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Friday 21 July 2000 4.00pm EDT
Several major solar flares and coronal mass ejections between July 12 and 14 caused enhanced particle rates in the Earth's vicinity lasting through July 16. We stopped execution of the on-board observing program at about 5pm on July 14, while all instruments were in a safe configuration for radiation belt passage. All observations on July 15 and 16 were postponed, and will be rescheduled as soon as possible. Following several team telecons through this time period, we determined that it was safe to resume observations upon exit from the radiation belts on Jul 17, and Chandra completed the observing schedule from that time on as planned. There is no apparent degradation of any science instrument or spacecraft system due to the solar particles.
A CAP was run Saturday night to unload momentum, which would have been done by the on-board stored commands if the observing program had not been stopped. Processing of data showed that the observations of COMET c/LINEAR 1999 were successful: Chandra pointed correctly so as to catch this moving object, and the comet can be seen in the series of eight ACIS images which were obtained. A routine real-time procedure was carried out to dump the CPE warm start counter, which showed the correct value of (1), as expected. The HETG was successfully inserted via stored commands, the first time this had been attempted since failure of the B-side retract limit switch on June 13. The planned observations for the coming week are as follows. |
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TERZAN 5 ACIS-I Jul 24 SGR 1806-20 ACIS-S 1746-331 ACIS-S Radiation Belt G347.5-0.5 ACIS-I Jul 25 G347.5-0.5 ACIS-I 4U 1543-47 ACIS-I Jul 26 ABELL 3266 ACIS-I CL J0542.8-4100 ACIS-I Radiation Belt Jul 27 A2597 ACIS-S Jul 28 ABELL 496 ACIS-S Q0054+144 ACIS-S M31 TRANSIENT ACIS-I A2204 ACIS-S KES 73 ACIS-S Jul29 TERZAN 5 ACIS-I A2163 ACIS-I ABELL 1995 ACIS-S M 87 ACIS-S Radiation Belt Jul 30 M 87 ACIS-S 1WGA1226.9+3332 ACIS-S
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All spacecraft subsystems continued to operate nominally.
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