NASA on Wednesday moved up the launch date of space shuttle Discovery one day to March 11, confident safety issues over fuel valves that prompted four previous delays have been resolved.

The shuttle will carry a final pair of solar wing panels to the International Space Station, which is nearing completion after more than a decade of work.

A final review of flight preparations is scheduled for Friday at the Kennedy Space Center in Florida. If managers clear the shuttle for flight, the seven astronauts assigned to the 14-day mission would fly to the spaceport on Sunday.

NASA's first flight of the year has been on hold due to lingering concerns over tiny pop-up valves that regulate pressure in the shuttle's hydrogen fuel tank.

During the last shuttle flight in November, one of the three valves cracked and NASA officials wanted to be sure they understood what could happen if a larger or more serious break occurred.

NASA replaced Discovery's three valves with spares that have made fewer flights. For the long term, the agency plans to redesign the valves.

NASA expects to fly eight or nine more missions to the space station to complete construction and service the Hubble Space Telescope for a fifth and final time before the shuttle fleet is retired in 2010.

The station is a $100 billion project of 16 nations. It is being prepared to house six astronauts full-time beginning in May.