NASA has postponed the launch of the Endeavour space shuttle for a second time.

The National Aeronautics and Space Administration (NASA) has been forced to postpone the launch of space shuttle Endeavour again after a new gas leak was discovered.

This is the second time NASA has had to postpone take-off for the Endeavour STS-127 mission to the International Space Station (ISS).

It was originally due to lift off on Saturday (13 June) but just hours before launch time, a leak was discovered in the gaseous hydrogen venting system. Teams had been working around the clock to ready the shuttle in time for launch today (17 June).

A further leak in the same system is to blame for this new postponement. The next opportunity for an Endeavour launch is 11 July due to an orbital sun-angle condition called a beta cut-out, which occurs between 22 June and 10 July. The cut-out makes shuttle and space station docked operations impossible.

The 16-day mission will include five spacewalks lasting 32.5 hours and will complete the construction of the Japan Aerospace Exploration Agency’s Kibo laboratory. It will be the 32nd mission to the International Space Station, which orbits 350 kilometres above the Earth.

For more information about the Endeavour STS-127 mission, visit: http://www.nasa.gov/shuttle