The Discovery space shuttle crew returned home to the Johnson Space Center in Houston on Sunday after completing a 12-day mission.

Discovery landed at the Kennedy Space Center in Florida at 3:14 p.m. Saturday, after traveling more than 5.3 million miles. Its crew delivered solar arrays to help power the International Space Station and science experiments taking place there. The astronauts completed three space walks, lasting more than six hours each, to install, repair, and maintain equipment for the station.

The STS-119 flight marked the first trip to space and the first spacewalks for former science teachers Joseph Acaba and Richard Arnold. Both are now NASA astronauts. The flight was Discovery's 36th trip to space. It marked the 125th space shuttle mission and the 28th shuttle trip to the space station.

The astronauts replaced a water-recovery system that converts urine into potable water, but it will take several weeks to analyze samples and determine whether it's working properly, NASA said. They also spoke with President Obama, members of Congress, and students from schools in the District of Columbia.

Flight Cmdr. Lee Archambault, pilot Tony Antonelli, and mission specialists Acaba, Steve Swanson, Arnold, and John Phillips returned over the weekend, while Japan Aerospace Exploration Agency astronaut Koichi Wakata remained at the International Space Station. Flight engineer Sandra Magnus took his place on the return trip and returned to Earth after 129 days aboard the station.

NASA plans to launch flight STS-125 May 12 for a mission that will return the shuttle Atlantis to NASA's Hubble Space Telescope for a final trip before the shuttle fleet retires in 2010. NASA plans five spacewalks during that 11-day mission. Astronauts embarking on the spacewalks will upgrade the Hubble and prepare it for another five years of research, NASA said.

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