for National Geographic News
NASA observers have their wary eyes set on Saturday's scheduled launch of the space shuttle Discovery.
Will it mark a triumphant beginning to the program's twilight years or signal that the program has become too troubled to continue?
"The folks who work on the shuttle program are feeling the pressure to do well," said Roger Launius, the chief space historian at the National Air and Space Museum in Washington, D.C.
"There's a lot riding on it for them. And maybe that's how it should be," he added.
Last year a chunk of insulating foam dislodged from a fuel tank during Discovery's liftoff and narrowly missed the shuttle's right wing.
Had the foam hit, it could have caused the same type of damage that led to the disintegration of the shuttle Columbia over Texas on February 1, 2003.
All seven Columbia astronauts died in the disaster.
After the tragedy NASA sidelined the shuttle program, launched an investigation, and diagnosed a "broken safety culture" at NASA. The U.S. space agency spent hundreds of millions of dollars redesigning the fuel tank and other shuttle parts.
Discovery's return to space last year was supposed to signal the shuttle program's renewed vigor. But, dismayed at the near miss on that mission, NASA officials again grounded the shuttle fleet and further tweaked the fuel-tank design, among other fixes.
(Read "Discovery Lands Safely, But Future Flights Are Uncertain" [August 2005].)
Now, amid the concerns of NASA's chief safety officer and engineer that foam could still dislodge and damage the shuttle, NASA Administrator Michael Griffin says the shuttle is safe enough to fly.
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