Fuel cell worries delay shuttle

Fueling the shuttle never got under way before one of three cells providing electricity to the space shuttle malfunctioned. The space agency planned to further examine the problem and try again at 12:03 a.m. EDT September 7.

"The launch rules say you need to have three good, operating fuel cells," said NASA spokesman Bruce Buckingham. "We're going to see if it's something that's a real problem or whether it's something we can rectify.''

The problem was discovered shortly before an overnight meeting to decide whether to start pumping the shuttle's fuel tank with supercold liquid hydrogen and liquid oxygen. When the shuttle's fuel cells were powered up, a low voltage reading came from one of the alternating current units. The other two alternating current units spiked up to compensate for the lower voltage in the first unit.

This wasn't the first time a fuel cell problem had caused a scrub, Buckingham said.

The delay puts more pressure on NASA to get Atlantis off the ground this week or postpone the launch until most likely late October so as not to interfere with a Russian mission to the space station later in the month.

NASA had planned to attempt a launch on all three days it had this week — September 6, 7 and 8. The space agency has tried launching three times in a row only once before, in 2000. The weather forecast for all three days put the chance of weather prohibiting the attempt at 30 percent.

NASA almost didn't get a chance to try a launch this week because of Tropical Storm Ernesto. Workers were halfway into moving the shuttle back to an assembly building because of the approaching storm last week when NASA managers reversed themselves and decided to leave the spacecraft at the launch pad so they could have a shot this week.

The shuttle, which is on a construction mission to the international space station, was already delayed by the Columbia shuttle accident, continued safety problems after Discovery's flight in 2005, a lightning strike in August and the threat of Tropical Storm Ernesto.

If Atlantis doesn't get in the air this week, the next chance probably won't come until late October.

The shuttle was to deliver a 35,000-pound, $372 million addition to the half-built international space station during an 11-day mission. Four astronauts will take three spacewalks to resume construction on the orbiting lab, the first such work in 3 1/2 years after the Columbia disintegrated while returning to Earth.

This mission to deliver two girders crucial to the space station's continued expansion must be done before the final 14 shuttle flights.

The Russians plan to launch a Soyuz capsule on Sept. 18 ferrying two new station crew members and the space station's first female tourist, Dallas-area entrepreneur Anousheh Ansari. Officials with both space agencies wanted to avoid the shuttle and Soyuz meeting at the station, fearing a traffic jam.

Atlantis' mission will be the first since late 2002 to expand the space station. The last two flights were tests evaluating a redesign of the external fuel tank, whose falling foam was blamed for the Columbia accident.