With a roar and a rush of water vapor, the Space Shuttle’s
Main Engines (SSME) reached a significant milestone Wednesday.
The system surpassed one million seconds of successful testing
and launch firings during a successful flight-acceptance test
at NASA’s Stennis Space Center in Mississippi.

The engine that was tested is scheduled for use on STS-121, the
mission following the Space Shuttle’s Return to Flight. The
test ran for eight-and-a-half minutes, the length of time it
takes the Space Shuttle to achieve orbit.

“This one millionth-second test is a testimony to the NASA and
contractor team that developed, tested and continues to improve
the SSME to safely take humans to low Earth orbit,” said NASA’s
Miguel Rodriguez, director of the Propulsion Test Directorate
at Stennis. “Personally, it is an honor to be part of this
great program,” he added.

The one million seconds of performance have been accrued
through more than 826,000 seconds in the test stand during
development, certification and acceptance testing, and almost
174,000 seconds of flight time during 113 Space Shuttle

The Main Engine that flies today has gone through major
upgrades and is safer, stronger and more reliable than the one
that flew on STS-1 in 1981. Reaching this milestone is a
historic moment for the Space Shuttle Program,” said Michael
Rudolphi, Space Shuttle Propulsion Manager.

Developed in the 1970s, the SSME is the world’s most
sophisticated reusable rocket engine. Each is 14 feet long,
weighs about 7,000 pounds and is seven-and-a-half feet in
diameter at the end of its nozzle. It generates almost 400,000
pounds of thrust.

Rigorous testing is used to verify that an engine is ready to
fly and is critical to any flight program. In 1998, engineers
developed and tested a new main combustion chamber, which
improved the SSMEs reliability by reducing operating
temperature and pressures. A new high-pressure fuel turbo pump
was also developed and implemented for its first flight in July
2001 on STS-104.

The Rocketdyne Propulsion and Power division of The Boeing Co.
of Canoga Park, Calif., manufactures the SSMEs. Pratt and
Whitney, a United Technologies Company, of West Palm Beach,
Fla., builds the high-pressure turbo pumps and NASA’s Marshall
Space Flight Center in Huntsville, Ala., manages the SSME
project for the Space Shuttle Program.

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