'Opening up the field'

There are alternative theories to explain the damage done to materials in LEO. For example, polyethylene damage is often chalked up to what is known as hydrogen abstraction in which hydrogen atoms are knocked from the polymer's structure and leave broken portions of the polymer to react and wreak havoc. Using their quantum mechanical approach, however, Massa's team has shown that chain breaking, in which oxygen atoms directly attack and break the polymer's carbon-carbon bonds, may also be a significant cause of damage.

Long Duration Exposure Facility, a NASA satellite used, among other things, to test the durability of spacecraft materials.

"We're not saying that chain breaking by atomic oxygen is the only culprit," says Massa. "Any number of other reactions could exist, and all of these mechanisms remain to be studied." The team has confirmed, however, that atomic oxygen in LEO has sufficient energy to break down polyethylene polymers by way of chain breaking and that the mechanism inflicts damage more efficiently than many other chemical processes.

More importantly, the team has provided a fundamental method for approaching the overall problem of polymers' interactions with atomic oxygen. "We've really suggested a new way for this thing to be looked at. Quantum mechanical research has been around for years. This problem has been around for years. But the marriage of the two is unique." says Massa.

Banks agrees. "Massa's team is really the only group that is giving us a structural understanding of the reactions. It's a solid contribution that will continue to grow in significance as the volume of their work increases."

This research is supported by NASA.