During the last 24 hours Chandra completed a pre-radiation belt ACIS CTI measurement, passed through the 9th eclipse of the season, exited the belts and performed a post-belt CTI measurement. The spacecraft performance during the 49 minute eclipse was as expected. The spacecraft systems continued to operate nominally.
The mission schedule for the next week was reviewed and will begin operating at 4PM 10/8. This load will continue until 12.00AM 10/18 and will include the GTO deep field observation. Given that no further degradation has occurred during the last 6 passages, measurements of the ACIS CTI will be performed only after exit of the radiation belts (i.e., not prior to entry as well). This approach has been implemented in the mission schedule beginning 10/8.
Work is underway to develop a software patch to modify the safing actions of the science instruments given the on-orbit experiences with ACIS. These actions will ensure that the instruments are placed with ACIS in the out-of focus position and HRC in-focus with its door closed. This will ensure that ACIS will not be in the focus during a belt passage in the event of a safe mode.
|
