Sampling, Mobility, and Anchoring in Small-Body Sampling Robots: A Comprehensive Review

Small-body sampling robots are crucial for asteroid and comet exploration as well as in situ resource utilization, yet they face unique challenges of microgravity, irregular terrain, and uncertain surface properties. Although existing studies have advanced sampling, mobility, and anchoring technologies, current reviews often treat these technologies in isolation, failing to reveal their intrinsic coupling relationships and hinder holistic research and development. To address this gap, this review provides a unified review of small-body sampling robots, focusing on the mechanical aspects of the three core functional modules: sampling, mobility, and anchoring. It surveys state-of-the-art techniques demonstrated in missions, highlights emerging approaches and compares performance trade-offs in efficiency, adaptability, and technology readiness. The review further highlights critical challenges, including the coupling effects among the three functional modules as well as additional challenges arising from other factors. Finally, this review outlines the prospective development trends of small-body sampling robots. By consolidating lessons from past missions and emerging innovations, this work aims to serve as both a reference for ongoing research and a road map for the design of next-generation autonomous sampling robots.