Low Cost Light Weight Graphite Fiber Reinforced Mg Space Mirrors

"MMCC will develop an isotropic graphite fiber reinforced magnesium rigid mirror material that will result in an areal density of 5 kg/m2, reduce lead times for paraboloid blanks by two-thirds, and cut mirror costs by at least 50% over Be mirror systems.Phase I will design, build, and test graphite magnesium composite variants and mechanical, thermophysical, and optical surface evaluations will be performed on flat graphite magnesium blanks, while a near net shape cast ROTF (rough oversize to finish)sub-scale component will be cast simultaneously to demonstrate efficiencies in manufacturing. Moreover, it will be shown, that an isotropic and dimensionally stable mirror can be produced through novel preforming methods, proper alloy selection, and heattreatment. An ultra-lightweight graphite magnesium mirror blank will be near net shape manufactured with a thermal expansion coefficient as low as 1 ppm/K, a thermal conductivity of 200-300 W/mK, stiffness approaching steel, and a density near that ofberyllium. Furthermore, the graphite fiber reinforced alloy will be engineered with isotropic mechanical and thermophysical properties, resulting in dimensionally stable optics for space. A 5 kg/m2 areal density space mirror material will become readily available to the space community with short lead times. Cost of fabricating mirrors will be a fraction of that of beryllium or other competitive materials. Innovative control of fiberarchit