Bay 3 at NASA's Kennedy Space Center is being installed in space shuttle Discovery.

In Orbiter Processing Facility bay 3 at NASA's Kennedy Space Center in Florida, space shuttle main engine No. 1 (top) is being installed in space shuttle Discovery. Each engine is 14 feet long, weighs about 6,700 pounds, and is 7.5 feet in diameter at the end of the nozzle. Discovery is being processed for its next mission, STS-119, targeted for launch on Feb. 12, 2009. Discovery and its crew will deliver integrated truss structure 6 (S6) and solar arrays to the International Space Station. Photo credit: NASA/Dimitri Gerondidakis