This paper discusses the design and fabrication of ultra lightweight laser scanning mirrors from two types of metal-matrix composites for the next generation Space Vision System (SVS). The materials selected for this study were SiC particulate reinforced aluminum composite and beryllium-aluminum (AlBeMet) composite. Three mirror designs were made and compared in terms of mass, rotating inertia and first mode natural frequency. Mirror surface layer selection and processing were discussed. Problems encountered during the mirror fabrication and the ways to solve it were presented.
Application of advanced composite material for lightweight mirror for space optics needs to know the exact thermal expansion behavior of the composite in space thermal environment. In this paper, thermal expansion behaviors of plasma thermal sprayed and powder metallurgy processed ceramic particulate reinforced aluminum metal-matrix composites in simulated space thermal environment were studied. Thermal cycling was found to cause hysteresis and non-linear thermal expansion responses to the composites when the thermal stress within the composite exceeds the yield strength of the matrix, and subsequently causes matrix plastic flow. High matrix yield strength is necessary for MMC to have linear, stable and repeatable thermal expansion response in severe space thermal environment. The study lays out a fundamental for choosing existed or developing a new MMC for lightweight mirror application.