Research On Structure Stability Of Three-Mirror Cassegrain Space Camera

The stability of space camera is an important issue in structure design of spacescience instruments, which has aroused the attention of researchers. With thedevelopment of space camera in the direction of large aperture and lightweight, thematerials and form of camera structure must be adjusted accordingly to reduce theweight and enhance the rigidity and stability. Due to the limits of weight and launchcosts, the structure cross-section size, the stiffness and reliability of the space cameraneed to be relatively reduced. The stability of space camera has become aparticularly important research problem. What's more, Space camera has to undergoexternal loads, temperature and other environment influences in the wholetransporting and working process. As the imaging performance is largely determinedby the camera's structure stability, the stability is of great importance.According to the camera's optical structure characteristics, studies/experimentshave been conducted on the flexible support of large-aperture primary mirror andfocusing mirror, the thin-walled cylinder between primary and secondary mirror, thecarbon fiber composite mount, and the moving parts.Firstly, the research method of space camera structure stability was introduced.The mechanical environment, the load characteristics and the evaluation of structureresponse were analyzed theoretically. The theory, processing and accuracy of finiteelement analysis were discussed. Secondly, the theoretical basis of optical structure design, the assemblytolerances, the imaging quality testing methods and the material of mirrors weredescribed.The support structure of primary mirror and focusing mirror were designed.Flexible support structure has a reasonable stiffness, environment adaptability andstructure stability. The structure design of mirrors and its support is reasonable.Thirdly, the Stiffener parameters of thin-walled cylinder were studied. Thedesign, analysis and optimization of the cylinder structure have been carried out.Theanalysis results show that the cylinder structure is stable. The structurecharacteristics, assurance measures, analysis and testing of camera mount andfocusing mechanism have been carried out. The testing results show that the designof camera mount and focusing mechanism is reasonable and reliable.Lastly, the finite element analysis and space camera structure test have beencarried out. The optical path after the first image plane was fold back on the basis ofthe coaxial optical system. The natural frequency analysis and structural stabilityevaluation of the folding space camera have also been carried out.The results haveproved that the space camera meets the customer's requirements and is of goodstructure stability.