MIT lunch box-sized machine could produce oxygen on Mars
Perspective: Oxygen will be an essential element of any crewed mission to Mars. Producing it on the red planet could be much more efficient than shipping it from Earth, and recent NASA experiments show that the idea is viable. Oxygen is mainly used for fuel and not for breathing.
During 2021, the machine that NASA sent to Mars with its 2020 Perseverance rover, called the In-Situ Oxygen Resource Utilization (ISRU) Experiment (MOXIE), produced about 50 grams of oxygen from the planet’s mostly carbon dioxide atmosphere. Recent MIT Research Paper explains how a lunchbox-sized machine successfully produced oxygen on Mars, and how researchers could expand its operations. The experiment is the first step towards sustainable human exploration of Mars.
The lunchbox-sized device absorbs and compresses CO2 from the atmosphere and then heats it up to 800°C. The process then electrolyzes it through a solid oxide assembly and decompresses it to oxygen and carbon monoxide. The machine can also confirm its purity and quantity. Since the experiments were part of a proof-of-concept, the device would give out the received items instead of storing them.
Alone, this is not much, only 6-8 grams per hour. However, scaling the process hundreds of times could solve a serious problem facing manned exploration of Mars.
Astronauts need oxygen not only for breathing, but also as fuel. It takes about 31 tons of oxygen (together with other elements) to lift a crew of six from the surface of the red planet. It would take about 500 tons to deliver that amount of oxygen from Earth for each mission, due to the fuel requirement to escape the Earth’s atmosphere. Creating oxygen on Mars would be much cheaper if the technology made it possible to do it quickly.
An enlarged MOXIE may need to produce 2-3 kg of oxygen per hour and operate on Mars for a little over two years before a team of astronauts arrives. However, this method may be just a step towards the Martian ingredient that researchers really want to use to produce oxygen: water.
Mars missions could use water captured by the planet’s glaciers, permafrost and possibly wet soil to create oxygen and methane for fuel. However, its extraction will require complex mining, smelting, water purification and ice transportation operations. Early missions could oxidize some of the fuel on Mars and bring the rest from Earth and build the infrastructure to access the Red Planet’s waters.
Researchers still need to investigate any unforeseen issues with MOXIE’s scalability and long-term reliability.