Abstract: The solar sail is a complex system composed of large，flexible membranes that are tensioned by light booms.However，when the solar sail experiences high and low temperatures in space due to variations in the environment，the sudden change in temperature field can cause the booms to deform and vibrate.This disturbance torque can affect the attitude of the solar sail，leading to an instability in the control system.To address this issue，an analytical method is proposed for thermal-induced disturbance torque of the solar sail.Firstly，a thermalstructural analysis model is established that considers the transient temperature fields of the structure when the solar sail enters and leaves the shadow.This analysis enables us to better understand how the sudden temperature changes impact the sail′s dynamics.Next，the dynamic responses of the sail under these temperature conditions are calculated，taking into account its deformation and vibration.Finally，the disturbance torque of the dynamic responses towards the central body of the solar sail is obtained.Results show that the thermal-induced deformation and vibration of booms when entering and leaving the earth′s shadow can cause significant disturbances to the central body of the solar sail，with an amplitude of the disturbance torque reaching 10^-3N·m.The simulation accurately predicts thermal disturbances in orbit，providing a valuable theoretical method for engineering purposes.

Key words:  , solar sail, thermal induced dynamic response, GEO, temperature field, disturbance torque