Smart Large Diameter Space Telescope System, The Primary Mirror

The smart large aperture space telescope is the most development potential space observation spacecraft in the future. It has a foldable and unfoldabe characteristic, has a large field, long focal length and the ultra-light optical system. Using it, the universe stars and galaxies are studied by using the imaging and spectral analysis methods. According the realizing function of the extensible main reflecting mirror optical system, the material design, the structural design and the technique of manufacture of the main reflecting mirror were deeply researched in this thesis.The main research contents , achievements and the innovations in this thesis are:(1) Material selection of main reflecting mirror in the smart large aperture space telescope systemDue to the smart large apertur space telescope optical system uses the reflective optical system, thus the main reflecting mirror besides must guarantee its can complete optics image formation task, but also must carry on the lightweight to the main reflecting mirror body, enable it to have the smart characteristic. The most important task of main reflecting mirror lightweight design is the selection of mirror body material. This thesis has systematically analyzed the tradition reflecting mirror body material behavior and the new reflecting mirror body materials behavior, simultaneously has carried on the comprehensive analysis comparison to each materials behavior. Under the guidance of new ideas in the design of materials, the conclusion is obtained that the designed characteristic composited materials have the advantageous superiority in the manufacture smart telescope mirror body. Therefore composited materials are selected to fabricate the main reflecting mirror body of the smart large aperture space telescope. Tasks had been completed in this thesis that the structural design and the fabrication of the carbon fiber composite materials reflecting mirror, the structural design and fabrication of Silicon carbide composite materials reflecting mirror.(2) Structure selection of main reflecting mirror in the smart large aperture space telescope systemThe structural design thought of the main reflecting mirror comes from its lightweight design were being applied in presently the large aperture optical system design, honeycomb sandwich structure and the back open shed structure were choosed as the main reflecting mirror structure(3) Structure design of main reflecting mirror in the smart large aperture space telescope systemGeneral methods of the composite material reflecting mirror structural design had been studied in this thesis.Has completed the carbon fiber composite materials reflector board layer design and the honeycomb core design with having honeycomb sandwich form, diameter is the 1m. First makes the statics analysis, the modality analysis and the thermodynamic analysis using the finite element method to each kind of layer form board, then the layer form style is determined according the principle of the minimum surface shape, the maximum foundational frequency and the minimum temperature gradient. The finite element analysis is carried on carbon fiber composite materials reflecting mirror body having honeycomb sandwich form of diameter at 1m. Although the diameter and thickness of reflecting mirror body are determinated in the same operation environment, the honeycomb core standard is asynchronization on mirror body deadweight distortion rule, foundational frequency changing rule and the thermal deformation rule. While satisfy the premise of optical system specification, the honeycomb core standard is determined according the principle of the minimum surface density. Finally, the structure sizes of two composite materials reflecting mirror are determined by using the optimized design methodBy static's analysis, modal analysis and thermomechanical analysis using finite-element method to back opening silicon carbide composite material reflecting mirror of diameter at 1m, the mirror's self weight distortion rule, basic frequency changing rule and thermal deformation rule were gotten out in the condition of decided diameter and thickness of the mirror, identical operating condition and different depth of backside blind hole and string thickness of the mirror.(4) The fabrication of carbon fiber composite reflecting mirror and silicon carbide composite material reflecting mirrorThe fabrication technology of carbon fiber composite reflecting mirror was studied. We had made, a good quality carbon fiber composite reflecting mirror of honeycomb sandwich manustucture with its diameter at 200mm, surface density at 3.72kg/m~2 and weight at 0.117kg. We also had made a silicon carbide composite material spherical mirror with its diameter at 650mm, a silicon carbide composite material plane mirror with its diameter at 240mm, and two silicon carbide composite material aspherical mirror with diameter at 520mm and 117mm respectively. The dockage ratio of the four mirror are more than 60% with good surface quality. The fabrication of carbon fiber composite reflecting mirror and silicon carbide composite material reflecting mirror had made a good foundation for the development of composite material reflecting mirror and accumulated vast experience.(5) The optical manufacture of carbon fiber composite material reflecting mirror and silicon carbide composite material reflecting mirrorThe manufacture technologies of carbon fiber composite reflecting mirror were deeply researched. By using the technologies, we had accomplished the optical manufacture of carbon fiber composite reflecting mirror of diameter at 200mm with honeycomb sandwich structure. The achievement had made some foundations for the fabrication of large aperture carbon fiber composite reflecting mirror. In addition, the optical manufacturing methods of silicon carbide composite material reflecting mirror were compared and analyzed, the choose of technological parameter in the process of optical manufacture and approaches to depress the surface roughness of carbon fiber composite reflecting mirror were discussed, and the manufacture of aspherical mirror with diameter at 520mm and plane mirror with diameter at 240mm was accomplished with high surface shape precision and low surface roughness that has a quite level with that of optical glass mirror surface...