ACIS Instrument Support - Monthly Progress Report for November 2024


1.  ACIS Characterization

1.3 Monitor scientific on-orbit performance of ACIS

  ...  The ACIS TXing radiation monitor triggerred a shutdown of science observing once on November 21 in response to elevated particle rates.  The shutdown was nominal.

  ...  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).

  ...  Analyzed new raw mode data frames and posted to https://space.mit.edu/home/fergason/acis/raw.html and https://space.mit.edu/home/fergason/acis/rawStats.html

  ...  Prepared a poster on ACIS status for the Twenty-five years of Chandra symposium in December.

  ...  Starting to plan for web service changes at MKI which will displace all the MKI ACIS web pages.

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 NOV0424A 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.  Weekly audits were nominal. 

2.2 Flight software maintenance

  ...  ACIS flight software patch H-J-K uploaded on September 19, 2023.  First new patch set since August 2022.

  ...  The TXing trigger during the Crab observation was due to a previously unknown bug in the exposure time calculation in a very small subset of observations. TXings Rev B does not include framestore dwell time in the exposure time calculation.  For >99% of observations, the framestore time is proportional to the image array time, so it doesn't matter.  For the few observations in which frametime is set to values different from the most efficient value, the Rev B calculation is under-estimating the actual exposure time to particles and artificially elevating the TXing rate.  An update to the FSW to correct this bug is under development as TXings Rev C.  Draft report on ACIS framestore exposure times in work.

  ...  We continue to monitor threshold crossing rates.  The current set of TXing parameters were uploaded on Oct 20, 2024.

2.3 Instrument science performance

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

  ...  Reconfigured MIT ACIS monitoring during Nov 23 work at CDP.

  ...  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.

4.2 Generation of commands for ACIS observations

   ...  Working with USINT to finish cycle 26 ACIS configurations.

  ...  Built, tested, and installed a new SI mode for a GO observation of Cas A.

  ...  Responded to question from the FOT about guidelines for telemetry loss during ACIS bias map transmision.  ACIS requirements have not changed.

  ...  Participated in discussion with Mission Planning Constraints WG on skipping preliminary schedule reviews for fast "pickup" replans.

  ...  Reviewed DEC1624 LTS OR list; DEC0224 preliminary schedule; DEC0224 final OR list; and DEC0224A weekly load.
 
  ...  Checking on automated processes associated with SACGS.