STS-31 was the thirty-fifth mission of the American Space Shuttle program, which launched the Hubble Space Telescope astronomical observatory into Earth orbit. The mission used the Space Shuttle Discovery, which lifted off from launchpad 39B on April 24, 1990 from Kennedy Space Center, Florida.
Discovery's crew deployed the telescope on April 25, and spent the rest of the mission tending to various scientific experiments in the shuttle's payload bay and operating a set of IMAX cameras to record the mission. Discovery's launch marked the first time since January 1986 that two Space Shuttles had been on the launch pad at the same time - Discovery on 39B and Columbia on 39A.
Launch date: April 24, 1990 13:33:51 UTC
Landing: April 29, 1990 13:49:57 UTC