STS-4 launched from Kennedy Space Center (KSC) on 27 June 1982 at 11:00 am EDT, with Ken Mattingly as commander and Henry Hartsfield as pilot. This mission marked the first time the Space Shuttle launched precisely at its scheduled launch time. It was also the last research and development flight in the program, after which NASA considered the shuttle operational. After this flight, "Columbia's" ejection seats were deactivated, and shuttle crews did not wear pressure suits again until STS-26 in 1988.