Design On The Primary Mirror Of A Space Camera Based On Finite Element Method

As space camera is showing its important effect in the domain of politics, military and national economy, more and more countries start theirs research and development about it. In the space camera, the most crucial optical component that affects the spatial resolution is the primary mirror, so the requirements of its surface figure and position precision are very strict. Because the strip mirror's dimension is large in this article, the design is more difficult. Naturally, the primary mirror design is becoming a key task of space camera development.Around design requirements of the primary mirror, the article mainly introduces the process of the primary mirror material selection and some structure parameter's decision. That is, by the calculation of the anti-thermal deformation quality factor and synthetic quality factor of some typical primary mirror materials, the primary mirror material is selected scientifically and rationally. By the finite element method and the conception of structure rigidity quality factor, researching the relation between the light-weighted cell shape, the mirror thickness and mirror structural rigidity quality. By the force-thermal coupling analysis of the primary mirror assembly, the relations between the thickness, height of the flexible support reed and primary mirror synthesis surface figure error (p-v) have been researched.The research result indicated: for the strip primary mirror discussed in this article, the hexagon light-weighted cell has the best structural rigidity quality, the square cell is a little worse, the triangle cell is the worst; there is an optimum on primary mirror thickness; on condition of 1g gravity load combining with 4 centigrade uniform temperature rising, the thinner and higher of the flexible support reed, the better of the primary mirror surface figure. The decision of the structural parameters of the flexible support reed must take static rigidity, dynamic rigidity, static strength and dynamic strength of primary mirror assembly into account.For the flexible support reed is very thin (1.3mm), it's necessary to study the buckle of the primary mirror assembly. The calculation indicates that when spacecamera is launched, the primary mirror assembly would work well.It is also an important consideration in the structural design of the primary mirror assembly whether the primary mirror assembly can withstand the effect of dynamic load from the ground transport and the space launch process. The dynamic analysis indicates that the design of the primary mirror assembly is good.The design of the primary mirror assembly meets requirements.