Effects of Sample Holder Edge Geometry on Atomic Oxygen Erosion Yield of Pyrolytic Graphite Exposed in Low Earth Orbit

The measurement of the erosion yield (volume lost per incident atom) of polymers and carbon using low Earth orbital (LEO) atomic oxygen exposure has typically involved placing small samples in holders that have chamfered edges. The chamfered edges have sometimes cause the samples to tear by their perimeters. This paper reports an evaluation of the erosion profile of a LEO atomic oxygen exposed pyrolytic graphite sample to determine the extent to which the erosion yield is altered by the chamfer and what the expected erosion yield would be for large area samples. The results indicate that the durability of large area samples would be approx. 5.2% lower than predicted based on mass loss of small samples with exposed diameters of 0.838 inch (2.13 cm) and chamfered sample holders.