MOXIE microwaved Mars air into oxygen, but now it's time for a breather

NASA has called time on the oxygen-generating experiment bolted to its Mars Perseverance rover. The Mars Oxygen In-Situ Resource Utilization Experiment (MOXIE), a device roughly the size of a microwave oven, was designed to extract oxygen from the atmosphere of Mars. During its time on the red planet, it has produced 122 grams …

[Caver_Dave]

Short sighted?

So Oxygen is in short supply in the Martian atmosphere. NASA are planning to extract it and use that oxygen to burn, either in people or rockets. Thereby reducing the atmospheric oxygen further. This doesn't sound like a long term solution to me.

[John Brown (no body)]

Re: Short sighted?

They are producing O2 and CO (which is just vented) from CO2, of which Mar has an abundance, ie 95% of the atmosphere.

[Richard 12]

Re: Short sighted?

There basically jsn't any free oxygen in the Martian atmosphere - any that forms reacts with the dust almost immediately.

MOXIE is breaking down CO2 into oxygen and carbon monoxide.

When it's burned, it becomes CO2 again, released in the gravity well.

Aside from that, the volumes in question are miniscule on a planetary scale. A few hundred tonnes isn't going to make any difference - terraforming Mars would take a huge effort over hundreds of years.

[Michael Wojcik]

Re: Short sighted?

This is like complaining about a desalination plant because there isn't much fresh water in the ocean. Except even dumber.

On the other hand, if you were trolling, then well played.

[John Brown (no body)]

Interesting...

Scaled up and taken to the extreme, convert loads of carbon dioxide into oxygen plus carbon monoxide, venting the CO and breathing the O2, converting a significant portion back into CO2. Repeat. Great if it scales nicely, but will we then be creating and even worse atmosphere on Mars? Or would it work out in a future colony that most of the exhaled CO2 becomes the prime source of O2, topped up from outside? Still all that CO being vented though.

Having said that, I doubt there'll ever be such a large human presence on Mars to have a measurable effect!

[Flocke Kroes]

Re: What happens to lots of carbon monoxide

IANAChemist.

The wikipedia page for oxocarbons gives a hint at how imaginative chemists can be even when restricted to two elements. Most of the ways of re-arranging carbon monoxide are not going to happen. The closest was reforming to carbon dioxide and carbon suboxide. There are trace amounts of oxygen and water in the Martian atmosphere so the most obvious fate of carbon monoxide is to burn to carbon dioxide or CO+H2O->CO2+H2. Formic acid is also a possibility.

The main thing that happens to Mars' atmosphere is it gets blown away by the solar wind. The Earth's magnetic field protects our atmosphere. Magnetising Mars would be an enormous proposition, but not necessary: a huge (but not planet sized) magnet at Mars-Sun L1 would to the trick. With one of those in place, the atmosphere would thicken up from volcanic outgassing. The pressure would get high enough for liquid water at the temperatures available with the green house effect from all the CO2. Add some cyanobacteria to make an ozone layer then some plants to convert CO2 to oxygen and more complex carbon compounds. You could get a breathable atmosphere in a few billion years and might even be able to enjoy it for a billion years or two before the sun goes red giant.

[Spazturtle]

Re: What happens to lots of carbon monoxide

"The Earth's magnetic field protects our atmosphere."

That's actually an unsubstantiated hypothesis, and the more recent evidence indicates that magnetic fields actual cause the atmosphere to be lost faster.

[cray74]

Re: What happens to lots of carbon monoxide

The main thing that happens to Mars' atmosphere is it gets blown away by the solar wind.

On time scales of 100 million to 4 billion years, yes. Mars has an additional issue with low escape velocity, which also makes it vulnerable to Jean's escape mechanism and impact-driven atmosphere ejection. A reasonable asteroid that is a non-issue to Earth's atmosphere (if of more concern to dinosaurs) can drive eject nearby Martian atmosphere at more than escape velocity.

The Earth's magnetic field protects our atmosphere.

