Providing a Special Thermal Environment of the ART-XC Reflecting X-ray Telescope as a Necessary Condition for Obtaining Significant Scientific Results

The article presents the main significant scientific results obtained by the first Russian reflecting X-ray telescope, the Pavlinsky ART-XC. This telescope has been operating as part of the Spektr-RG observatory since 2019. It is shown that the prerequisite for obtaining these results was to maintain a special thermal regime of telescope components with high accuracy and stability. The problems of telescope thermal control are presented. The engineering solutions and control algorithms that allowed solving these problems in the ART-XC are described. Experimental data, including flight data, illustrating the implementation of these solutions are presented. Recommendations on thermal-control systems for similar telescopes are given.