Hubble Space Telescope be kept in a clean room, powered up and purged with nitrogen, until a launch could be rescheduled. This costly situation (about per month) pushed the overall costs of the project even higher. This delay did allow time for engineers to perform extensive tests, swap out a possibly failure-prone battery, and make other improvements. Furthermore, the ground software needed to control Hubble was not ready in 1986, and was barely ready by the 1990 launch. Eventually, following the resumption of shuttle flights in 1988, the launch of the telescope was scheduled for 1990. On April 24, 1990, successfully launched the
Space Shuttle retirement Space Shuttle retirement The retirement of NASA's Space Shuttle fleet took place from March to July 2011. "Discovery" was the first of the three active space shuttles to be retired, completing its final mission on March 9, 2011; "Endeavour" did so on June 1. The final shuttle mission was completed with the landing of "Atlantis" on July 21, 2011, closing the 30-year Space Shuttle program. The Shuttle was presented to the public in 1972 as a "space truck" which would, among other things, be used to build a United States space station in low earth orbit in the early 1990s