Endeavour launch postponed due to hydrogen leak

The launch had been scheduled for 7:17 am (1117 GMT) from Cape Canaveral in Florida.

But "the launch is scrubbed, it's official," spokesman Kyle Herring told reporters, saying it would not be rescheduled for at least 24 hours.

Meanwhile, the National Aeronautics and Space Agency said in a statement posted on its website that the leak was detected near the Ground Umbilical Carrier Plate, which is attached to the external tank at its intertank area.

The leak was similar to one that occurred during the first launch attempt of the space shuttle Discovery in March.

After the leak is assessed, shuttle managers planned to meet Saturday to discuss what steps to take next, including targeting a new launch date for Endeavour's mission to the International Space Station, NASA said.

In the future, the ISS is set to be a temporary home to 13 astronauts -- the first time so many people have stayed on the orbiting station at once.

The six US astronauts and a Canadian female astronaut that Endeavour is expected to eventually bring to the ISS will join another US astronaut and one more from Canada, as well as two Russians, a Belgian and Japan's Koichi Wakata who are currently living on the ISS.

Construction began on the ISS a decade ago, and the push is on to complete the building before NASA ends its shuttle missions in September 2010.

Endeavour's crew are tasked with installing the final elements of the Japanese laboratory Kibo during their 16-day mission.

The station has become a sophisticated platform for scientific experiments after the installation of a European laboratory last year and the arrival of the hi-tech Japanese lab that is currently being completed.

When Endeavour finally lifts off, it will be the 32nd mission to the ISS, which orbits 350 kilometers (220 miles) above Earth, and the last of three missions to assemble the Kibo laboratory.

Over the five planned spacewalks lasting some 32.5 hours, the astronauts will install a permanent 1.9 tonnes platform to Kibo, which will serve as one of the station's porches for conducting experiments in the vacuum of space.

Endeavour will also deliver a large number of spare equipment, and bring up an unpressurized storage area for keeping the experiments that have been exposed to the extremes of space.

It will also bring with it another platform that can be detached from the space station and then flown back to Earth in the Endeavour's cargo hold.

NASA is seeking to make maximum use of its flights to the space station with only another seven planned after the Endeavour's trip before the shuttles are retired.

Senior NASA official Bill Gerstenmaier has offered assurances that the space station has the capacity to play host to 13 astronauts at once, after a fourth solar panel was erected along with other equipment including toilets, a kitchen and a machine to recycle urine into drinking water.

But he acknowledged: "It's a very complex and challenging mission for the team."

(c) 2009 AFP