The shuttles are grounded again — except, of course, for the one still in orbit. The embarrassment might not be so great for NASA if what went wrong during the launch of Discovery was something other than smacking a piece of foam debris detached from the fuel tank. NASA assured everyone before this week’s flight that Discovery’s fuel tank “is undoubtedly the safest, most reliable tank ever built.” That might be so. But given the fact that within two minutes of the launch the debris performed exactly like the debris from the doomed Columbia, it’s time to ask serious questions.
Indeed, questions were raised before Discovery’s launch by the Columbia Accident Investigation Board, which NASA established to suggest safety improvements. The board was concerned that NASA had failed to “eliminate all … debris shedding.” At the time NASA director Michael Griffin said that there were some improvements that simply could not be made. We accepted this explanation, because the nature of space travel is inherently risky. However, the investigation board noted that during liftoff the shuttle and the fuel tank are operating “near the limits of their performance,” meaning that the foam insulation surrounding the fuel tank can never be adequately tested in a controlled environment. If it’s impossible to test the durability of the foam under launch conditions, is every shuttle then in the same danger as Columbia was? Something obviously must be done to correct this. Risks are acceptable; disasters are not.
After the crew performed a preliminary survey, NASA officials determined Wednesday that Discovery “appears to be in good shape.” That’s certainly good news. But Wayne Hale, the deputy shuttle program director, conceded that if the 33-inch-long bit of foam insulation had struck the orbiter at a lower altitude “we think this would have been really bad.” So, another question becomes pertinent: How can any design allow a one-pound piece of foam to bring down a 165,000-pound shuttle?
Other problems surfaced during take-off. A chip of ceramic thermal protection tile from the forward-landing-gear door broke off. NASA doesn’t foresee that as a problem and says that Discovery’s re-entry is on schedule for Aug. 7. The September launch of Atlantis, however, has been postponed indefinitely.
The larger question concerns the shuttle program’s future. NASA expects the shuttles to be in service for another five years, after which presumably NASA will have built something else that better aligns with the president’s vision of returning to the moon. If the problems plaguing the shuttle cannot be fixed, this might be the time to accelerate those plans, and retire the fleet sooner rather than later.