Oxygen Production on Mars: A Research Review of In-Situ Resource Utilization and the MOXIE Experiment

One of the greatest obstacles to sending humans to Mars is not the journey itself — it is what happens when people arrive. Mars has an atmosphere composed of roughly 95% carbon dioxide, with almost no oxygen. Astronauts cannot breathe there, and any rocket that needs to return them to Earth would require enormous quantities of propellant that would be nearly impossible to transport from home.

This is why scientists have long focused on a concept called In-Situ Resource Utilization — the idea of producing what you need from the resources already present on Mars, rather than carrying everything from Earth.

What Is In-Situ Resource Utilization?

In-Situ Resource Utilization, commonly abbreviated as ISRU, refers to the practice of harvesting, processing, storing, and using materials found at the destination rather than launching them from Earth.

On Mars, ISRU strategies include:

• Extracting water ice from the subsurface or polar caps
• Converting carbon dioxide into oxygen and carbon monoxide
• Producing rocket propellant from local atmospheric gases
• Processing Martian soil (regolith) for construction materials

Of all these approaches, oxygen production from atmospheric carbon dioxide has attracted the most immediate research interest — both for life support and for fuel manufacturing. A human mission to Mars would require approximately 25 metric tons of oxygen for propellant alone, plus additional amounts for crew breathing over a surface stay of hundreds of days.

Shipping that quantity of oxygen from Earth would be prohibitively expensive and technically impractical. Producing it on Mars changes everything.

The MOXIE Experiment: First Oxygen Made on Another World

In February 2021, NASA's Perseverance rover landed in the Jezero Crater on Mars. Among its suite of scientific instruments was a toaster-sized device with a name that belied its historical significance: MOXIE, the Mars Oxygen In-Situ Resource Utilization Experiment.

MOXIE was designed and built by researchers at the Massachusetts Institute of Technology (MIT), with support from NASA's Jet Propulsion Laboratory. Its purpose was straightforward but revolutionary — to demonstrate, for the first time in history, that oxygen could be produced directly from the Martian atmosphere on the surface of another planet.

The instrument operates through a process called solid oxide electrolysis. Here is how it works:

1. Martian air is pulled in and filtered to remove contaminants such as dust
2. The air is pressurized and delivered to a solid oxide electrolyzer cell (SOXE)
3. The device heats the carbon dioxide to approximately 800 degrees Celsius
4. At this extreme temperature, the electrolyzer splits CO₂ molecules into oxygen ions and carbon monoxide
5. The oxygen ions are drawn through a solid ceramic membrane and recombined into breathable O₂
6. The carbon monoxide is vented back into the atmosphere

The process requires significant electrical energy, which MOXIE draws from Perseverance's multi-mission radioisotope thermoelectric generator (MMRTG).

Results and Scientific Achievements

MOXIE conducted its first oxygen production run on April 20, 2021 — a date researchers now describe as a milestone moment in the history of space exploration. The device successfully produced 5.4 grams of oxygen in one hour, roughly equivalent to what an astronaut would breathe in ten minutes.

Over the following two years, MOXIE completed a total of 16 oxygen production runs under a wide range of Martian seasonal and atmospheric conditions. Key findings from these experiments include:

• MOXIE produced oxygen consistently across all runs, demonstrating operational reliability
• The device generated oxygen at varying times of day and across different Martian seasons, confirming it could function in changing conditions
• Peak production reached approximately 10.44 grams per hour — nearly double initial targets
• The purity of the oxygen produced exceeded 98%, meeting the standards required for both life support and rocket propellant
• MOXIE successfully operated in Martian dust storm conditions, a critical test for any hardware that must survive the Martian environment

The final MOXIE run was completed in August 2023, after which the experiment concluded its science mission. In total, MOXIE produced approximately 122 grams of oxygen across all its operations — a modest quantity by any practical measure, but a profound proof of concept.

