| With the development of space optical technology, there exits higher demands for the larger-diameter primary mirror for the space usage. Increasing in diameter, however, lead to the following technological problems: the distortion caused by deadweight of mirror will increase, and the heat-swell distortion of the mirror face due to the change of the environment temperature and the mirror grads will increase too. At the same time, the primary mirror should be light-weighted to reduce the launch cost. But the distortion will increase even more under gravity after this process, which, in turn, will directly affect image quality of the space mirror, as well as the machining and the checking. Consequently, how to minimize the deadweight distortion becomes an important subject for research.The thesis makes a brief introduction to the recent research within this field. Then, according to the actual project requirement, SiC is chosen as the material for the primary mirror, and a proper form of lightweight is selected for support structure analysis as well. The mechanical conditions satisfied for the mirror face distortion are discussed at first. Then, with borderline condition set for actual condition. We designed a same support structure under two different cases, horizontally and vertically. The finite element method (FEM) is employed to carry out the support structure analysis of the primary mirror. With the cause of distortion obtained from the analysis, the support structure is optimized accordingly.7y using the least square method, the data of the distortion of the mirror surface are analyzed. A specific program is compiled to deal with Patran data, and PV and RMS figures are gained from the calculation.The final constructed data indicate that the support structure discussed in the thesis satisfies the actual project request, since the RMS criteria under two operating modes for the change of the mirror surface are both within the range of X/60 (X=632.8nm) .
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