MTA Monitoring Report 11/07/25 - 11/13/25

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Radiation

(Nov 11, 2025, 8:01 AM) SOT Yellow Alert Radiation Levels High
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There was an X 5.1 solar flare this morning at roughly 5 am local time, which was accompanied by a very rapid rise in the GOES protons. The HRC proxy and the ACIS txings proxy (see plot) both spiked. The latter has turned over very recently but is still high.
It depends on the precise timing of the spike with respect to the ACIS startScience command for OBSID 30162, but it is extremely likely that we will come up on the 11:20 am ET comm already shut down.
ACE P3 levels are elevated near ~5000 but not extremely high. ACIS operations will monitor those in the coming hours.
ACIS ops would like to call for a teleconference to discuss the radiation situation at 11:00 am ET on the anomaly response line:
(Nov 11, 2025, 1:54 PM) SCS-107 and telecon summary
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Following a message from ACIS and an sot_red_alert notice, a discussion of rising radiation rates was held at 11AM local today (Tuesday). In view of the increasingly adverse radiation environment expected, it was decided to run SCS 107 manually if needed; at the beginning of comm at 11:20AM local it was found that TXINGS had already triggered safing of the instruments.
SCS 107 was triggered at 315:10:58:50z.
During the comm, the SOP-SAFE-SAFING-ACTIONS procedure was run, SSR data were dumped and pointers reset, and pre-approved CAPs 893B (to disable SCS-29) and 1230 (to reset the ObsID) were run. The ObsID was reset to 65517 at approximately 17:12z.
The status of the spacecraft is currently nominal and the science instruments are safed.
(Nov 11, 2025, 5:08 PM) ACE P3
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A Radiation violation of P3 (130KeV) has been observed by ACE Observed = 3.7176e+08 (limit = fluence of 3.6e8 particles/cm2-ster-MeV within 2 hours)
(Nov 12, 2025, 12:27 PM) Radiation Shutdown and Return to Science Plan
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Immediately following the 9AM operations tagup this morning (Nov 12 Wed) the team discussed the radiation status and possible paths to return to science.
The current adverse radiation environment is expected to continue for several more days. Possible comms for uplinking return-to-science loads were discussed, and mid-day Friday (Nov 14) identified as a target toward which to plan. Mission planning considerations identified following the morning discussion currently favor the second of the comms, starting at 3:35 PM local.
This will permit a 'pickup schedule' that resumes the observing plan developed earlier; the new schedule would continue through the NOV1725 week.
The ACIS team is currently planning to start an ECS measurement to begin at the 7:50PM local comm tomorrow (Nov 13 Thu)
(Nov 14, 2025, 10:56 AM) Expected Return to Science
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Immediately following the 9AM operations tagup this morning (Nov 14 Fri) the team discussed the radiation environment and confirmed plans to uplink the NOV1425 return to science load approved yesterday at the 3:35PM EST comm this afternoon.
Given the somewhat unsteady radiation environment, we will continue monitoring radiation levels and will convene a telecon if needed.

Detrended CTI

Although we prefer to quote CTI values of the cleanest data (FT <= -119.7 C, int time > 7000sec), the data that fulfills these conditions are getting rare. We now quote CTI based on temperature corrected data for Focal plane temperature <= -118.5 C).

The unit is now CTI/year not CTI/day.

ACIS Warm Pixels

We display all bad pixels that have showed up in past, and, if any, previously unknown bad pixels appeared in the last 14 days. We also list hot pixels (defined as 1000 above the average of bias background). Warm columns 509-514 are probably due to boundaries.

New definitions of warm pixels and flickering pixels (May 15, 2014). If a pixel displays the level beyond a threshold for more than 70% of the time in the past two weeks, the pixel is categorized as a "warm" pixel. If a pixel is above the threshold more than 30% of time but less than 70% of the time in the past two weeks, the pixel is categorized as a "flickering" pixel.

ACIS Focal Plane Temperature

For this period, 7 peaks are observed.

Day (DOY)	Temp (C)	Width (Days)
309.30	-108.69	1.01
311.94	-105.28	2.24
312.39	-111.47	0.41
312.82	-111.95	0.37
313.81	-106.14	2.27
315.49	-110.76	0.38
315.82	-113.48	0.33

Weekly focal plane temperature with sun angle, earth angle, and altitude overplotted. Sun angle is the solar array angle, that is the angle between the sun and the optical axis (+X axis). The earth angle is the angle between earth and the ACIS radiator (+Z axis). Altitude varies from 34 kkm to 128 kkm.

SIM Movements

6 TSC moves this period

weekly average time/step	0.00131 s
mission average time/step	0.00132 s

Telemetry

New violations or new extrema are shown in blue cells.

IRUs

Gyro Bias Drift	Gyro Bias Drift Histogram

Recent Observations

Trending

This week's focus is ACIS

Last reported on Aug 28.

Only the most interesting or representative msids are shown below. For a full listing choose the bulletted link.

• ACIS Thermal

• DEA/DPA Thermal

• DEA/DPA Electronics

If you have any questions, please contact: swolk@head.cfa.harvard.edu