Temperature mapping methods for thermoelastic analyses of the ARIEL spacecraft payload module

Abstract

The ARIEL mission is a European space project that aims to detect exoplanets with a spacecraft orbiting around the L2 point of the Sun-Earth system. The main payload consists of a Cassegrain telescope composed of mirrors that reflect and concentrate the incoming light from the deep space observations to finally guide it to the detectors. As in many other space missions, a dedicated complex assessment is established during the design phase to evaluate the impact on the optical performance caused by thermoelastic effects, which involves the coordinated work of the thermal, structural, and optical engineers. Despite that well-known and standardized processes and tools are established separately in each involved area, there is a lack of standardization about the way of exchanging the data between them, where additional calculations are required in some cases. This work focuses on the temperature mapping, which is the intermediate step between thermal and structural analyses, where temperatures are transferred to the structural model. The main difficulty of this process is related to the differences in modelling methods and approaches between both models, being necessary the development of an adequate algorithm to find the most accurate transfer of temperatures. This paper shows two different options for temperature mapping, detailing the proposed flowcharts. One of these methods requires the performance of an additional thermal conductive analysis, where a new improved procedure has been implemented in this work to solve some computational issues that made its application for large models difficult or even unfeasible. Both temperature mapping methods have been applied to the payload module of the ARIEL spacecraft, comparing the output results in terms of temperatures, stresses, forces, and displacements to evaluate their differences.