Design overview of a thermally stable high NA telescope using ceramics and composite materials

Laser satellite communication offers new opportunities in global data transfer, and can provide crucial infrastructure to facilitate the ever-growing demand. Creating an optical link of 10.000 km in length requires a telescope with extreme thermal stability, in an environment where thermal loading is periodical as a result of the satellite’s orbit. As requirements get increasingly demanding, all-aluminium telescope designs require more and more complex solutions to work around thermal gradients. This thesis presents a number of telescope designs comprising different material combinations in order to increase thermal stability, including silicon carbide (SiC) and carbon fibre, integrated with aluminium where possible. Difficulties in manufacturing and alignment are treated as they have a critical impact on final performance. A critical thermal load case is defined for which the performance of each design can be tested. The most promising design comprises a carbon fibre hexapod in combination with an aluminium spider, which was built and tested for validation. The thermal stability was improved by factor 20 with respect to an all-aluminium design. / Mechanical Engineering | Optomechatronics