Aerogel-based collection of ejecta material from asteroids from libration point orbits: Dynamics and capture design

Abstract

Scientific interest in asteroids and their physical characteristics is growing. These bodies provide insights into the primordial solar system and represent a valuable source of metals, silicates, and water. Several missions over the past few years have aimed to improve and better identify the main properties of these poorly known celestial bodies. However, these missions relied on touchdown(s) on the target asteroid to gather samples, which is complicated owing to the difficulty of accurately reaching and rendezvousing with the body. This study aims to assess the feasibility of an in-orbit asteroid sample collection mission. Such a strategy could prevent complex operations related to landing and touchdown maneuvers and avoid the dead times present in a mission requiring several landings. The presented collection scenario, which focuses on the asteroid Ryugu, proposes gathering samples using a spacecraft injected into a halo orbit around the second libration point, L₂. For this purpose, the orbits in the neck region of the zero velocity curves are analyzed. A novel methodology to characterize bouncing behavior is introduced. An interpolation-based approach was used to recover the appropriate restitution coefficients for each collision occurring at a specific impact angle. This was applied to both the rigid body model and the point mass approximation studied for two different sites on the asteroid. Furthermore, the study enlarged the region of interest from only L₂ to its neighboring zones to return a more global and realistic point of view. Considering the solar radiation pressure and asteroid aspherical potential, particles of different sizes ejected from different longitudes and with different ejection angles were classified according to their trajectories to finally build a database. Based on this analysis, an aerogel-based collection strategy inspired by that used in the Stardust-NExT (NASA) mission was investigated to assess its possible applicability to the analyzed scenario.