HANCOCK COUNTY, Miss. – With a roar and a rush of water vapor, the Space
Shuttle’s Main
Engines reached a significant milestone Jan. 21 when it surpassed 1 million
seconds of successful test
and launch firings during a flight acceptance test. The engine is scheduled
to fly on Space Shuttle
mission STS-121.
The engine test, which began at 3:30 p.m. CST at NASA’s Stennis Space Center
in Mississippi, ran
for eight-and-one-half minutes, the length of time it takes the Space
Shuttle to achieve orbit.

“This 1 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. “It is a
huge sense of pride to the
NASA and Boeing team that the engines, which began testing in June 1975,
have never experienced a
major anomaly. Personally, it is an honor to be part of this great program.”
The 1 million seconds of performance has been accrued through more than
826,000 seconds in the
test stand during development, certification and acceptance testing, and
nearly 174,000 seconds of
flight time over 113 missions.

“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

Developed in the 1970s, the Space Shuttle Main Engine is the world’s most
sophisticated reusable
rocket engine. Each powerful main engine is 14 feet long, weighs about 7,000
pounds and is 7.5 feet in
diameter at the end of its nozzle and generates nearly 400,000 pounds of

Rigorous testing is used to verify that an engine is ready to fly and is
critical to any flight program.
As recently as 1998, engineers developed and tested a large-throat main
combustion chamber, which
improved the Space Shuttle Main Engines reliability by reducing operating
temperature and pressures.
A new high-pressure fuel turbopump 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 Space Shuttle Main Engines. Pratt and Whitney, a United
Technologies Company of
West Palm Beach, Fla., builds the high pressure turbopumps, and the Marshall
Space Flight Center in
Huntsville, Ala., manages the Space Shuttle Main Engine project for NASA’s
Space Shuttle Program.