Illustration:  Getty Images/Steven Hobbs/Stocktrek Images
© Getty Images/Steven Hobbs/Stocktrek ImagesMars colony dome concept
Researchers have developed a new system to separate salty water into both breathable air and fuel simultaneously in a major breakthrough for life here on Earth and even future colonies on Mars. Engineers at the McKelvey School of Engineering at Washington University in St. Louis developed a patented brine electrolysis system that not only works without the need for purified water but actually performs better thanks to the saltiness of the input water.

Salty water isn't potable, and the standard method of separating oxygen from hydrogen contained in water, electrolysis, is notoriously cumbersome and expensive here on Earth, making it orders of magnitude more expensive on the Red Planet. On Mars, water that isn't frozen is extremely salty, which lowers its freezing temperature but restricts options for hydrolysis, until now.

"Our Martian brine electrolyzer radically changes the logistical calculus of missions to Mars and beyond," says lead researcher Vijay Ramani. "This technology is equally useful on Earth where it opens up the oceans as a viable oxygen and fuel source." Ramani and his team operated their device, which employs custom-engineered ruthenate pyrochlore anodes and a platinum on carbon cathodes, in a simulated Martian atmosphere at -33 degrees Fahrenheit (-36 degrees Celsius) to produce both oxygen and hydrogen.

The European Space Agency's Mars Express has discovered several ponds of underground water on the Red Planet which remain liquid due to the presence of substantial amounts of magnesium perchlorate, a kind of salt. The magnesium salt prevents the water from freezing and lowers electrical resistance at the same time, greatly aiding the system as normal electrolyzers use highly purified, deionized water which significantly bumps up the cost. In-situ water and fuel manufacturing are the Holy Grail for any hopes of manned missions to Mars and eventual colonization.

NASA's Perseverance rover, currently en route to the Red Planet, is carrying the Mars Oxygen In-Situ Resource Utilization Experiment (MOXIE) which employs high-temperature electrolysis to produce oxygen using only carbon dioxide in the air. However, the McKelvey School brine electrolysis system can produce 25 times more oxygen than MOXIE for the same power input, while also producing hydrogen which could be used for fuel. The design and composition of the team's device precludes the need for heating or purifying the water, thereby reducing the input power required for the system to operate, simplifying potable water and fuel production simultaneously, making a possible Mars colony much more feasible.

The device also has a myriad of applications back here on Earth, throwing open the possibility of repurposing brackish water used in oil and gas fracking, or revolutionizing seawater hydrolysis for on-demand oxygen supplies in submarines or for ultra-deep sea vessels exploring the ocean floor.