NASA's Compton Gamma Ray Observatory drifts away from the space shuttle Atlantis on April 7, 1991, following its deployment during the STS-37 mission. Compton's successful career ended in June 2000 when the observatory reentered Earth's atmosphere. STS-37, launch date April 5, 1991, the 8th flight of the Space Shuttle Atlantis, was a 6 day mission with the primary objective of launching the Compton Gamma Ray Observatory (GRO), the second of the Great Observatories program which included the visible-spectrum Hubble Space Telescope, the Chandra X-ray Observatory and the infrared Spitzer Space Telescope.