Thin-film electronics materials developed in space laboratories

GREENBELT, Md. - Launch services and communications satellites represent the primary efforts to commercialize space, but new research seeks to develop advanced electronic materials, particularly thin films, says Arnauld Nicogossian, NASA associate administrator in charge of the Office of Life and Microgravity Sciences and Applications.

By John Rhea

GREENBELT, Md. - Launch services and communications satellites represent the primary efforts to commercialize space, but new research seeks to develop advanced electronic materials, particularly thin films, says Arnauld Nicogossian, NASA associate administrator in charge of the Office of Life and Microgravity Sciences and Applications.

Nicogossian spoke at the annual Goddard Memorial Symposium sponsored by the American Astronautical Society at the Goddard Space Flight Center of the National Aeronautics and Space Administration in Greenbelt, Md.

While NASA`s commercial space centers are supposed to attract partnerships with industry to make the most of developments in space technology, results of the centers` efforts are still sketchy, concedes Nicogossian. "For the most part, past successes in commercial space activities have been largely anecdotal," he says.

Some experts, however, point to success stories in space-based materials development. Alex Ignatiev, a researcher at the University of Houston`s Space Vacuum Epitaxy Center (SVEC), says his organization had been able to develop electronic materials of high purity using the hard vacuum and microgravity conditions of space. SVEC scientists used a free-flying platform, known as the Wake Shield Facility, deployed from the NASA space shuttle, to fabricate thin-film materials.

Development is continuing in four areas, Ignatiev says: optoelectronic devices, advanced photovoltaic devices, thin-film oxide devices, and large bandgap devices. The last is particularly critical for high-power avionics applications. The experiments have yielded a mid-infrared laser able to operate at room temperature, an uncooled pyroelectric infrared detector, and a quantum well design radiation-hardened solar cell.

Also at the symposium, William Powell of the commercial space center at NASA Marshall Space Flight Center in Huntsville, Ala., reported improved processing of aerogels during 7-minute rocket experiments. Aerogels are microstructured, open-pore materials with unusual properties of transparency, high thermal resistance, and low refractive index. Processing on earth is difficult, however, because of the need to maintain tight tolerance over the pore sizes, particularly for electro-optical applications.

During the rocket experiments, Powell reported, the aerogels were processed in microgravity conditions. They were found to have smaller pores - by more than 40 percent - and the center is now preparing a longer term experiment to fly in the Space Shuttle in early 1998.

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