Exploration-related contamination of lunar polar regions: consequences and considerations for lunar science in the context of planetary protection

The reinvigorated focus on lunar exploration, particularly targeting the southern polar region and its Permanently Shadowed Regions (PSRs), necessitates an evaluation of potential organic and biological contamination and their potential consequences in the context of planetary protection. While these regions are thought to preserve water ice and volatiles of high scientific value, including prebiotic organic molecules, they are vulnerable to contamination introduced by spacecraft outgassing, propulsion systems, and in-situ robotic and human activities. Such contaminants can persist, migrate, and become cold-trapped in PSRs, potentially compromising records of prebiotic chemistry preserved in these regions. While biological activity is unlikely in lunar PSRs, dormant microorganisms and biomolecular residues may survive in protected environments. Significant knowledge gaps remain regarding contaminant behaviour, transport, and long-term stability under lunar conditions. Moreover, other types of contaminants may require further investigation. This study provides a non-exhaustive review of current knowledge and understanding of the potential of the lunar polar regions to preserve a record of materials or processes relevant to the origin of life, as well as the risk that future lunar exploration activities may compromise this record. In this context, we offer recommendations, such as the establishment of a framework combining environmental impact assessment, monitoring, and mitigation strategies, including improved contamination inventories, modelling, and international coordination. An ideal approach would be to adopt a harmonised planetary protection policy and a phased approach to the exploration of lunar polar regions, preserving the scientific integrity of PSRs while enabling sustainable exploration.