Stray light control in an off-axis three-mirror anastigmat telescope

Stray light is a critical factor affecting the performance of optical payloads, particularly in off-axis three-mirror anastigmatic (TMA) telescopes, whose asymmetrical geometry makes the mitigation of scattered light particularly challenging. This thesis addresses the issue of controlling stray light in an off-axis TMA telescope designed for a CubeSat platform. The work is divided into two main parts: the mitigation of stray light outside the field of view, and the characterisation of in-field stray light. For the former, a complete system of baffles was designed to minimise unwanted light coming from outside the field of view, ensuring that its contribution remains below an acceptable threshold. In parallel, the in-field analysis focused on evaluating the optical quality of the mirrors that had already been produced for the breadboard model. This involved the characterisation of the surface through profilometric and interferometric data, to verify compliance with modulation transfer function (MTF) requirements and identify potential improvements in the manufacturing processes. Given the size and resource limitations typical of CubeSat missions, particular attention was paid to ensuring that all proposed solutions were compatible with these constraints. The thesis includes a description of the TMA's optical design, the analysis methodology adopted, and a discussion of the results obtained for both stray light sources. The study concludes with an assessment of the system's performance and potential improvements to increase optical quality and reduce the contribution of scattered light.