Structural design of primary mirror subassembly for space telescope

In order to design a large aperture primary mirror with the diameter of 1150 mm, the parameters impacting on gravity deformation of the mirror were analyzed and discussed in detail, including material selection, diameter-thickness ratio, the number of the support points, location selection and lightweight structure, etc. A novel space mirror structure system was put forward, and its back was opened and supported by six points on back. The dynamic and static and thermal characteristics were analyzed based on the finite element method. Analysis results showed the surface figure accuracy reached to RMS 14.5nm under the action of gravity load along the optical axis direction and the first-order natural frequency was 214Hz which met to the designed indexes requirements.