ACIS Instrument Support - Monthly Progress Report for May 2021

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).

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


2.  Engineering

2.1 Instrument hardware engineering performance

  ...  Continue to monitor long term ACIS instrument performance.  Engineering trending over the past 60 days indicate a stable environment.

  ...  The EEPROM checksum was verified in the MAY1021A load.   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.  Supported EU power-off/on during building electrical work.

2.2 Flight software maintenance

  ...  ACIS flight software patch G-H-I (improved buscrash and new deahktrip) uploaded on January 24, 2020.  First new patch set since June 2014.  No issues to date.

  ...  We continue to monitor threshold crossing rates.  The current TXINGS parameters were last updated on July 28, 2016.  Threshold crossing rates have flattened out and started decreasing, indicating the end of solar minimum. We anticipate needing to lower the trigger threshold in the next year as rates continue to drop and activity increases.

  ...  Continued work on QEMU ACIS emulator development .Augmented QEMU/Backend Processor manual page to describe canned fixed passive analog telemetry points. Started QEMU/Frontend Processor manual page.  Revised QEMU BEP/FEP shared-memory implementation to support direct execution under Mac OS X 11.4 (Intel/Big Sur)
 
  ...  Continued team review of ACIS Flight Software User's Guide, newly updated in May 2021.  Reviewed sections on event grade codes, starting and stopping a science run, and jitter DACs.
  
2.3 Instrument science performance

  ...  Participated in monthly ACIS operations meetings.  Discussed thermal issues associated with upcoming low perigee in 2023, plans for a SAR with new power commands to better test thermal coupling between the FEPs, and the SCS106 patch.

  ...  Participated in a review of past radiation events and the Chandra response to better prepare for the upcoming solar maximum.

  ...  Reviewed proposed changes to SCS-106, the command sequence that safes ACIS.  Power command will be switched from WSPOW00000, which powers down all video boards and FEPs, to WSPOW0002A, which powers down all video boards but leaves FEPs 1,3,5 on.  Answered questions about delays between commands.

  ...  Investigated complaint of large data gap in DEA housekeeping in the Ska cheta telemetry archive.  MIT processing showed no substantial gaps, and the problem was tracked to the CXCDS pipeline.

  ...  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 new web page (http://acis.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 ACIS response discussion group.  Discussed PCA method for fitting ECS and Cas A data to calibration time dependent gain and status of cold ECS observations during the science orbit.

  ...  Assisted V&V investigation into dropped frames from telemetry saturation in observation of bright source.  Confirmed source rates were substantially higher than the telemetry limits and ACIS data was as expected.

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

  ...  Served as technical host for IACHEC virtual working group talks.  Presented for the Detectors and Background Working Group.


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.  Checked and restarted both EGSE multiple times during Wayside firewall work.

4.2 Generation of commands for ACIS observations

  ...  Reviewed high count rate Chandra cycle 23 proposals for potential health and safety issues

  ...  Reviewed HST/Chandra joint proposals for health and safety issues

  ...  Submitted test plan for ACIS testing of CXCDS 10.10, including SACGS, load review scripts, and the MIT processing pipeline.  Started testing.

  ...  Built and tested one new power command to support testing of thermal models in the low temperature regime.  The command powers on S3 only, but also FEPs 1, 3, and 5, and will be used during an otherwise standard S3 only science observation at cold pitch.

  ...  Fixed minor typo in new ECS SI mode, installed in the ACIS tables at the OCC.

  ...  Reviewed MAY0521A and MAY1021A command loads, MAY0521 and MAY1021 final OR lists, MAY0521 and MAY1021 preliminary schedules, and MAY2421 LTS OR list.

  ...  Dropped chips from 23 ObsIDs

  ...  Checking on automated processes associated with SACGS.