Friday 26 January 2024 9.00am EST
During the last week the observing schedule was interrupted due to high radiation associated with solar activity. The loads were halted at 2:50pm EST on Jan 22 through a ground command to execute the SI Safing SCS 107. This prevented further exposure to damaging radiation for the ACIS instrument detectors. All spacecraft actions were nominal. Loads for a replanned schedule were uplinked on Jan 23. Planned observations that were impacted by the interruption and will be rescheduled. Chandra entered Normal Sun Mode (NSM) at 4:44am EST on Jan 24 as the result of failing to acquire at least two stars at the end of a maneuver. This was due to the confluence of a sparse star field at the science target attitude and chance occurrence of known issue with the Aspect Camera Assembly software that caused the loss of two acquisition stars. Entry into NSM was nominal and assessment of the telemetry indicated that all spacecraft hardware was performing nominally. The recovery operations took place over Jan 24-25. Loads for a replanned schedule were uplinked on Jan 26 and science observations are scheduled to resume on Jan 26 at 4:36pm EST. Scheduled observations that were impacted by the anomaly and replan will be rescheduled in future weeks. Science loss times will be provided in a future update. A real-time procedure was executed on Jan 25 to initiate a long ACIS CTI data collection while waiting to return to observing. Chandra passed through the 6th and 7th eclipses of the season on Jan 22 and 25 respectively, with nominal power and thermal performance. The schedule of targets for the next week, with a planned start of Jan 29, is still in work. |
All spacecraft subsystems continued to support nominal operations.
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