NASA says Endeavour shuttle launch will likely take place June 17

Canadian astronaut Julie Payette and her six American crew mates will have to be patient for a few more days after NASA announced the launch of Endeavour was re-scheduled for sometime between this coming Wednesday and Saturday.

The scheduled weekend launch was cancelled after a gaseous hydrogen leak was found near the external fuel tank.

NASA engineer Leroy Cain said Sunday that repairs on Endeavour are coming along and the U.S. space agency has found no other problems with the shuttle.

A similar problem developed last March during the first attempt to launch the shuttle Discovery.

Hydrogen gas is extremely volatile and can burn in large enough quantities.

At the Kennedy Space Center in Florida for the launch, fellow astronaut Chris Hadfield said a few extra days wait is almost a gift to the astronauts readying for the Endeavour flight.

"The best part of an astronaut's life is when you're training for a specific flight," he told The Canadian Press on Sunday.

"And the best part of that is in the few weeks before flight when everything else in your life is sort of stripped away and you're focused on this very complicated, challenging, pure part of your life."

The crew is in quarantine before the flight and spend their days preparing physically and psychologically, he said.

"You're sort of cocooned away from the world," Hadfield said. "And it's also a very nice time to relax and gather your thoughts and really focus yourself because space flight is extremely difficult. There's definitely a Zen component to getting yourself ready."

If Endeavour hadn't been scheduled to fly before next Saturday, it would have had to wait until July 11 for the next launch attempt due to unfavourable sun angles that would make the shuttle too hot while docked at the International Space Station.

NASA managers have to juggle Endeavour's launch with a scheduled launch of a moon probe committed to fly between June 17 and 18.

"Either of them between now and then could have a problem," Hadfield said.

"And then you'll want to have the other one ready. So we'll keep getting them both ready."

NASA will commit to set launch dates for the probe and the shuttle Monday.

After NASA scrapped Saturday's planned launch, Payette apologized to disappointed friends and family who had travelled to Florida to see the crew lift off on board Endeavour.

Payette last visited the space station in 1999 when there was no one on board. She was the first Canadian astronaut to visit the now-giant space complex.

When Endeavour finally pulls up, there will be 13 people together in orbit for the first time, including Canadian astronaut Bob Thirsk who is on a six-month visit.