During the past week the recovery from the Mar 3 Safe Mode completed and Chandra resumed observing. Real-time procedures were executed on Mar 4 to transition to attitude control by pointing at stars, update the spacecraft attitude and maneuver to a cooling attitude to prepare for observing and to warm-boot ACIS to clear a process that didn't stop as expected during the Safe Mode transition. A new mission schedule and loads were approved and began operating at 11:28pm EST on Mar 4. This anomaly resulted in 79.5ks of science loss. Scheduled observations that were impacted by the Safe Mode will be rescheduled.

At 1:29pm EST on Mar 5 the Chandra observatory telescope health check temperature monitor ran SCS-26 to swap telescope thermal control to the B-side equipment in response to elevated temperatures measured by the HRMA_AVE health check. A review of SSR date showed that no hardware issues contributed to the SCS-26 run. The elevated temperatures that led to the SCS-26 execution were a result of heat trapped in the HRMA region due to the Safe Mode that had not fully dissipated before moving to a forward sun attitude to accommodate a time-critical target in the observing schedule. The dwell at this forward sun attitude significantly slowed the heat dissipation, allowing elevated surrounding temperatures to continue to drive the HRMA_AVE calculated temperature higher at a slow rate. The HRMA_AVE temperature peaked at 71.56F, approximately 0.02F above the trip threshold of 71.54F. Subsequent scheduled attitudes allowed the telescope components to cool below the threshold. A real-time procedure was executed on Mar 6 to swap the telescope thermal control hardware back to the A-side.

The recovery schedule was replanned to incorporate observations of M87, which were accepted as a Director's Discretionary Time Target of Opportunity on Mar 9. Loads for the replanned schedule were uplinked on Mar 11. Scheduled observations that were impacted by the replan will be rescheduled in future weeks.

A Chandra image release was issued on Mar 10 describing observations of two galaxy clusters, MACS J0416.1-2403 and MACS J0717.5+3745, that are part of the "Frontier Fields" project, which obtains long observations with multiple telescopes. Galaxy clusters are important because they are the largest structures in the Universe held together by gravity. Both of these objects are sites where multiple galaxy clusters are colliding. X-rays from Chandra reveal the massive amounts of hot gas that pervade each galaxy cluster. For details see: http://chandra.si.edu/photo/2016/frontier/

The schedule of targets for the M87 DDT-TOO replan and for the next week is shown below and includes an observation of SMC X-1, which was accepted as a Target of Opportunity on Jan 26.