He has flown two missions and logged over 422 hours in space, including 9 hours and 58 minutes of EVA. He served as a mission specialist on the crew of STS-89 (January 22-31, 1998), the eighth Shuttle-Mir docking mission, during which the crew transferred more than 8,000 pounds of scientific equipment, logistical hardware, and water from Space Shuttle Endeavour to Mir. In the fifth and final exchange of a U.S. astronaut, STS-89 delivered Andy Thomas to Mir and returned with David Wolf. The mission lasted 8 days, 19 hours, and 47 seconds, traveling 3.6 million miles in 138 orbits of the Earth.