NASA fuels shuttle test for cracks

CAPE CANAVERAL, FL Discovery is grounded until February because of cracks that popped up in its fuel tank during last month's launch attempt. The cracks have been fixed. But engineers still do not understand why they occurred.

So in a countdown test Friday morning, the launch team began pumping more than 500,000 gallons of liquid hydrogen and oxygen into Discovery's external fuel tank. The tank is rigged with dozens of strain gauges and temperature sensors to provide clues to the cracking.

Whenever Discovery flies, it will be its last trip into orbit. It's loaded with cargo for the International Space Station.