The milestone, which the MOXIE instrument achieved by converting carbon dioxide into oxygen, points the way for future human exploration of the Red Planet.
The growing list of “firsts” for Perseverance, NASA’s latest six-wheeled robot on the surface of Mars, includes converting some of the Red Planet’s thin, carbon dioxide-rich atmosphere into oxygen. An experimental instrument the size of a toaster aboard Perseverance, called the Mars Oxygen In-Situ Resource Utilization Experiment (MOXIE), accomplished the task. The test took place on April 20, the 60th day of Mars, or sol, since the mission landed on February 18.
While the technology demonstration has only just begun, it could pave the way for science fiction to become science fact – by isolating and storing oxygen on Mars to power rockets that can lift astronauts off the Earth’s surface. Such devices could one day also provide the astronauts themselves with breathing air. MOXIE is an exploration technology study – much like the Mars Environmental Dynamics Analyzer (MEDA) weather station – and is sponsored by NASA’s Space Technology Mission Directorate (STMD) and Human Exploration and Operations Mission Directorate.
“This is a critical first step in converting carbon dioxide into oxygen on Mars,” said Jim Reuter, STMD associate administrator. “MOXIE has more work to do, but the results of this technology demonstration are very promising as we get closer to our goal of one day seeing humans on Mars. Oxygen isn’t just what we breathe. Rocket propellant depends on oxygen, and future explorers will depend on Mars’ propellant production to make the journey home. “
For rockets or astronauts, oxygen is key, said MOXIE’s lead researcher, Michael Hecht of the Massachusetts Institute of Technology’s Haystack Observatory.
After a two hour warm-up period, MOXIE started to produce oxygen at a rate of 6 grams per hour. The value was decreased twice during the run (referred to as “current sweeps”) to assess instrument status. After one hour of work, the total oxygen produced was about 5.4 grams, enough to keep an astronaut healthy for about 10 minutes of normal activity.
Credit: MIT Haystack Observatory
To burn its fuel, a rocket must contain more oxygen. Getting four astronauts off the surface of Mars for a future mission would require approximately 15,000 pounds (7 tons) of rocket fuel and 55,000 pounds (25 tons) of oxygen. In contrast, astronauts living and working on Mars would need much less oxygen to breathe. “The astronauts who stay on the surface for a year will use maybe a ton between them,” Hecht said.
It would be a daunting task to transport 25 tons of oxygen from Earth to Mars. Transporting a one-ton oxygen converter – a larger, more powerful offspring of MOXIE that could produce those 25 tons – would be much more economical and practical.
The atmosphere of Mars is 96% carbon dioxide. MOXIE works by separating oxygen atoms from carbon dioxide molecules, which are made up of one carbon atom and two oxygen atoms. A waste product, carbon monoxide, is released into the atmosphere of Mars.
The conversion process requires high levels of heat to reach a temperature of about 1,470 degrees Fahrenheit (800 degrees Celsius). To compensate for this, the MOXIE unit is made of heat-tolerant materials. These include 3D printed nickel alloy parts, which heat and cool the gases flowing through them, and a lightweight airgel that helps retain heat. A thin gold coating on the outside of MOXIE reflects infrared heat, preventing it from radiating outward and potentially damaging other parts of Perseverance.
Illustration of the MOXIE instrument, showing the elements in the instrument. Credit: NASA / JPL
In this first operation, MOXIE’s oxygen production was quite modest – about 5 grams, which equates to about 10 minutes of breathing oxygen for an astronaut. MOXIE is designed to generate up to 10 grams of oxygen per hour.
This technology demonstration was designed to ensure that the instrument survived the launch from Earth, a nearly seven-month journey through space, and the landing with persistence on February 18. MOXIE is expected to extract oxygen at least nine more times over the course of a Martian year (nearly two years on Earth).
These oxygen production runs will take place in three stages. The first stage will examine and characterize the function of the instrument, while the second stage will allow the instrument to operate in varying atmospheric conditions, such as different times of day and seasons. In the third phase, Hecht said, “we’re going to the limit” – trying out new operating modes or “introducing new wrinkles, such as a run where we compare operations at three or more different temperatures.”
“MOXIE is not only the first instrument to produce oxygen in another world,” says Trudy Kortes, director of technology demonstrations at STMD. It is the first technology of its kind that will help future missions “live off the land”, using elements from a different world environment, also known as in-situ resource use.
“It takes regolith, the substance you find on the ground, and passes it through a processing plant, makes it into a large structure, or takes carbon dioxide – most of the atmosphere – and converts it into oxygen,” she said. . “This process allows us to convert these abundant materials into useful things: propellant gas, breathable air or, in combination with hydrogen, water.”
More about persistence
A major goal of Perseverance’s mission on Mars is astrobiology, including the search for signs of ancient microbial life. The rover will characterize past geology and climate, pave the way for human exploration of the Red Planet, and be the first mission to collect and store Martian rock and regolith (broken rock and dust).
Subsequent NASA missions, in collaboration with ESA (European Space Agency), would send spacecraft to Mars to collect these sealed samples from the surface and return them to Earth for in-depth analysis.
The Mars 2020 Perseverance mission is part of NASA’s Moon to Mars exploration approach, including Artemis missions to the moon that will help prepare for human exploration of the Red Planet.
NASA’s Jet Propulsion Laboratory in Southern California, operated for NASA by Caltech in Pasadena, California, built and operated the Perseverance rover.
For more on perseverance:
https://mars.nasa.gov/mars2020/
and
https://www.nasa.gov/perseverance
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