ACA Operations
ACA Operations and Ground Aspect Solution
Used improved data filtering and processing to get a more accurate assessment of boresight alignment drift. Data are fit very well with a decaying exponential with a time scale of about 360 days, and amplitude of about 3 arcsec. The data are consistent with a long-term drift of the FTS periscope.
Started working with CXCDS aspect software development team to prepare for aspect hardware failure contingencies. Modified ground aspect pipeline to process aspect data if as few as two channels of gyro data are available.
Performed ACA dark current calibration on Feb 26, 2002 via normal command load. Analysis shows that the number of warm pixels (greater than 200 e-/sec) is increasing at a steady rate of about 20,000 new warm pixels per year. New ACA bad pixel list and centroiding error array were derived from these data, and have been delivered to the OCC for testing and incorporation into the ODB.
Started a program to use monitor windows during perigee passage to investigate the ACA 'flickering pixel' phenomenon. Evidence thus far shows that the value of dark current in warm pixels jumps between different distinct values.