Cape Canaveral, Fla. NASA postponed the launch of space shuttle Discovery just hours before it was to head to the International Space Station on Wednesday because of a hydrogen gas leak that could have been catastrophic at liftoff.
The shuttle was scheduled to take Steamboat Springs High School alumnus and NASA astronaut Steve Swanson on a 14-day mission. Swanson was scheduled for three spacewalks to install a solar panel array on the International Space Station.
The leak was in the same system that already has caused a vexing one-month delay. Shuttle managers were shooting for another launch attempt tonight 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 already is 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 will elevate the orbiting outpost to full power.
Associated Press writer Mike Schneider and Steamboat Pilot & Today reporter Zach Fridell contributed to this report.