Argonne, NASA team up on shuttle safety

ARGONNE, Ill (Aug. 29, 2003) — Argonne is collaborating with National Aeronautics and Space Administration (NASA) to develop a method of inspecting the leading-edge thermal protection system for Space Shuttle wings. Researchers in Argonne's Energy Technology Division have been conducting tests on shuttle wings since April and are working to meet an early fall deadline to provide two to three of their best potential investigation methods.

The Argonne work is a part of NASA's effort to examine the cause of the Feb. 1 Columbia accident, in which the space ship broke up upon re-entering the Earth's atmosphere. Researchers want to define methods to eliminate or significantly reduce the chance for reoccurrence.

Launch films show that a piece of foam insulation from the external fuel tank on the shuttle broke off during liftoff and possibly smashed into the front of the left wing at about 500 mph. The impact may have have created a hole about the size of a small suitcase, according to simulations performed at the Southwest Research Institute in San Antonio, Tex.

NASA researchers suspect that the impact may have damaged one of the ceramic composite panels that protect the wing's leading edge. Upon re-entering the atmosphere, the shuttle creates hot gases with temperatures of up to 3,000 degrees Fahrenheit. Such gases could eat away the wing's frame in minutes, it is believed, and could have led to the shuttle's break-up.

"NASA invited us to work on this very short-term effort because we have been funded by the Department of Energy for 20 years to work on inspection methods for ceramics," said Argonne engineer Bill Ellingson. "We have the knowledge base for developing inspection methods for ceramics at high temperatures."

The leading edge of the wing and the nose cap of the space shuttles are composed of reinforced carbon-carbon material, which is made up of carbon fibers in a carbon matrix. The matrix is like a filler. This type of ceramic composite is extremely tough at high temperatures.

"The material is so tough that even at extremely high temperatures it can be thrown at a brick wall and only the brick will chip," said Ellingson.

Researchers have intentionally been putting flaws in the NASA samples to see if flaws can be detected using their proposed inspection methods. So far the tests have been successful.

Four teams are working with the thermal material leading edge of the wings. Argonne heads the team working on ultrasound and has technical members in the three other teams dealing with infrared imaging, eddy-current technology and shearography. Members of these teams include Energy Technology Division researchers Ellingson, Jiangang Sun, Chris Deemer and Sasan Bakhtiari. Staff member Dick Koehl and students Julian Benz, Zachary Metzger and Jeffrey Wheeler are also involved in the research.

Other researchers participating in the teams are from the NASA Langley Research Center, NASA Marshall Space Flight Center, Sandia National Laboratories and commercial vendors.

"After the meeting this fall, when we decide which method to further develop, we will need the commercial vendors to build the hardware," said Ellingson. "Each of the four teams has involved at least one commercial vendor to make the appropriate equipment."

The NASA Johnson Space Center in Houston is managing this project.

"We have worked with NASA prior to this project, but mostly through research operations," said Ellingson. "The work on the shuttle is the first work that we've done as a direct application. It is more likely that we will have more interaction with NASA on other shuttle parts following the completion of this project."

Argonne National Laboratory brings the world's brightest scientists and engineers together to find exciting and creative new solutions to pressing national problems in science and technology. The nation's first national laboratory, Argonne conducts leading-edge basic and applied scientific research in virtually every scientific discipline. Argonne researchers work closely with researchers from hundreds of companies, universities, and federal, state and municipal agencies to help them solve their specific problems, advance America 's scientific leadership and prepare the nation for a better future. With employees from more than 60 nations, Argonne is managed by UChicago Argonne, LLC for the U.S. Department of Energy's Office of Science.

For more information, please contact Steve McGregor (630/252-5580 or media@anl.gov) at Argonne.