Simulation of Lunar Dust in Airlocks Using Discrete Element Method (DEM) and Extended Reality (XR)

SIMULATION OF LUNAR DUST IN AIRLOCKS USING DISCRETE ELEMENT METHOD (DEM) AND EXTENDED REALITY (XR). J. Dyson1,2, K. Hadler1,2 R. McCall3, M. Ismael3 European Space Resources Innovation Centre (ESRIC)1 University of Luxembourg2, HANDS Dept. Luxembourg Institute of Science and Technology3 Introduction: From experiences acquired during the Apollo missions, some characteristics of lunar dust present numerous challenges to lunar operation such as its small particle size, abrasive nature, and electrostatic properties. In addition to damaging spacesuits, hardware, and mechanical and electrical components, lunar dust potentially poses significant threats human health during prolonged lunar operations [1]. Dust intrusion is unavoidable during lunar surface activities, making airlocks crucial as interfaces between the lunar vacuum and partially pressurised interior environments. However, the effectiveness of dust mitigation technologies within pressurised spaces such as airlocks or habitats remains largely unexplored. In this research, Discrete Element Method (DEM) simulations were developed using the Unity 3D game engine to investigate integrating full-scale DEM simulations into Extended Reality (XR) environments. To ensure compatibility with XR hardware, the computationally demanding Hertz-Mindlin contact model typically used in DEM was modified, allowing for simulations without excessively small timesteps. To validate the adapted contact model, Unity simulations were compared against results from a customised version of LIGGGHTS (LAMMPS Improved for General Granular and Granular Heat Transfer Simulations) [2], an opensource DEM platform that was extended to include triboelectric interactions among particles using a modified version of the condenser method [3]. Here, we report findings from a pilot study evaluating the utility of Augmented Reality (AR) simulation compared with traditional DEM simulations, emphasising three primary metrics. These metrics are, perceived realism by users, interactivity levels, and each platform’s educational effectiveness. Participants could alter five simulation parameters to observe their effects on dust behaviour. These parameters were triboelectric charging constant, particle diameter, Coulombic cutoff radius, number of particles, and gravitational acceleration. The study highlights various methodologies that can inform airlock designs aimed at minimising dust ingress. References: [1] Benaroya, H. (2017) ‘Lunar habitats: A brief overview of issues and concepts’, REACH,7–8, pp.14–32. [2] CFDEM Project (2021) LIGGGHTS, https://www.cfdem.com/liggghtsr-open-sourcediscrete-element-method-particle-simulation-code. [3] Rasera, J. N., Cruise, R. D., Cilliers, J. J., Lamamy, J.-A., Hadler, K. (2022). Modelling the tribocharging process in 2D and 3D. Powder Technology, 407, 117607. https://doi.org/10.1016/j.powtec.2022.117607 .