Surface characterization of SiC mirrors exposed to fast atomic oxygen

Two chemical vapor deposited silicon carbide (SiC) mirrors were exposed to the 5 eV fast atomic oxygen environment in low Earth orbit on NASA's Long Duration Exposure Facility (LDEF) which remained in space for nearly 6 years. The samples were characterized using the techniques of x‐ray photoelectron spectroscopy (XPS), ellipsometry, and reflectance measurements. The normal‐incidence optical reflectance of the atomic‐oxygen‐exposed portion of one sample degraded considerably over the 60–160 nm span. The XPS results showed the presence of SiO2‐like species, the thickness varying from 1 to 8 nm depending upon the location of the samples on the spacecraft. The XPS results are in good agreement with those from ellipsometry measurements.