Research And Design On Airship Onboard Earth Observation Telescope

Space optical remote sensor is one of the significant means of observation from space to earth, whose importance has been highly attached by many countries worldwide. With the utilization of the optical instrument of space to earth observation, the austronaut, by scouting around,making observation and surveillance on the areas for target of interest, could obtain consecutively many important information with high value. Then the result of the surveillance, after being analyzed, judged and recorded, is transferred to the earth in order to achieve the purpose of the command and control from space to earth.Taking fully the space environment into account, this paper emphaticly makes a thorough research and design of a kind of Airship onboard earth observation telescope, which mainly consists of the following several aspects:the principle and design of zoom mechanism, the analysis and design of Iris diaphragm applied to the automatically adjustable optical-intensity video system, the analysis of space dynamic environment and the efficacy of man-machine in the process of space work.Zoom lens plays an important role in the optical information capture of the whole optical system. In this paper, the selection of optical scheme , the choose of zoom mode and the mechanical design of the zoom cone have been deeply expounded and studied. By virtue of comparing two methods of zoom lens compensation ?optical compensation and mechanical compensation, the former way is selected to achieve the zoom purpose. During the zoom, the front lens and rear lens are fixed , and two zoom lens groups having the middle lens groups between them have been coupled together and move synchronically in a linear way, the range of zoom is 178mm. By making a systematic theory analysis, specifically calculating deduction, an ideal zoom lens which has simple configuration, performance reliability,good image quality has been successfully gained.When observing the object on ground from space, with the variation of the atmosphere, the solar altitude angle as well as the illumination of the scenery on ground affect the definition of the image on the CCD focal plane. In order to obtain the suitable illumination on the focal plane of the CCD camera in the video system thus observe a clarifiableimage on the LCD screen. Adjustable Iris diaphragm cooperating with the electrical shutter to dodge is adopted. It is not suitable to dodge with the variable density plate in consideration of the rigour environment in space while adopt the adjustable Iris diaphragm with high reliability. The mechanical design of adjustable Iris diaphragm dodging component and the method to design the parameter of Iris diaphragm are mainly presented. The experiment is verified that the cooperation of the Iris diaphragm with the electrical shutter well satisfies the dynamic dodging range required for the space to earth observation video system.The special working environment of the space optical instrument determinds that it is not only suffered from the effect of the asperity of space environment but also is affected by the environmental factors such as mounting, debugging and launching phase before it is put into the function mode. In order to ensure that the optical instrument will work normally, and do not suffer from destruction in the process of launch and conveyance. In the phase of design, the optical instrument is respectively analyzed by means of Finite Element Method(FEM), involving the analysis of dynamic properties and dynamic response. Then the vulnerable part and defect will be found and the reason will be analyzed, as a result, the dynamic performance of the instrument structure is ameliorated by modifying the corresponding design of the instrumental structure. In this paper, for the primary mirror assembly and the whole system of the telescope, the dynamic analysis and vibriating experiment are both conducted, the result of experiment indicates that the design of structure entirely meets the specification of rigidity constrained by the space dynamic environment.