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Jet spray cleaning of optics

Space optical systems operating at cryogenic temperatures may have stringent contamination levels due to high off-axis rejection requirements for the optics. The extreme difficulty in launching and maintaining clean cryogenic optics on-orbit is alleviated by incorporation on-orbit cleaners. This paper describes a jet spray method for removing contaminants from space optics operating down to 30 K and the apparatus. Results of experiments performed on four substrate materials using various cleaning snows and jet spray arrangements will be discussed. Cleaning efficiencies of the jet spray were measured using an in situ bidirectional reflectance distribution function (BRDF) scatterometer built into the space simulation chamber.