Status Report # 13

October 17th 1991

SASS processing status:

ROSAT calibration data have been processed using the new aspect solution. The calibration data comprise June 16th - July 22nd 1990 observations. June 16 through 21st have been completed, while June 22nd through July 22nd sequences are partially complete. The last part of the processing will be run in parallel with AO1 processing (the early stages of processing, ie the telemetry, aspect and data screening stages of processing had to be run separately for calibration and AO1 data, as different housekeeping data flags were required). These calibration data will be used by the Guest Observer Facilities to produce data sets (point spread and vignetting functions etc) that will enable detailed ROSAT data analysis. AO1 processing was paused as the quality flags used in data processing are different for the calibration or AO1 data. GSFC will resume processing AO1 data October 21 with March 25th 1991 data.

Satellite status:

GSOC have successfully uplinked and started the final patch of software regarding the magnetic field control. In the first attempt a damaged memory cell in the external ROM was detected, so that the code had to be changed slightly.

First on-board comparisons between measured and predicted magnetic field indicated quite good accuracies (about 1 degree). Despite early problems due to a software bug, ROSAT successfully completed a test of the new pointing system on Tuesday, with about 25 slews across the sky. Now GSOC is in the process of analysis, to check the detailed attitude behavior and whether all options in the software have been enabled correctly.

IF ALL IS AS WELL AS PRELIMINARY INDICATIONS SUGGEST, THEN ROSAT IS NOW CAPABLE OF RESUMING THE NORMAL OPERATIONAL MODE IT USED PRIOR TO THE GYRO FAILURE.

Preparation of the AO2 long term mission timeline is in progress, and this timeline is expected to be ready for release during the first week of November.

Status Report #14 Previous