Thermo-elastic study of the pointing platform for space telescopes

Resumo

The aerospace industry is experiencing a paradigm shift driven by cost reductions in launches and the standardization of platforms for small satellites. The primary motivation of this research is to address the technological gap in the pointing capabilities of small satellites, aiming to enhance the potential of these platforms. To achieve this, it is essential to consider all error sources, including thermo-elastic disturbances. Over the last two decades, the importance of thermo-elastic analyses has been increasing in the development of space programs. Recently, the European Guidelines for Thermo-Elastic Verification have been published, demonstrating the European Space Agency (ESA) interest in developing tools for accurately predicting these deformations, especially in applications with strict dimensional requirements. The thermo-elastic analysis methodology developed in this thesis is consistent with the approach adopted in the European guidelines. However, a different method is proposed to assess the degradation of optical performance parameters: the propagation of uncertainties throughout the analysis chain. This method allows for the standardization of language between thermal and structural analyses, as well as assessing which elements contribute to optical performance degradation and to what extent, breaking down the contribution to total uncertainty based on different parameters studied. This methodology was applied to the preliminary design of VINIS, an Earth observation space telescope developed by the Instituto de Astrofísica de Canarias (IAC). Thanks to the application of the uncertainty method for thermo-elastic evaluation of the instrument, two design elements affecting telescope operation were identified, which would not have been conclusively determined using traditional thermo-elastic analysis alone. It is important to note that not only space telescopes would benefit from the application of this methodology, but it could also be easily extended to any thermo-elastic analysis of space instruments.