It may help. However, Earth has a couple of other advantages: a much higher escape velocity and much larger reservoirs of volatiles than Mars.

a huge (but not planet sized) magnet at Mars-Sun L1 would to the trick.

A LaGrange magnetic shield would help protect Mars on giga-year time frames. It wouldn't make much difference to most terraforming schemes or reasonable periods of human occupation.

[DS999]

Re: Interesting...

Are you seriously worried that a Mars colony could get so large that it would affect Mars' entire atmosphere? Look how many humans were required to really start messing with Earth's atmosphere, and that's because we were digging up a bunch of stored carbon on a worldwide industrial scale for a century not because of our breathing!

Not sure what a "worse" atmosphere on Mars is, exactly. It is far too thin and unbreathable today, and would be far too thin and unbreathable in the future even if we changed the relative percentages of CO2 and CO. Even if there is life on Mars, clearly it does not depend on the atmosphere for respiration.

I still say a Mars colony is a dumb idea. There are zero advantages for a Mars colony over a Moon colony, but a lengthy list of disadvantages. Plus we can extract oxygen from the regolith via electrolysis, though assuming there is water there that's a simpler/cheaper substance from which to extract oxygen.

[John Brown (no body)]

Re: Interesting...

No, which I why I closed with "Having said that, I doubt there'll ever be such a large human presence on Mars to have a measurable effect!" :-)

[Fruit and Nutcase]

Future Experiment

NASA should send an experiment called PLANT to convert CO₂ into O₂

[Snowy]

Re: Future Experiment

May be they could grow POTATOES, thinking about it I think I may have have hear about a documentary about it.

[John Brown (no body)]

Re: Future Experiment

Ye, and the project name for the growing medium could Super High Intensity Tatties

[vogon00]

Chemisty is not my strong suit....

...but after dredging up something hammered into my thick grey matter by the excellent Dr. Mike Bee (At THS), something doesn't read quite right to me...

OK, Carbon Dioxide is CO₂, and the article says "an electrochemical process in which one oxygen atom is extracted from each carbon dioxide molecule" is used (My emphasis).

If I understand things correctly :-

[a] After 'cracking' the CO₂, that leaves you with a molecule of CO and one atom of oxygen, AKA 'Elemental Oxygen'.

[b] What we want is good old O₂, meaning a molecule of Oxygen rather than just a single atom of the stuff.

Now given that "NASA noted that the most important use of oxygen", doesn't that suggest there has to be a process for combining the single atoms of Oxygen extracted into actually-useful O₂ molecules that we want ( And presumably *NOT* Ozone/ Trioxygen / O₃ or tetraoxygen / O₄ )?

Why not 'Crack' out and discard the C/Carbon leaving the O₂...or have I missed something? Chemists, please educate me:-)

[elDog]

Re: Chemisty is not my strong suit....

I'm guessing that you've done the chemical mathematics correctly.

My slim remembrances from times past in chemistry was that O (the element) doesn't really float around freely in "nature" and that it will rapidly combine into the O2 of which you speak.

[diodesign]

Fuhgeddaboudit

Don't read too much into that bit. We've now simplified it in the piece. It's just extracting O from CO2.

C.

[Richard 12]

Re: Chemisty is not my strong suit....

Free O will react extremely quickly with whatever is nearby. They use a catalyst to get as much O2 as possible.

The reason for the waste product being CO is twofold:

1. Carbon is quite reactive. It'll grab something else, probably O2 and oxidise back to CO2 quite rapidly, releasing a lot of heat. CO is less reactive so easier to avoid that happening.

2. Carbon-Carbon compounds are solid at reasonable temperatures. It's quite difficult to get rid of a solid, so if that's your output the machine fills up with soot and stops working. CO is a gas, so is quite easy to eject.

[Spherical Cow]

Re: Chemisty is not my strong suit....

"Carbon is quite reactive. It'll grab something else, probably O2 and oxidise back to CO2 quite rapidly, releasing a lot of heat."

How come I can hold a lump of charcoal without going up in flames? Carbon doesn't seem all that reactive to me.

[Michael Wojcik]

Re: Chemisty is not my strong suit....

Try doing that at 800° C.