Scientists have recently confirmed that there used to be (and still is) abundant water on Mars. The discovery is huge not only because where there’s water there’s life, but also because it means that humans can potentially rely on that water for life support and fuel sources for future interplanetary missions, instead of transporting everything from Earth.
Until now, there’s been one big problem: Almost all water on the Red Planet today exists in the form of brine ice, left behind by ancient saltwater lakes and oceans. Turning it into usable fuels is a complicated and costly process. First, water from salt needs to be separated from the water—usually through heating—and then the purified water must be electrolyzed get oxygen and hydrogen.
A new invention by a group of engineers at Washington University is about to change that forever.
In a study published in the journal Proceedings of the National Academy of Sciences (PNAS) on Monday, researchers at Washington University’s McKelvey School of Engineering laid out the design of a special electrolyser that can extract hydrogen and oxygen directly from saltwater. The system is proven to work perfectly in a simulated Martian atmosphere at -36°C.
“Our approach provides a unique pathway to life-support and fuel production for future human missions to Mars,” the study’s authors wrote in the abstract.
A traditional electrolyzer consist of an anode and a cathode separated by an electrolyte membrane. At the anode, water reacts to form oxygen and positively charged hydrogen ions. Select hydrogen ions then flow through the electrolyte membrane to the cathode and form hydrogen gas by combining with electrons from an external circuit.
To modify this system for a saltwater environment, the Washington University lab used novel materials for the anode and the cathode. “Our brine electrolyser incorporates a lead ruthenate pyrochlore anode developed by our team in conjunction with platinum on carbon cathode,” explained Vijay Ramani, the study’s lead author. “These carefully designed components, coupled with the optimal use of traditional electrochemical engineering principles, has yielded this high performance.”
According to the study, this electrolyser can produce 25 times more oxygen than the MOXIE oxygen generator aboard NASA’s Perseverance rover. MOXIE is short for “Mars Oxygen In-Situ Resource Utilization Experiment.”
“Our Martian brine electrolyser radically changes the logistical calculus of missions to Mars and beyond,” Ramani added.
Before humans land on Mars, this system can also be used to electrolyze seawater on Earth in deep ocean explorations, such as creating oxygen on-demand for submarines.