NASA has confirmed that it has delayed the launch of the Discovery space shuttle for the fourth time.

The decision came after a 13-hour meeting on Friday between shuttle managers, where they opted to postpone the flight due to problems with the shuttle's valve system.

The scheduled lift-off was meant for 27 February, some three months after its proposed first launch back in November.

Flying with wings

The seven-man Shuttle Discovery's mission is to take a final set of solar wings to the International Space Station, but there is now no ETA on when the shuttle will launch.

Program Manager John Shannon, said about the delay: "This is just one of those things in a complicated vehicle like this."

Bill Gerstenmaier, Associate Administrator for Space Operations at NASA Headquarters in Washington, was not too worried about the latest delay, explaining that safety is priority: "We need to complete more work to have a better understanding before flying.

"We were not driven by schedule pressure and did the right thing. When we fly, we want to do so with full confidence."

There is a further meeting planned to take place 25 February, at the Kennedy Space Centre, to determine when the next scheduled flight will be.

Let's just hope its before 2010, when the current crop of US space shuttles are set for retirement.