NASA working to launch shuttle despite problem

CAPE CANAVERAL, Florida (Reuters) - NASA on Friday worked to find a way around a suspected wiring glitch that scuttled the first launch attempt of space shuttle Atlantis carrying a European unit to the International Space Station.

Atlantis might now lift off at 3:43 p.m. EST on Saturday. Managers planned to meet later on Friday to decide if a Saturday attempt was possible.

Meteorologists said there was a 60-percent chance that the weather would be suitable for a launch.

The U.S. space agency wants to fit in an 11- to 13-day shuttle mission to deliver and install Europe's Columbus science laboratory -- a project that has been waiting for five years.

But its first attempt to get the shuttle underway was stopped hours before launch from the Kennedy Space Center on Thursday, when two fuel sensors failed, perhaps due to a wiring problem.

NASA's LeRoy Cain, who oversees shuttle operations at the Florida spaceport, said experts would work on ways to fly the mission anyway.

The plan "would be with the intent of flying with one or more failures potentially in the system," Cain told reporters on Thursday night. "Maybe we won't be comfortable with that risk."

MANUAL CONTROL

One plan would have the shuttle crew, with support from ground controllers, take over manual control of a backup emergency engine cutoff system should a problem arise during the 8.5-minute climb to orbit.

The suspected wiring problem affects two of four gauges in the bottom of the shuttle's fuel tank that monitor, like a dipstick, how much frozen hydrogen is left in the container.

The system ensures that the shuttle's three main engines cut off if there is no fuel for them to burn. It is a backup to the shuttle's flight computers that normally control engine cutoff once the shuttle is in orbit or if there is an engine problem during ascent.

If the engines, which have the power to drain an average-sized home swimming pool in 25 seconds, ran dry, they could seize up and break apart, possibly with catastrophic results.

NASA wrestled with fuel sensor problems as it prepared to return the space shuttle fleet to flight after the 2003 Columbia accident.

Armed with that research, engineers are weighing options to work around the balky sensors and still maintain the backup engine cutoff system, said Cain.

Any actual repairs likely would bump Atlantis' launch to mid-January so the ship could be returned to its processing hangar where workers could more easily access the sensors and related electronics equipment.

NASA has 10 shuttle missions remaining to complete construction of the $100 billion space station. It also would like to fly two resupply flights and a servicing call to the Hubble Space Telescope. The missions must be complete by September 30, 2010, when the shuttle program ends.

(Editing by Maggie Fox and Xavier Briand)