22 April 2003
22 April 2003
In their first round of recommendations, Columbia accident investigators urged NASA to more thoroughly inspect space shuttle wings and require picture-taking in orbit to check for potentially catastrophic damage.
The investigation board said Thursday that NASA's current methods for checking the crucial thermal protection along the leading edge of the wings are inadequate and may have contributed to the disaster.
NASA also did not request help in photographing Columbia while it was still in orbit, to assess damage caused by a chunk of foam insulation that struck the wing during liftoff. The space agency already has agreed to do this on future flights, with the military's cooperation.
The two preliminary recommendations come 2 1/2 months after Columbia disintegrated over Texas, almost certainly because of a breach along the leading edge of the left wing that let in hot atmospheric gases. The gap may have been caused by the suitcase-sized piece of foam that broke off the ship's fuel tank shortly after liftoff.
NASA Administrator Sean O'Keefe said he intends to act on every one of the recommendations and is targeting a return to flight within this calendar year. ""That's the earliest opportunity,"" he said.
Before shuttle flights resume, the board said, NASA should implement a comprehensive inspection plan for the reinforced carbon-fiber panels and seals that cover the leading edges of shuttle wings. This inspection plan should take advantage of advanced technology, the panel noted.
NASA's current methods for inspecting the carbon pieces between flights — tapping on them to find hidden air pockets and conducting visual checks — are inadequate, the board said. Defects have since been found in some preapproved parts through X-ray tests and CAT scans.
But in comments at the National Press Club in Washington, O'Keefe noted: ""We're going to have a challenge of developing the technology to do that.""
The chairman of the Columbia Accident Investigation Board, retired Navy Adm. Harold Gehman Jr., has said repeatedly that age-related wear and tear may have weakened some of the wing parts enough to break when struck by foam.
Gehman said this week that more preliminary recommendations will be released as soon as they are formally reviewed. The board's final report will be released this summer and will include the probable cause of the Feb. 1 accident as well as contributing factors.
It is possible the board will not be able to pinpoint the exact cause, Gehman said. ""That's why we're being so careful about the recommendations, to make sure they're generic enough to not fall in love with a specific scenario,"" he said.
Indeed, O'Keefe said it likely will be a combination of hardware and process failures as well as judgment calls that led to the tragedy.
NASA already is looking at ways to improve shuttle safety. Engineers are considering putting a lightweight metal cover over the area where the foam peeled off Columbia's fuel tank in January to prevent future shedding, and are studying ways that spacewalking astronauts could repair any damage to their ship's outer thermal layer.
The astronauts aboard Columbia had no such repair kit. NASA and contractor engineers concluded during the 16-day flight that the launch debris caused no severe damage and posed no safety threat; as a result, no photographs of the wing were ordered, despite prodding by some.