Chandra entered Normal Sun Mode (NSM) at 6:41am EDT on Oct 23 as the result of a reset of the Interface Unit (IU) on-board the spacecraft. Entry into NSM was nominal and assessment of the telemetry indicated that all spacecraft hardware was performing nominally. Engineering assessment suggested that the reset of the IU and subsequent transition to NSM was due to a single event upset and the decision was made to recover to normal pointing mode and continue with science. The recovery operations took place on Oct 23 and observations were resumed on Oct 24 at 10pm EDT. Scheduled observations that were impacted by the anomaly will be rescheduled in future weeks. A total of 97.0 ks of science time was lost due to the anomaly.

Additional real-time procedures were executed on Oct 25-26 to dump OBC-A and -B memory as a follow-up to a patch during the NSM recovery. The dump will be used to update the baseline memory images maintained on the ground.

Following resumption of science observations, the Chandra schedule was then interrupted by a high-radiation event that activated the science instrument safing sequence (SCS 107) and stopped observing at 12:35pm EDT on Oct 28. All spacecraft actions were nominal. A real-time procedure was executed on Oct 28 to update the observation identifier number to aid CXCDS processing. Planning efforts for the resumption of the observing schedule are on-going and observing will resume Saturday evening assuming the radiation environment settles. Observations that were impacted by the interruption will be rescheduled. A total of 113.6 ks of science time was lost due to the radiation shutdown.

Preparations were completed for the Fall 2021 eclipse season; the season contains 19 eclipses and runs from Oct 29 to Dec 16. A real-time procedure was executed on Oct 28 to prepare for the first eclipse by dumping and clearing the EPS glitch counters.

A Chandra press release was issued on Oct 19 describing observations of a possible planet outside of the Milky Way galaxy. This "exoplanet" would be much farther away than any of the thousands of others scientists have found in our Galaxy in recent years. This planet candidate was identified with NASA's Chandra X-ray Observatory that detected a temporary dimming in X-rays in a binary system. Researchers interpret this dimming as a planet passing in front of an X-ray source around a neutron star or black hole orbiting a companion star. For details see: https://chandra.harvard.edu/press/21_releases/press_102521.html