for National Geographic News
"Welcome back," said astronaut Blaine Hammond from Mission Control in Houston, Texas, as the Discovery space shuttle landed at California's Edwards Air Force Base, completing the first U.S. manned space mission in 32 months.
That was in October 1988, almost three years after the space shuttle Challenger exploded after liftoff, killing all seven crew members.
Tomorrow, almost 17 years after Hammond welcomed it home, Discovery will once again return to flightthis time on the heels of the Columbia catastrophe.
Columbia exploded over central Texas as it reentered the Earth's atmosphere on February 1, 2003.
In the wake of that accident, which also killed a crew of seven, NASA has made a series of safety improvements to the shuttles. Officials say they are now confident that Discovery is safe to fly.
"The proximate causes of the loss of Columbia have been addressed," NASA Administrator Michael Griffin said at a recent news conference. "We honestly believe this is the cleanest flight we have ever done."
Discovery will blast off from Cape Canaveral, Florida, carrying seven crew members to the International Space Station. Since NASA suspended shuttle missions after the Columbia disaster, the Russian spaceship Soyuz has been the only means for getting crew and supplies to the space station.
The delivery and repair mission will be the 114th space shuttle flight and the 31st for Discovery.
But the latest return to flight also marks the beginning of the end for the aging space shuttle fleet, which is slated for retirement in 2010.
Investigators concluded that the Columbia accident was caused by a chunk of foam insulation that had broken off during liftoff, piercing the heat-resistant tiles on the left wing of the spacecraft.
This allowed superhot gases to penetrate the spacecraft's heat shield, causing the shuttle to disintegrate upon reentry.
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