基于SiC材料的空间相机非球面反射镜结构设计

针对空间相机中优质轻型光学反射镜对材料提出的要求，详细讨论了设计基于SiC材料空间反射镜的一系列问题，包括径厚比的选择、支撑点数量、轻量化结构形式、材料特性匹配等，提出了一种背部半封闭、三角形孔的轻量化形式，并设计制造了 Φ600 mm轻量化SiC反射镜实验件。抛光后反射镜面形精度优于λ/20 rms。为验证重力变形的影响，将反射镜分别旋转了90°和180°，用Zygo干涉仪检验，3个方向检测结果误差均小于λ/100 rms。在此基础上设计完成了某空间相机中的SiC非球面主镜、次镜、第三镜，结果表明基于SiC材料的反射镜在重力变形、谐振频率、热变形等方面均能满足使用要求，而且与玻璃材料相比，在很大程度上降低了重量。

Space telecope aspherical mirror structure design based on SiC material

According to the demand of material of high quality reflection mirror in space telescope，the design issues for SiC mirror such as aspect ratio of diameter to thickness, light-weighting structure, number of support points, characteric match and so on are discussed. A new design with semi-closed back and triangular hole light-weighting structure is proposed. To verify its reliability, a 600 mm diameter light-weighting SiC mirror was designed and manufactured, the final surface figure accuracy is superior to λ/20 rms after polishing. Interferometric measurement with Zygo interferometer at three orientations of 0°, 90°, 180° was taken respectively, the difference is less than λ/100 rms.Based on the above discussions, the primary mirror, secondary mirror and tertiary mirror in a space telescope and the primary mirror of missile guider optics were designed, it has proven that the performance such as self-weight deflection, fundamental frequency, thermal stability all meets the requirement. In addition, compared to glass mirrors, SiC mirrors can reduce big amount of weight.