The space shuttle Discovery lands, ending Mission STS-124 to the International Space Station, at the Kennedy Space Center in Cape Canaveral, Florida June 14, 2008. [Xinhua/Reuters]

The launch of space shuttle Discovery has been postponed again due to concerns over a valve that keeps fuel flowing in Discovery's main engines, the National Aeronautics and Space Administration (NASA) said Saturday in a press release.

The valve is one of three that channel gaseous hydrogen from the engines to the external fuel tank. Discovery's valves were removed, inspected and reinstalled as a precaution after one valve in shuttle Endeavor had been found damaged following its mission in November.

NASA's Space Shuttle Program will convene a meeting on Feb. 13 to review data and determine whether to move forward with a flight readiness review on Feb. 18. The official launch date will be set at the readiness review, but for planning purposes launch is no earlier than Feb. 22.

Discovery's latest mission to the International Space Station originally had been scheduled for Feb. 12. During a review of Discovery's readiness for flight, NASA managers decided on Tuesday to plan a launch no earlier than Feb. 19.

Discovery's 14-day mission will deliver the International Space Station's fourth and final set of solar arrays, completing the orbiting laboratory's truss, or backbone. The arrays will provide electricity to fully power science experiments and support the station's expanded crew of six in May. Altogether, the station's 240-foot-long arrays can generate as much as 120 kilowatts of usable electricity -- enough to provide power to 42 homes of 2,800square feet.

Discovery will also carry a replacement distillation assembly for the station's new water recycling system.

(Xinhua News Agency February 8, 2009)