Credit: NASA/JPL


If all goes as scheduled for NASA’s Mars 2020 mission, a first-time experiment for the Red Planet is the production of on-the-spot oxygen.

The Mars Oxygen In-Situ Resource Utilization Experiment (MOXIE) represents the first time that NASA is demonstrating In-Situ Resource Utilization (ISRU) on the surface of another planetary body. MOXIE will produce oxygen from atmospheric carbon dioxide on Mars.

To predict performance of MOXIE but avoid subjecting flight hardware to unsafe conditions, a dynamic model has been developed that simulates MOXIE’s operation on Mars. The approach became a fast and inexpensive way to test MOXIE. Also, the modeling of this instrument is similarly unique. The results of this model have been validated against data from Jet Propulsion Laboratory’s MOXIE testbed activities.

Mars Oxygen In-Situ Resource Utilization Experiment (MOXIE) schematic.
Credit: Hinterman and Hoffman

Core technology

MOXIE modeling is detailed in a recent paper: “Simulating oxygen production on Mars for the Mars Oxygen In-Situ Resource Utilization Experiment,” written by Eric Hinterman of the Department of Aeronautics and Astronautics at the Massachusetts Institute of Technology (MIT) and former astronaut, Jeffrey A. Hoffman, an MIT professor in the department and a director of the Human Systems Laboratory. Hoffman is also MOXIE’s Deputy Principal Investigator.

“The team has conducted a significant amount of testing on MOXIE over the past few years that has brought its core technology a long way,” Hinterman told Inside Outer Space. “Demonstrating it on Mars is a valuable proof of concept, but the real learnings have come during the development process here on Earth!”

MOXIE is roughly 0.5% of the scale that would be necessary to produce oxygen for breathing and utilization as a propellant for a human Mars mission, Hinterman and Hoffman explain in their paper. On Mars, the hardware will produce greater than 99.6% pure oxygen through solid oxide electrolysis.

MOXIE, an inside/outside look.
Credit: Hinterman and Hoffman


A dynamic model was developed that simulates MOXIE’s operation. Simulink, a package contained within the MATLAB programming language, was chosen as a convenient way to build a dynamic representation of MOXIE.

MATLAB (matrix laboratory) is a special app that makes it easy for users to create and edit technical work.

The MOXIE model is a combination of theoretical and empirical values regarding the gas flows, thermal transfers, electrochemistry, and control loops that are representative of the true MOXIE system.

In addition, a graphical user interface (GUI) was developed to allow members of the MOXIE science team to easily understand and operate the complex model.

Humans on Mars – the reach for the Red Planet.
Credit: Boeing


“MOXIE is an important step in the effort to put humans on Mars,” explain Hoffman and Hinterman. “It will demonstrate the usefulness of the Martian atmosphere in producing oxygen for rocket propellant. This application of ISRU on Mars is critical to reducing the cost of a human mission to the planet, one of the main barriers that is faced by human exploration of space today,” they note.

In a JPL posting, Michael Hecht, MOXIE’s Principal Investigator at MIT adds: “When we send humans to Mars, we will want them to return safely, and to do that they need a rocket to lift off the planet. Liquid oxygen propellant is something we could make there and not have to bring with us. One idea would be to bring an empty oxygen tank and fill it up on Mars.”

To find out more on “Simulating oxygen production on Mars for the Mars Oxygen In-Situ Resource Utilization Experiment,” go to Acta Astronautica, Volume 170, May 2020, Pages 678-685 at:

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