Friday 28 August 2020 9.00am EDT
During the last week Chandra's observing schedule was interrupted by an anomaly connected with the High Resolution Camera (HRC) 15V power supply that occurred at 11:45pm EDT Aug 23, when Chandra was out of ground contact. The anomaly was identified at the next ground contact and led the flight team to turn off the HRC and suspend the science loads at 10:15am EDT Aug 24. Related actions included the manual commanding of a support heater and three ACIS video boards to maintain the appropriate thermal posture. After analysis it was determined that possible causes included a transient load fault or a single event latchup. Either would be expected to clear after power cycling. Real-time procedures were executed Aug 26 to perform a controlled power-on of the HRC, following which all voltages returned to nominal. However, the anomaly spontaneously recurred on Aug 27 and the HRC was again commanded off. The team is currently developing procedures to execute a swap of the HRC to its B-side electronics. All science observations are temporarily suspended because the HRC anticoincidence shield provides real-time data for safing of the science instruments in the event of elevated space radiation levels. A NASA Press release was issued Aug 25 describing Chandra and VLBA observations of the active galaxy TXS 0128, colloquially known as the "TIE-Fighter" due to its morphology of opposing radio jets. The Chandra observations indicate the galaxy has a large amount of dust and gas surrounding its core, which is consistent with a highly inclined viewing angle. For details see: https://chandra.si.edu/press/20_releases/press_082520tiefighter.html |
All spacecraft subsystems continued to support nominal operations.
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