Research On The Optimization And Support Of The Large Aperture Space Primary Mirror

With the continuous development of space technology, space optical remotesensor is becoming more and more useful, it plays an important role in the fieldsof space exploration, energy exploration, weather forecast, militaryreconnaissance, national construction and ocean research. As a result, countriesaround the world are racing to carry on the research and development of spaceoptical remote sensor. In the future, space remote sensor will be the importantembodiment of developed countries’ comprehensive national strength. Opticalmirror is an important payload of space optical remote sensor whose performanceis directly related to the imaging quality of mirror. According to the theory ofoptics, the diameter of reflector is larger, the image quality is better. In the future,the large aperture reflector will become the important trend of remote sensor. Thebigger the relative aperture is, the greater the resolution is, and at the same time,the more intense the illuminance of image plane is, so that the exposure time canbe shortened. However, the larger the mirror diameter is, the heavier the weightof mirror is.At the same time, the deformation of the reflector is greater as thetemperature changes. So we must design a reasonable structure of reflectorcomponents to meet the performance requirements.In this paper,firstly, the work environment of mirror is listed, and the designprinciple of the reflector components is given then. On this basis, combiningprevious research results, the design of the reflector is provided, includingmaterial selection, back form, basic thickness, support position andlightweight.For the lightweight, there are two ways, the traditional way and thetopology optimization. From the results of the analysis, the topology optimizationreflector is lighter, and has a better performance. Then, on the basis of the fixedstructure of the mirror, its supporting structures are designed reasonably. To makesure that the reflector image can reach the standard under the gravity load and theload case of gravity coupled with temperature rise, using the Whiffle-tree support,a middle structure with a spherical hinge-column and bearings is designed.Lastly,all parts are endowed with reasonable materials.After the structures are designed, in order to determine whether the structureperformance meets the design requirements,the simulation analysis was carriedout on the structures with the finite element software WORKBENCH, includingstatic analysis and dynamic analysis. In the static analysis,the structures areplaced in the gravity load and the load case of gravity coupled with temperaturerise respectively to observe whether the structures can satisfy the index of opticaldesign. At last,using Zernike polynomials,the result data is analyzed in thenumerical calculation software MATLAB. The dynamics analysis includes modalanalysis，harmonic response analysis and random vibration analysis. The resultsshow that the reflector structures meet the design requirements.