MTA Monitoring Report 05/30/25 - 06/05/25

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Radiation

Radiation Telecon Summary and SCS-107 on Comm: (June 1, 2025 9:08 am)
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At the 2025:153:12:30 (08:30 AM Jun 1 Sun) comm SCS-107 was observed to have run at 2025:152:05:51:32 in response to an ACIS/TXings high radiation flag. The cause was an Earth-directed CME associated with an M8 flare Friday evening. The transition was nominal, with science loads halted and the spacecraft and instruments in a safe configuration.
Pre-approved CAP 893B to disable SCS 29 was run as a clean-up action.
P3 rates are already down to near restart levels. The comm passes at 153:19:30 and 154:02:30 (Jun 2, Mon at 3:30 PM or 10:30 local) is being considered for uplink of replan loads, which are expected out for review later today or early tomorrow. Any updates will follow the 9 AM tag-up tomorrow (Monday).

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, 5 peaks are observed.

Day (DOY)	Temp (C)	Width (Days)
149.05	-107.67	1.79
150.07	-115.99	0.33
150.95	-104.42	1.38
152.61	-109.85	0.81
154.49	-105.48	2.02

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

15 TSC moves this period

weekly average time/step	0.00126 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 Gratings

Last reported on Mar 20.

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

• Gratings

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