Modified Pseudostate Method for Three-Body Problem Under Ephemeris Model

A new method to propagate the three-body trajectories under the ephemeris model that improves the precision of the traditional pseudostate theory is presented. This method is based on an autonomous selection mechanism between the primary–secondary and the secondary–primary computational modes of pseudostate theory. The semi-analytical [Formula: see text] and [Formula: see text] series solutions to the elliptic restricted three-body problem and the pseudostate method are derived in order to rapidly evaluate the propagation errors of the two computational modes. Following the selection of the computational mode with the lower error, the terminal states are enhanced using the derived semi-analytical solutions, which simultaneously preserve the three-body nonlinearity of the elliptic restricted three-body problem and the ephemeris information of the pseudostate method. Furthermore, the trajectory is divided into multiple segments for successive propagation to introduce more ephemeris data and achieve higher precision. Simulations involving Earth–moon transfer, resonant orbit, and near-rectilinear halo orbit demonstrate that the proposed method improves propagation accuracy by approximately two orders of magnitude compared to the traditional pseudostate method with the same runtime.