"This milestone concludes the assembly, processing, inspection, data review and tests required for acceptance of engines," said Space Shuttle Main Engine project manager, Gene Goldman, at NASA's Marshall Space Flight Center, Huntsville, Ala.

The Return to Flight mission, designated STS-114, is targeted for a launch opportunity beginning in May 2005. The seven-member Discovery crew will fly to the International Space Station primarily to test and evaluate new procedures for flight safety, including Space Shuttle inspection and repair techniques.

Returning the Space Shuttle to flight is the first step in realizing the Vision for Space Exploration. The Vision calls for a stepping-stone strategy of human and robotic missions to achieve the nation's new exploration goals, starting with returning the Shuttle safely to flight and completing the International Space Station.

"Although there is still much work to be done, the engines are the last big components to install on the orbiter prior to rolling over to the Vehicle Assembly Building," said Stephanie Stilson, NASA's Discovery vehicle manager. "This shows we're moving in the right direction for Return to Flight," she added.

Engines number 2057, 2056 and 2054 were installed on Discovery. STS-114 is the first flight for engine 2057, third for engine 2056 and fifth for engine 2054. Weighing slightly more than 7,000 pounds, the main engine is the world's largest reusable liquid rocket engine.

During liftoff, each of the three engines consumes 132,000 gallons of liquid hydrogen and 49,000 gallons of liquid oxygen fuel. That's more than half a million gallons of fuel during an eight-and-one-half-minute launch. If the three engines pumped water instead of fuel, they could drain an average-sized swimming pool in 25 seconds. At full power, the three engines generate as much energy as 23 Hoover Dams. They operate at temperatures ranging from minus 423 F to 6,000 F, hotter than the boiling point of iron.

After a Shuttle mission, the engines are taken to the Space Shuttle Main Engine Processing Facility at Kennedy for post- flight inspections and maintenance. Then they are sent to NASA's Stennis Space Center, Miss., for a pre-flight acceptance test.

The Rocketdyne Propulsion and Power division of The Boeing Co. of Canoga Park, Calif., manufactures the main engines. Pratt and Whitney, a United Technologies Company of West Palm Beach, Fla., builds the high-pressure turbo pumps. Marshall manages the Space Shuttle Main Engine Project for the Space Shuttle Propulsion Program.

NASA TV will feed b-roll and sound bites related to the engine installation beginning today at 3 p.m. EST. NASA TV is available on the Web and via satellite in the continental U.S. on AMC-6, Transponder 9C, C-Band, at 72 degrees west longitude. The frequency is 3880.0 MHz. Polarization is vertical, and audio is monaural at 6.80 MHz. In Alaska and Hawaii, NASA TV is available on AMC-7, Transponder 18C, C- Band, at 137 degrees west longitude. The frequency is 4060.0 MHz. Polarization is vertical, and audio is monaural at 6.80 MHz.

For NASA TV information and schedules on the Internet, visit:

http://www.nasa.gov/ntv

For more information on Return to Flight on the Internet, visit:

http://www.nasa.gov/returntoflight

For photos of engine installation on the Internet, visit: http://mediaarchive.ksc.nasa.gov/search.cfm?cat=42