Water Extraction from Rock Gypsum on Mars

In situ resource utilization has long been considered crucial for sustainable human space exploration. With the confirmation of large amounts of water and water containing minerals on Mars, we are now looking at how to extract water from these sources. The most promising nonce source of water is gypsum. Pure gypsum contains 20.9% water by mass, which is released at temperatures below 210°C. We have been studying an approach to mining gypsum rock (or other hydrated minerals) on Mars using a high-pressure water jet. The water jet breaks up the rock in small particles that then get pumped up in slurry form to a separation system after which the particles and adherent water get heated to release all the water in the gypsum rock particles. This water can then be recycled to the water jet or stored for creation of rocket propellant or other purposes. We found that this approach is feasible and can excavate and process the desired 1.4 kg/h water production needed to refuel a Mars Ascent Vehicle in 480 Sols for return to Earth. Water jet excavation is also less massive and has fewer wear parts than conventional mechanical excavation machines and combines the excavation, crushing, and transportation functions in one device. This paper will discuss the experimental methods, results, and a prototype design to be tested in simulated Mars environmental conditions.