Ground recovery and conservation of property degradation of ZnO-pigmented white paints in space

The large differences between the ground environment and space environment have important repercussions for the study of property degradation of ZnO-pigmented white paints. In order to conserve the optical degradation of ZnO-pigmented white paints in the ground experiments, S781 white paints were irradiated with 150-keV protons in a simulated space environment, and the irradiation-induced spectral reflectance change and solar absorptance change were studied in situ, in air, in vacuum, in Ar, and in liquid-nitrogen, respectively. The results show that the chemisorption of oxygen on ZnO causes the optical degradation to recover markedly when the irradiated samples are exposed to air. The vacuum, Ar, and liquid-nitrogen environments can suppress the chemisorption of ambient gases, and therefore conserve the optical degradation. Furthermore, the freeze-out effect of liquid-nitrogen is also useful for suppressing the recovery of optical degradation.