Abstract: The solar-radiation disturbance exists in the optical payloads onboard the three-axis stabilized satellite platform. It leads to thermal distortion, which obviously affects the imaging quality of optical system. The approximate modeling technique of complex external heat flux was applied, as well as the multi-software-coupled finite element simulation. The thermal effect of the imager′s scan mirror caused by solar radiation was researched, and compared under different thermal design conditions on the FY-4 imager. The optimal scheme of the thermal design of the scan mirror was obtained. The result shows that the thermal distortion is closely related to the thermal coating on the side and the back of the scan mirror. It is difficult to  resolve  the conflict  between the temperature fluctuation and the thermal distortion if only using the thermal design method. It is necessary to improve the material of the scan mirror or adjust the optical-mechanical structure.

Key words: Scan mirror, Solar radiation, Thermal effect, Three-axis stabilized platform, Satellite