Friday 28 June 2013 10.00am EDT
During the last week Chandra completed the observing schedule as planned.
A real-time procedure was completed on Jun 28 to patch the MUPS-firing parameters in the A-side Control Processing Electronics (CPE-A) and to add these updated parameters to SCS-101, which is used to patch the CPE during safe mode transitions. These updated firing parameters match those in the on-board computer and are less stressing on the MUPS thrusters.
A second real-time procedure was executed on Jun 28 to reconfigure the battery reconditioning resistors for batteries 2 & 3 to adjust the battery trickle charge currents. An associated flight software patch was uplinked to update the EPS fault detection logic on the Reconditioning Resistor Relay configuration. These changes are in response to expected efficiency drops due to aging of the solar arrays. However, at the end of this real-time procedure, the EPS Charge Current Monitor tripped when the full-charge current for Battery 3 dipped below the flight software threshold. This lower Battery 3 full-charge current level is also the result of efficiency drops due to aging of the solar arrays. The effect of this EPS monitor trip is that Battery 3 is now in a disabled state. Follow-on actions are being planned to patch the flight software threshold and to re-enable Battery 3.
A Chandra image release was issued on Jun 26 describing observations of G1.9+0.3, the remains of the most recent supernova (in Earth's time frame) known to have occurred in the Milky Way. If gas and dust had not heavily obscured it, the explosion would have been visible from Earth just over a century ago. For details see: http://chandra.si.edu/photo/2013/g19/
The schedule of targets for the next week is shown below and includes an observation of GRB 130420A, which was accepted as a Target of Opportunity on Jul 12.
MKN421 ACIS-S/HETG Jun 30 MKN421 ACIS-S/LETG MKN421 HRC-S/LETG MKN421 ACIS-S/LETG Jul 1 MKN421 HRC-S/LETG MKN421 ACIS-S/LETG MKN421 HRC-S/LETG MKN421 ACIS-S/HETG NGC1399 ACIS-S AntliaE3 ACIS-I Jul 2 SgrA* ACIS-S Radiation Belts RCW106 ACIS-I Jul 3 Sh2-27 ACIS-I IGRJ17091-3624 ACIS-S/HETG Jul 4 GS0834-430 ACIS-S Jul 5 Radiation Belts COSMOSLegacy ACIS-I G247.17-23.32 ACIS-I Jul 6 NGC188 ACIS-I GRB130420A ACIS-S SDSSJ111547.46+5024 ACIS-S Jul 7 SDSSJ105104.52+6251 ACIS-S
All spacecraft subsystems continued to support nominal operations.
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