Press Release

Pratt & Whitney Rocketdyne’s Space Shuttle Main Engines to Power Final Flight to International Space Station

By SpaceRef Editor
July 5, 2011
Filed under , ,
Pratt & Whitney Rocketdyne’s Space Shuttle Main Engines to Power Final Flight to International Space Station

Three Space Shuttle Main Engines (SSMEs) will power the launch of Space Shuttle Atlantis on the program’s final flight to the International Space Station (ISS) – just as NASA prepares to hot-fire test the new J-2X upper-stage rocket engine developed by Pratt & Whitney Rocketdyne. The SSME is the only fully reusable high-performance rocket engine rated for human spaceflight, having delivered the majority of U.S. astronauts into space since its maiden Mission STS-1 on April 12, 1981. Pratt & Whitney Rocketdyne is the SSME prime integrator since program inception and is a United Technologies Corp. (NYSE: UTX) company.

“The Space Shuttle Main Engines have laid the foundation of safety, performance and innovation for continued space exploration,” said Jim Paulsen, SSME program manager, Pratt & Whitney Rocketdyne. “It is only fitting that that the final flight of the program coincides with testing of the next-generation engine, which could power the upper stage of the nation’s future heavy-lift launch vehicle.”

Atlantis will launch from NASA’s Kennedy Space Center on July 8 with a crew of four on Mission STS-135, which will carry the Raffaello multipurpose logistics module packed with supplies and spare parts for the station. The orbiter will also deliver a system that will be used to investigate the potential for robotically refueling existing spacecraft, and return a failed ammonia pump module to help NASA better understand the failure mechanism and improve pump designs for future systems.

The Space Shuttle Main Engines have boosted every shuttle launch since the program began in 1981, allowing astronauts from 14 different countries to travel to the ISS to conduct scientific experiments that forever changed life on earth. Scientific experiments conducted in space now commonplace include everything from smoke detectors and firefighter gear, to cardiac pacemakers and breast-cancer screening technology, to de-icing systems for airplanes. Also developed in space are nutrients now found in 90 percent of infant formulas sold worldwide.

The J-2X engine is scheduled to begin a series of hot-fire tests in June that will last several months at Stennis Space Center in Mississippi. Designed specifically to power heavy-lift launch vehicles into low-Earth orbit and beyond, the J-2X engine employs design concepts of its historic J-2 predecessor, with modern analyses, materials and processes for greater efficiency and increased power. Total thrust in a vacuum will be 294,000 pounds, and specific impulse will be 448 seconds.

Each J-2X is rated for a design life of eight starts and 2,600 seconds. and will be able to restart in space. The engine will use a gas-generator power cycle and burn liquid hydrogen with liquid oxygen.

To hear directly from some of the people who have dedicated their lives to the success of the SSME program, go to:

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 the main engines for the space shuttle, Atlas and Delta launch vehicles, missile defense systems and advanced hypersonic engines. Pratt & Whitney Rocketdyne is headquartered in Canoga Park, Calif., and has facilities in Huntsville, Ala.; Kennedy Space Center, Fla.; West Palm Beach, Fla.; Stennis Space Center, Miss; and Carlstadt, N.J. For more information about Pratt & Whitney Rocketdyne, go to

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 products and services to the global aerospace and commercial building industries.

SpaceRef staff editor.