Creating Oxygen on Mars: MOXIE Ends Mission Success

NASA has officially concluded one of the most significant experiments in the history of space exploration. The Mars Oxygen In-Situ Resource Utilization Experiment, better known as MOXIE, has completed its mission aboard the Perseverance rover. This toaster-sized device successfully demonstrated that humans can generate breathable oxygen from the thin, carbon dioxide-rich atmosphere of the Red Planet.

A Historic Achievement in Resource Utilization

When NASA’s Perseverance rover landed in Jezero Crater in 2021, it carried several high-tech instruments, but MOXIE was unique. It was the first attempt to chemically transform materials found on another planet into resources humans could use. In September 2023, NASA announced the experiment had finished its operations with results that exceeded expectations.

Over the course of two years, MOXIE generated oxygen 16 separate times. By the time the final run concluded, the device had produced a total of 122 grams of oxygen. To put that into perspective, 122 grams is roughly what a small dog breathes in 10 hours. While that volume might sound small, it serves as a powerful proof of concept. The primary goal was to reach a production rate of 6 grams of oxygen per hour. MOXIE eventually doubled that target, producing 12 grams per hour at its peak performance with a purity of 98% or better.

How MOXIE Works: Science at 800 Degrees

The Martian atmosphere poses a challenge for human visitors because it is roughly 96% carbon dioxide. For humans to survive there, or for rockets to launch off the surface, oxygen is required. MOXIE solves this problem through a process called solid oxide electrolysis.

The device works by pulling in the Martian air and compressing it. It then heats the air to an intense temperature of approximately 800 degrees Celsius (1,470 degrees Fahrenheit). At this heat, the device uses electricity to split the carbon dioxide molecules (CO2) into oxygen ions and carbon monoxide.

The oxygen ions are then combined to form breathable molecular oxygen (O2). The leftover carbon monoxide is harmlessly vented back into the Martian atmosphere. Throughout this process, MOXIE analyzes the gas stream to ensure the oxygen purity is safe for human respiration and that the system is operating correctly without damaging the rover’s other sensitive instruments.

Testing Against the Martian Elements

Reliability was the key success metric for the Massachusetts Institute of Technology (MIT) team that led the operation. A device that only works on a calm, warm day is useless on Mars, where temperatures can plummet to -100 degrees Fahrenheit at night and dust storms are common.

NASA pushed MOXIE to its limits by running it in a variety of conditions. The team operated the device during the Martian day and night, and throughout different seasons of the Martian year. It successfully produced oxygen even during the highest density of atmospheric pressure and the lowest. This durability proves that the technology acts robustly enough to support a full-scale human mission, regardless of the harsh environmental variables.

Why This Matters: The ISRU Strategy

This experiment validates a concept known as In-Situ Resource Utilization (ISRU). ISRU is the practice of “living off the land” rather than bringing everything from Earth. Launching supplies into space is incredibly expensive and weight-restricted.

While breathable air is vital, the most critical need for oxygen on Mars is actually rocket propellant. To launch a crew of four astronauts off the Martian surface and back to Earth, a rocket needs about 7 metric tons of fuel and 25 metric tons of oxygen to burn that fuel. Transporting 25 tons of oxygen from Earth to Mars is currently logistically impossible.

However, transporting a one-ton oxygen generator is feasible. The success of MOXIE proves that NASA can send an empty oxygen tank and a generator to Mars, let it fill the tank over time, and have a fully fueled return vehicle waiting when astronauts arrive.

The Future: Scaling Up for Humans

Now that MOXIE has retired, researchers at MIT and NASA’s Jet Propulsion Laboratory (JPL) are looking toward the next phase. The data gathered from the 16 runs will be used to design a full-scale system.

While MOXIE fit inside the rover chassis, the future version will likely be a standalone unit. Engineers envision a system roughly the size of a chest freezer or a small backup generator. This future system will need to run continuously, rather than in short bursts like MOXIE. The target for a full-scale system is to produce between 2,000 and 3,000 grams of oxygen per hour.

Plans suggest this larger system would be sent to Mars ahead of the first human crew. It would run for approximately 14 months (one Earth year and a bit) to liquefy and store enough oxygen to support the astronauts’ life support systems and, more importantly, fuel their ascent vehicle for the journey home.

Frequently Asked Questions

What happened to MOXIE after the mission ended? MOXIE remains inside the Perseverance rover. While it is no longer being turned on for experiments, it serves as a permanent testament to the first time humans generated resources on another world. The rover continues its primary mission of searching for signs of ancient microbial life.

Did MOXIE run on solar power? MOXIE drew its power from the Perseverance rover, which is powered by a Multi-Mission Radioisotope Thermoelectric Generator (MMRTG). This nuclear power source allowed MOXIE to run at night when solar power would not be available. Future large-scale versions will likely require a dedicated engaging power plant, potentially utilizing surface solar arrays or small nuclear fission reactors.

Is the oxygen MOXIE made safe to breathe? Yes. The oxygen produced was analyzed and found to be over 98% pure. This is well within the safety standards for human respiration and medical use, as well as for use as a rocket propellant oxidizer.

How much did MOXIE cost? The MOXIE instrument itself was part of the larger Mars 2020 mission, which had a total cost of roughly $2.7 billion. The development and operation of the specific MOXIE instrument cost approximately $50 million.