Rocketdyne was an American rocket engine design and production company headquartered in Canoga Park, in the western San Fernando Valley of suburban Los Angeles, in southern California. The Rocketdyne Division was founded by North American Aviation (NAA) in 1955, and was later part of Rockwell International (1967–1996) and Boeing (1996–2005). In 2005, the Rocketdyne Division was sold to United Technologies Corporation, becoming Pratt & Whitney Rocketdyne as part of Pratt & Whitney. In 2013, Pratt & Whitney Rocketdyne was sold to GenCorp, which merged it with Aerojet to form Aerojet Rocketdyne. History After World War II, North American Aviation (NAA) was contracted by the Defense Department to study the German V-2 missile and adapt its engine to Society of Automotive Engineers (SAE) measurements and U.S. construction details. NAA also used the same general concept of separate burner/injectors from the V-2 engine design to build a much larger engine for the Navaho missile project (1946–1958). This work was considered unimportant in the 1940s and funded at a very low level, but the start of the Korean War in 1950 changed priorities. NAA had begun to use the Santa Susana Field Laboratory (SSFL) high in the Simi Hills around 1947 for the Navaho's rocket engine testing. At that time the site was much further away from major populated areas than the early test sites NAA had been using within Los Angeles. Navaho ran into continual difficulties and was canceled in 1958 when the Chrysler Corporation Missile Division's Redstone missile design (essentially an improved V-2) had caught up in development. However the Rocketdyne engine, known as the A-5 or NAA75-110, proved to be considerably more reliable than the one developed for Redstone, so the missile was redesigned with the A-5 even though the resulting missile had much shorter range. As the missile entered production, NAA spun off Rocketdyne in 1955 as a separate division, and built its new plant in the then small Los Angeles suburb of Canoga Park, in the San Fernando Valley near and below its Santa Susana Field Laboratory. In 1967, NAA, with its Rocketdyne and Atomics International divisions, merged with the Rockwell Corporation to form North American Rockwell, becoming in 1973 Rockwell International. Thor, Delta, Atlas Rocketdyne's next major development was its first all-new design, the S-3D, which had been developed in parallel to the V-2 derived A series. The S-3 was used on the Army's Jupiter missile design,