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Gas leak postpones space shuttle Discovery launch

 Space shuttle Discovery stands ready at pad39a in the early morning hours before a scheduled evening launch at Kennedy Space Center in Cape Canaveral...
 A full moon begins to set as the space shuttle Discovery sits on Kennedy Space Center's Launch Pad 39-A before sunrise Wednesday morning March 11, 20...

Space Shuttle

Space shuttle Discovery stands ready at pad39a in the early morning hours before a scheduled evening launch at Kennedy Space Center in Cape Canaveral...

APTOPIX Space Shuttle

A full moon begins to set as the space shuttle Discovery sits on Kennedy Space Center's Launch Pad 39-A before sunrise Wednesday morning March 11, 20...

NASA postponed the launch of space shuttle Discovery just hours before it was to head to the international space station Wednesday because of a hydrogen gas leak that could have been catastrophic at liftoff.
The leak was in the same system that has already caused a vexing one-month delay. Shuttle managers were shooting for another launch attempt Thursday night provided they could fix the problem quickly.
The gaseous hydrogen began leaking just as the launch team was close to wrapping up the loading of Discovery's external fuel tank for a late night liftoff. The seven astronauts had yet to board the spaceship.
Discovery's flight to the space station is already late because of concern about hydrogen gas valves in the ship's engine compartment. NASA spokesman Allard Beutel said Wednesday's leak was in plumbing outside Discovery, between the shuttle and the fuel tank, and had nothing to do with the valves. But it still could have been dangerous at liftoff.
"When you're launching, you have pyrotechnics going off," said another NASA spokesman, Steve Roy. "You can't have hydrogen leaking out in the vicinity of a launch pad ... it's possible it could explode."
As NASA drained the external fuel tank and pondered its next move, Mission Control notified the three astronauts aboard the space station that their visitors would not be arriving on time. Commander Mike Fincke asked to be kept abreast of any developments.
NASA has until Monday to send Discovery to the space station, otherwise the flight will have to be put off until April. That's because a Russian Soyuz rocket is slated to blast off in two weeks, on a higher priority mission, with a fresh space station crew.
Discovery's liftoff originally was targeted for mid-February, but concern about the shuttle's three hydrogen gas valves resulted in four delays.
Shuttle managers said they're convinced after extensive testing that the valves are safe and won't break like one did during the last shuttle launch in November. The valves are part of the main propulsion system and control the flow of hydrogen gas into the fuel tank, in order to maintain proper tank pressure.
The cargo on Discovery includes 31,000 pounds of framework that holds two folded-up solar wings and a radiator. The space station already has six electricity-producing wings; the two going up will be the last ones and elevate the orbiting outpost to full power.
A Japanese astronaut, Koichi Wakata, is going up on Discovery. He will become the first person from Japan to live on the international space station, an achievement that has drawn more than 200 Japanese to NASA's launching site.
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Associated Press writer Mike Schneider contributed to this report.
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On the Net:
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