Shuttle readied for liftoff despite worries

By Mike Schneider

updated 2:09 p.m. ET June 25, 2006

CAPE CANAVERAL, Fla. - A grounded space shuttle. Countless months trying to fix foam insulation problems on the fuel tank. A faulty fuel tank sensor that delayed a launch in May.

If this list looks familiar, it should.

With a possible liftoff of Discovery just seven days away, NASA is dealing with many of the same problems it faced almost a year ago in what could be called the space agency's version of the movie "Groundhog Day."

The shuttle program manager, Wayne Hale, acknowledges that. But he contends progress is being made. "In terms of the foam, we are so much smarter this year than we were last year," he says.

Smarter, but still unable to stop it from flying off the shuttle's external tank. It's the same worrisome problem the space agency has wrestled with since falling foam damaged Columbia in 2003 and caused the deaths of seven astronauts.

Despite a redesign of the tank, foam continued to drop off last year during the launch of Discovery. That foam loss caused NASA to ground the shuttle fleet for almost a year — another delay after the 2½-year hiatus following the Columbia disaster. NASA has spent at least $1.2 billion on changes to the shuttle since 2003.

For the upcoming launch, set for July 1, engineers have modified the tank even further by removing about 35 pounds of foam in areas where a foam chunk dropped off last year. NASA describes the removal of the foam as the greatest aerodynamic change ever made to the shuttle's launch system.

"Foam will come off. There's no way around that. It is an expected event," said John Chapman, NASA's external tank project manager. "Our objective is to make sure if it does come off, it comes off in small enough pieces that it doesn't cause any harm."

Debate over design changes
Some at NASA think there should be even further design changes with more foam removal before a shuttle flies again.

At a meeting two weeks before the expected launch, leaders with NASA's Office of the Chief Engineer and Office of Safety and Mission Assurance recommended that the shuttle not fly until further design changes had been made to the tank. NASA Administrator Michael Griffin decided to have the shuttle fly without more changes, but with plans to make the modifications in the future.

A design with greater amounts of foam removed from the tank didn't test well in wind-tunnel trials.

Discovery's commander, Steve Lindsey, said he was encouraged by the forthright design debate since NASA was criticized after the Columbia disaster for squelching dissent.

"Both sides were listened to, very vocally and very publicly," Lindsey said. "You had a group of engineers who said, 'Change it.' Managers decided, 'Don't change it.' I guess time will tell which side was really right."

Armed with data from each new flight, NASA managers and engineers plan to make changes to the foam on the tank before each future flight until the fleet is grounded in 2010. The next-generation vehicle isn't expected to fly until around 2014.

NASA managers have acknowledged that another fatal mistake could ground the three remaining shuttles before the international space station is finished being built. It also could rule out any chances of a repair mission to the Hubble Space Telescope.

"Look, if we go fly and have another accident, that will be the end of the program," Hale said recently. "I'd rather not fly and say we couldn't get our act together ... than rush into some ill-advised launch where we had a catastrophe."

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