Influence of apophis’ spin axis variations on a spacecraft during the 2029 close approach with earth

Abstract

Tumbling asteroids belong to a group of objects, whose angular velocity vector is unaligned with any of its principal axes of inertia. This rotation state leads to challenges when modelling a spacecraft's orbit around these bodies. In this work, we refine a previous study on this topic, concerning asteroid (99942) Apophis during its close encounter with the Earth in 2029. We analyze the orbital behaviour of a spacecraft orbiting the asteroid during this event by including the effects of the changes of orientation of the spin axis of the asteroid, depending on two sets of initial conditions. We analyze the global dynamics of the spacecraft around the target using three approaches, MEGNO, PMap, and Time-Series prediction. We limited our work on the equatorial plan choosing critical initial conditions of the span orientation of the target. We confirm that no spacecraft with natural orbits (orbits without control) could survive the high perturbations caused by the close encounter with our planet.