The effect of spacecraft charging on the interaction of atomic oxygen with polymers

We have measured scattering and reactions of atomic oxygen (AO) with polysulfone-resin targets, simultaneously bombarded with an electron beam. We the measured rates for reactions leading to CO, CO2, SO and SO2 in the final state, and found that they increased when the target was electrically isolated, allowing it to charge. We verified that the increase in reaction rate was due to the electric fields from target charging, by using an external bias supply and turning off the electron bombardment. We have developed a simple theory which accounts for the effects observed. If substantiated by further studies, this result has implications for the effects of atomic oxygen on spacecraft which are subject to charging.