If people are ever going to go to Mars, they might nicely must make some essential sources whereas they’re there in an effort to survive lengthy sufficient to discover and restock for the lengthy return journey. Though the times of flowing floor water are lengthy gone, the crimson planet just isn’t fully with out the uncooked components to make this work.
The Mars 2020 mission that launched in July is carrying an experiment with precisely this purpose in thoughts. MOXIE—the Mars Oxygen In-Situ Useful resource Utilization Experiment—is a field not a lot larger than a toaster that produces oxygen from atmospheric CO2. Whereas a a lot bigger model could be required to make liquid-oxygen gasoline for a rocket, MOXIE is sized to provide in regards to the quantity of oxygen an energetic individual must breathe.
A brand new research led by Pralay Gayen at Washington College in St. Louis, Missouri, checks a tool that would faucet a unique useful resource—perchlorate brine believed to exist within the Martian floor at some places. The gadget can break up the water in that brine, producing pure oxygen and hydrogen.
Perchlorate (ClO4) salts, now we have found, are widespread on Mars. These salts have an affinity for water molecules and may acquire water vapor over time, turning right into a brine with a really low freezing temperature. There’s proof of sizable quantities of what might be this brine beneath the floor of Mars’ north polar area, and smaller quantities have been invoked as a attainable rationalization for the energetic streaks that generally seem on Martian slopes.
To check whether or not we may faucet this useful resource, the researchers constructed an electrolysis gadget that they ran in Mars-like situations. It makes use of an ordinary platinum-carbon cathode and a particular lead-ruthenium-oxygen anode the researchers developed beforehand. They blended up a believable focus of magnesium perchlorate brine and crammed the headspace in that container with pure CO2 for a Mars-like environment. The entire thing was stored at -36°C (-33°F). When powered up, brine flowed by means of the gadget, splitting into pure oxygen fuel captured on the anode facet and pure hydrogen fuel on the cathode facet.
The gadget labored fairly nicely, producing about 25 occasions as a lot oxygen as its MOXIE counterpart can handle. MOXIE requires about 300 watts of energy to run, and this gadget matches that oxygen output on about 12 watts. Plus, it additionally produces hydrogen that might be utilized in a gasoline cell to generate electrical energy. And it could be smaller and lighter than MOXIE, the researchers say. Finally, all this simply illustrates that MOXIE is working with a decrease high quality—however extra broadly accessible—useful resource in atmospheric CO2 as a substitute of water.
A tool like this would wish to undergo long-term stress testing, after all, to make sure that efficiency does not degrade over time and it’s typically strong. The membrane that separates the cathode and anode sides was operated rigorously to stop the CO2 from fouling it up, for instance. In case your survival will depend on a tool you delivered to Mars, malfunctions aren’t an choice.
PNAS, 2020. DOI: 10.1073/pnas.2008613117 (About DOIs).