Quasi-Terminator Orbits for Mapping Small Primitive Bodies

A common objective for primitive body missions (i.e., those to asteroids, comets, and small planetary moons) is to map the target body surface as completely as possible. Ideally, this map is constructed from a large collection of images containing multiple views of every point on the surface in a variety of lighting conditions and from a variety of viewpoints. For most missions to near- Earth objects (NEOs), the inherent instability of the orbital environment due to solar radiation pressure (SRP) necessitates a mapping trajectory strategy that requires deterministic maneuvers every few days for several weeks to achieve the desired imaging geometries. The recently discovered quasi-terminator orbits (QTOs) offer an alternative approach that can achieve the imaging geometries needed for mapping without any deterministic maneuvers. By eliminating the need for frequent maneuvering, QTOs can significantly reduce the complexity and intensity of global mapping operations for robotic or manned missions to NEOs.