Structure Design For The Sparse Aperture Telescope

With the development of science and technology,the high imaging resolution of space telescope becomes more and more urgent.The aperture of space telescope needs to be increased to improve resolution of telescope system.However,the development of largeaperture telescope system is restricted by many factors such as optical processing,cost,quality,and emission.For this purpose,people begin to propose new technical solutions to solve the above problems.The sparse aperture optical system is one of the techniques to overcome the problem.The sparse aperture optical system is constitued by a number of small apertures or reflector optical system according to certain rules.It reduces the processing difficulty,the system quality,and the cost of the telescope system while its resolution is equivalent to that of a single-aperture telescope system.Because each sub-aperture in the sparse aperture telescope optical system is off-axis system and co-phase imaging,it has high requirements on the accuracy of the fixed and adjusted structure of primary and secondary mirror.Meanwhile,the actual working environment of sparse aperture telescope can also lead to the deformation and surface shape error of all optical components,resulting in the effect on the imaging quality of the system.Therefore,it is necessary to make further study on the structure for the sparse aperture optical system and the effects of environment factor.This paper introduces its system structure and optical parameters,analyzes the modulation transfer function characteristic,etc.,and calculates the visual resolution and CCD imaging resolution of the system based on the Golay3 sparse aperture optical system.The mechanical structure of Golay3 multiple-mirror telescope is designed,including primary telescope structure,fixed and fine-tuned structure of off-axis,support and adjustment structure of secondary telescope,compensation telescope structure.It calculates the dimensions of the primary and secondary mirror hoods and designs the structure according to stray light analysis.It performs finite element analysis on the designed structure under the condition of gravity and different temperature,and calculates the surface shape error of each optical components.The results show that tilt error and surface shape error of each component are within the design requirements,and the first-stage natural frequency is 342.08 Hz with good dynamic stiffness.The Golay3 multiple-telescope telescope is designed,and the mechanical structure and fine-tuned structure of each component is confirmed too.According to the results of finite element analysis,the relationship between radial thickness and imaging of secondary mirror support structure is analyzed.The support structure of the secondary mirror is optimized to a gradual change from 5 mm to 15 mm.The maximum stress of the system is 136.3 MPa which is lower than the proportional limit of the material,so the telescope does not undergo plastic deformation.The surface shape error and tilt error of each component meets the design requirements.