During the last week, following observation of higher than predicted HRC Central Electronics Assembly (CEA) temperatures and the application of an improved HRC thermal model to upcoming observations, it was concluded that future HRC observations were at risk of causing the CEA temperature to exceed its 12 C limit. On Dec 8 at 8:59pm EST, a real time procedure was executed to prevent subsequent HRC observations in the weekly loads from running. The procedure completed nominally and disabled SCSs 92, 93, and 134. There were no remaining HRC observations in the scheduling week beginning on Dec 4. The eight scheduled HRC observations in the approved loads beginning Dec 11 can no longer execute and result in science idle time. They will be rescheduled at a later date. ACIS observations are continuing as scheduled.

Another real time procedure was executed on Dec 8 to uplink a patch to reduce the charge current minimum limit to account for expected aging of solar arrays.

Real-time procedures were executed on Dec 9-11 to dump OBC-A and -B memory as a follow-up to the flight software patch on Dec 8. The dump will be used to update the baseline memory images maintained on the ground.

Of note this week was the release on Dec 14 of the Cycle 26 Call for Proposals. The proposal submission deadline is 14 March 2024. In conjunction with the call was the release on Dec 12 of the CIAO ("Chandra Interactive Analysis of Observations") version 4.16 analysis software system, Chandra CalDB ("Calibration Database") version 4.11, SAOImage DS9 (the astronomical imaging and data visualization application) version 8.5, and MARX (the Chandra on-orbit performance simulator) version 5.5.3. For details see: https://cxc.cfa.harvard.edu/proposer
https://cxc.cfa.harvard.edu/ciao/download
https://ds9.si.edu/site/Download.html and
https://space.mit.edu/CXC/MARX

The schedule of targets for the next week is shown below and includes observations of OrionNebulaCluster coordinated with the VLBA.