Robert Clyde "Bob" Springer is a retired American astronaut and test pilot who flew as a Mission Specialist on two NASA Space Shuttle missions in 1989 and 1990. A decorated aviator in the United States Marine Corps, Springer also flew more than 500 combat sorties during the Vietnam War. He has logged over 237 hours in space and 4,500 hours flying time, including 3,500 hours in jet aircraft.