Study of the Interaction Between Engine Plumes and the Lunar Surface with Chang'e-4 and Chang'e-5 Data

STUDY OF THE INTERACTION BETWEEN ENGINE PLUMES AND THE LUNAR SURFACE WITH CHANG’E-4 AND CHANG’E-5 DATA. Xiaoping Zhang1 and Jilin You1, 1State Key Laboratory of Lunar and Planetary Sciences, Macau University of Science and Technology, Avenida Wai Long, Taipa, Macau, [email protected] The landing and touchdown of spacecraft on extraterrestrial surfaces constitute a critical phase in planetary exploration missions. As the lander approaches the surface, the plume generated by the retro-propulsion engine ejects dust, small rocks, and other regolith materials from the landing zone, resulting in obscured visibility and significant risks to safe landing. With the increasing mass of spacecraft in future lunar and Martian exploration missions, the impact of engine plumes has become increasingly pronounced [1, 2]. To ensure the successful implementation of subsequent lunar and Mars exploration programs, a systematic investigation into the interaction between retro-propulsion engine plumes and surface materials is imperative to determine key parameters governing the erosion processes during landing. Furthermore, the erosion of surface materials near the landing site caused by plume effects may compromise the execution and interpretation of subsequent scientific investigations, necessitating comprehensive studies on plume-induced erosion dynamics. This study integrates image data analysis (from the Chang'e-4, Chang'e-5 missions) with fluid numerical simulations to systematically analyze the erosion mechanisms of retro-propulsion plumes on lunar and Martian surfaces [3-5]. Critical parameters, including plume-induced erosion depth and total erosion mass, were quantified. Comparative validation of widely adopted erosion models revealed substantial discrepancies with observational data. To address these inconsistencies, a novel aerodynamic model was developed and validated with observational data, enabling predictive analysis of airflowinduced erosion phenomena. Furthermore, we have established a methodology to derive the adhesion force and maximum static friction coefficient of lunar regolith based on plume data analysis. The findings provide critical insights for evaluating plume erosion effects during the analysis of Chang'e-5 lunar samples and future soft-landing missions on the Moon, thereby advancing the optimization of landing strategies and risk mitigation protocols. References: [1] Metzger P. T. et al. (2012) AIAA, 2009-1204. [2] Luo P., Zhang X. et al. (2023) Eng. Geol., 325, 107278. [3] You J., Zhang X. et al. (2021) Acta Astron., 185, 337. [4] Zhang H. et al. (2022) aerospace, 9, 358. [5] You J., Zhang X. et al. (2023) Acta Astron., 208, 343.