His three space shuttle flights include the January 1993 mission of Endeavour to deploy a Tracking and Data-Relay Satellite, and another Endeavour flight in May 1996 during which he deployed two satellites. He has logged over 551 hours in space, including four and a half hours on the space walk. Runco went on to become an earth and planetary scientist in the Human Exploration Science Office at the Johnson Space Center. He also worked on the NASA programme to develop optical-quality windows for the International Space Station and was assigned as a CapCom (spacecraft communicator) in the mission control team. Runco was selected as an astronaut in 1987, and retired as a NASA astronaut in 1994.