ACIS Instrument Support - Monthly Progress Report for February 2024

1.  ACIS Characterization

1.3 Monitor scientific on-orbit performance of ACIS

  ...  Due to high radiation environment, the HRC team recommended a shutdown of science observing on Feb 9.  Shutdown was nominal.  Supported the radiation environment discussions pre- and post-shutdown, and return to science efforts.

  ...  Following Chandra safing action on Feb 3 due to Normal Sun Mode transition, verified ACIS was safe, and supported recovery.  Science instrument safing was nominal.  Wrote and ran CAP 1733 to collect ECS data during recovery.  The 85 ksec at a focal plane temperature of -105C, along with the 69 ksec a few weeks ago, 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).

  ...  Submitted a SAR (special activity request) for new raw mode runs.   Completed at end of February.

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

  ...  Working to update monitoring pipeline to accept ECS data in Very Faint mode, like the recent long ECS observations.


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 FEB0724A 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 February.

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.  Two new memory dump commands added to the ACIS tables which dump the BEP Control and Actel Registers and the BEP Mongoose Registers.  Updated report on boot-via-uplink memory dumps.  (http://acisweb.mit.edu/pub/bepuplinkdump-v1.1.pdf)  Working on changes to existing DEA_FEP_DIAGS procedure to avoid FEP firmware latch-ups.

  ...  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

  ...  Monitored new 2-CCD eventless mode to report TXings rates during HRC runs in format 1.  Worked as planned with no telemetered event data, only exposure records, including threshold crossing rates, and no telemetry saturation.

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

  ...  Notified GOT of mislabelled SSR dump file.

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


3.  CXC Support

3.1 Provide user support

  ...  Answered user question on ACIS gain calibration for bright exteneded sources where sacrificial charge may be important.

  ...  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 recent long warm ECS observations, tgain updates, Cas A at -105C, contamination measurements, improving CTI correction calibration, and warm focal plane RMFs.

  ...  Discussed with Calibration scientists how best to justify long ECS datasets during Chandra shutdowns, as requested by a Flight Director.

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

  ... Participated in planning telecon for upcoming IACHEC meeting in May. 


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.

  ...  After reports of a loud grinding sound from one of two MIT EGSE, directed ACIS on-duty person to shut it down.  Investigation confirmed the noise was coming from a fan, not from a disk problem.  Reseating the fan and computer box quieted the noise.  Machine was returned to service.  A new fan has been ordered and will be installed in March.

4.2 Generation of commands for ACIS observations

  ...  Supported discussion of quick-turn-around load reviews, in particular, procedure for dropping chips in the absence of a preliminary schedule.

  ...  Worked with USINT on configuring DDT HETG observation, coordinated with XRISM.

  ...  Reviewed FEB2624A command load; FEB2624 final OR list; FEB2624 preliminary schedule; and MAR0424 and MAR1124 LTS OR lists.

  ...  Checking on automated processes associated with SACGS.