Trajectory Options for Hera’s Milani CubeSat Around (65803) Didymos

The dynamical environment in the close-proximity of small celestial bodies is characterized by a very weak and irregular gravity field. In this low-acceleration deep-space environment, small dynamical perturbations might affect significantly the dynamics of a spacecraft hovering near the surface of such objects. This poses a challenge to the efficient design of trajectories of space probes for space missions aimed at the exploration of small Solar System bodies. This applies especially to CubeSats, small spacecraft with limited autonomy and maneuvering capabilities. In this case, a careful and efficient design of the operational trajectory is mandatory to accomplish the objective of the mission. As a representative and timely case study, we investigate the dynamics around binary asteroid (65803) Didymos, the target of NASA’s Double Asteroid Redirection Test (DART) and ESA’s Hera missions. We analyze all the relevant dynamical contributions concurring to the acceleration environment near Didymos and provide a subdivision of it into subregions, each identified by a different dynamical regime. With reference to the Hera Milani CubeSat mission scenario, we describe the methodology and design approach to find trajectories in the dayside of Didymos system. Finally, we provide examples of suitable trajectory options to host the operational phase of the Hera Milani CubeSat.