Long-duration orbital effects on optical coating materials

We flew specimens of eight different optical coating materials in low earth orbit as part of the Long Duration Exposure Facility manifest to determine their ability to withstand exposure to the residual atomic O and other environmental effects at those altitudes. We included samples of Al, Au, Ir, Os, Pt, Al + MgF(2), Al + SiO(x), and chemical-vapor-deposited SiC, representing reflective optical applications from the vacuum ultraviolet through the visible portions of the spectrum. We found that the majority of the materials suffered sufficient reflectance degradation to warrant careful consideration in the design of future space-flight instrumentation.