His three space shuttle flights include the Atlantis mission in September 1996 that docked with the Russian space station Mir. During the docking astronauts were exchanged there for the first time. He has logged 672 hours in space and went on to become the associate administrator for space flights at NASA's headquarters in Washington, DC. Readdy joined NASA in 1986 as an aerospace engineer and instructor pilot, and was selected as an astronaut in 1987.