Researchers at the City University of New York, Hunter College, improve the durability of spacecraft materials using Alliance resources.

Lucite is so unyielding to weather and shock that it is used in aircraft canopies. Nomex shows such heat resistance that firefighter suits are made from it. And Kevlar—the stuff of bullet-proof vests—has the tensile strength of mild steel. Not one of them, however, is impervious when used as a building material in spacecraft and satellites. Atomic oxygen constantly bombards any spacecraft in low earth orbit (LEO), and these highly reactive atoms break down the materials at the chemical level.

Electron density contours for the transition state of ethane reacting with atomic oxygen.
Click the image to enlarge.

Chemists at the City University of New York, Hunter College, are using the Alliance's IBM SP supercomputer at the Maui High Performance Computing Center to study the interaction between atomic oxygen and spacecraft materials. By creating very precise quantum mechanical simulations of more than 30 of the most common polymers used in spacecraft and the polymers' interactions with atomic oxygen, they are getting an explicit understanding of how the structures are damaged. They are also getting some strong hints about how to slow that damage. Understanding these interactions and the long-term durability of these materials is crucial to any number of space missions and experiments.

"In just a few days in orbit, there's a noticeable amount of damage due to the atomic oxygen in LEO," says Lou Massa, the chemistry professor at Hunter College who heads the project. "It's not as if the space shuttle is going to fall apart. The structure isn't threatened, but certain properties of that structure are. And those properties—the surface's absorptive and reflective properties, or its ability to radiate heat and control temperature—are very important."

Access Online | Posted 12-12-2000