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Discovery's Last LiftoffAfter months of anticipation, the space shuttle Discovery lifted off February 24 from Kennedy Space Center in Florida on its 39th and final scheduled mission, as NASA's space shuttle program nears its end. Discovery is scheduled to land just before noon, eastern time, today.Built after Columbia and Challenger, Discovery was NASA's third space shuttle, and it's now the U.S. space program's oldest and most traveled spaceship. (See pictures of space shuttle Discovery's milestone moments.)For the STS-133 mission, Discovery carried supplies, spare parts, and the Permanent Multipurpose Module, a storage unit that's the final piece of the International Space Station.Due to a series of leaks, Discovery's launch had been postponed from its original November date. On February 24 a last-minute repair to a chipped tile and a computer problem pushed liftoff to within four seconds of the launch window's closing—any later and the mission would have had to have been rescheduled.For any launch, those last three seconds "can feel like an eternity," said NASA test director Steve Payne, who added that watching Discovery take off was "kind of an odd feeling."Although the launch was a poignant moment, "we've been working on this one for months," he said, and sending the shuttle up after so long was a relief.—Rachel Kaufman

Photograph courtesy NASA