MTA Monitoring Report 10/29/21 - 11/04/21

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Radiation

Several shocks related to C-class flares passed over the weekend including one on Saturday Oct 30 and a bigger one on Sunday Oct 31. An M1.7 class flare on Tue, Nov 2, also produced an Earth directed CME. This resulted in a sharp increase in the ACE P3 rates which reached ~10,000, putting ACIS on track to exceed the attenuated orbital fluence limit of 2e9 by >~50%. ACIS requested a radiation shutdown meeting on Wed, Nov 3, at 5:30PM EST. At 6:40PM EST, comm was established, autonomous safing had not occurred. FD and ACIS continued to monitor the situation but no action was required, the ACE P3 rates stayed at ~80,000. ACIS would have received about 1/2 its threshold orbital dose over the next 4 hours before radzone SIM translation if the rates did not go down. Geomagnetic field stayed unsettled until the end of the week, and the ACE P3 rates stayed elevated with a decreasing trend.

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, 10 peaks are observed.

Day (DOY)	Temp (C)	Width (Days)
301.25	-116.80	0.43
301.95	-113.09	0.58
303.07	-107.54	0.54
303.90	-114.88	0.44
304.16	-115.36	0.34
304.64	-115.45	0.42
305.23	-113.25	0.55
305.70	-101.47	0.51
306.91	-112.61	0.65
307.74	-112.44	0.50

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

8 TSC moves this period

weekly average time/step	0.00136 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 Aug 19.

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