空间太阳望远镜主光学望远镜热效应分析

Thermal effect analysis of main structure in space solar telescope

空间太阳望远镜(SST)直接对日成像,其1 m口径的主反射镜(MOT)接收到的上千瓦热量将严重影响望远镜的成像质量,因此必须进行热控设计以确保SST的性能。首先讨论了SST主镜筒内的热状况,分析了对日观测时主镜筒内的热流分布情况;然后根据SST轨道参数计算望远镜的空间轨道外热流状况;在此基础上提出了相应的热控措施,并使用热分析软件Sinda/G与Nevada计算了SST主镜筒温度分布;最后计算了SST主镜相应的热变形,对主镜镜面热变形采用Zernike多项式拟合,热变形精度小于λ/40(λ=633 nm),确保SST获取0.1″～0.15″的高分辨率成像目标,验证了SST主镜筒热控设计的有效性。

Space solar telescope（SST） is designed to observe the sun.With an effective aperture of Φ1 m,the main optical telescope（MOT） of faces the sun directly,which receives more than 1 000W heat that will lead to unacceptable thermal distortion.Therefore,the temperature field of SST,which is changing with its orbital position,is critical in its design.The thermal condition in the SST was discussed firstly.Furthermore,the heat flux of orbit was calculated with the thermal softerware Nevada-according to the orbit parameters of SST.To study the impact of the thermal environment on the optical performances of the SST,a thermal control design of SST was performed on the basis of the numerical simulation of the observing thermal condition in the space.The thermal design software Sinda/G（System Improved Numerical Differencing Analyzer/Gaski）,the radiation analysis software Nevada and the finite element analysis software MSC.Patran were used to simulate the temperature field of the SST.In the end,the temperature distribution of the primary mirror was calculated,and the deformed surface points of the primary mirror was fitted using Zernike formula.The temperature level of the primary mirror contributes to less than λ/40（λ=633 nm） to the surface error,which indicates that the system can achieve high spatial resolution with 0.1″-0.15″.It also means that the thermal control design is effective.