Since SpaceX started in 2002, the company has created three types of rocket engines — Merlin and the retired Kestrel for launch vehicle propulsion, and the Draco control thrusters. SpaceX is currently working on two further rocket engines: SuperDraco and Raptor. Merlin is a family of rocket engines made by SpaceX for use on their rockets. The Merlin engine was originally designed for sea recovery and reuse. Kestrel is a Liquid Oxygen/Rocket fuel pressure-fed rocket engine and was used as the Falcon 1 rocket's second stage main engine. Both names for the Merlin and Kestrel engines come from species of North American falcons: the kestrel and the merlin.