Stability Analysis of Coupled Orbit–Attitude Dynamics Around Asteroids Using Finite-Time Lyapunov Exponents

This paper investigates coupled orbit–attitude dynamics around asteroids subject to solar radiation pressure and gravity irregularities. The solutions of sun-synchronous orbits with sun-tracking attitude motion are analytically derived, and their stability is evaluated by applying linearization and averaging. To validate the analytical solutions, numerical simulations are performed based on nonlinear coupled orbit–attitude equations of motion. In addition, the nonlinear stability of such coupled motion is analyzed using finite-time Lyapunov exponents. It is demonstrated that the sun-synchronous orbit–attitude coupled motions exhibit long-term stability under certain conditions, and thus, these motions are promising options for asteroid missions.