Demonstration of integrated lunar water extraction and capturing system: overview of results from the LUWEX project

Sustainable lunar exploration requires efficient in-situ resource utilisation, particularly for water extraction to enable life support and propellant production. The LUWEX project addressed this need by experimentally demonstrating the functionality of an integrated thermal water extraction and capturing system under simulated lunar polar conditions. In a series of tests in a vacuum chamber, a crucible-based heating system with integrated stirring capability was used to sublimate water from icy regolith simulants (up to 13 kg per run, containing 5 wt.% of ice in the simulant material). The vapour was deposited on a cryogenic cold trap before liquefaction. Various operational scenarios were examined, including different simulant types, the use of mechanical stirring, and the introduction of contaminants (e.g. methanol) to evaluate their effects on performance. Key findings show that the end-to-end process is feasible at a multi-kilogram scale in a lunar polar crater-like environment, achieving significant water recovery, with over half of the sample’s water recovered, peaking at ∼73 %. Energy-wise, recovery energy efficiency reached 66.33 g/kWh for the icy glass beads simulant and 22.88 g/kWh for the icy regolith simulant experiments. The resulting average water recovery rate corresponds from 2.06 g/h to up to 7.76 g/h (which corresponds to 0.05 - 0.19 kg/day) in the best-performing run. These values reflect the energy required to recover water and maintain operational temperatures within a permanently shaded region on the Moon. However, dust generation impaired seal integrity and camera visibility. Trace volatiles, such as methanol, markedly reduced capture efficiency by forming a liquid barrier on the capturing device. Nonetheless, these results demonstrate the viability of large-scale lunar water extraction with an integrated system. Critical challenges such as dust mitigation, vapour capture capacity, and contaminant management remain to be solved. The insights gained are relevant to designing robust ISRU water extraction units for future lunar missions.