ACIS Instrument Support - Monthly Progress Report for May 2024

0.  Supported preparations for the Operation Paradigm Change Review

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 May 10.  This decision saved the ACIS focal plane from an accumulated fluence of nearly half the annual budget.

  ...  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).

  ...  Reviewed memo on the March 2024 radiation shutdown decision.

  ...  Provided comments and corrections for "Twenty-four Years of Radiation Protection of the Chandra X-ray Observatory", submitted to AIAA Technical Journal.

  ...  Working on proceedings paper and slides for upcoming SPIE Astronomical Telescopes + Instrumentation 2024 meeting on "The Advanced CCD Imaging Spectrometer on the Chandra X-ray Observatory: Twenty five years of on-orbit operation".

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 MAY0624A 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.  Swapped the image loader for a spare in an attempt to diagnose anomalous behavior. (In June swapped back to the original which solved the problem.)

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.

  ...  Continued development of diagnostic BEP/FEP memory dump procedures.  Testing of FEP memory dump commands in realistic conditions on the EU has revealed differences from the flight.  Investigating EU hardware by switching to a spare Image Loader.

  ...  We continue to monitor threshold crossing rates which have recently flattened out. The current set of TXing parameters were uploaded on May 7, 2023 in the MAY0624A load via a SAR to further lower the FI threshold trigger levels.

2.3 Instrument science performance

  ...  Participated in monthly ACIS operations meeting.  Discussed focal plane temperature during perigee, new ACIS focal plane temperature limits, continuing work on memory dumps, and an upcoming change to the MUPS temperature limit.

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

  ...  Replaced a malfunctioning RAID system supporting the ACIS team web interface.

  ...  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.

3.2 Provide data analysis support

  ...  Participated in CXC Cal/Ops response discussion group.  Discussed big dither contamination results, RMFs at warm FP temperatures, and the upcoming IACHEC meeting.

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

  ...  Attended IACHEC meeting in May in Spain as a representative of the ACIS team and as part of the organizing team.

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

  ...  Reviewed JUN0324A command load; JUN0324 final OR list; JUN0324 preliminary schedule; and JUN1724 LTS OR list.
 
  ...  Checking on automated processes associated with SACGS.