Future human exploration missions to Mars will need many resources including oxygen. Now a NASA technology has shown that it is possible to produce it directly on the Red Planet, exploiting the elements already present
The technical problems that delayed the launch of the Artemis 1 mission intended to pave the way for the second phase of human exploration of the Moon and in perspective of Mars, remind us how difficult it is to face space travel. In particular sending men to Mars is a colossal challenge which goes far beyond the (already enormous) difficulties of an eight-month interplanetary journey. Once they arrive, in fact, the astronauts will have to survive on an alien world hundreds of millions of kilometers from Earth and they will need food, water and especially oxygen. Bringing everything from home, however, is neither technologically simple nor economically sustainable and so other solutions are needed. One of these was NASA developed and it worked.
For space exploration it is necessary to exploit local resources
One of the possible solutions to the problems of exploring other planetary bodies is constituted by ISRU technologies (In Situ Resource Utilization), i.e. those technologies designed for collect and process native resources directly on site present on other planetary bodies. Recently NASA proved that it is possible to produce oxygen directly from the Martian atmosphere thanks to a device about the size of a toaster. Is called MOXIE (Mars Oxygen In-Situ Resource Utilization Experiment) and is a tool capable of convert carbon dioxide (equivalent to about 96% of the Martian atmosphere) into oxygen and make it available to astronauts. In this way, Moxie has established a very important record: to be the first Isru technology that really works on another planetary body. As she explained Jeffrey Hoffmanformer NASA astronaut, professor of aerospace engineering at MIT in Boston and deputy principal investigator of the Moxie mission, “That’s what explorers have been doing since time immemorial: figuring out what resources are available where they’re going and finding out how to use them.”
Moxie arrived on Mars in February 2021 with the Perseverance mission and from April until the end of the year it produced oxygen seven times. To do this the device aspires Martian atmospherefilters it to retain suspended dust, heats it to 800 ° C and passes it through a system based on solid oxides in which, by electrolysis, CO2 separates into CO and oxygen ions. The latter then pass through another system which recombines them in the form of molecular oxygen O2 whose quantity and purity are measured, before being released into the Martian atmosphere. In each test Moxie managed to produce on average about six grams of oxygen per hour which corresponds more or less to the amount of oxygen produced by a small tree on Earth, with peaks of almost ten grams in the latest experiments. Another important result obtained from the experiment is that it proved itself effective at different times of the Martian day e under different conditions during the seasons. In practice, the engineers have shown that the device can work during most of the Martian day, except in some special cases, as recalled by Michael Hecht, principal researcher of the Moxie experiment at MIT: “The only thing we have not yet managed proving is the possibility of functioning at sunrise or sunset, when temperatures on Mars change dramatically. But now we have an ace up our sleeve – continued Hecht confidently – which will allow us to succeed and once we have tested it in the laboratory, we will be able to demonstrate that we are truly capable of operating at any time ».
What are the next goals
Despite this justified enthusiasm for a result of historic significance, the road to real use of Moxie is still long and the extremely complex challenges to be faced. If scientists can fully master this technology and make sure it can work continuously, the next step will be to scale the machine several hundred times to allow it to be used in real-world conditions. It is in fact pass from a production of oxygen of a few grams to very different quantitiesnecessary not only to support a human mission to Mars (it will be necessary to produce between 2 and 3 kg per hour) but also to produce the oxygen necessary as part of the propellant to face the return journey of a human mission from Mars to Earth. For a crew of six, it is estimated that they would be necessary 31 tons of oxygen (plus 9 of methane) to bring the MAV (Mars Ascent Vehicle) from the surface of Mars to its orbit, where it would dock with another vehicle for the Mars-Earth journey. That’s why the engineers intend to push Moxie to the limit of its possibilities by increasing its production capacity as much as possible and making sure it can operate during the Martian spring, when the atmosphere is thick and carbon dioxide levels are high. One of the main challenges to be faced will then be that of continuously monitor the wear of the device to understand if it will be able to withstand the prolonged stress of Martian conditions, before being converted into a full-scale system that will have to work continuously for thousands of hours and on which the very survival of future Martian explorers will depend.