April 14, 2005
Students Find Inclusions in Shuttle Debris
BETHLEHEM, Pa. (AP) -- Students who spent more than a month testing pieces of the Columbia say that today's space-age materials - unavailable when the doomed shuttle was built more than two decades ago - might make a next-generation space vehicle safer.
The Lehigh University students, who got access to shuttle debris under a NASA program to make pieces available for research, are presenting their findings this week to space agency officials.The 50 shuttle parts shipped to Lehigh in early March had not been closely analyzed by NASA experts because they were not believed to have played a role in Columbia's disintegration over Texas two years ago. All seven shuttle astronauts were killed in the crash.
The high-speed, high-altitude breakup, which left a debris field 645 miles long and 10 miles wide, was "unprecedented in aviation history," Rick Russell, an engineer at NASA's Orbiter Project Support Office, told students on Tuesday, the first day of a two-day conference at Lehigh.
Students reached a variety of conclusions about the pieces they were given.
Using sophisticated imaging equipment, for example, they were able to show how pieces of structural aluminum were laced with "inclusions" - foreign substances likely introduced during the manufacturing process. The substances had a lower melting point than the surrounding aluminum alloy, which in turn might have caused each aluminum piece to fail more quickly than it would have otherwise.
"Today, if you were going to redesign that material, I would pick a better type of aluminum," said materials science expert Arnold Marder, the Lehigh professor who led the project. "The aluminum of the '70s had stuff in it that didn't belong."
Marder was quick to add that Columbia's aluminum skeleton was not unsafe; no manmade material could likely have withstood the extreme forces at work in the shuttle disaster. The point, Marder said, is that materials are often improved by finding out at what point they cease performing as they should - and why.
"The concept of failure analysis is to make a better product in the end," he said.
Students showed Russell and Steve McDanels, chief of NASA's Failure Analysis and Materials Evaluation Branch, what they learned about three pieces of aluminum, two pieces of tile, a piece of a strut, and a piece of the payload bay door.
As eerie PowerPoint slides showed the twisted, burned pieces under magnification, students gave highly technical explanations of the properties of each piece, what they surmise might have happened to it, and what they recommend be done to improve the material.
"They answered some questions we would have asked ourselves a couple of years ago," had the pieces been chosen for further study by NASA experts, McDanels said.
Added Russell: "I didn't learn anything shockingly new about what caused the accident, but I saw things I would consider corroborating evidence."
The symposium concludes Thursday with more student presentations and talks by shuttle astronaut Pamela Ann Melroy and other NASA officials, along with a media briefing.
On the Net:
NASA's Columbia site: http://www.nasa.gov/columbia/home