It took space shuttle Discovery several months to get off the ground on its final mission, but the shuttle's landing came off without a hitch. Discovery touched down on schedule, just before noon March 9, putting an end to its 26 years of service, in which the orbiter made 39 trips to space and logged more than 230 million kilometers.

The shuttle was originally scheduled to lift off in November, but a series of delays and glitches at the launch pad kept it grounded until February. Having completed its final mission, officially designated STS-133, Discovery is now headed to retirement as NASA phases out the shuttle program. Discovery will likely end up as an exhibit at the Smithsonian National Air and Space Museum, but NASA will not make an official proclamation on the future home of the three remaining shuttles until April 12.

The astronauts of the STS-133 mission delivered to the International Space Station (ISS) two major pieces of hardware: a module to provide additional storage and work space, and an external platform for storing spare parts on the station.

"This is very bittersweet for all of us," NASA administrator Charles Bolden, a former astronaut, said at Kennedy Space Center in Florida after the landing, according to a NASA statement. "Discovery holds a special place for me and for [Kennedy director] Bob Cabana over here because we both had the opportunity to fly on it twice."

Two shuttle launches remain on NASA's calendar. In the first, targeted for April, Mark Kelly, the husband of Rep. Gabrielle Giffords, will command space shuttle Endeavour on a trip to the ISS. The second mission, the last one for the shuttle program, is scheduled for June. That flight will send the Atlantis orbiter to the ISS.

Photo of Discovery landing at Kennedy Space Center: NASA