It is built around the same pintle architecture as SpaceX's Merlin engine but does not have a turbo-pump, and is fed only by tank pressure. Its nozzle is ablatively cooled in the chamber and throat, is also radiatively cooled, and is fabricated from a high strength niobium alloy. Both names for the Merlin and Kestrel engines are derived from species of North American falcons: the American kestrel and the merlin.[11]