The U.S. space shuttle Discovery has landed in California, safely ending the first shuttle mission since the loss of the orbiter Columbia in 2003. The touchdown ended a mission to resupply and repair the International Space Station, a flight in which the shuttle itself underwent an unexpected repair in orbit. The landing came one day late, because of bad weather on the ground.
Discovery glided down to Edwards Air Force Base in the California desert, after plunging at high speed through the atmosphere at fiery temperatures of more than 1,600 degrees Celsius.
With memories of the Columbia accident still fresh, an obviously relieved mission control welcomed Commander Eileen Collins and her six colleagues home after two weeks in orbit.
Mission Control: "Congratulations on a truly spectacular test flight. Welcome home, friends."
Collins: "Thank you. Those are great words to hear. We're happy to be back and we congratulate the whole team for a job well done."
The U.S. space agency NASA wanted Discovery to land on the other side of the country at Kennedy Space Center in Florida, but bad weather blocked runway visibility on Monday and Tuesday. Now NASA has to wait several days for a jumbo jet airliner to ferry the shuttle to Florida at an expense of $1 million.
Discovery's mission is the last for an unknown period of time. The space agency has grounded the shuttle fleet again until it can determine why a piece of hard insulation foam broke off from the orbiter's external fuel tank during liftoff. This was the same kind of mishap that damaged the wing of the shuttle Columbia in 2003, dooming it to perish upon re-entry.
Discovery escaped serious damage from the foam, but an unprecedented array of shuttle cameras and in-flight inspection techniques installed because of the Columbia accident showed minor damage. Some of Discovery's protective thermal tiles had chipped and part of its thermal blanket had ripped, but NASA engineers determined the damage would not leave the orbiter vulnerable to re-entry heat.
However, they did worry about two pieces of protective fabric wedged between the tiles that had popped out a few centimeters. They feared that resulting changes in airflow around them at supersonic re-entry speeds would increase the extreme heat on the orbiter. So astronaut Steve Robinson embarked on the first shuttle repair spacewalk to pull them out.
Deputy shuttle program manager Wayne Hale says this mission did not experience more problems than a typical shuttle flight, but there was much more strain this time on the ground support team because of the new in-flight views of the orbiter.
"We had seen problems before, but we have always seen them post-flight, when we dumped [data from] the recorders, when we got the film back from the [external fuel tank] separation cameras," said Mr. Hale. "So we always worked it post-flight and we would have weeks to work these things and come to a resolution. Now, we're seeing them in flight and we're trying to work them all [out] before we land in hours or days. So it has really put a lot of stress on the engineering work force on this flight."
Despite the technical setbacks, NASA has declared Discovery's mission a success. Astronauts resupplied the space station and fixed its steering system during a spacewalk. During another spacewalk, they tested methods for repairing shuttle tiles in orbit to prevent a tragedy like Columbia from happening again.