Atomic Oxygen Concentrators for Material Exposure Acceleration Tests in Low Earth Orbit

Abstract

Atomic oxygen concentration technology was investigated with two types of concentrators. One is a “horn-type” andtheotherisa“multiplering-type”concentrator.Bothofthemweredesignedwithacomputersimulationusinga hard-cube model. It was made clear that the primary factor for limiting the concentration factor is the gas buildup near the focal point. In the ground test using a laser-detonation source, which gave an intense atomic oxygen beam pulse, the concentration factor of 2–3, which is lower than the theoretical expectations, is obtained. However, it is suggested that the low concentration factor is due to the recombination reaction of atomic oxygen into molecular oxygenbythehighpeak fluxinthepulsedatomicoxygenbeam.The fluxlimitoftheconcentrationfactorisnotacase in the real low Earth orbit space environment, and the multiple ring-type concentrator can be expected to achieve a concentration factor of over 40 in a low Earth orbit exposure condition. Nomenclature A = area of quartz C = concentration factor d = thickness of quartz E = energy F = flux f0 = resonant frequency