The reason -- foam insulation that often has broken from shuttles' disposable booster rockets since the flights began more than two decades ago. Bill Gerstenmaier, NASA's manager of space operations, said engineers are beginning to understand how the foam broke off during the launch of the shuttle "Discovery" last month.
The "Discovery" returned to Earth safely. But "Columbia," the shuttle that made the previous mission in early 2003, burned up during reentry to Earth's atmosphere because of an errant piece of foam that had cracked one of its heat-resistant tiles.
Gerstenmaier said NASA is shifting its approach to shuttle flights away from individual missions. Now, he said, shuttle flights will be part of an overall strategy to serve the International Space Station.
"Instead of looking at these as individual shuttle flights, we're really looking at them as a series of flights that are integrated together to support the [space] station," Gerstenmaier said. "So how do we build the most robust manifest to support the station? In other words, how do we string these flights to give us not just a one-flight opportunity, but [the opportunity for] several flights, and really make the whole sequence flow much better?"
NASA administrator Michael Griffin reminded reporters that the shuttle will be phased out over the next five years. But he said before that, it would fulfill its commitment to its space-station partners by completing the building of the orbiting laboratory.
But journalists' questions kept returning to the critical minority report issued by the Stafford-Covey Task Group, named for its two co-chairmen, retired astronauts Thomas Stafford and Richard Covey. Griffin said he agreed to include the minority report as an appendix to the panel's primary report to avoid even the appearance that NASA does not listen to criticism. He said the agency will fairly evaluate all the commission's recommendations.
One reporter pointed to NASA's recent management shakeup and asked Griffin if NASA had what he called a "crisis of confidence" in his top staff. Griffin replied by acknowledging that NASA had been ignoring the problems with foam insulation for 113 flights until one caused the "Columbia" disaster.
"Shame on us," Griffin said, but he added that NASA grounded all shuttles until it was satisfied that all safety issues had been resolved. And of the thousands of problems that could have occurred during last month's shuttle mission, Griffin said, only a very few arose.
"There were five areas that didn't work right, and almost everything did work right," he said. "So do I have a crisis of confidence in the team that made almost everything work right? Of course not. As Bill [Gerstenmaier] just said a few minutes ago, we're going to take the data and see where it leads us, and we're going to fix those things that we didn't get right."
Another question involved the minority report's criticism of the so-called "behavioral issues" of NASA managers -- for example, smug certainty taking precedence over knowledge and caution. The reporter asked how NASA can plan a shuttle launch in seven months under these circumstances.
Griffin replied that he has just named Gerstenmaier, a respected official, as the agency's manager in charge of space operations as part of NASA's broader staff changes. He said further changes may still be made, in response to issues raised by the report.
"I want to assure everybody that we will go over, in detail, the minority report -- as well as the majority report in the Stafford-Covey Task Group report," Griffin said. "We'll go over it all, and we will decide what we want to do in as responsible a fashion as we can muster. But I'm just not going to sit here and make off-the-cuff, speculative remarks about how we're going to handle a report that we received yesterday."
Evaluating the report's recommendations may take time. Not only is Gerstenmaier new to his job; Griffin said he himself has been NASA's administrator for only four months. So it's probably too early to say just how NASA will change between now and the next shuttle mission -- whenever that may be.