(04/25/2001) -- In Orbiter Processing Facility bay 3, a new block 2 engine, at left, is moved into position for installation on Atlantis. The engine will have its first flight on mission STS-104, scheduled for launch June 14. The Block II Main Engine configuration is manufactured by Boeing Rocketdyne in Canoga Park, Calif., and includes a new Pratt & Whitney high-pressure fuel turbo pump. Engine improvements are managed by NASA’s Marshall Space Flight Center in Huntsville, Ala. Each Space Shuttle Main Engine is 14 feet (4.3 meters) long, weighs about 7,000 pounds (3,175 kilograms), and is 7.5 feet (2.3 meters) in diameter at the end of the nozzle