Space Shuttle Discovery lands safely at Kennedy Space Center in Florida at 9:14 AM EDT (13:14 GMT) Monday, after completing a 13-day flight mission, NASA television showed.

The orbiter landed on schedule under overcast skies at the Kennedy Space Center, and just after the safe return, NASA hailed this as a highly successful mission.

"Welcome back Discovery and congratulations on a great mission," Mission Control told Commander Steve Lindsey after Discovery rolled to a stop.

"It was a great mission, a really great mission, and enjoyed the entry and the landing," Lindsey replied.

The mission, designated STS-121, marks a critical step for the US space program's recovery from the 2003 Columbia disaster.

Discovery gave the United States a birthday present when it launched on July 4. The shuttle spent just under 13 days in orbit, with almost nine days at the International Space Station.

The shuttle delivered a new Expedition 13 crew member and much needed supplies and equipment to the international outpost. The shuttle crew also conducted three spacewalks to perform maintenance on the station and to test on-orbit heat shield repair techniques.

Outside experts say Discovery's performance allows the shuttle program to return to its old job before Columbia shattered in pieces on its return in 2003, killing seven astronauts. NASA's mission is to finish building the international space station with a flurry of 15 more shuttle flights.

"We're going in the right direction," lead flight controller Tony Ceccacci said. "It's time to get going and start building the station."

Space shuttle Atlantis is scheduled to blast off as early as Aug. 27. Unlike Discovery's missions, which focus primarily on the flight test aspects, the Atlantis crew will haul up a major space station piece, a building-block beam, and attach it to the orbiting outpost.

The space station is just half finished, eight years after the first piece went up.

NASA wants it completed by the time the three remaining shuttles are retired in 2010, to make way for a new spaceship capable of carrying astronauts to the moon.

(Xinhua News Agency July 18, 2006)