Lightweight SiC foamed mirrors for space applications

By combining the excellent intrinsic thermo-mechanical properties of the silicon carbide (SiC) with a structural design based on a sandwich structure composed of two SiC face sheets deposited on a foam core of the same material, it is possible to manufacture very light and stiff mirrors for space applications. This paper presents some results of a technological development study, including the realization of a lightweight athermalized SiC telescope with a 310 mm diameter foamed-SiC primary mirror. An ion beam figuring equipment has been developed to improve the optical quality of the mirror.