空间遥感相机大口径变方位反射镜设计

Design of large-aperture variable-direction mirror for space remote sensing camera

随着遥感技术的发展,新型相机对变方位反射镜提出了口径更大,精度更高的需要。针对1000 mm×700 mm大口径变方位反射镜提出了一种新式背部高稳定支撑设计,相对于常规变方位反射镜设计,具有体积包络小、重量轻、适应性广的特点。反射镜采用ULE材料,蜂窝夹层的轻量化结构形式,通过背部三点关节球铰卸载了反射镜的装配应力和在轨热变形应力,达到反射镜的无应力静定支撑。通过重力卸载结构的设计和卸载力的优化,解决了光学反射镜地面测试结果天地一致性问题。仿真分析表明地面重力环境下,在90°反射镜面型测试方位时,面型为0.006λ(λ=632.8 nm);在75°整机成像方位Ⅰ测试时,面型为0.005λ;在45°整机成像方位Ⅱ测试时,反射镜面型为0.011λ。反射镜组件的一阶频率达到83.2 Hz,具有较高的刚度,能够满足发射时力学环境要求。这种大口径变方位反射镜组件设计能够满足新型遥感相机的需求,也可为同类反射镜的设计提供参考。

With the development of remote sensing technology,new camera requires large aperture variabledirection mirrors with higher accuracy.A new type of back support structure with highly stable support design was proposed for 1000 mm×700 mm large-aperture variable-direction mirror.Compared with the conventional design,it had the characteristics of small volume envelope,light weight and wide adaptability.The mirror was made of ULE,and the light weight form of honeycomb layer was used.The mirror was mounted by means of a 3-point ball joint flexures system on the back.The stress in reflector assembling and the influence of thermal stress on the orbit was eliminated.It reached the stress-free support of the mirror.The problem of consistency between the ground test and in orbit was solved through the design of gravity unloading structure and the optimization of the unloading force.The simulation analysis shows that the surface RMS is 0.006λ(λ=632.8 nm)at 90°mirror testing direction.The surface RMS is 0.005λat 75°camera imaging testing directionⅠ.The surface RMS is 0.011λat 45°camera imaging testing directionⅡ.The first order modal of the component is 83.2 Hz,which has a high design stiffness and can meet the requirements of the mechanical environment during launch.This largeaperture variable-direction mirror design can meet the needs of new types of remote sensor and can provide a reference for the design of similar mirrors.