Colloquia

Summary

Over the past decade, advancements in space technologies and exploration missions have revealed the presence of water on the Moon. Water is a crucial resource for human life support and the creation of a sustainable space environment. The development of In-Situ Resource Utilization (ISRU) technologies is key to enabling sustainable space exploration, and water will play a vital role in future deep space missions. Once extracted, water can be split into hydrogen and oxygen through electrolysis, both of which are essential compounds for producing rocket propellants. The Lunar surface contains these compounds both separately and as water ice.

This research investigates thermal extraction methods for water, particularly through electrical heating. A water extraction system was designed and tested for future space missions, with performance analysed in a thermal vacuum chamber that simulates Lunar conditions, reaching pressures as low as 1x 10^-6 mbar and temperatures of 140 K. During the first stage of extraction, water-ice sublimation, electrical heating is applied to overcome the latent heat of water. To ensure rapid and uniform temperature distribution, a stirring mechanism rotates the icy-regolith mixture, significantly increasing its effective thermal conductivity - up to 75 times higher than in a static configuration. This results in sublimation rates exceeding 300 grams per hour. Once the water vapour is fully outgassed, it is captured on a cold surface, transitioning back into solid ice in the second stage. However, the deposition rate is much slower than the sublimation rate, indicating that the current cold trap design is not optimized for matching the high sublimation rate. Finally, before the solid ice enters the liquefaction chamber to become liquid water, it delaminates. This is the final stage where liquid water is obtained. These three stages of phase transition have been optimized through detailed multi-physics modelling and programming, with the models serving to validate experimental results and vice versa.

As the research addresses the technical challenges of water extraction, the vision of establishing a self-sustaining presence on the Moon is becoming more attainable. 
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This study is conducted as part of an ongoing project:
LUWEX | https://luwex.space/