http://sirtf.caltech.edu/newsarchive/iocstatusupdates.shtml

SIRTF Update
October 21, 2003

This is Day 58 of the 90-day in-orbit checkout and science verification period. Tests of the pointing calibration and reference sensor (PCRS) have been completed successfully. The PCRS is a cryogenic optical imager that serves as the observatory's fine guidance sensor by providing an alignment reference between the telescope boresight and the spacecraft attitude detrmination system. Those tests indicate that SIRTF will meet, and perhaps exceed, its pointing requirements. The next update will be provided on Friday, October 24.