Design And Analysis Of2m SiC Primary Mirror’s Lightweight And Support Structure

In a space camera, the primary mirror does not only decide the optical properties such as theground pixel resolution, but also affect the mechanical properties, thermal stability and themanufacturing cost. Therefore, the design of primary mirror has become a vital procedure in thedevelopment of a space camera, in which the lightweight and support structure take the mostimportant part. The total weight of primary mirror and its supporting structure must be lightenough in order to satisfy the payload restriction of launching conditions. On the other hand,surface figure is greatly influenced by gravity during ground tests, a lighter weight primarymirror will decrease this influence and the difficulty to design the support structure. The supportstructure must ensure the mechanical properties and thermal stability of the primary mirrorassembly, enable its surface error to satisfy the precision demand which guarantee a good imagequality.This paper mainly focused on the lightweight and designing of support structure of a2m-aperture SiC primary mirror of a space camera. CAD and CAE methods have been used todesign and analyze the structures. Further improvements of key parameters were made based onthe ISIGHT modification method. A step type double arch SiC primary mirror design was madeand tow18-point backside support structures have been designed. A flexible component wasdesigned to improve the performance in the thermal analysis, it effectively reduced the influenceof temperature change on the surface figure of the primary mirror.