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

Atomic oxygen concentration technology was investigated with two types of concentrators. One is a "horn-type" and the other is a "multiple ring-type" concentrator. Both of them were designed with a computer simulation using a 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 oxygen by the high peak flux in the pulsed atomic oxygen beam. The flux limit of the concentration factor is not a case 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. [PUBLISHER ABSTRACT]