This is the Redstone rocket engine and was the U.S.'s first operational large-scale rocket engine. Development began in 1950 by North American Aviation. The engine used liquid oxygen and alcohol and developed 75,000 pounds of thrust.
On January 31, 1958, a modified Redstone rocket called the Jupiter-C, using more powerful fuel, launched Explorer 1, the first successful U.S. satellite, into orbit. On May 5, 1961, a Redstone launched Alan B. Shepard, the first American astronaut into space. The Redstone was the forerunner of other important large-scale U.S. engines, including those for the Thor, Jupiter, and Atlas missiles, the Saturn V launch vehicle, and the Space Shuttle Main Engine (SSME). This object was donated to the Smithsonian in 1991 by the U.S. Army.
This object is on display in Rockets & Missiles at the Steven F. Udvar-Hazy Center in Chantilly, VA.