Launch of a three-stage Vanguard (SLV-7) from Cape Canaveral, Florida, September 18, 1959. Designated Vanguard III, the 100-pound satellite was used to study the magnetic field and radiation belt. In September 1955, the Department of Defense recommended and authorized the new program, known as Project Vanguard, to launch Vanguard booster to carry an upper atmosphere research satellite in orbit. The Vanguard vehicles were used in conjunction with later booster vehicle such as the Thor and Atlas, and the technique of gimbaled (movable) engines for directional control was adapted to other rockets.