KENNEDY SPACE CENTER, Fla. — The space shuttle Endeavour roared to life Thursday as the countdown clock read zero. Then it suddenly shuddered into silence--its main engines shut down before the scheduled dawn launch because of an overheated fuel pump.
It was the fifth engine shutdown at the pad in 13 years of shuttle flights and the third since March, 1993. But none had been so close to launch.
Deidra Baker, wife of the shuttle commander, was watching from the launch control center three miles away with their two daughters. Her voice quivered as she described seeing husband Michael Baker stuck inside a vibrating, rumbling, 2,000-ton rocket ship filled with explosive fuel.
Baker said he and the five other astronauts fell silent when red warning lights flashed in the cockpit.
The astronauts were strapped in their seats for about an hour after the launch was aborted, as ground crews rushed to make sure that Endeavour was safe. The launch team's prime concern was the possibility of hydrogen fuel leaks; that's why 300,000 gallons of water were sprayed at the pad.
"I think everything went well. The systems did their job and shut us down," said Baker, a Navy captain and former test pilot.
When the three main engines fired on cue 6 1/2 seconds before liftoff and spewed huge clouds of steam, NASA's deputy manager for engines, Boyce Mix, said he thought "we had it in the bank."
One by one, the engines were turned off automatically by computer command, starting 1.9 seconds before the solid rocket boosters were to have ignited. NASA's countdown clocks got all the way to zero when the launch was halted.
Mix said the problem was with a high-pressure fuel pump in main engine No. 3 that overheated. The pump had just been refurbished, and there was no immediate explanation for why it failed, he said.
The National Aeronautics and Space Administration is testing a redesigned version of the pump that is intended to improve safety while reducing maintenance.
If an engine had failed soon after liftoff, Baker would have had to attempt a dangerous emergency landing at the space center.
The Earth-monitoring mission--a repeat of an April flight--is off until early October. Shuttle managers decided to proceed with Discovery's scheduled Sept. 9 launch and move Endeavour off the pad next week in order to replace all three engines.