In the trail of shattered metal, scorched tiles and human remains that fell from the disintegrating space shuttle Columbia across Texas and Louisiana, accident investigators may be able to read the cause of the catastrophe, aerospace experts said yesterday.
"It's a daunting task, because the evidence is spread over 500 miles," said John C. Macidull, an engineer and former Navy test pilot who was a lead investigator of the Challenger disaster in 1986. "But it is possible."
One critical task is establishing the sequence of events leading to the breakup of the 90-ton craft 39 miles over Texas.
"You usually work backwards from the pieces that flew off first, to the cause of the initial failure," said Jim Burnett, who was chairman of the National Transportation Safety Board when the Challenger blew apart shortly after launch.
In an investigation that is likely to take months, everything from amateur videos of the smoking debris arcing toward earth to decades-old paperwork documenting the design of shuttle parts is likely to be scrutinized by scientists.
The investigators will use microscopic examination and chemical tests on metal scraps to determine where they originated on the shuttle and how they broke off. They will examine critical parts of the remaining three shuttles, trying to locate design weaknesses.
"You've got to look at everything," said Robert B. Hotz, who was editor of Aviation Week for 25 years and later served on the presidential commission that investigated the Challenger. "When you start out on an accident investigation you don't know where it's going to lead."
NASA officials were considering yesterday whether overheating on the left side of the 122-foot craft may have caused the breakup, possibly because insulating tiles had fallen off.
But both NASA officials and outside experts emphasized that the quest for answers in the tragedy is just beginning. It's important not to leap to any single conclusion, thus closing out other possibilities, they said.
"The first thing is to gather materials, recollections, data and imagery," said James E. Oberg, who worked at Mission Control for 22 years and is now an aerospace author and consultant. "It can be damaging to jump too quickly to any hypothesis."
Ron Dittemore, NASA's shuttle program manager, offered a similar caveat even as he told a press conference last night what he knew.
"First reports are notoriously unreliable," he said.
Immediately after declaring a "contingency," NASA's keep-calm term for an emergency, administrators ordered workers Saturday morning to secure all documentary evidence of the accident, from maintenance logs to flight data files and handwritten notes of ground controllers.
"It's going to take days and weeks to put it together and see what we have," Dittemore said.
Hundreds of people have been mobilized under the direction of the Federal Emergency Management Agency to identify, document and collect the thousands of pieces of debris on the ground and in lakes and reservoirs.
Ranging from chunks the size of a compact car to individual bolts, they will be transported to Barksdale Air Force Base in Shreveport, La., for cataloging and analysis.
Body parts - officials said remains of all seven astronauts had been found - will be documented before being transported as families desire for burial or cremation.
Much of the work will be aimed at putting together a minutely detailed, moment-by-moment account of what happened. The Challenger investigation broke down that disaster to each thousandth of a second.
Such a timeline will draw on the masses of telemetry data on temperature, pressure, speed, flap positions and many other indicators that Columbia sent to Mission Control in the last minutes of the flight.
Those sophisticated computer records - including a mix of accurate and erratic data in the last 32 seconds that NASA has yet to analyze - will be combined with videos sent in by Texans who ran outside to capture the fiery descent on film.
Dittemore said 600 people had called to offer videotapes and other bits of information, and NASA had received about 200 e-mails, half of them including digital photographs.
"All that information is being pored over right now," he said.
Another focus will be the moment 80 seconds after takeoff Jan. 16 when foam insulation from the external fuel tank broke off and struck the shuttle's left wing. NASA technicians will re-examine video of the mishap, trying to assess whether the light but fast-moving foam might have done serious damage to the insulating tiles.
Foam being studied
NASA dispatched a team of investigators yesterday to study the foam at a NASA-Lockheed Martin manufacturing plant in New Orleans where shuttle tanks are manufactured.
Officials said chunks of foam have broken loose from the same part of the shuttle fuel tank on at least three flights - Atlantis in October, and Columbia on a 1997 launch and on Jan. 16.