Email: Radiation telecon and SCS-107 shutdown summary: Jan 22 2024 3:09 pm
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At the day 22 1940z comm this afternoon, SCS-107 was manually run in order to safe the science instruments in light of high ACE radiation rates. The SCS ran nominally. The ACE p3 rates had sharply increased earlier in the day, with high rates (about 50000) and a relatively slow decline at the start of the comm.

The plan is to restart the current load schedule at the 2024:023:13:45:00 Comm pass on DSS-26 (8:45 AM Tue 23-Jan). This will mean fast-turnaround loads which are expected out this evening.

Email: Radiation tagup following 9am meeting: Jan 23 2024 8:05 am
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It seems that the ACE P3 radiation levels are still somewhat elevated but trending downward. Since the 8:45am comm is 2 hours and we have time,
let's have a radiation discussion immediately after the 9am meeting for a go/no-go on uplinking the JAN2324B loads.

Ops crew: do not uplink any loads prior to this discussion. The first command in the replan loads is at 2024:023:14:57:00.000 (9:57am EST).

Email: Radiation telecon summary: Jan 23 2024 9:19 am
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After the 9am meeting this morning we discussed the radiation environment and decided to proceed with uplinking and running the JAN2324B loads.

Based on the current trend we estimated that P3 rates should be around 10000 by the time the SIM translates to ACIS-S for the first science observation (shown at the red vertical line below). This meets the standard criteria for restart: 1/3 of 50000 and descending.

Email:  2024:24 Normal Sun Mode transiton: Jan 24 2024 12:26 am
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At 2024:024:09:44:06 Chandra transitioned to Normal Sun Mode (NSM) following the maneuver
to ObsID 29211. The transition was nominal, science instruments were safed properly, and all
telemetry appears as expected. The immediate cause of the transition was a trip of the Bright
Star / Commanded Attitude Monitor. Unfortunately due to station RFI issues we were unable to
downlink the back-orbit telemetry covering the NSM transition so the root cause is unavailable
at this time. However, given that there was not an IU or CTU reset and the transition occurred at
the time of attempted star acquisition following a maneuver, we suspect a recurrence of the
Post-Maneuver Star Acquisition (PMSTA) Anomaly.