Garn asked to fly on the Space Shuttle because he was head of the Senate appropriations subcommittee that dealt with NASA, and had extensive aviation experience. He had previously flown a
Northrop Grumman B-2 Spirit prototype and driven a new Army tank. He began publicly asking NASA about flying on the Shuttle in 1981, and the agency had long planned to fly "citizen passengers" such as artists, journalists, entertainers, and the
Teacher in Space Project, but the November 1984 announcement that a member of Congress would go to space surprised most observers. Garn said that flying on the Shuttle would be a fact-finding trip: "I do really think that it is a necessity that Congressmen check things out that they vote for and make certain that funds are being spent adequately. It might be necessary to have a Senator kick the tire".
STS-51-D was launched from and returned to land at the
Kennedy Space Center in the U.S. state Florida in April 1985. Its primary objective was to deploy two communications satellites, and to perform
electrophoresis and echocardiograph operations in space in addition to a number of other experiments. As a
payload specialist, Garn's role on the mission was as a congressional observer and as a subject for medical experiments on
space adaptation syndrome. At the conclusion of the mission, Garn had traveled over in 108 Earth orbits, logging over 167 hours in space. The space sickness Garn experienced during the journey was so severe that a scale for space sickness was jokingly based on him, where "one Garn" is the highest possible level of sickness. Some NASA astronauts who opposed the payload specialist program, such as
Mike Mullane, believed that Garn's space sickness was evidence of the inappropriateness of flying people with little training. Garn was in excellent physical condition, however, and began flying at the age of 16. Astronaut
Charles Bolden described Garn as "the ideal candidate to do it, because he was a veteran Navy combat pilot who had more flight hours than anyone in the Astronaut Office". Fellow 51-D payload specialist
Charles Walker—who also suffered from space sickness on the flight despite having flown before—stated that: The Jake Garn Mission Simulator and Training Facility, NASA's prime training facility for astronauts in the Shuttle and Space Station programs, is named after him. Upon his return, he co-wrote the 1989 novel
Night Launch. The book centers around
terrorists taking control of the
Space Shuttle Discovery during the first NASA–USSR Space Shuttle flight. ==Personal life==