Repaired space shuttle ready for launch

NASA will try again on Sunday to launch space shuttle Discovery on a construction mission to the International Space Station after fixing a fuel leak that triggered a delay last week.

Blastoff is set for 7:43 p.m. (2343 GMT) from Kennedy Space Center in Florida.

Engineers installed new seals in a fuel vent line, hoping that will solve the problem that postponed NASA's first launch attempt on Wednesday when hydrogen gas leaked from the shuttle's fuel tank, posing a fire hazard.

Technicians were unable to find the exact cause of the leak.

"I was a little surprised that we didn't find something more obvious because it was a healthy leak," shuttle launch director Mike Leinbach told reporters on Saturday.

Still, if the shuttle does not leak when it is fueled for flight on Sunday, it will be safe to fly, he added.

NASA plans to start filling the shuttle's tank with 500,000 gallons of liquid oxygen and liquid hydrogen at about 10:30 a.m. (1430 GMT) on Sunday.

NASA has until Tuesday to launch the shuttle or face a delay until April 7 to avoid a schedule conflict with a Russia-led Soyuz mission to replace the station's prime crew.

Discovery will be carrying the fourth and final solar power module for the U.S. part of the station, a $100 billion project of 16 nations. The crew includes Japanese astronaut Koichi Wakata, who will be left behind to serve as a station flight engineer and the first Japanese to live on the outpost