On the red and dusty surface of Mars, nearly 100 million miles from Earth, an instrument the size of a lunchbox is proving it can reliably do the work of a small tree.
The MIT-led Mars Oxygen In-Situ Resource
Utilization Experiment, or MOXIE, has been successfully making oxygen from the
Red Planet’s carbon-dioxide-rich atmosphere since February 2021, when it
touched down on the Martian surface as part of NASA’s Perseverance rover
mission.
In a study published in the journal Science
Advances, researchers report that, by the
end of 2021, MOXIE was able to produce oxygen on seven experimental runs, in a
variety of atmospheric conditions, including during the day and night, and
through different Martian seasons. In each run, the instrument reached its
target of producing six grams of oxygen per hour — about the rate of a modest
tree on Earth.
Researchers envision that a scaled-up
version of MOXIE could be sent to Mars ahead of a human mission, to
continuously produce oxygen at the rate of several hundred trees. At that
capacity, the system should generate enough oxygen to both sustain humans once
they arrive, and fuel a rocket for returning astronauts back to Earth.
So far, MOXIE’s steady output is a
promising first step toward that goal.
“We have learned a tremendous amount
that will inform future systems at a larger scale,” says Michael Hecht,
principal investigator of the MOXIE mission at MIT’s Haystack Observatory.
MOXIE’s oxygen production on Mars also
represents the first demonstration of “in-situ resource utilization,” which is
the idea of harvesting and using a planet’s materials (in this case, carbon
dioxide on Mars) to make resources (such as oxygen) that would otherwise have
to be transported from Earth.
“This is the first demonstration of
actually using resources on the surface of another planetary body, and
transforming them chemically into something that would be useful for a human
mission,” says MOXIE deputy principal investigator Jeffrey Hoffman, a professor
of the practice in MIT’s Department of Aeronautics and Astronautics. “It’s
historic in that sense.”
Hoffman and Hecht’s MIT co-authors
include MOXIE team members Jason SooHoo, Andrew Liu, Eric Hinterman, Maya Nasr,
Shravan Hariharan, and Kyle Horn, along with collaborators from multiple
institutions including NASA’s Jet Propulsion Laboratory, which managed MOXIE’s
development, flight software, packaging, and testing prior to launch.
Seasonal
air
The current version of MOXIE is small by
design, in order to fit aboard the Perseverance rover, and is built to run for
short periods, starting up and shutting down with each run, depending on the
rover’s exploration schedule and mission responsibilities. In contrast, a
full-scale oxygen factory would include larger units that would ideally run
continuously.
Despite the necessary compromises in
MOXIE’s current design, the instrument has shown it can reliably and
efficiently convert Mars’ atmosphere into pure oxygen. It does so by first
drawing the Martian air in through a filter that cleans it of contaminants. The
air is then pressurized, and sent through the Solid OXide Electrolyzer (SOXE),
an instrument developed and built by OxEon Energy, that electrochemically
splits the carbon dioxide-rich air into oxygen ions and carbon monoxide.
The oxygen ions are then isolated and
recombined to form breathable, molecular oxygen, or O2, which MOXIE then measures for quantity and purity
before releasing it harmlessly back into the air, along with carbon monoxide
and other atmospheric gases.
Since the rover’s landing in February
2021, MOXIE engineers have started up the instrument seven times throughout the
Martian year, each time taking a few hours to warm up, then another hour to
make oxygen before powering back down. Each run was scheduled for a different
time of day or night, and in different seasons, to see whether MOXIE could
accommodate shifts in the planet’s atmospheric conditions.
“The atmosphere of Mars is far more
variable than Earth,” Hoffman notes. “The density of the air can vary by a
factor of two through the year, and the temperature can vary by 100 degrees.
One objective is to show we can run in all seasons.”
So far, MOXIE has shown that it can make
oxygen at almost any time of the Martian day and year.
“The only thing we have not demonstrated
is running at dawn or dusk, when the temperature is changing substantially,”
Hecht says. “We do have an ace up our sleeve that will let us do that, and once
we test that in the lab, we can reach that last milestone to show we can really
run any time.”
Ahead of
the game
As MOXIE continues to churn out oxygen
on Mars, engineers plan to push its capacity, and increase its production,
particularly in the Martian spring, when atmospheric density and carbon dioxide
levels are high.
“The next run coming up will be during
the highest density of the year, and we just want to make as much oxygen as we
can,” Hecht says. “So we’ll set everything as high as we dare, and let it run
as long as we can.”
They will also monitor the system for
signs of wear and tear. As MOXIE is just one experiment among several aboard
the Perseverance rover, it cannot run continuously as a full-scale system
would. Instead, the instrument must start up and shut down with each run — a
thermal stress that can degrade the system over time.
If MOXIE can operate successfully
despite repeatedly turning on and off, this would suggest that a full-scale
system, designed to run continuously, could do so for thousands of hours.
“To support a human mission to Mars, we have to bring a lot of stuff from Earth, like computers, spacesuits, and habitats,” Hoffman says. “But dumb old oxygen? If you can make it there, go for it — you’re way ahead of the game.”
This research was supported, in part, by
NASA.
Source: https://news.mit.edu/2022/moxie-oxygen-mars-0831
Journal article: https://www.science.org/doi/10.1126/sciadv.abp8636
Photo Credit: NASA/JPL-Caltech
Source: MOXIE
experiment reliably produces oxygen on Mars – Scents of Science
(myfusimotors.com)
No comments:
Post a Comment