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Friday 23 September 2005 11.00am EDT
| Observations were resumed on Sept 16 following last week's solar
activity and the unexpected shutdown of the ACIS Digital Electronics
Assembly side-A (DEA-A) on Sept 15. Initial analysis of the event
indicated similarities to two prior shutdowns of the ACIS Digital
Processing Assembly in 2000 and 2002 that were attributed to a cosmic
ray hit to the opto-isolator resulting in a spurious command to turn
off. Following a detailed engineering assessment, a real-time
procedure was conducted on Sept 16 to turn the DEA-A back on, and the
science program was resumed. Further analysis of the anomaly is
on-going. A total of 160 Ks of science time was impacted by the solar
event and DEA-A shutdown.
A real-time procedure was completed on Sept 16 to update the on-board ephemeris. A Chandra press release was issued on 22 Sept describing observations of Tycho's supernova remnant that provide compelling evidence that a supernova shock wave has produced a large amount of cosmic rays, particles of mysterious origin that constantly bombard the Earth. For details see: http://chandra.harvard.edu/press/05_releases/press_092205.html The schedule of targets for next week is shown below and includes a series of calibration observations of the target AR Lac. |
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M33 Field 5 ACIS-I Sep 26 The Crab Nebula ACIS-S/HETG ELAIS-S1 A ACIS-I AR Lac (11 obs) HRC-I Sep 27 Radiation Belts EGS-3 ACIS-I Sep 28 RCS2319.9+0038 ACIS-S M33 Field 5 ACIS-I Sep 29 EGS-3 ACIS-I Radiation Belts Sep 30 EGS-7 ACIS-I RCS2319.9+0038 ACIS-S Oct 1 M33 Field 5 ACIS-I Capella HRC-S/LETG Oct 2 RCS2319.9+0038 ACIS-S AR Lac (2 obs) HRC-I
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All spacecraft subsystems continued to support nominal operations.
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Revised: July 08, 2022