Process used to aid design of xEMU Lunar Dust Mitigation Devices

The Exploration Extravehicular Mobility Unit (xEMU) Design, Verification, and Test (DVT) prototype is being developed and tested at NASA Johnson Space Center to supply astronauts with a safe environment during terrestrial exploration. Lunar dust is identified as one of the greatest challenges to a space suit during lunar exploration. Fine, glass like dust particles proved detrimental to Apollo hardware operation, having potential to cause significant performance degradation to future manned flight. The intent is to explore elements within the design process used to develop Lunar Dust Mitigation Devices (LDMD). Discussion includes how testing was performed to observe dust behavior, within a Dusty Plasma Chamber, to support analytical efforts. A central analytical effort is to predict the cohesion and adhesion of dust to LDMD surfaces and how well xEMU supplied gas flow could shear or roll collected dust toward lunar vacuum. This supports a NASA Small Business Innovative Research Phase II, mitigating the threat of lunar dust particles to the operation of six space suit venting components. A Computational Fluid-Dynamics and Discrete Element Method simulation tool was developed to predict the response of lunar dust with assumed charge, cohesive strength and shearing strength to gas flows of different velocities. Past research has been unsuccessful in determining appropriate magnitudes of required dust parameters. Best-fit values of model parameters will be determined for "dusty plasma" lunar regolith simulant in the intake gas-flows into vacuum (~10-6Torr). Subsequent simulations can test sensitivity of dust removal to parameters such as charge, gravity-level, and exit vacuum-level. LDMD prototypes and development devices will also be tested, within a Dusty Plasma Chamber, at Auburn University, Auburn to determine how increased gas flow removes charged dust particles from different surface roughness and finishes. The empirical data will be imported to the tool, attempting to replicate observed effects at test conditions.