This is the H-1 liquid-fuel rocket engine, the first stage powerplant for the Saturn 1 and Saturn 1B launch vehicles, the precursors to the Saturn V that took men to the Moon in the Apollo program. The Saturn 1 and Saturn 1B were each fitted with eight H-1 engines in their first stages. The engine was developed and built by the Rocketdyne Division of North American Aviation, Inc., and used RP-1 (kerosene) and liquid oxygen. The H-1 evolved from the Jupiter missile engine.
The version of the engine shown here developed about 188,000 lbs of thrust. The Saturn 1B launched Apollo 7 in 1968, Skylab missions in 1973, and the Apollo-Soyuz Test Project in 1975. This engine was donated in 1968 to the Smithsonian by Rocketdyne.