(04/25/2001) -- A new block 2 engine heads toward Atlantis in Orbiter Processing Facility bay 3. There the new engine will be installed for its first flight on Atlantis, for mission STS-104. 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