Rocket plume impingement may cause significant damage and contaminate co-landed spacecraft and surrounding habitat structures during Lunar landing operations. Under this proposed SBIR program, CFDRC and the University of Florida will develop an innovative high-fidelity simulation system for predicting surface erosion and debris transport caused by rocket plume impingement on lunar surface. This simulation system will combine 1) a unified continuum-rarefied flow solver capable of simulating plume impingement flow in lunar vacuum, 2) granular flow solid-fluid interaction technology for developing lunar soil grain erosion and debris particle release mechanism models, and 3) particle tracking tools to simulate debris kinetics, dispersion and contamination after liberation. In Phase I, the plume stagnation layer flow conditions at the soil surface will be modeled and computed. The solid-fluid interaction physics in the soil layer in response to this surface flow environment will be simulated and a generalized soil erosion model will be derived. The erosion model will then serve to prescribe debris mass and initial conditions for the debris-tracking module embedded in the flow solver. In Phase II, the individual modules will be combined into a single simulation system. The simulation system 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. He will spend at least 35 % of his time on this project and his commitment to other projects is less than 50 %.