Why Oxygen on Mars Matters

I’m sure at some point in one’s life, everyone has had some sort of experience related to swimming and you may have found it difficult to hold your breath underwater for a long time. That’s because in the respiratory process inside the human body, CO2 accumulates and it isn’t healthy for your body. This is why we exhale to expel built-up CO2, then inhale to get more oxygen for energy through respiratory processes.

Now picture yourself on the surface of Mars and try this again. You might be able to hold your breath for as long as you can, but as soon as you try to inhale again, you wouldn’t be taking in O2 — you would be flooding your lungs with CO2. Not exactly healthy.

The atmosphere of Mars is about 95% carbon dioxide with less than 0.2% oxygen. In comparison, Earth’s atmosphere contains 78% nitrogen and 21% oxygen. On top of that, the air pressure on Mars is less than 1% of Earth’s, meaning even the tiny amount of oxygen available would be too thin to breathe.

For astronauts, oxygen serves two primary roles:

  • Life support: Breathable oxygen keeps humans alive.
  • Rocket oxidizer: Oxygen is required to help spacecraft propel and return to Earth.

So the question becomes: can we produce oxygen on Mars using the resources already present there?

Meet MOXIE: Mars’ Oxygen Machine

MOXIE stands for the Mars Oxygen In-Situ Resource Utilization Experiment. It is essentially a technology demonstration designed to convert Martian air into oxygen.

About the size of a toaster, MOXIE traveled to Mars aboard the Perseverance rover and landed in Jezero Crater in 2021. It was not designed to support astronauts directly, but rather to prove that oxygen production on Mars is possible.

MOXIE represents the first time humans have produced oxygen on another planet. It is a proof of concept demonstrating that local Martian resources can be transformed into usable materials.

Developed by engineers at MIT and NASA’s Jet Propulsion Laboratory, MOXIE pioneers a concept called In-Situ Resource Utilization (ISRU). Instead of transporting all supplies from Earth, ISRU focuses on using materials already available on Mars to support life and fuel missions.

How MOXIE Works

Here is the step-by-step process of how MOXIE produces oxygen:

  • Inhale: MOXIE pulls in thin Martian air through a dust filter.
  • Compress: The air is pressurized to approximately 0.7–1.0 bars to enable processing.
  • Heat: The air is heated to about 800°C using special ceramics.
  • Split: Through solid oxide electrolysis, CO2 molecules are split into carbon monoxide (CO) and oxygen.