Technology Studying On The Supporting Structure Between Primary Mirror And Second Mirror On The Space Camera

Space remote sensing is one of the main resources for the acquisition of ground information,and has become an important means of modern military reconnaissance. Space camera are main equipments of space remote sensing. In the military applications,space cameras should have high spatial resolution;at the same time it should be minimized and integrated. Therefore,lots of countries spare no effort to improve the characteristics of space camera. Compared with foreign counties,the development of space camera of China is relatively backward.With the constant improvement of space camera resolution,space camera having long focal length,large diameter was developed,and space camera having larger diameter primary mirror and ratio of a larger primary and secondary mirror magnification was adopted. No matter what type of three-reflector system,secondary mirror was inevitably located in the front of primary mirror,the variation of relative position between primary mirror and secondary mirror has a great impact on the camera's image quality. For large diameter space camera,secondary mirror is a very sensitive optical components,because the distance between primary mirror and secondary mirror is far,it will result in poor rigidity for sub-mirror connection structure. Therefore,in order to meet the requirements of the optical design and the adaptation of harsh mechanical environment on the space camera,it is necessary to study the supporting structure between primary mirror and secondary mirror. Based on the analysis of research and development situations of space camera and its structure,the supporting structure between primary mirror and secondary mirror was emphasized in this paper and and several research works were done in this dissertation:(1)The form of the supporting structure between primary mirror and secondary mirror of space camera was introduced,the analysis,optimization methods and experimental study of the supporting structure were explained.(2)According to the camera optical system,the combination means of the connecting cylinder and the support bar between primary mirror and secondary mirror were chosed,the structure optimization methods based on the finite element were studied,the invar supporting structure was optimized,the size parameters of the main structure parts were defined,and the invar supporting structure between primary mirror and secondary mirror was designed and analyzed detailedly.(3) The carbon fiber composites supporting structure was designed and studied,statics and dynamics analyses show that the carbon fiber composites supporting structure has better dynamics characteristics,having reached to the camera requirement.(4)The supporting structure stability of the two materials was validated by the crescent mechanic test and optical measurement method;harsh damp heat test show that invar support structure is much better than the carbon fiber composites support structure. Taking all considerations,invar supporting structure between primary mirror and secondary mirror was chosed.Analyses,experiment and optical measurement method adopted show that supporting structure between primary mirror and secondary mirror has better structure stability and dynamics characteristics,having reached to the camera requirement.