ACIS Instrument Support - Monthly Progress Report for January 2024

1.  ACIS Characterization

1.3 Monitor scientific on-orbit performance of ACIS

  ...  Due to high radiation environment, the ACIS team recommended a shutdown of science observing on January 22.  Shutdown resulted in approximately 70 ksec of down time, but kept the CCDs below the orbital fluence budget.  Without a shutdown, ACIS would have received more than double the budget.  Science instrument safing was nominal.

  ...  Following Chandra safing action on January 24 due to Normal Sun Mode transition, verified ACIS was safe, and supported recovery.  Science instrument safing was nominal.  Wrote and ran CAP 1730 to collect ECS data during recovery.  The 69 ksec at a focal plane temperature of -105C should be very helpful at anchoring the warm temperature gain calibration.

  ...  Continued monitoring of ACIS CTI, gain, trailing pixel pulseheight, detector efficiency, corner pixel distribution, spectral line centroid and width, and focal plane temperature. Updated monitoring web pages.  (http://space.mit.edu/~cgrant/monitor.html).


2.  Engineering

2.1 Instrument hardware engineering performance

  ...  Continue to monitor long term ACIS instrument performance.  Engineering trending over the past 60 days is nominal.

  ...  The EEPROM checksum was verified in the JAN0824A loads. Will continue to run monthly.  MIT telemetry processing will automatically check the results and send out an alert if the checksum is unexpected.

  ...  Continued weekly physical audit of the ACIS Engineering Unit lab.  All nominal in January.

2.2 Flight software maintenance

  ...  ACIS flight software patch H-J-K uploaded on September 19, 2023.  First new patch set since August 2022.  No issues to date.

  ...  Working on procedures to be used in the event of a BEP anomaly to dump various parts of BEP memory.  Some standard commands and CLD files exist.  Created a web page listing their relevant information to assist with assembling a diagnostic CAP.  Working on a "boot-by-uplink" procedure which would better preserve memory before the dump.  Released a report describing what boot-by-uplink would entail (https://acisweb.mit.edu/pub/bepuplinkdump-v1.0.pdf)

  ...  Began testing acis-gdb debugger for the ACIS QEMU flight software emulator

  ...  We continue to monitor threshold crossing rates which have recently flatten out. The current set of TXing parameters were uploaded on October 11, 2023.

2.3 Instrument science performance

  ...  Analyzed anomaly in ObsID 26826 bias map reported by CXCDS.  Confirmed the problem was localized to one CCD/FEP and one observation.  This was a particularly extreme version of of a known problem -- large blooms from cosmic rays saturating the A/D, causing the following pixels to have anomalously low values, which then pollute the bias calculation.

  ...  Participated in monthly ACIS operations meeting.  Discussed radiation environment, BEP anomaly response plans, and the new NIL SI mode.

  ...  Participated in SOT radiation working group.  Discussed recent radiation shutdown, mission fluence management, a machine learning project for solar storm prediction, and techincal approval for use of STK AE8/AP8 in orbit event generation.

  ...  Continued daily quick-look processing of ACIS telemetry and maintained web interface to ACIS real-time data.  

  ...  Continued to publish the "annotated DOT" timeline reports.


3.  CXC Support

3.1 Provide user support

  ...  ACIS memo listing calibration ObsIDs and observation characteristics (ACIS Memo #165) will no longer be updated.  Functionality is replaced by web page (http://acisweb.mit.edu/asc/evt-page.html), which provides the same information but is more automated.

  ...  Provided technical reviews of Chandra Legacy white papers.

3.2 Provide data analysis support

  ...  Participated in CXC Cal/Ops response discussion group.  Discussed tgain updates, Cas A at -105C, contamination measurements, improving CTI correction calibration, and warm focal plane RMFs.

  ...  Continued to maintain ACIS calibration database of ground and flight data products.


4.  OCC Support

4.1 Use of MIT/ACIS EGSE at OCC

  ...  Continued support and maintenance of ACIS EGSE software and hardware at the Wayside OCC.  Restarted both EGSE machines routinely.

4.2 Generation of commands for ACIS observations

  ...  Continued to work with USINT on remaining problematic ACIS configurations in cycle 25.  New joint XMM-CXO proposal ingested which needs ACIS configuration work.

...  Reviewed JAN2324B, JAN2624A, JAN2924A command loads; JAN2924, JAN2624 final OR lists; JAN2924 preliminary schedule; and FEB1224, FEB0524 LRS OR lists.

  ...  Checking on automated processes associated with SACGS.