Developing SiC for optical system applications

Future large-aperture optical space systems will need to use lightweight materials that meet stringent requirements, and that reduce program and launch costs. Lightweight optical systems produced quickly and cost-effectively, and the resultant lighter payloads, can reduce these costs. Mirrors for future systems have areal density goals of less than 5 kg/m(2) and will need to use new materials'. A promising one is silicon carbide (SiC) because of its physical and mechanical properties. These enable the production of low areal density, high quality mirrors, as well as lightweight athermal telescope structures. Athermal structures are desirable because they simplify designs and reduce tolerance requirements to maintain performance during on-orbit temperature changes. The use of SiC to make mirrors and structures is in the developmental stage and has limited space heritage. To ensure the use of this material in space applications, qualification and system performance in the space environment must be addressed. This paper provides an overview of SiC, along with recommendations to further the development of SiC into a mature technology that can be successfully integrated into future large-aperture optical space programs.