The Redstone engine is one of the most historic developments in U.S. rocket technology. As the powerplant for the Redstone missile, it was this country's first large-scale operational rocket engine. It went on to power the Jupiter-C, a modification of the Redstone missile that placed the U.S.'s first artificial satellite, Explorer 1, in 1958. In 1961, another modified Redestone, the Mercury-Redstone 3, launched the first American into space, Alan B. Shepard. The thrust of the engine as used in the Redstone missile was 78,000 lbs. As modified for use as a booster for Shepard's Mercury spacecraft, it produced 83,000 lbs of thrust. The engine shown here appears to have been an earlier experimental model of the A-7 version. It was donated to the Smithsonian in 1970 by the Rocketdyne Division of North American Aviation, Inc.