Space shuttle Discovery’s launch date has been postponed.

The US space agency has delayed the launch of the first space shuttle of the year, due to ongoing concerns about safety.

During a review of the Discovery space shuttle’s readiness, NASA decided to halt the launch in order to collate more data and spend more time testing. It is the fourth time Discovery has been delayed from taking off.

Engineers at NASA have been working to identify what caused damage to a flow control valve on shuttle Endeavour during the last shuttle mission in November 2008.

Bill Gerstenmaier, Associate Administrator for Space Operations at NASA, said: “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.”

Discovery has three flow control valves that channel hydrogen gas from the engines to an external fuel tank. The engineering teams are trying to determine what consequences would arise if a valve piece were to break off.

A new launch date for the Discovery has yet to be set.

For further information about the Space Shuttle Program, visit: http://www.nasa.gov/shuttle.