Mission managers scrubbed today's scheduled launch of Space Shuttle Endeavour and mission STS-69 due to the failure of one of the orbiter's three fuel cells.
Fuel cells provide electricity to the orbiter while in space.
Mission rules state that all three fuel cells must be up and operational prior to launch. Managers have indicated the fuel cell will be removed and replaced, effectively postponing the launch about a week. A briefing is being planned for about 10 a.m. EDT today to discuss the problem and likely turn-around timelines.