Mars colony: how to make breathable air and fuel from brine – new research

Header image: Artist’s concept of astronauts and human habitats on Mars. NASA

Words by David Rothery, The Open University

NASA is planning to land a crew on the Moon by 2024, and then onward to Mars, possibly in the 2030s. One day, we will have permanently crewed bases on both worlds. Unlike the initial short-stay visits, long-term bases will have to be self sufficient in as many essentials as possible.

A lot of research has gone into preparing for In Situ Resource Utilization (ISRU) that could help to build and sustain a lunar base. Now, similar ideas for Mars are catching up, with a new study, published in PNAS, suggesting a way to use the brine (salty water) found on Mars to make breathable air and fuel.

“Living off the land” will be even more important on Mars than on the Moon, because Mars is much further away – making transport costs (and time) correspondingly greater.

One major resource issue is how to provide enough oxygen for the Mars-base crew to breathe. Mars has only a thin atmosphere, with a surface pressure less than a hundredth of the Earth’s. Even worse, it is 96% carbon dioxide with only about 0.1% oxygen. Earth’s atmosphere is 21% oxygen.

NASA’s Mars2020 rover, Perseverance, which is already on its way to Mars, carries an experiment called MOXIE, a name imaginatively contrived from Mars OXygen In situ Experiment.

MOXIE’s purpose is to demonstrate that oxygen can be made from the carbon dioxide in Mars’s atmosphere by using electricity to split it into a mixture of oxygen and carbon monoxide, via a process called electrolysis. If this works as expected, the oxygen could be collected and used to give colonists something to breathe or as a component in fuel. The carbon monoxide would be unwanted, and would be