Scout-Rover cooperation: online terrain strength mapping and traversal risk estimation for planetary-analog explorations

TL;DR

This paper introduces a cooperative robot framework using legged and wheeled robots to map terrain strength and estimate traversal risks in planetary exploration, improving safety and operational reach.

Contribution

It presents a novel hybrid scout-rover system that uses legged robot proprioception for terrain mapping and risk estimation, enabling safer navigation in deformable planetary terrains.

Findings

Terrain strength maps accurately reflect spatial variability.

Traversal risk estimation improves navigation safety.

Framework validated in analogue planetary environments.

Abstract

Robot-aided exploration of planetary surfaces is essential for understanding geologic processes, yet many scientifically valuable regions, such as Martian dunes and lunar craters, remain hazardous due to loose, deformable regolith. We present a scout-rover cooperation framework that expands safe access to such terrain using a hybrid team of legged and wheeled robots. In our approach, a high-mobility legged robot serves as a mobile scout, using proprioceptive leg-terrain interactions to estimate regolith strength during locomotion and construct spatially resolved terrain maps. These maps are integrated with rover locomotion models to estimate traversal risk and inform path planning. We validate the framework through analogue missions at the NASA Ames Lunar Simulant Testbed and the White Sands Dune Field. Experiments demonstrate (1) online terrain strength mapping from legged locomotion and (2) rover-specific traversal-risk estimation enabling safe navigation to scientific targets. Results show that scout-generated terrain maps reliably capture spatial variability and predict mobility failure modes, allowing risk-aware path planning that avoids hazardous regions. By combining embodied terrain sensing with heterogeneous rover cooperation, this framework enhances operational robustness and expands the reachable science workspace in deformable planetary environments.