The SpaceX Kestrel was an LOX/RP-1 pressure-fed rocket engine. The SpaceX Kestrel engine was developed in the 2000s by Space Exploration Technologies Corporation, doing business as SpaceX, for upper stage use on the Falcon 1 two-stage small-lift launch vehicle that was operated from 2006 to 2009 by SpaceX. Kestrel is no longer being manufactured; the last flight of Falcon 1 was in 2009.