A review of lunar water extraction technologies: comparison, classification, and research gaps

Abstract Sustainable exploration of space can be greatly enhanced by the effective use of lunar resources. This review systematically evaluates current lunar water extraction technologies through comparative analysis of experimental and simulated setups, proposing a classification framework based on operational principles such as thermal, mechanical, convection-assisted, and ionisation extraction methods. For all 27 reviewed studies, a summary was compiled, including design, objective, environmental parameters, masses, and other relevant parameters. Despite considerable advancements, meaningful comparisons across studies remain challenging due to inconsistencies in data reporting, mostly due to sources having varying objectives. To address this, the authors suggest adopting a standardised reporting framework for water extraction technologies encompassing clear definitions of essential metrics like extraction and recovery efficiencies, power usage, and environmental conditions. Additional steps required to evaluate the entire water extraction process chain are further discussed. Identified research gaps include an end-to-end, comparable evaluation framework that accounts for pre- and post-extraction steps; comprehensive integration of extraction with vapour-capture; and development of scalable pilot systems, including large integrated tests and surface demonstrations. Addressing these areas through standardisation and collaborative research will significantly enhance technology development and mission planning efficiency for future lunar exploration.