Halo Orbits Near Small Bodies in the Elliptic Restricted Problem

In this study, the feasibility of using halo orbits to explore small solar system objects, including asteroids and comets, is considered. Human-based missions in particular are the focus, although robotic missions are included as well. Specifically, the existence of L1/L2 periodic orbits is demonstrated by numerically computing halo-like orbits in the circular as well as elliptic restricted three-body problems for a range of small mass ratios. A two-level differential corrector scheme is utilized for the numerical continuation of halo orbits from the circular restricted problem into the elliptic problem. A stability analysis of these orbits is made and the results are compared with similar orbits in the Sun-Earth system. In considering a human exploration mission to asteroids or comets, halo orbits may provide benefits including a safe vantage point for staging/observation, reduced perturbation effects from the nonuniform gravitational field of the body, fewer communication blackouts, ease of guidance and control of a lander on the surface, etc. This work will be followed by a complete analysis of perturbation effects on these orbits along with an examination of station-keeping costs. © 2012 by Bharat Mahajan, Henry J. Pernicka.