LDEF Satellite
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08-May-2001 10:59 AM U.S. EDT
By AviationNow.Com Staff
LDEF Satellite |
With a $5 million grant from the U.S. Defense Department, the University of Chicago will become a new national headquarters for studying the long-term performance of high-tech materials in space.
The unclassified research program could lead to new and improved materials for satellites, space stations and high-altitude aircraft.
"We're trying to understand how all sorts of materials are going to perform in a very aggressive chemical environment, " said project leader Steven Sibener, a chemist and head of the university's Materials Research Science and Engineering Center.
"Right now, the actual atomic-level details by which high-performance materials react, erode, and ultimately age when subjected to the harsh chemical environment of low-earth orbit are very poorly understood. This is a superb opportunity to explore materials chemistry in an extreme environment."
The grant is part of a national program designed to study large and complex science and engineering problems that have potential for future military and civilian applications.
Five years of funding began May 1 for the university's new Center for Materials Chemistry in the Space Environment. Co-investigators are coming from Yale, Northwestern, Notre Dame, Penn State, Montana State, NASA, the U.S. Air Force Research Laboratories and Boeing.
The work initially will focus on understanding the chemistry of polymers in space.
Polymers -- widely used in spacecraft design -- are a class of relatively soft, lightweight materials that include Teflon and Kapton.
"The current materials being used in space are still what I would call first-generation space materials that just happen to work at some level," Sibener said.
"We intend to go beyond such fortuitous situations and actually develop improved new materials using molecular-level understanding of the relevant chemistry to achieve intentionally designed performance advantages. Recent advances in materials experimentation, chemical synthesis and theory make this the right time to tackle this challenging problem."
Far from being empty and quiet, space is a hotbed of corrosive forces capable of destroying a wide variety of materials. Space is filled with highly energetic and destructive ultraviolet radiation from the sun. Equally harmful are swarms of electrons and oxygen atoms that permeate the orbital environment depending on the altitude, time of day and cycle of solar activity.
Much of what is known about the effects of such phenomena on materials resulted from the study of NASA's Long Duration Exposure Facility (LDEF).
Launched in 1984 by the space shuttle Challenger, the LDEF (photo) was covered with a variety of metals, polymers and ceramics to see how those materials would fare in space.
The satellite made more than 32,000 orbits of Earth at altitudes ranging from 275 to 175 miles before the shuttle Columbia retrieved it and returned it to Earth in 1990.
LDEF demonstrated how little scientists knew about the durability of materials in space. Some samples that experts thought could survive disappeared, while others that were expected to be destroyed managed to endure.
"It tells us that we do not yet really have a good predictive understanding of the underlying chemistry that determines how many of these materials age in space," Sibener said.
Orbital debris -- both man-made and from meteors -- takes its toll, too, as LDEF also showed. One question Sibener and his colleagues hope to answer is how the microscopic defects left by debris impacts influence the subsequent chemistry and structural evolution of such materials.
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