Space Shuttle program March 25, 1979, and was first launched on April 12, 1981—the 20th anniversary of Yuri Gagarin's space flight—with a crew of two. "Challenger" (OV-099) was delivered to KSC in July 1982, "Discovery" (OV-103) in November 1983, "Atlantis" (OV-104) in April 1985 and "Endeavour" in May 1991. "Challenger" was originally built and used as a Structural Test Article (STA-099), but was converted to a complete orbiter when this was found to be less expensive than converting "Enterprise" from its Approach and Landing Test configuration into a spaceworthy vehicle. On April 24, 1990, "Discovery" carried the Hubble Space Telescope into space during
Hopkins Ultraviolet Telescope on Astro-2 (in 1995). HUT is on display at the Smithsonian National Air and Space Museum in Washington, D.C. in the United States. Hopkins Ultraviolet Telescope The Hopkins Ultraviolet Telescope (HUT) was a space telescope designed to make spectroscopic observations in the far-ultraviolet region of the electromagnetic spectrum. It was flown into orbit on the Space Shuttle and operated from the Shuttle's payload bay on two occasions: in December 1990, as part of Shuttle mission STS-35, and in March 1995, as part of mission STS-67. HUT was designed and built by a team based at Johns Hopkins University, led by