Abstract: The solar sail is a type of continuous low-thrust spacecraft that generates propulsion through solar radiation pres-sure. Due to its fuel-free operation, it is particularly suitable for long-duration deep space exploration missions. Based on the dynamical models of the Sun-Mercury elliptic restricted three-body problem, this study proposes three progressive solar sail steering laws. These steering strategies enable the normal vector of the solar sail plane to transition from pointing directly toward the Sun, to deviating within the gravitational plane, and finally to deviating out of the gravitational plane. By employing a multiple-shooting method combined with continuation techniques, families of resonant halo orbits with different resonance ratios are obtained for solar sail spacecraft. Under the three proposed steering laws, parameter continuation is performed with respect to the sail’s area-to-mass ratio, cone angle, and pitch angle, respectively. The first two steering laws yield resonant halo orbits that are symmetric about the XZ-plane of the rotating coordinate system. In contrast, the third steering law produces periodic orbits that are asymmetric with respect to any plane or line, exhibiting complex three-dimension structures with periodicity remained. Finally, the stability of the solar sail resonant halo orbits under different steering laws is analyzed within a high-precision ephemeris model. The results indicate that these orbits can maintain their overall shape without sig-nificant divergence for approximately 4 to 6 Mercury orbital periods (about 352 to 528 days) without station-keeping maneuvering.

Key words: Elliptic restricted three-body problem, Solar-sail spacecraft, Resonant Halo orbit, Solar sail steering law, Ephemeris model