Thermoelastic evaluation of the payload module of the ARIEL mission

The ARIEL mission is a space project consisting of a spacecraft with the goal of detecting exoplanets and observing the characteristics of their atmospheres. One of the main sub-systems of the payload is the telescope that must operate under cryogenic conditions to guarantee its adequate performance and the mission success. One of the critical aspects in the development of a space telescope is the stability and the related analyses required to evaluate the degree of deformation of the system under all environmental conditions, with special emphasis on the different and extreme temperature ranges reached during the mission. This assessment involves the close collaboration between three different disciplines: thermal, structural and optical design. This paper describes the work done in the ARIEL project in the field of the structural stability analysis, showing the process to achieve reliable and accurate results. The main novelty of this work is the validation of the structural model to achieve the required level of precision in the displacements fields calculated numerically to provide reliable and accurate deformations that will allow the assessment of the thermoelastic effects on the optical performance of the main telescope. The results of the structural simulations show how the telescope assembly is deformed under the different analysed conditions, which will allow the design of compensation mechanisms to mitigate these effects.