Electrostatic particle-size classification of lunar regolith for in-situ resource utilization

To realize long-term lunar exploration, it is essential to develop technologies such as drilling, extraction, and chemical processing of lunar soil to achieve in-situ resource utilization (ISRU). Classification of particle size is one of the most important technologies required for ISRU. Because conventional techniques that utilize air flow and require high power are not suitable for operation on the Moon, the authors have developed two new technologies for electrostatic particle-size classification utilizing the balance between the electrostatic force and gravitational force. Our experiment demonstrated that particles less than 20 μm in size could be efficiently separated from the bulk of the regolith. Numerical method that can predict the performance in the lunar environment has been developed based on a three-dimensional Discrete Element Method.