What the MOXIE Results Mean for Future Missions

The significance of MOXIE lies not in the amount of oxygen it produced, but in what it demonstrated is possible. NASA researchers have described the experiment as analogous to the Wright Brothers' first powered flight — a short, humble demonstration that opens an entirely new era of capability.

A full-scale ISRU system capable of supporting a crewed Mars mission would need to be roughly 100 times larger than MOXIE. Scientists estimate that such a system, operating continuously for about 26 months before a crew arrives, could produce the 25 metric tons of liquid oxygen needed for the ascent rocket propellant — in addition to supplying oxygen for the crew to breathe during their surface operations.

This approach could dramatically reduce the mass that must be launched from Earth. A Mars mission architecture that relies on ISRU-produced propellant for the return journey essentially eliminates the need to transport return fuel — one of the heaviest components of any Mars mission design.

Several important engineering challenges remain before a full ISRU system can be deployed on Mars:

• Scaling up the electrolyzer technology to industrial-level production rates
• Designing systems that can operate autonomously for months or years without human maintenance
• Managing the high temperatures required by solid oxide electrolysis in a Mars environment
• Integrating oxygen liquefaction and long-term cryogenic storage on the Martian surface
• Ensuring the system can survive Martian dust storms and extreme cold

NASA's ongoing ISRU research program, along with contributions from international space agencies and private spaceflight companies, is addressing each of these challenges in preparation for future crewed missions.

ISRU in Broader Context: Mars as a Self-Sustaining Destination

Oxygen is only one part of the ISRU puzzle. Researchers are simultaneously investigating how to extract water from Martian ice deposits, how to produce methane fuel by combining atmospheric hydrogen with Martian carbon, and how to use regolith as a building material for habitats that can shield astronauts from radiation.

Together, these capabilities represent a vision of Mars as a place where human civilization could eventually become self-sustaining — not dependent on endless supply shipments from Earth, but able to manufacture what it needs from local resources.

The MOXIE experiment is the first confirmed step along that path. It proved that the chemistry works on Mars, in Martian gravity, with Martian air, under real Martian conditions. Everything that comes next builds on that foundation.

FAQ

Q1: What does MOXIE stand for?

MOXIE stands for Mars Oxygen In-Situ Resource Utilization Experiment. It is a technology demonstration instrument carried aboard NASA's Perseverance rover.

Q2: How much oxygen did MOXIE produce in total?

Across 16 operational runs between 2021 and 2023, MOXIE produced approximately 122 grams of oxygen in total, with individual runs producing up to 10.44 grams per hour.

Q3: Why is oxygen production on Mars so important?

Oxygen is essential both for human breathing and as a component of rocket propellant. A crewed Mars mission would need approximately 25 metric tons of oxygen for the return journey alone. Producing it on Mars instead of transporting it from Earth makes the mission far more feasible.

Q4: What process does MOXIE use to make oxygen?

MOXIE uses solid oxide electrolysis to split carbon dioxide molecules from the Martian atmosphere into oxygen ions and carbon monoxide at high temperatures. The oxygen ions are then recombined into breathable molecular oxygen.

Q5: Could a scaled-up version of MOXIE support a human Mars mission?

Researchers believe so. A system approximately 100 times larger than MOXIE, operating continuously for about 26 months before crew arrival, could theoretically produce enough oxygen for both propellant and life support for a crewed Mars surface mission.

References

• NASA Jet Propulsion Laboratory — MOXIE Instrument Overview and Mission Results
• MIT — Mars Oxygen In-Situ Resource Utilization Experiment (Principal Investigator: Michael Hecht)
• Hecht et al. (2021) — "Mars Oxygen ISRU Experiment (MOXIE)" — Science Advances
• NASA Perseverance Rover Science Mission Documentation
• NASA Human Research Program — ISRU Technology Development Roadmap
• European Space Agency — ISRU Technology Strategy for Human Mars Exploration

Author: ScienceTrace Editorial | Published: 2026