The Martian atmosphere is ninety five percent
carbon dioxide, about a few percent nitrogen,
a few percent argon, trace amounts of everything
else. But there’s still a lot of CO2, and
so that’s probably the most abundant resource
on Mars other than dirt. CO2 has oxygen bound
in it. And if we can liberate that oxygen
from some of that CO2, then we can use it
to do something useful. The goal is to pave
the way for future human exploration of Mars
by demonstrating the ability to generate oxygen.
That's where the magic happens is inside that
box. NASA is set to launch its next rover
to the red planet in 2020. Stacked inside
are seven science instruments, six of which
are focused on sample analysis like this SuperCam
and a spectrometer called PIXL that’ll measure
chemical signatures inside Martian rocks.
And this box getting lowered inside the belly
of the rover is MOXIE, or the Mars Oxygen
In-Situ Resource Utilization Experiment. It’s
got an agenda separate from the others, and
that’s to make oxygen on Mars for the first
time. Well, at least in real life. In the
Martian, there was something that was called
the oxygenator. If the oxygenator breaks,
I’ll suffocate. If the water reclaimer breaks,
I’ll die of thirst. So we jokingly refer
to MOXIE as the oxygenator. It's unclear in
the movie what technology the oxygenator is
actually using, but it's very likely that
it would be something like MOXIE but scaled
up. MOXIE uses a technology called solid oxide
electrolysis. It works a lot like a reverse
fuel cell where instead of putting in a fuel
and getting electricity out, we can put electricity
in and electrolytes and basically get a fuel
and an oxidizer out. On the outside the rover,
we have a small box with a filter. The filter
is to make sure that we don't draw in any
dust from the Martian atmosphere into our
system, because the next thing in the path
is a scroll compressor. The scroll compressor
takes this low pressure Martian gas from the
atmosphere and compresses it and brings it
up to something closer to Earth's atmospheric
pressure. Because the next thing that we do
is we run it into this thing. We call this
our solid oxide electrolysis stack and it
is basically a layer cake of a bunch of metal
plates, which are the dark green things. And
then these light colored layers are thin ceramic
cells that have particular chemical properties
where at high temperature, they can conduct
electricity using oxygen as the charged carrier.
We heat this guy up to about eight hundred
degrees Celsius. You have oxygen ions on one
side and you apply a voltage, then you can
selectively dry the oxygen through the ceramic
membrane and separate it out from whatever's
on the other side. It goes through a set of
sensors very much like these sitting here
on the table in front of me. And we measure
what fraction of CO2 is there. We put CO2
in here. Oxygen comes out here. And the waste
product, which is a mixture of CO and carbon
monoxide and unreacted CO2 comes out here.
It’s gold because we were concerned that
MOXIE itself would run hotter than everything
else around it. And we wanted to make sure
we didn’t impact any of the nearby electronics
boxes inside the rover. And so, gold has very
low emissivity, so it doesn’t radiate heat
effectively. This particular chemistry process
is sort of unique to Mars in its applicability,
and also the packaging and how we actually
build this system to survive launch and get
to Mars. No one has ever done anything like
this. MOXIE is going to make about six grams
per hour of oxygen. It's not very much. It's
about enough to keep a small dog alive. We
don't have the resources available on the
rover to run MOXIE for long periods of time
continuously because a lot of the rover energy
has to be used for other science that they
want to do. We will probably run MOXIE at
roughly once every two months. The goal for
us is to sample different environmental conditions
on Mars. So day versus night, summer versus
winter, dust storm versus not dust storm...to
assess how the technology behaves in response
to these changing environmental conditions.
What might happen in the future really depends
on the technology that NASA decides to go
with on Mars. If you're assumption is that
you only have the CO2 in the atmosphere available,
then you'd have something like MOXIE scaled
up by about a factor of two hundred. You'd
launch it and deliver it to Mars about two
years before humans set foot there. It would
have a bunch of supporting equipment like
a power system and a storage system, and it
would sit for two years and just generate
oxygen and collect it, and then it would be
ready for use by the humans when they show
up two years later. It's really exciting for
me to be able to build something that's going
to land on another planet. I hope that it's
gonna work the way we expect it to. And that
paves the way for future human exploration
in the not too distant future.
