ACIS Instrument Support - Monthly Progress Report for August 2025


1.  ACIS Characterization

1.3 Monitor scientific on-orbit performance of ACIS

  ...  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 AUG0425B 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. The EU room had a temperature excursion August 16-19. The temperature was monitored but remained below the level requiring a hardware shutdown. The temperature returned to nominal after building HVAC repairs. All other weekly audits were nominal. 

2.2 Flight software maintenance

  ...  ACIS flight software patch H-K-L uploaded on August 15, 2025. First new patch set since September 2023.

  ...  ACIS flight software patch HKL was successfully uplinked on August 15.  ACIS FSW  has been performing nominally since that time.  Preparation for the uplink included CAP reviews, sharing notes on patch verification process, restarting the MIT EGSE at Wayside, and setting the ACIS science monitor PMON to send out alerts for v=61 instead of v=60.
  
   ...  We continue to monitor threshold crossing rates.  The current set of TXing parameters were uploaded on Aug 15, 2025.  New commands were required for TXings revC but the rate limits are nearly the same as used previously, uploaded on Oct 20, 2024.

  ...  Planned for the migration of acis.mit.edu services, the last ACIS Solaris machine, to Linux hardware.  Started a light feasibility study to extend the original ACIS documentation tools beyond hardware retirement, examining the use of QEMU to support the version of Framemaker used by ACIS during development.

2.3 Instrument science performance

  ...  Participated in monthly ACIS operations meetings. Reviewed status after FSW patch uplink and any lessons learned.

  ...  Continued daily quick-look processing of ACIS telemetry and maintained web interface to ACIS real-time data. Updated TXings plot generation software to distinguish revision levels.

  ...  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

  ...  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.  Generated and loaded reference TXings revC parameter dumps for comparison during the flight software patch uplink.

4.2 Generation of commands for ACIS observations

  ...  Assigned SI modes for most of cycle 27 (328 ObsIDs). Checked all chip drop configurations for existing SI modes.  Started work with USINT to verify or update parameters for the remaining problematic configurations.

  ...  Worked with FOT on wording about TXings in the radiation zone guideline.

  ...  Checking on automated processes associated with SACGS.