Press Release

Three Pratt & Whitney Rocketdyne RS-68A Engines Power Delta IV Heavy Upgrade Vehicle on Inaugural Flight

By SpaceRef Editor
June 29, 2012
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The sky rumbled and the ground shook as the three most powerful hydrogen-fueled liquid rocket engines ever built successfully boosted a U.S. government satellite into orbit. Developed by Pratt & Whitney Rocketdyne, the RS-68A engines thundered into the sky on their inaugural launch, boosting a United Launch Alliance Delta IV Heavy rocket from the pad at Cape Canaveral Air Force Station, Fla. Once above Earth’s atmosphere, the reliable Pratt & Whitney Rocketdyne RL10B-2 engine provided upper-stage propulsion. Pratt & Whitney Rocketdyne is a United Technologies Corp. (UTX) company.

“The RS-68A engines were specifically developed for this mission, and to watch them fly successfully for the first time, with so much power, is truly gratifying,” said Steve Bouley, vice president, Launch Vehicle & Hypersonic Systems, Pratt & Whitney Rocketdyne. “This launch is testament to the reliability of our propulsion systems, and the capabilities of the talented people who make them a reality. We are proud to help place these critical national security payloads into orbit to support our service men and women worldwide.”

“The RL10B-2 performed exactly as planned, boosting a payload that will benefit the United States and its allies,” said Christine Cooley, RL10 program manager, Pratt & Whitney Rocketdyne.

The RS-68A is a liquid-hydrogen/liquid-oxygen booster engine designed to provide increased thrust and improved fuel efficiency for the Delta IV family of launch vehicles. It evolved from the RS-68 engine, which was developed and certified for commercial use with private company funds. Each RS-68A provides 702,000 pounds of lift-off thrust, or 39,000 more pounds of thrust than the RS-68 engine, with increased combustion efficiency as well. During hot-fire tests, the RS-68A engine demonstrated the ability to operate for 4,800 seconds of cumulative run time – more than 10 times what’s needed to boost the Delta IV Heavy rocket into space.

The RS-68, RS-68A and RL10 engines will power the Delta IV Evolved Expendable Launch Vehicles through the decade.

Pratt & Whitney Rocketdyne, a part of Pratt & Whitney, is a preferred provider of high-value propulsion, power, energy and innovative system solutions used in a wide variety of government and commercial applications, including engines for launch vehicles, missile defense systems and advanced hypersonic engines. Behind its successful designs, manufacturing processes, and hardware are Pratt & Whitney Rocketdyne’s research and development engineers, who solve tough problems in extreme environments. For more information, go to Follow us at and

Pratt & Whitney is a world leader in the design, manufacture and service of aircraft engines, space propulsion systems and industrial gas turbines. United Technologies, based in Hartford, Conn., is a diversified company providing high technology

SpaceRef staff editor.