Selected by NASA in January 1978, Mullane became an astronaut in August 1979. He flew on three Space Shuttle missions, serving as a mission specialist on the crew of STS-41-D in August 1984, on STS-27 in December 1988, and on STS-36 in March 1990. On his first mission Mullane served as a Mission Specialist on the crew of STS-41-D which launched from Kennedy Space Center, Florida, on August 30, 1984. This was the maiden flight of the OrbiterDiscovery. During this seven-day mission the crew successfully activated the OAST-1 solar cell wing experiment, deployed three satellites, operated the CFES-III experiment, the student crystal growth experiment, and photography experiments using the IMAXmotion picture camera. STS 41-D completed 96 orbits of the Earth in 145 hours before landing at Edwards Air Force Base, California, on September 5, 1984. Mullane then was assigned to STS-62-A, the first Shuttle mission scheduled to launch from Vandenberg Air Force Base, but the mission was canceled after the Space ShuttleChallenger disaster. After the Shuttle returned to service, he flew aboard the Orbiter Atlantis, on STS-27, which launched from Kennedy Space Center, Florida, on December 2, 1988. The mission carried a Department of Defense payload, as well as a number of secondary payloads. After 68 orbits of the earth, the mission concluded with a dry lakebed landing on Runway 17 at Edwards Air Force Base, California, on December 6, 1988. Mission duration was 105 hours. The mission is noteworthy due to the severe damage Atlantis sustained to its critical heat-resistant tiles during ascent. On his third flight, Mullane served on the crew of STS-36 which launched from the Kennedy Space Center, Florida, on February 28, 1990, aboard the Space Shuttle Atlantis. This mission carried DOD payloads and a number of secondary payloads. After 72 orbits of the earth, the STS-36 mission concluded with a lakebed landing at Edwards Air Force Base, California, on March 4, 1990. With the completion of his third flight, Mullane logged a total of 356 hours in space. He retired from NASA and the Air Force in 1990.
Post-NASA career
In 2006, Mullane published an autobiography, Riding Rockets: The Outrageous Tales of a Space Shuttle Astronaut, that details his life before and during the space program, and expresses critical views towards the culture of the NASA Astronaut Corps. Mullane appeared on the United States television show The Daily Show with Jon Stewart on Monday, February 13, 2006 to promote his book.