Trajectory Optimization Method for Spacecraft Orbit Transfer with Finite Thrust

In order to achieve the rapid maneuver and effective fuel saving of the spacecraft with finite thrust in flight, trajectory planning based on psedospectral method was studied. Orbit transfer was modeled mathematically with Gauss dynamics equations by using improved equatorial orbital elements. The model could overcome the singularity problems when the orbital eccentricity was 0? or the orbit inclination was 0 or 90. Then, the fuel optimal performance index function, terminal constraint, and path constraint conditions were given; and the original continuous optimization problem was converted to the equivalent finite nonlinear planning problem by psedospectral method. Finally, the sparse nonlinear optimizer (SNOPT) algorithm was utilized to solve the trajectory planning problem, and the specific design steps and methods were given. Compared with the optimization method using fmincon function, the proposed method can reduce the optimization time by 61% and save the fuel consumption by 18% when the maximum thrust is 20 N.