Discovery Mission Won't Fly As Scheduled

ANN REAL-TIME NEWS: 1400 EDT -- NASA has scrubbed Wednesday's planned launch of the space shuttle Discovery.

The culprit in Wednesday's delay, just two-and-a-half hours before the scheduled Return to Flight, was a faulty fuel tank sensor, according to the space agency. The sensor notices low fuel, feeding an engine cut-off system that stops the engine from running when there's nothing to run on, according to NASA.

"We really don’t want the engine to be running at high speed and then suddenly run out of fuel," said astronaut Dave Wolf. "That can lead to a devastating breakdown of the engine. So there are four sensors on the vehicle. Two are required to detect low-level fuel."

It was the same sort of problem that caused engineers to take Discovery from the launch pad in May after the issues surfaced during a fueling test in April. The shuttle was slowly carried back to the Vehicle Assembly Building and the fuel tank was replaced. NASA officials decided not to re-run the fueling test on the new tank in order to save time.

"We are disappointed, but we'll fly again on another day," Wolf said, quoted by the Associated Press.

FMI: www.nasa.gov