Launch from Cape Canaveral (KSC); landing on Cape Canaveral (KSC).

Third Hubble-Servicing-Mission; Hubble was captured successful; first EVA by Smith and Grunsfeld on 22.12.1999 (8h 15m) in which three Rate Sensor Units with each two gyroscopes were replaced, because four gyroscopes had failed; they also opened valves on the NICMOS to purge nitrogen coolant from that instrument and installed Voltage/Temperature Improvement Kits.

Second EVA by Foale and Nicollier on 23.12.1999 (8h 10m); they replaced the outmoded DF-224-Computer and installed a new and better computer (20 times faster) and replaces a 500-pound fine guidance sensor.

Third and final EVA by Smith and Grunsfeld on 24.12.1999 (8h 8m), replacing a failed S-band-transmitter and a Solid State Recorder; they also applied some new insulation on equipment bay doors to minimize degradation of the telescope's protective thermal coverings; after that, Hubble was deployed again.