- NASA - space shuttle
AFP - The US space shuttle Endeavour's launch was delayed on Saturday following a hydrogen leak, postponing a mission to the International Space Station by at least four days.
The launch had been scheduled for 7:17 am (1117 GMT) from Cape Canaveral in Florida. Now the earliest opportunity for the shuttle's liftoff will be on June 17, officials said.
The National Aeronautics and Space Agency said in a statement that the leak in a venting system was detected near the Ground Umbilical Carrier Plate, which is attached to the external tank at its intertank area.
The system is used to carry excess hydrogen safely away from the launch pad at NASA's Kennedy Space Center in Florida.
Shuttle managers have set a meeting for 2:00 pm Sunday (1800 GMT) to discuss the repair options and Endeavour's launch attempt opportunities.
It will now take the space agency 24 hours just to empty Endeavour's external tank, which contains two million liters of liquid hydrogen and oxygen.
But officials said the new target date of June 17 may also present a conflict as NASA has scheduled for that day the launch of the Lunar crater observation and sensing satellite, which is due to lift off on top of an Atlas V rocket from Cape Canaveral Air Force Station, Florida.
The leak was similar to one that occurred during the first launch attempt of the space shuttle Discovery in March.
But mission manager Mike Moses acknowledged that even now NASA did not know what had caused Discovery's leak in March.
"We did not really find anything, but obviously something is going on, the second time over three flights," he said.
In the future, the International Space Station where Endeavour is planning to go 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 and 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."