In In the Orbiter Processing Facility bay 1 a maneuvers a main engine into position for installation into Discovery.

In In the Orbiter Processing Facility bay 1, a Hyster forklift maneuvers a main engine into position for installation into Discovery. The main engine configuration is manufactured by Boeing Rocketdyne in Canoga Park, Calif., and includes a Pratt & Whitney high-pressure fuel turbo pump. Each space shuttle main engine is 14 feet (4.3 meters) long, weighs about 6,700 pounds (3,039 kilograms), and is 7.5 feet (2.3 meters) in diameter at the end of the nozzle. Discovery is being processed for the second return-to-flight mission STS-121.