In the practice of designing spacecraft thermal control systems, the reliability of radiators is traditionally assessed by the probability of sudden failure due to micrometeor breakdown. Degradation of the thermal control coatings optical characteristics can lead to gradual failure, which is taken into account in the initial data when selecting design parameters based on expert assessments of known prototypes. The article sets and solves the problem of studying the parametric failure scheme and constructing a mathematical model of the radiator parametric reliability using a degradation process model based on a random Wiener process with a nonlinear time scale. The parameters of the degradation process model are determined by statistical processing of flight experimental data, taking into account the stochastic nature of the influencing factors of outer space. An algorithm for point estimates of degradation and parametric reliability model parameters based on the maximum likelihood method has been developed. A simulation modeling algorithm has been proposed for constructing a confidence interval. Based on flight experimental data, a parametric reliability model is constructed and recommendations are given for estimating the radiator area of the thermal control system of the habitable module in low Earth orbit. The result of the developed parametric reliability model is the possibility of simultaneous accounting for sudden and gradual failures in a complete model for assessing the reliability of space radiator.

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