Rutledge and her colleagues test materials for use in low Earth orbits, where the space shuttles fly in an atomic oxygen-rich environment. Investigators at Lewis make atomic oxygen by forcing ordinary oxygen gas through electric and magnetic fields, which split the oxygen-atom pairs. Then the atomic oxygen goes in a vacuum chamber, where it can be applied to potential space-shuttle materials. In either case, the varnish would break down and the carbon gases could be pumped away. In many cases, the paint below would be inorganic, and the atomic oxygen would not attack it.
Some organic pigments do exist.
In those cases, the atomic-oxygen process would need to be stopped when the varnish was removed, which could be determined visually. The procedure would progress slowly, requiring as long as several hours to remove varnish in one spot, leaving little risk of removing any paint. Despite the theoretical predictions for success, the investigators wondered if the process would work in practice. To find out, Christman went shopping at a flea market. It removed the varnish without any obvious effects on the painting itself.