Accelerating binary asteroid system propagation via nested interpolation method

The binary asteroid system has become a topic of great interest from planetary science to planetary defense. A desire to understand the dynamics of binary asteroid systems during their formation and evolution motivates the study of the propagation of binary asteroid systems. The gravitational mutual potential, force, and torque, which are the three key elements for the propagation of binary asteroid system, are modeled by a hybrid gravity model of the primary and a finite element model of the secondary, resulting in a nested interpolation method. This method achieves a significant computational speedup compared with the pure finite element method benefited from the employing of the hybrid gravity model of the primary and the removal of a large number of element pairs. Benchmarking tests are performed to confirm the accuracy and efficiency of the proposed method. The dynamics of the binary asteroid system Moshup-Squannit have been investigated through comparisons of the propagation of the mutual orbit between different internal structures of the primary. The simulation results show that there is a reduction in the spin–orbit coupling of the system as the mass of the primary becomes more concentrated toward its barycenter.