Rocket plume impingement can cause significant damage and contaminate co-landing spacecraft and surrounding habitat structures during lunar landing operations. CFDRC and the University of Florida will develop an innovative simulation system for predicting surface erosion and debris transport caused by lunar surface rocket plume impingement. This simulation system combines 1) a unified continuum-rarefied flow solver capable of simulating plume impingement flow in lunar vacuum, 2) granular solid-fluid interaction simulation models for developing databases for lunar soil erosion and debris particle release mechanism, and 3) particle tracking tools to simulate debris kinetics and dispersion after liberation. During Phase I, the Unified Flow Solver (UFS) capabilities in simulating hybrid rarefied-continuum plume flow, and the debris dispersion tracking capabilities were demonstrated. The fluid-solid simulation tools realistically simulated jet induced soil grain response characteristics, clearing the path towards establishing working models of erosion and particle release mechanisms. In Phase II, the individual modules will be refined, validated and integrated into a coherent simulation system. The solid-fluid interaction physics will be refined for the peculiar lunar soil layer characteristics and consequently soil erosion models will be derived. The erosion models will serve to prescribe debris initial conditions for a debris-tracking module developed and integrated with the flow solver. The simulation capability will be essential for predicting the severity and range of dust and debris transport and for designing lunar settlement layout, dust and debris impact mitigation measures.