An Exploration of Sample and Return from Rubble Pile Asteroids via Capture of Ejected Particles

Rubble pile asteroids such as (101955) Bennu and (162173) Ryugu are primarily comprised of carbonaceous chondrites, which are solid condensates left over from the original formation of the solar system. Sample and return from these bodies provides science with direct access to material which has orbited the sun effectively unchanged for 4.56 billion years, allowing scientists to establish the basic solar system timeline and formation process. The recent success of OSIRIS-Rex and Hayabusa 2 in collecting material is a remarkable achievement which belies underlying difficulties as about half of all sample and return missions fail. This paper explores an alternative collection method by capturing and returning to Earth the particles being regularly ejected by Bennu, thus avoiding the complexities associated with surface operations. An examination of the ejected particle environment informed by published OSIRIS-Rex material is used as a basis to establish swarm guidance, navigation and control techniques for a nanospacecraft based particle collection mission.