Shuttle Launch Delayed 3 Weeks by Hydrogen Leak

(The space shuttle Endeavour won't be able to launch until July 11 at the earliest due to a persistent leak in a hydrogen tank. Engineers will begin investigating the problem, but the setback has caused the launch to miss a window of opportunity -- an unfavorable sun angle will remain until next month. The problem puts further pressure on the tight 2010 deadline NASA is under to finish its final eight shuttle flights.)

For the second time in four days, a potentially dangerous hydrogen gas leak forced NASA to delay shuttle Endeavour's launch to the international space station, this time until July at the earliest.

Launch officials waited almost an hour after the leak appeared during fueling, trying to fix it through remote commands, before calling off Wednesday's pre-dawn launch.

The leak occurred in the same place as one that cropped up Saturday: in the hydrogen gas vent line that hooks up to the external fuel tank. A similar problem stalled a shuttle flight three months ago.

"We're going to step back and figure out what the problem is and go fix it," said deputy space shuttle program manager LeRoy Cain. "And then we'll fly as soon as we're ready to safely go do that."