Spring was selected as an astronaut in May 1980. His technical assignments have included software verification at the Shuttle Avionics Integration Laboratory and Flight Simulation Laboratory; vehicle and satellite integration at the Kennedy Space Center, Florida, for STS-5, 6, 7, 8, and 9; Astronaut Office EVA (Extra-vehicular activity) expert; and Space Station construction, EVA maintenance, and design. Spring served as a mission specialist on STS-61-B which flew November 26, 1985, through December 3, 1985. During that mission, he was responsible for launching three communications satellites and performed two EVAs. During the EVAs, which totaled more than 12 hours, Spring investigated Space Station construction techniques, large structure manipulation while on the end of the remote arm, and a time and motion study for comparison between Earth training and space performance, with the &lt;a href="EASE/ACCESS"&gt;EASE/ACCESS&lt;/a&gt; experiment. With the completion of STS-61-B, he has logged a total of 165 hours in space. After the Space Shuttle "Challenger" accident, Spring participated in the Kennedy Space Center Tiger Team for accident investigation, then led the Astronaut Office EVA (Extra Vehicle Activity) program until 1988.