This was the twenty-second flight of Discovery. Second in a series of planned servicing missions to Hubble Space Telescope (HST). Conducted four spacewalks (also called Extravehicular Activities or EVAs) for various servicing tasks, installing new instruments and replacing other existing hardware with upgrades. Landed at Kennedy Space Center, FL on February 21, 1997. Mission Duration: 9 days 23 hours 38 minutes 9 seconds. Launch Date: February 11, 1997 at 3:55 AM EST. Launch Vehicle: Discovery. Crew: Commander – Kenneth D. Bowersox, Pilot – Scott J. Horowitz, Mission Specialists – Mark C. Lee, Steven A. Hawley, Gregory J. Harbaugh, Steven L. Smith, Joseph R. Tanner. Iron-on. 4″ diameter.