The Mars rover Perseverance has already sent thousands of photos and scientific measurements back to Earth, but one experiment with key potential for future manned flights has remained rather in the background until now. However, a team of authors from MIT, NASA and other organizations have now published their results in the journal Science.
It’s about the device MOXY (Mars Oxygen ANDSRU Experiment) that was able to produce oxygen using electrolysis and ubiquitous atmospheric carbon dioxide. ISRU is short for ANDn WITHit Resource ATtilization – the production of resources right on the spot – and oxygen is one of the most pressing challenges if we are to transport mass to Mars that we will later want to send back home.
MAV will need 39 tons of oxidizer
Mars has only 38% gravity compared to Earth and its atmosphere is also much thinner, so we need much less fuel to launch a body into its orbit. In the case of the Red Planet, they are working with methane and oxygen-based propulsion.
Illustration of the first generation of MAV small cargo ships
Device I have (Mars Ascent Vehicle), which will transport a crew of six into orbit to the main ship will need about 40 tons of fuel: 39 tons of oxygen and 9 tons of methane.
To transport 40 tons of cargo to Mars, we need 500 tons of fuel
But there is a catch. Transporting just 40 tons of cargo from the Earth’s surface to the Martian surface requires rocket technology at the current state around 500 tons of fuel. And we are only talking about the transport of fuel for the MAV module.
One of the MAV ideas for a human crew
So if we were to import all the cargo from Earth as we have done so far, the costs will be astronomical. Simply put, getting a rover to Mars is one thing, but it has little to do with what we’ll need to get a human crew to Mars to survive and have the luxury of being healthy will return
A small tree on Mars
ISRU is therefore the basis, with local production of fuel then an absolute necessity. And this is precisely what the MOXIE experiment successfully verified several times, which produced oxygen in the Perseverance rover using the electrolysis of atmospheric carbon dioxide at high temperatures of around 800 °C.
Measuring 23.9 x 23.9 x 30.9 centimeters, the device can produce 6-8 grams of pure oxygen per hour aboard Perseverance
MOXIE was able to synthesize 6-8 grams of oxygen per hour (theoretically up to 10 g/hour), which corresponds to the output of a small tree. On the face of it, it’s a small miracle that it was successful at all, but to produce several tens of tons of oxidizer for rocket engines, we would need continuous operation for up to 742 yearswhich is somewhat longer than the expected frequency of flights to the red planet.
We need the whole forest to produce fuel
On the other hand, MOXIE was only an experiment, as the production unit could achieve performance according to the scientists 2-3 kilograms of oxygen per hourwhich would be more than enough for the expected flight cycle in length 26 months.
Moxie is carry-on size
The principles of In Situ Resource Utilization will also be key for a longer stay on Mars and later extraction and production of fuel from frozen surface water and permafrost, which according to geographers occurs roughly from 40-50° latitude. But we are already getting into a more distant future, which, with a little luck, your graying children will probably read about.
First we have to retake the moon
In order to achieve all of this, ideally within this decade we must first reconquer the Moon, build a base on it and carefully test all technologies at a ridiculous distance from Earth.
So, if you’re wondering why we’re returning to our natural satellite as part of the Artemis program, one reason is that the Moon is by far the most suitable—many say even absolutely necessary—simulator for manned journeys much further afield.
Artemis Live: Man’s Return to the Moon
Artemis is NASA’s space program, whose mission is to restore human flights to the Moon. A Gateway station will be built in lunar orbit. The crew will be transported to the station by the Orion spacecraft, launched by the SLS rocket. The HLS module will transport astronauts to the surface of the moon, which will be SpaceX’s Starship at least for the first landing.
- Artemis 1: An unmanned flight where the Orion spacecraft will be guided into orbit around the Moon and then back to Earth. Deadline: end of 2021
- Artemis 2: A manned orbit around the moon. Deadline: 2023
- Artemis 3: Man landing on the moon. Deadline: 2024 at the earliest
- CLPS: Transportation of scientific experiments to the surface of the Moon in support of the Artemis program. Deadline: from 2021