Bill Nelson Bill Nelson Clarence William Nelson II (born September 29, 1942) is an American politician serving as the senior United States Senator from Florida, first elected to that seat in 2000. A member of the Democratic Party, he previously served in the Florida House of Representatives from 1972 to 1978 and in the United States House of Representatives from 1979 to 1991. In January 1986, he became the second sitting member of Congress to fly in space when he served as a payload specialist on the Space Shuttle "Columbia". Before entering politics he served in the U.S. Army Reserve in the
Space Shuttle main engine Space Shuttle main engine The Aerojet Rocketdyne RS-25, otherwise known as the Space Shuttle main engine (SSME), is a liquid-fuel cryogenic rocket engine that was used on NASA's Space Shuttle and is planned to be used on its successor, the Space Launch System. Designed and manufactured in the United States by Rocketdyne (later known as Pratt & Whitney Rocketdyne and Aerojet Rocketdyne), the RS-25 burns cryogenic liquid hydrogen and liquid oxygen propellants, with each engine producing of thrust at liftoff. Although the RS-25 can trace its heritage back to the 1960s, concerted development of the engine began in the 1970s,