Modeling Plume-Surface Interactions for Landing Pads and Untreated Ground

Outward Technologies with support from its subcontractor Astrobotic Technology proposes to continue developing Free Open-Source Software (FOSS) for simulating Plume-Surface Interactions (PSI) relevant to lunar and Martian landing conditions. These software tools include 1) a two-way coupled Computational Fluid Dynamics (CFD) and Discrete Element Method (DEM) numerical modeling framework for simulating regolith-plume interactions; 2) a grain-based DEM model of lunar regolith ejecta with accurate distributions of grain types, sizes, and shapes capable of receiving input from the plume model to predict erosion physics and ejecta dynamics; 3) a damage calculator for identifying the location and extent of pitting and fracturing produced by soil ejecta impacting near- and far-field surfaces; 4) a calibrated and validated set of model input parameters to fit the soil mechanics response of ground obtained from PSI experimental data, to include time-dependent crater geometry and ejecta trajectories and velocities; and 5) a demonstration model incorporating the full capabilities of this developed software to simulate PSI during a landing event at large-scale, deployed in a massively parallel cloud computing environment. These combined tools and calibrated model inputs will enable high-fidelity PSI models to be run in a reasonable time to aid Commercial Lunar Payload Services (CLPS) lander companies such as project partner Astrobotic in planning for near-term missions, while also enabling design studies of lunar Human Landing Systems (HLS). Test performance will be documented to demonstrate agreement with analytical and experimental predictions of PSI across a range of conditions. The results of these proposed Phase II efforts represent a robust engineering and analysis tool for NASA and its commercial partners in the design and evaluation of landers in support of the Moon-to-Mars program and missions to other planetary bodies.