A Comparative Rover Mobility Evaluation for Traversing Permanently Shadowed Regions on the Moon

Discovery of water ice within permanently shadowed regions (PSRs) at the southern polar region of the Moon mo-tivates in situ robotic exploration of these sites. To access multiple PSRs, a robotic agent would need to descend into and ascend out of craters, traversing inclines covered with lunar regolith and unstructured obstacles. We present a systematic and quantitative comparison of existing rover designs to deter-mine suitable mobility systems for traversing PSRs at the lunar southern polar region. This simulation-based study evaluates six different mobility systems with varying sizes and terrain types. All simulations are performed using the Wheeled Mobile Robot Dynamics Engine (WMRDE) software toolbox [1]. A set of simulated terrains are formulated to emulate actual lunar terrain topography. Six mobility systems that are based on ex-isting rover designs and proposed rover concepts are evaluated. This evaluation identifies the traversability limitations of each mobility system by identifying minimum terrain geometries that prevent traverse. Relative performance is further quantified on a variety of lunar terrain analogues by comparing energy consumption, slip, static stability, and path deviation. Results highlight the superior traversability of a six-wheeled actively articulated suspension system, while also demonstrating that relatively simple four-wheeled articulated mobility systems have equivalent, if not better performance to the flight-proven rocker-bogie suspension system. Additionally, this study provides a framework for which further mobility system evaluations may be performed based on the specific requirements and constraints of a given planetary exploration mission.