EDWARDS AIR FORCE BASE, Calif. (Reuters) - The space shuttle Discovery and its seven astronauts glided safely back to Earth on Tuesday, successfully completing NASA's troubled return to human space flight 2 1/2 years after the Columbia disaster that killed all the astronauts on board.
NASA officials appeared relieved after the predawn landing at Edwards Air Force Base in California's Mojave Desert. But the mission may be the shuttle's last for some time as recent safety upgrades failed to prevent Discovery from shedding insulating foam at launch, the same problem that doomed Columbia.
"Discovery is home, the crew is safe and we've come full circle now," said NASA launch director Mike Leinbach.
Following a smooth and problem-free re-entry into the atmosphere, Discovery Commander Eileen Collins gently settled the 100-ton ship onto a concrete runway just as the first rays of morning light emerged across the rugged landscape.
Collins said she thought daily about Columbia's crew and their fate and she and her colleagues on Discovery kept a photo of the seven astronauts.
NASA diverted the shuttle to California after skipping four chances to land at Discovery's home port, the Kennedy Space Center in Florida, because of menacing thunderstorms Monday and Tuesday. Discovery will travel back to Kennedy in about 7 to 10 days atop a modified Boeing 747 aircraft.
The manned space flight was NASA's first since Columbia broke apart over Texas on Feb. 1, 2003, killing all seven astronauts on board.
"There was a little bit of trepidation," pilot Jim Kelly said at a news conference after the landing. "I wouldn't be human otherwise."
NASA suspended shuttle missions after Discovery's external fuel tank shed a piece of foam during lift-off nearly as big as the chunk that smashed into Columbia's wing in 2003. That damage was blamed for bringing Columbia down 16 days later.
PLEA FOR SUPPORT
NASA spent more than $1 billion fixing the shuttle's tank and implementing other safety upgrades, but officials said more work remains before the fleet will be fit to fly again.
Collins, however, made a passionate plea for continued public support of the 24-year-old shuttle program.
"Some people say we should stop flying the shuttle because we had an accident," Collins told reporters. "But we are people who believe in this mission and want to continue it, and I ask you to please support us."
President George W. Bush applauded both NASA and the shuttle's crew.
"It was an important step for NASA as it regains the confidence of the American people and begins to transition to the new mission we've set out for NASA. So congratulations, Commander Collins. It's quite an achievement," Bush said.
The shuttles, scheduled to be retired in 2010, are key to the future of the unfinished International Space Station because they are the only spacecraft capable of carrying large components into space.
After the station is complete, President Bush wants NASA to replace the shuttle with a new generation of spacecraft capable of reaching the moon, Mars and beyond.
During the mission, Discovery's crew restocked the space station's pantries, restored its key steering system, removed discarded equipment and trash and added a new stowage platform for spare parts.
They also for the first time checked the ship's heat shield while in orbit, and made an impromptu repair when astronaut Steve Robinson conducted an unprecedented spacewalk to Discovery's belly, where he removed two protruding cloth strips from the smooth surface of the ceramic-tiled heat shield.
Managers were concerned the strips could disrupt air flow and raise temperatures dangerously on re-entry.
NASA extended the Discovery crew's visit at the outpost from eight to nine days to transfer extra supplies when it became evident the next mission would likely be delayed.
Joining Collins, Kelly and Robinson for NASA'S 114th shuttle mission was Japan's Soichi Noguchi, and astronauts Wendy Lawrence, Charles Camarda and Andy Thomas.
(Additional reporting by Irene Klotz, Jim Loney and Deborah Zabarenko in Cape Canaveral)