Studies of 3D dust motion about asteroids

Dust poses significant challenges to future exploration missions on asteroids. From the Apollo era, we know that highly abrasive regolith particles have a potential to coat instruments and astronauts as well as cause clogging and excess wear in mechanical devices. In the reduced gravity environment of asteroids, dust will be easily released from the surface due to vehicle activities and may stably levitate above the surface, which could obscure observations. Electrostatically-dominated dust motion has been hypothesized to occur since the Surveyor spacecraft observed the Lunar Horizon Glow. The Lunar Horizon Glow was thought to be due to the motion of micron-sized dust particles above the Lunar surface. Since asteroids have much weaker gravity than the Moon, the hypothesis of electrostatically-dominated dust motion was easily extended to these bodies. Additionally, since the launching of dust particles from the surface is poorly understood, numerical models of dust motion have been forced to use initial conditions that may not have any relation to the actual in situ conditions. Numerical models have shown that for a small range of initial conditions dust particles may levitate above the surface of a body. Through a dynamical systems analysis of the 1D system, we have been able to constrain the initial conditions that result in dust levitation and demonstrate that the behavior of levitating particles is more strongly tied to the size of the dust particle than to the mass of the central body. In this work, we extend our dynamical systems analysis to rotating, 3D bodies. The inclusion of rotation causes the plasma environment experienced by the levitating dust particle to vary with time. We will investigate the effect of a changing plasma environment on the levitation of dust particles. Understanding the large-scale dust motion on asteroids will prove scientifically interesting in addition to providing needed information about the asteroid surface environment for futur- exploration missions.