The scan motors of the AMSU-A1 on NOAA-17 suffered a power supply failure on 28 October 2003. Several attempts were made over the next two days to thermally and electrically cycle the instrument in an attempt to recover functionality. These efforts failed, and the instrument has been powered down with survival heaters turned on. The instrument is deemed lost, and no other recovery efforts are planned.
Further information is available at http://www.oso.noaa.gov/poesstatus/