Space Shuttle's Foam Problem Still Unsolved

Aug. 12, 2005 — -- After two weeks of poring over the pictures of the space shuttle Discovery's giant fuel tank, NASA concedes it still has no idea why that troubling piece of foam fell away during liftoff.

And unless NASA engineers have a "eureka moment" that solves the mystery, it's unlikely they will be able to launch the next shuttle in September as they had hoped.

"There's no obvious root cause," said Bill Gerstenmeier, NASA's space station program manager, who has been called in to help figure out the shuttle's problem. "More than likely there are some minor engineering modifications that will be needed to the tank."

But he said he had no idea, for now, what those modifications might be.

Gerstenmeier tried to remind reporters that Discovery's flight had been a rousing success, despite the foam issue. The shuttle orbiter itself had worked fine, and the space station had been restocked with water, a new gyroscope to keep it oriented in orbit, new pressure suits for spacewalks and other supplies.

Simple Part Seems Most Confounding

But the external tank -- the simplest part of the shuttle, the one part that does not have to be designed so meticulously that it can be reused -- continues to confound its makers.

A 1.6-pound piece of insulating foam is believed to have caused the Columbia tragedy in 2003. NASA spent two years and more than $100 million changing the way foam is applied to the tank. But after all that, video clearly shows a 1.1-pound piece falling off Discovery's tank, two minutes and seven seconds after launch.

Discovery was undamaged, of course. The space agency spent much of its effort during flight examining the shuttle's wings and bottom to make sure it was safe for re-entry. NASA went public with every flaw, bringing extensive media attention, which reportedly caused a great deal of anxiety within the organization. Engineers agree that even without all the self-examination, chances are Discovery would have landed safely.

But NASA is in a difficult position. In the wake of the Columbia crash, President Bush ordered the agency to turn in new directions, retiring the shuttles by 2010 if possible to make way for a new "Crew Exploration Vehicle" that would take astronauts to the moon and eventually Mars.

Meanwhile, the Columbia Accident Investigation Board mandated that the shuttles be regarded as "experimental" vehicles, to be flown with renewed caution -- even after 24 years and 112 successful flights. In essence, NASA was being ordered to make the shuttles' flights worthy -- just so they could finish the space station assembly and be retired.

The next scheduled mission, another test flight, is to be flown by the shuttle Atlantis. Like Discovery, it will have to be launched in daylight so that cameras can watch for falling foam. Earlier this week, NASA Administrator Michael Griffin said it might be able to launch between Sept. 22 and 28 this year. If it cannot launch during that small window, there is another short one in November. Then, there are no other opportunities for the shuttle to fly until 2006.

ABC News correspondent Ned Potter originally filed this report for "World News Tonight."