Lunar Regolith Sampling Technologies: A Critical Review

Abstract For future lunar exploration missions, In Situ Resource Utilisation (ISRU) is widely gaining attention. It refers to the creation of products by using natural resources locally available at the mission destination to sustain long-duration space missions while reducing risk and cost. With this aim, a key resource is represented by lunar regolith since it contains crucial components for supporting human life, propellant production, and the construction of habitats, tools, and other infrastructures. For the development of lunar ISRU technology, regolith samples returned during past missions (i.e., Apollo, Luna, and Chang’E programs) are key to informing technology requirements. Therefore, it is crucial to understand whether returned samples accurately reflect the physicochemical properties of the lunar regolith environment (i.e., being representative samples) and, subsequently, how representative regolith sampling processes could be implemented to minimize potential biases in the collected samples. The present paper reviews the working principles of geological sampling technologies used during past lunar missions to collect currently available regolith samples. In this context, errors and biases related to the different sampling methods are detailed based on the different elements of a sampling methodology. In addition, novel approaches recently proposed for lunar regolith collection are reviewed in terms of working principles, sampling performance and errors/biases potentially encountered during operation. Evaluated sampling systems consider both surface and subsurface regolith applications and include drills, diggers, bioinspired devices, pneumatic and non-pneumatic systems, to provide guidelines supporting the development of representative sampling systems while maintaining light-weight structures, low actuation system and energy requirements.