An independent panel of experts declined yesterday to fully endorse new safety measures for the space shuttle but said the orbiter is nevertheless "ready to fly" and praised NASA for its exhaustive efforts to overcome the critical flaws that caused the Columbia disaster.
The findings did not appear to present an obstacle to NASA's plans to give the space shuttle Discovery its final checkout later this week in preparation for launch during a window that opens July 13. But NASA Administrator Michael D. Griffin was noncommittal on the possible effect that the panel's work might have on launch plans.
Retired Air Force Col. Richard O. Covey, a former astronaut and co-chairman of the NASA-appointed Return to Flight Task Group, also suggested the panel's somewhat ambiguous assessment occurred because it had been required to say yes or no on safety questions that did not lend themselves to simple answers.
"You have to look at the progress that has been made," Covey said at a task group news conference to announce its findings. "Is it a miss if you're at 95 percent? We haven't seen anything that says that [there is] any danger to the vehicle."
Covey, who flew the first shuttle after Challenger blew up during launch in 1986, even acknowledged that "if I were a young flying person" given an opportunity to fly Discovery, "I would not have a concern."
Griffin did not directly address the findings but simply issued a statement thanking the group for its "valuable public service," noting that "a vigorous discussion of these complex issues can make us smarter" and adding: "We appreciate the input."
The group, led by Covey and Thomas Stafford, also a retired astronaut, was formed by NASA to assess the agency's success in complying with 15 safety recommendations made by the Columbia Accident Investigation Board in late 2003. Columbia disintegrated during reentry on Feb. 1, 2003, because of damage to its heat shielding by a chunk of insulating foam that broke off its external fuel tank during launch.
The panel had "closed" 12 of the recommendations in the past two years but balked yesterday on the last three. These included efforts to eliminate damage from debris coming off the external fuel tank, "hardening" the orbiter to make it more resistant to debris during launch, and development of in-flight repair techniques.
NASA has postponed Discovery's launch twice to make design modifications and conduct further tests on the external tank, but Joseph W. Cuzzupoli, head of the task group's technical panel, said questions remain about ice buildup on a tank fitting exposed to supercooled liquid oxygen and hydrogen.
Also unresolved is the need to "harden" areas around the shuttle's doors and other openings by installing better thermal insulation. Finally, the panel found that onboard repair techniques being developed by NASA could only be deemed "contingencies" rather than "capabilities" until they had been further tested.
Throughout their presentation, however, Covey, Cuzzupoli and retired Army Col. James C. Adamson, another former astronaut and head of the panel's operations team, repeatedly called attention to the exhaustive efforts NASA had made in reducing the safety risk to the orbiter.
"We feel that it is a safe vehicle to fly -- that's where we're coming from," Cuzzupoli said. "From an operational-readiness standpoint, the data that they presented to us so far says that it's ready to fly."
Adamson said a further postponement of Discovery's launch would probably not make any difference in readiness "since a lot of this stuff would depend on flying to find out what you need to know."