Mars Oxygen ISRU Experiment

Mars Perseverance Rover
MOXIE Components

The main objective of this experiment is to produce molecular oxygen (O₂) from the atmospheric carbon dioxide (CO₂) which makes up 96% of the Martian atmosphere.[1][9] Scientists will record the efficiency of the O₂ production rate, and the resulting oxygen and carbon monoxide will be vented out after measurements are done.

To achieve this objective, the MOXIE instrument has a goal of producing 22 g of oxygen (O₂) per hour with >99.6% purity for 50 sols (~1230 hours).[1][4][10]

NASA officials stated that if MOXIE worked efficiently, they could land a 100 times larger MOXIE-based instrument on Mars, along with a radioisotope thermoelectric generator. Over the course of some years the generator would power the system, which would produce up to two kilograms of oxygen per hour, and fill an oxygen reservoir that could be used for a sample return mission,[8] or for when NASA astronauts could arrive sometime in the 2030s.[4][11] The stored oxygen could be used for life support, and can also be used as rocket propellant oxidizer to power their return trip to Earth.[12][13] High purity is crucial as future astronauts will breathe it.[14] N
₂ and Ar are not separated from feed, but vented with carbon monoxide (CO). The CO, a byproduct of the reaction, may also be collected and used as propellant[15] or converted to methane (CH
₄) for use as propellant.[2][16]

The MOXIE experiment follows up on an earlier experiment, Mars ISPP Precursor ("MIP"), which was designed and built to fly on the Mars Surveyor 2001 Lander mission.[19] was intended to demonstrate In-Situ Propellant Production ("ISPP") at a laboratory-scale using electrolysis of carbon dioxide to produce oxygen on Mars. The MIP experiment was postponed when the 2001 Lander mission was cancelled following the failure of the 1998 Mars Polar Lander.

The Principal Investigator is Michael Hecht and Deputy Principal Investigator Jeffery Hoffman from the Massachusetts Institute of Technology. Collaborators include the University of Copenhagen, Arizona State University, Imperial College of Science, International Program Manager Jeff Mellstrom from NASA Jet Propulsion Laboratory, Ceramatec, Inc.(SOXE), Air Squared (compressor) Space Exploration Instruments LLC., Destiny Space Systems LLC, and the Technical University of Denmark.[20][21]

Mars Perseverance Rover – MOXIE

Overview

Testing

Installed

MOXIE collects CO
₂ from the Martian atmosphere, then electrochemically splits the CO
₂ molecules into O
₂ and CO. A solid oxide electrolysis cell works on the principle that, at elevated temperatures, certain ceramic oxides, such as yttria-stabilized zirconia (YSZ) and doped ceria, become oxide ion (O^2–) conductors. A thin nonporous disk of YSZ (solid electrolyte) is sandwiched between two porous electrodes. For oxygen generation from carbon dioxide, CO₂ diffuses through the porous electrode (cathode) and reaches the vicinity of the electrode-electrolyte boundary. Through a combination of thermal dissociation and electrocatalysis, an oxygen atom is liberated from the CO
₂ molecule and picks up two electrons from the cathode to become an oxide ion (O^2–). Via oxygen ion vacancies in the crystal lattice of the electrolyte, the oxygen ion is transported to the electrolyte-anode interface due to the applied DC potential. At this interface the oxygen ion transfers its charge to the anode, combines with another oxygen atom to form oxygen (O₂), and diffuses out of the anode.

The net reaction is thus 2CO
₂ ${\displaystyle \longrightarrow }$ 2CO + O
₂

MOXIE will generate O
₂ from CO
₂ in the Martian atmosphere in a process called solid oxide electrolysis. It will fly to Mars on board the Perseverance rover.

Either by design or by astonishing coincidence, MOXIE is also the name of a oxygen-producing building in the building simulation video game Surviving Mars.