February 19, 2003
SPACE CENTER, Houston -- Space shuttle Columbia began losing pieces over the California coast well before it disintegrated over Texas, the accident investigation board reported Tuesday, finally confirming what astronomers and amateur skywatchers have been saying from Day One.
But board member James Hallock, a physicist and chief of the Transportation Department's aviation safety division, said the fragments were probably so small they burned up before reaching the ground.
He said the conclusion that the space shuttle was shedding pieces a full six minutes before it came apart over Texas was based on images of the doomed flight. Astronomers and amateurs on the West Coast photographed and videotaped the shuttle's final minutes.
"Obviously, it would be very important to understand what those pieces are, particularly the ones that started falling off at the very beginning," because they would shed light on the earliest stages of the breakup, he said.
However, Hallock said the pieces that came off early did not seem to be very big, judging from the light reflected off them.
"For us to find something that far back along the path, I think it's going to have to be a pretty substantial piece of the shuttle itself," he said.
In their second news conference in two weeks, the board members also said they are not convinced the debris that hit the left wing shortly after liftoff on Jan. 16 was insulating foam from the external fuel tank. It is possible the debris was actually ice or much heavier insulating material behind the foam, they said.
Hallock said the suspected breach in Columbia's left wing had to have been bigger than a pinhole, in order to allow the superheated gases surrounding the ship to penetrate the hull.
In other news:
The board said it hopes to hold its first public hearing next week, possibly on Feb. 27, to listen to non-NASA experts who have theories about what destroyed the shuttle. The hearing will be in the Houston area. The board has been criticized by some U.S. lawmakers as being too closely tied to NASA.
The board split into three teams Tuesday -- materials, operations and technology -- and began delving into what may have caused a breach in the shuttle's left wing.
An Air Force telescope in Maui took pictures of Columbia as the shuttle orbited overhead during its mission. The images were still being analyzed, said board chairman Harold Gehman Jr., a retired Navy admiral.
An external fuel tank identical to the one used by Columbia has been impounded at the Michoud Assembly Facility in New Orleans and will be tested. If any destructive testing is performed, engineers need to be careful because "we only get one shot at it," Gehman said.
Nearly 4,000 pieces of debris have been shipped to Florida's Kennedy Space Center, of which 2,600 have been identified and cataloged, Gehman said. Investigators hope to partly assemble the pieces. An additional 10,000 pieces are headed to Barksdale Air Force Base in Louisiana and Kennedy.
It is impossible to calculate how much of Columbia the recovered pieces represent, the board said. In terms of weight, it represents only a tiny portion because so much of the wreckage is small, like fragments of insulation.