CAPE CARNIVERAL: The US space shuttle Endeavour’s launch was delayed today 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 (11:17 GMT) from Cape Canaveral in Florida. Now the earliest opportunity for the shuttle’s lift-off 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 Centre in Florida.

Shuttle managers have set a meeting for 2:00 pm on 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 litres 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.