Methods for estimating the precipitate thickness on the surface of cooled optical elements in vacuum with contamination sources

We describe a simple method for estimating contamination (thickness and growth rate of precipitate layers) on the surfaces of elements of an optical system operating in vacuum. Experimental results of physical simulation of contamination of on-board optical elements of a spacecraft orbiting with its own external atmosphere are reported and compared with calculated values. The results of this research can be used in cryostatting of optical elements in the residual atmosphere of a vacuum chamber.