The Martian environment, in its present state, shouldn’t be Earthling-friendly in any respect. It is extraordinarily skinny, over 100 occasions much less dense than Earth’s, and is made up principally of carbon dioxide. Any people making an attempt to breathe it could quickly discover themselves not respiratory in any respect.
However on that dusty, dry, alien world, a small instrument, a little bit larger than a briefcase, has been reliably pumping out breathable oxygen from the Martian environment.
It is the primary demonstration of the processing of in situ sources for human use on one other planet – establishing a method that breathable air could possibly be generated for a human mission to the pink planet.
It is referred to as MOXIE ( Mars Oxygen In-Situ Useful resource Utilization (ISRU) Experiment) and, put in within the stomach of NASA’s Perseverance rover, it makes use of a course of referred to as electrolysis to separate the Martian carbon dioxide into carbon monoxide and oxygen.
Between February 2021, when Perseverance landed, and the top of 2021, MOXIE produced oxygen seven occasions – and can proceed to take action, the researchers stated.
“That is the primary demonstration of truly utilizing sources on the floor of one other planetary physique, and reworking them chemically into one thing that may be helpful for a human mission,” says former NASA astronaut and MOXIE deputy principal investigator Jeffrey Hoffman of MIT.
“It is historic in that sense.”
The manufacturing of oxygen by means of electrolysis shouldn’t be a brand new factor. The Worldwide Area Station, for instance, makes use of electrolysis to split water into hydrogen and oxygen, and thus complement its provide of breathable air.
Nevertheless, on Mars, water could also be too treasured to be used on this method, if there’s one other methodology accessible.
Fortunately, oxygen is the part of many compounds, together with the carbon dioxide that makes up roughly 96 % of the environment on Mars: a molecule composed of 1 carbon and two oxygen atoms.
The electrochemical discount of carbon dioxide into its constituent components is nicely studied, identified and understood; the problem was to develop, right here on Earth, an instrument that may have the option to take action on Mars with the elements at hand.
MOXIE’s manufacturing of oxygen is a multi-step course of.
First, it attracts in Martian air via a filter that scrubs it clear. This purified Mars air is then compressed, heated, and despatched via the Stable OXide Electrolyzer (SOXE). The electrolyzer splits the carbon dioxide into carbon monoxide, which is vented again into the Martian environment, and oxygen ions.
The oxygen ions are then recombined into O2, or molecular oxygen, which is then measured for amount and purity earlier than being vented again out once more.
This course of, scientists have decided, has reliably resulted within the manufacturing of breathable oxygen. Following a number of hours of warming up, it runs for 1 hour per experiment adopted by a interval of powering down. On this 1 hour of operation, MOXIE is designed to supply as much as 10 grams – about 20 minutes value of breathable oxygen for one astronaut.
In every of its seven runs, MOXIE produced between 5.4 and eight.9 grams of molecular oxygen, for a complete of 49.9 grams.
Since Mars is very variable in each temperature and air density, not simply from day to nighttime however all through the altering seasons of the yr, MOXIE wants to have the ability to run in a variety of temperatures and air densities.
In its seven runs, MOXIE was capable of produce oxygen in a wide range of circumstances: through the day, at night time, and all year long.
“The one factor we’ve got not demonstrated is working at daybreak or nightfall, when the temperature is altering considerably,” says MOXIE principal investigator Michael Hecht of MIT’s Haystack Observatory.
“We do have an ace up our sleeve that can allow us to try this, and as soon as we take a look at that within the lab, we will attain that final milestone to indicate we will actually run any time.”
Ideally, after all, the objective is a life help system that may run repeatedly since that is how folks have to breathe. And it’ll should be rather a lot larger than MOXIE: A small staff of astronauts, Hecht said final yr, would require round one metric ton of breathable oxygen for a single yr on Mars.
And that does not embody the oxygen required for propellant for the journey dwelling – in complete the mission would wish an estimated 500 tons of oxygen, the staff calculated.
What the staff has learnt within the first yr of MOXIE’s operations will inform the event of this bigger system… however there’s nonetheless a solution to go.
The subsequent experimental run will happen through the time of yr when the environment is at its densest. Then, the staff stated, they are going to be pushing the instrument as arduous as it may go, to attempt to produce as a lot oxygen as it may.
This won’t solely present what MOXIE is able to, however show its limitations, which, in flip, will help in constructing a extra strong machine for the eventual crewed mission to Mars.
And that can resolve a big a part of the puzzle concerned in not solely making an inhabitable place extra welcoming to people – however making certain their protected return dwelling.
“To help a human mission to Mars, we’ve got to convey a number of stuff from Earth, like computer systems, spacesuits, and habitats,” Hoffman says.
“However dumb previous oxygen? If you can also make it there, go for it – you are method forward of the sport.”
The analysis has been printed in Science Advances.
