作为空间相机光学元件的载体，主支撑结构对于确保光学元件相对 位置的长期准确稳定具有决定性作用。由于具有比刚度高、热稳定性好等优点，高体分碳化硅颗粒增强铝基(SiCp /Al)复合材料 非常适用于航天光机结构。利用超声波钎焊技术可以解决高体分SiCp /Al材料的焊接问题，这 为其在空间相机主支撑结构上的应用奠定了基础。介绍了一种基于高体分SiCp /Al材料的某空 间相机的主支撑结构。通过工程分析比较了同一主支撑结构分别采用TC4和高体分 SiCp /Al两种材料时的力学性能差异。结果表明，采用高体分SiCp /Al材料制成的主支撑结构在质量上轻了31.8%，在一阶频 率上高了25%。通过力热试验可知，该主支撑结构在焊缝强度和尺寸稳定性等方面均满足使用要求。

As a carrier of the optical elements in a space camera, the main supporting structure of the space camera plays a decisive role in making the relative positions of optical elements accurate and stable for a long time. Because of the advantages of high specific stiffness and high thermal stability, high volume SiCp /Al composites are very suitable for making opto-mechanical structures for space application. Since the ultrasonic-aided brazing technique can solve the welding problem of high volume SiCp /Al composites, it has laid a foundation for the application of high volume SiCp /Al composites in the main supporting structures of space cameras. A main supporting structure for a certain space camera based on high volume SiCp /Al composites is presented. The mechanical properties of two similar main supporting structures made of TC4 and high volume SiCp /Al composites respectively are analyzed. The results show that the weight of the main supporting structure made of high volume SiCp /Al composites decreases by 31.8% and the first-order frequency increases by 25%. It is known in the mechanical and thermal tests that the main supporting structure meets the requirements in weld strength and size stability.