Friday 14 May 2021 9.00am EDT
During the last week Chandra completed the observing schedule as planned. At 1:06 am EDT on May 12, the on-board F_ECLIPSE flag in the On-Board Computer indicated an eclipse state for a single readout while not in eclipse. Due to a confluence of nominal onboard conditions with regards to equipment states, a maneuver in progress, and the random nature of heater cycles, the power demand on the load bus momentarily dropped to an historically low level. The power output from the –Y solar array briefly dropped to the on-board limit which triggers eclipse load configuration setup via SCS 29. In this case there was no change to the configuration required and the event was benign. A real-time activity was executed on May 13 to disable and then re-activate SCS 29 in preparation for the next eclipse of the season. Analysis is underway to determine if the eclipse power limit needs to be lowered to better account for the normal variations in power demand, as was done in the fall of 2020. Preparations were completed for the Spring 2021 eclipse season; the season contains 10 eclipses and runs from May 11 to June 3. Real-time procedures were executed on May 9 to prepare for the first eclipse: one to activate SCS 29 and one to dump and clear the EPS glitch counters. Chandra passed through the first and second eclipses of the season on May 11 and 13, with nominal power and thermal performance. The schedule of targets for next week is shown below and includes observations of IC 1657 coordinated with NuSTAR, an observation of Sgr A* coordinated with VLTI-Gravity, and observations of MAXI J1803-298, which was accepted as a Director's Discretionary Time Target of Opportunity on May 7. |
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SN2014df ACIS-S May 16 CasJ005311 ACIS-I HD221416 ACIS-S May 17 MAXIJ1803-298 ACIS-S/HETG WISEAJ213202.20-3342 ACIS-S CasJ005311 ACIS-I 2RXSJ161816.6+09120 ACIS-I KeplerSNR ACIS-S/HETG 2MASSJ20320890-4742 ACIS-S May 18 IC1657 ACIS-S KeplerSNR ACIS-S/HETG Radiation Belts May 19 PSZ2G126.57+51.61 ACIS-S XIBOO HRC-I SS433 ACIS-S/HETG H1821+643 HRC-S /LETG HD202772 ACIS-S May 20 GDHIdp41 ACIS-I GDHIdp41 ACIS-I GDHIdp41 ACIS-I GDHIdp41 ACIS-I GDHIdp41 ACIS-I GDHIdp41 ACIS-I TOI-132 ACIS-S Tycho'sSNR ACIS-I 2RXSJ162820.2+01063 ACIS-I Tycho'sSNR ACIS-I SS433 ACIS-S/HETG May 21 Radiation Belts AHCep ACIS-S 2RXSJ200845+223911 ACIS-I May 22 SS433 ACIS-S/HETG IRAS16382-0613 ACIS-S AHCep ACIS-S SgrA* ACIS-S HZ43 HRC-I /LETG May 23 H1821+643 HRC-S /LETG 2MASXJ08244333+29592 ACIS-S MAXIJ1803-298 ACIS-S/HETG Radiation Belts
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All spacecraft subsystems continued to support nominal operations.
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