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This is the RL10, the world's first operational liquid-hydrogen/liquid oxygen high energy rocket engine and was re-startable in space. It was developed and built by the Pratt & Whitney Aircxraft Company. Two RL10s, each of 15,000 pounds of thrust, made up the Centaur upper stage of Atlas and Titan launch vehicles. A cluster of six RL10s also powered the second stage of the Saturn 1, a precursor to the Saturn V manned Project Apollo lunar launch vehicle.

The Atlas-Centaur first successfully flew in 1966 and was the first full-thrust re-start in space. Atlas-Centaur missions included Surveyor lunar probes, Mariners (Mars, Venus, and Mercury probes), and Pioneers 10-11 to Jupiter and Saturn. This engine was transferred to the Smithsonian in 1974 from the NASA Marshall Space Flight Center.

Display Status

This object is not on display at the National Air and Space Museum. It is either on loan or in storage.

Object Details
Country of Origin United States of America Type PROPULSION-Rocket Engines Manufacturer Pratt & Whitney
Dimensions Other: 31 in. diameter x 68 in. long, 300 lb. (78.74 x 172.72cm, 136.1kg)
Materials Chamber, 347 stainless steel brazed with silver; piping, polished stainless steel; aluminum casting pump; heat exchanger of nickel alloy
Pump, aluminum casting
Nozzle ring, upper, plastic
Inventory Number A19740902000 Credit Line Transferred from NASA, Marshall Space Flight Center Data Source National Air and Space Museum Restrictions & Rights Usage conditions apply
For more information, visit the Smithsonians Terms of Use.