Optimal out-of-ecliptic trajectories for space-borne observatories

In this paper novel trajectories that are particularly suitable for space-borne observation missions are introduced. Based on the framework of the spatial circular restricted three-body problem with the Sun and the Earth as the primaries and a special selection of a coordinate system, a family of trajectories with considerable displacements above the ecliptic plane is found. Stability analysis of these trajectories is carried out using practical stability theory. The normal component of motion results in significantly reduced noise from the interplanetary (zodiacal) dust and a concomitant reduction in the necessary size of the optical collecting area. The reduced size of the mirrors allows a considerable reduction in payload mass and manufacturing costs. The quest for optimal trajectories is performed using genetic algorithms. First, types of trajectories are characterized using a genetic search. Utilizing the results and insight obtained from the characterization process, optimal trajectories are designed. The first optimal trajectory requires low launch energy and yield a maximum decrease of 67% in the zodiacal cloud brightness. The second optimal trajectory requires higher launch energy, but it renders a dramatic 97% maximum noise decrease.