Transient Response Analysis in Spacecraft Thermal Protection Structures Under Periodic Thermal Disturbances

This study introduces frequency-domain analysis and transfer functions into spacecraft thermal analysis, presenting a fast approach for analyzing the temperature response of spacecraft thermal protection structures under periodic external heat flow. By employing Fourier transform, the complex external radiation boundary was simplified into the input signal of harmonic superposition. A transfer function was established, correlating the conduction and radiation properties of the structure with its damping effects. The analytical solution was validated against fourth-order Runge–Kutta numerical solutions, with less than 1% relative errors in mean temperature values and less than 2% in fluctuation amplitudes and high phase consistency. This method enables the rapid computation of temperature responses, providing valuable guidance for the engineering inverse design of thermal protection structures. The practical applicability of the approach is demonstrated through simulations of a specific satellite model, ensuring that the working temperature and fluctuations of the electronic devices meet the preset design requirements.