Shuttle Touches Down Safely

APThe Discovery space shuttle landing at a base in California early Tuesday.
EDWARDS AIR FORCE BASE, California -- The Discovery space shuttle and its seven astronauts returned to Earth safely on Tuesday successfully completing NASA's troubled resumption of human space flight 2 1/2 years after the Columbia disaster.

Discovery's mission eased some of NASA's woes after the deaths of Columbia's seven astronauts but it may also have been the last shuttle flight for some time.

The U.S. space agency grounded the space shuttle fleet after Discovery shed insulating foam during its launch, the same problem that doomed Columbia.

Discovery made a fiery re-entry into Earth's atmosphere at 27,000 kilometers per hour and swooped over the Pacific Ocean before gliding to a smooth predawn landing at Edwards Air Force Base in California.

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.

"Congratulations on a truly spectacular test flight," astronaut Ken Ham at Mission Control in Houston told the Discovery crew as the shuttle stopped on the runway. "Welcome home friends."

Discovery's crew -- Eileen Collins, Jim Kelly, Steve Robinson, Soichi Noguchi, Andy Thomas, Wendy Lawrence and Charlie Camarda -- performed a traditional walk-around to inspect the ship after landing. All appeared to be in good shape.

NASA accomplished its main goal for the mission -- safely launching and landing the aging shuttle.

But when chunks of insulation flew off Discovery's fuel tank during launch, the U.S. space agency was disappointed to find it had failed to fix the problem that led to Columbia's demise on Feb. 1, 2003.

Investigators blamed Columbia's disintegration over Texas on a large piece of insulating foam that broke off the tank during launch and punched a hole in the orbiter's wing, allowing superheated gases to enter as the ship returned to Earth.

For Discovery's return, NASA had commander Collins adjust the shuttle's orbit so that it would not fly over the most heavily populated areas of Los Angeles in case of another accident. Columbia showered Texas and Louisiana with debris.

Radio communications between the shuttle commander and mission control fell largely silent as the shuttle nosedived toward the Mojave Desert landing strip. Double sonic booms sounded over southern California as the shuttle dipped below the speed of sound.

Pilot Jim Kelly steered Discovery in a wide circle to burn off speed 9,000 meters above the runway -- a point in the flight Columbia never reached.

Collins took over the final maneuvers and gently eased the 100-ton spacecraft onto the concrete landing strip.

"We're happy to be back, and we congratulate the whole team on a job well done," she said.

NASA scored some notable successes on its long-awaited return-to-flight mission, launched on July 26 after the agency spent $1 billion on repairs and safety upgrades.

Discovery carried badly needed supplies and equipment to the space station and used new technology, including laser scanners, to search for damage on the outside of the shuttle.

Discovery's crew performed three successful spacewalks -- replacing a faulty steering gyroscope and reviving another on the space station.

But the crew also had to perform an unexpected repair with an unprecedented and risky spacewalk to the belly of the shuttle to remove bits of cloth filler protruding from the spacecraft's heat-shield tiles, which NASA managers feared could cause dangerous overheating on re-entry.

The fuel tank foam problem prompted NASA to ground the shuttle fleet until it can find a fix. The U.S. space agency has set Sept. 22 as a target for the next shuttle launch but NASA managers have said the date is unrealistic.

"We're going to try as hard as we can to get back in space this year, because we have a big construction project we're working on and we need the shuttle to do it," Griffin said. "So we're going to try as hard as we can, but we're not going to go until we're ready to go."

The shuttle, scheduled to be retired in 2010, is the key to the future of the unfinished international space station because it is the only spacecraft capable of carrying large components into space.