If humans are ever going to visit Mars, they need to build some crucial resources while they are there to survive long enough to explore and resume their long journey. Although the days of surface water flow are long, the red planet has no raw materials at all.

Launched in July, Mars carries the 2020 mission An experiment With exactly this goal in mind. The Moxy-Mars Oxygen In-situ Resource Utilization Test is a box that is no larger than a toaster that produces oxygen from atmospheric CO.₂. Although it takes a much larger version to produce liquid-oxygen fuel for a rocket, the MOXIE is large enough to produce the amount of oxygen an active person needs to breathe.

A new study led by Prale Guyan of the University of Washington in St. Louis, Missouri, is testing a device that can tap another resource – perchlorate salt water is believed to be present in some places on the ground on Mars. The device can split water in that salt water to produce pure oxygen and hydrogen.

Perchlorate (ClO₄) The salts we found are common on Mars. These salts have a close proximity to water molecules and can also accumulate water vapor over time, turning it into salt water at very low freezing temperatures. there is Evidence Substantial amounts of what this saltwater might be beneath the surface of Mars’ polar region were requested as an explanation for the small amount of activation. Stripes that sometimes appear On the slopes of Mars.

To test whether we can tap this resource, the researchers built an electrolytic device that works in a Mars-like state. It uses a standard platinum-carbon cathode and a special lead-ruthenium-oxygen anode previously developed by researchers. They mixed the concentration of magnesium perchlorate in salt water and filled the headspace with pure CO in that container.₂ For a Martian-like atmosphere. Everything was stored at -36 C (-33 ° F). When powered, the salt water flows through the device, splitting into pure oxygen gas captured at the anode and pure hydrogen gas at the cathode.

The device worked very well, producing 25 times more oxygen than its moxie counterpart could handle. MOXIE requires about 300 watts of power to operate, and this device is compatible with an oxygen output of about 12 watts. In addition, it produces hydrogen, which can be used to generate electricity in a fuel cell. Researchers say it is smaller and lighter than moxie. Ultimately, all of this makes it clear that MOXIE works with low-quality but more widely accessible sources of atmospheric CO.₂ Instead of water.

A device like this has to go through a long period of stress testing, which, of course, ensures that the performance does not decrease over time and that it is generally robust. The membrane separating the cathode and anode sides was carefully operated to prevent CA₂ For example, from misunderstanding it. If your survival depends on a device you brought to Mars, failures are not an option.

PNAS, 2020. DOI: 10.1073 / pnas.2008613117 (About DOIs).