月基极紫外相机光机结构设计

Design of optical-mechanical structure for lunar-based extreme ultraviolet camera

为了对地球等离子体层产生的30.4nm辐射进行全方位的长期监视和观测,研制了月基极紫外相机。相机主体采用多层膜单反射镜光学系统以及30.4nm球面光子探测器的结构形式,跟踪机构采用俯仰-方位模式,由步进电机驱动实现对地球的捕获。针对卫星发射、地月变轨、月表着陆过程中的振动冲击以及月表残酷的温度环境,月基极紫外相机的光机结构设计考虑了环境(力学、温度)适应性,有限元分析结果表明,光机结构在整机质量<15kg条件下,一阶谐振频率为49.3Hz;运动机构在-50～+80℃运转自如;在50℃均匀温降载荷作用下反射镜面形精度RMS值为13.44nm(<14nm),满足相机的技术指标要求。

To monitor and research 30.4 nm radiation generated by the plasmasphere,a lunar-based Extreme Ultraviolet（EUV） camera was developed.A multilayer mirror optical system and a 30.4 nm photon counting detector were adopted as the main body of the camera,and a two-dimensional tracing mechanism drived by a stepping motor was used to trace the earth.Aim to the vibration and impact from the process of satellite launching,orbit changes from earth′s to moon′s,moon landing,and the cruel temperature environment of the moon,the optical-mechanical design of EUV camera gave a consideration to the environmental adaptability.After the optimization by finite element analysis,it shows that the first order resonant frequency of the optical-mechanical structure is 49.3 Hz with the mass less than 15 kg,the motion mechanism operates freely within-50~＋80 ℃,and the mirror surface accuracy（RMS） is 13.44 nm（14 nm） under the load of uniform temperature drop of 50℃. Those results meet the technical requirements of the camera.