the loads were replanned (3 times) and resumed at 1.17am EDT on 6 Apr. The observations of 1928+738, 1641+399, the XMM 13 hr Survey Field and V-1121+2327 were impacted and will be rescheduled in a future load. The load was resumed in time for a coordinated observation of the Crab Nebula with the Hubble Space Telescope. A real-time procedure was completed on Apr 6 to insert the LETG grating. Telemetry indicated a nominal insertion, and the retraction is scheduled for Apr 7. The planned observations for the coming week are shown below and include an observation of NGC 3516 with XMM, RXTE, and BeppoSAX, and an observation of Mkn 509 with the Hubble Space Telescope. |
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ISO NW #2 ACIS-I Apr 8 NGC 3516 ACIS-S/HETG Radiation Belts Apr 9 NGC 3516 ACIS-S/HETG Apr 10 Radiation Belts Apr 12 Mkn 509 ACIS-S/HETG Apr 13 EXO 0748-676 ACIS-S/HETG A3558 ACIS-S Apr 14 NGC 5018 ACIS-S TWA-5 ACIS-S Apr 15 Radiation Belts
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All spacecraft subsystems continued to operate nominally.
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