US: The countdown continued yesterday for a scheduled launch today of the space shuttle Discovery as programme managers said they would be willing to blast off even if a dodgy fuel sensor fails again.
But Nasa officials admitted the choice to go ahead despite an unexplained glitch in the shuttle electronics could appear questionable since the agency is still trying to shed an image of sloppiness after the loss of Columbia more than two years ago.
"I wake up every day and ask myself, 'Are we pushing too hard?'" Wayne Hale, the deputy shuttle programme manager, said at a news briefing at Kennedy Space Center in Florida. "We are still struggling with the ghosts of Columbia."
Columbia's seven astronauts died in 2003 when the orbiter broke up while attempting a landing at the space centre.
An investigatory panel later said the accident was caused by a piece of lightweight foam that fell off the external fuel tank and struck the left wing. The panel also cited a Nasa culture that, among other things, was preoccupied with meeting launch schedules.
Discovery, the first launch since the Columbia tragedy, was scheduled to lift off on July 13th. But a faulty sensor in the liquid hydrogen portion of the fuel tank caused the launch to be cancelled. Since then a dozen teams of engineers have been working to find the source of the trouble.
After testing hundreds of possibilities in the so-called "fault-tree" between the sensors and the orbiter's computer, investigators believe they have narrowed the cause to either a problem with the sensor or wiring in the point sensor box.
The sensors are designed to shut off the main engines before they run out of fuel, potentially destroying the engines. If they cut off the engines too soon, they could prevent the orbiter from reaching space, an equally dangerous event.
The launch is scheduled for 3:39pm Irish time today.