Simulation of Outgassing Processes in Spacecraft Coatings Induced by Thermal Vacuum Influence

The mathematical models describing the outgassing processes and deposition of volatile products under thermal vacuum exposure to coatings applied to space vehicles are given. The models are based on assumptions that changes of outgassing product concentrations in material under investigation take place as a result of desorption from surface on the material-vacuum boundary, first-order chemical reactions, and diffusion specified by the aforesaid processes, and that a part of the surface deposited mass reevaporates. Analytical expressions for the space-time distribution of outgassing products in material and dependence of mass deposited on unit surface on time were obtained from the model equations for the influence of individual processes on outgassing and deposition kinetics to be investigated numerically. According to the obtained results, an analysis of how parameters of the model, separate and in combination, exert influence on alteration of outgassing product concentrations, on outgassing, and deposition kinetics has been carried out.