Mars' underground brine could be a good source of oxygen
MOXIE—the Mars Oxygen In-Situ Resource Utilization Experiment—is a box not much bigger than a toaster that produces oxygen from atmospheric CO2. While a much larger version would be required to make liquid-oxygen fuel for a rocket, MOXIE is sized to produce about the amount of oxygen an active person needs to breathe.
A new study led by Pralay Gayen at Washington University in St. Louis, Missouri, tests a device that could tap a different resource—perchlorate brine believed to exist in the Martian ground at some locations. The device can split the water in that brine, producing pure oxygen and hydrogen.
[...] To test whether we could tap this resource, the researchers built an electrolysis device that they ran in Mars-like conditions. It uses a standard platinum-carbon cathode and a special lead-ruthenium-oxygen anode the researchers developed previously. They mixed up a plausible concentration of magnesium perchlorate brine and filled the headspace in that container with pure CO2 for a Mars-like atmosphere. The whole thing was kept at -36°C (-33°F). When powered up, brine flowed through the device, splitting into pure oxygen gas captured on the anode side and pure hydrogen gas on the cathode side.
The device worked quite well, producing about 25 times as much oxygen as its MOXIE counterpart can manage. MOXIE requires about 300 watts of power to run, and this device matches that oxygen output on about 12 watts. Plus, it also produces hydrogen that could be used in a fuel cell to generate electricity. And it would be smaller and lighter than MOXIE, the researchers say. Ultimately, all this just illustrates that MOXIE is working with a lower quality—but more widely accessible—resource in atmospheric CO2 instead of water.
Also at The Conversation.
For those who may not be familiar, Moxie is a "thing". Wikipedia summarizes thusly:
Moxie is a brand of carbonated beverage that is among the first mass-produced soft drinks in the United States. It was created around 1876 by Augustin Thompson (born in Union, Maine) as a patent medicine called "Moxie Nerve Food" and was produced in Lowell, Massachusetts. Moxie's flavor is unique, a sweet drink with a bitter aftertaste. Moxie is flavored with gentian root extract, an extremely bitter substance commonly used in herbal medicine.
[...] The name has become the word "moxie" in American English, a noun meaning courage, daring, or determination.
Journal Reference:
Pralay Gayen, Shrihari Sankarasubramanian, Vijay K. Ramani. Fuel and oxygen harvesting from Martian regolithic brine [$], Proceedings of the National Academy of Sciences (DOI: 10.1073/pnas.2008613117)
(Score: 2) by Freeman on Tuesday December 01 2020, @03:59PM (4 children)
I assume, the whole idea of a Mars Colony rests on the fact that there is water there somewhere. Not just oh, there is water, but also there is a reasonably easy to access, large quantity of water. Thus, something that can make use of that water for coming up with breathable air and fuel, is a very good thing. Water is one thing we can't import to Mars. The quantities needed to sustain life indefinitely, must already be there.
Joshua 1:9 "Be strong and of a good courage; be not afraid, neither be thou dismayed: for the Lord thy God is with thee"
(Score: 2) by takyon on Tuesday December 01 2020, @04:33PM
https://en.wikipedia.org/wiki/Korolev_(Martian_crater) [wikipedia.org]
[SIG] 10/28/2017: Soylent Upgrade v14 [soylentnews.org]
(Score: 3, Insightful) by Immerman on Tuesday December 01 2020, @05:34PM (2 children)
I don't understand why people keep bringing this up - Mars has HUGE amounts of water - radar analysis of the northern polar icecap alone reveals roughly 821,000 cubic km of water ice, the southern ice cap contains a smaller but still huge amount as well, and there are many smaller deposits that have been identified scattered around the planet if you'd rather not live near enough the poles for them to be convenient.
Also, it takes negligible amounts of water (or any other raw materials) to sustain life indefintiely, assuming decent ecological recycling. Think of those sealed terrariums that can survive for decades without any added material. You only need large quantities of raw materials when *growing* your ecosystem.
(Score: 0) by Anonymous Coward on Wednesday December 02 2020, @05:35PM (1 child)
In any closed system, someone has to eat shit. That is an axiom of space travel.
(Score: 3, Touché) by Immerman on Wednesday December 02 2020, @06:10PM
Heck, it's an axiom of life anywhere. Or do you think shit magically disappears here on Earth, while food magically appears from unrelated material?
(Score: 3, Interesting) by GalFisk on Tuesday December 01 2020, @04:04PM (2 children)
A solar concentrator (or nuclear heat source) could also boil the water (which could then be condensated as potable water), and decompose the dried perchlorate at 250°C.
The resulting magnesium chloride is a desiccant, which might be useful for things like recovering moisture from waste gas streams. Heat it again, maybe even in the same apparatus, to drive off the water.
(Score: 0) by Anonymous Coward on Tuesday December 01 2020, @04:53PM (1 child)
And ... why? Remind us again.
(Score: 0) by Anonymous Coward on Tuesday December 01 2020, @05:14PM
For the Mars Prison.
(Score: 3, Insightful) by JoeMerchant on Tuesday December 01 2020, @05:13PM (5 children)
Summary mentions that hydrogen can be used in fuel cells - sure can, but not if you are already using the oxygen for other things and you're on Mars where there isn't ambient oxygen available.
🌻🌻🌻 [google.com]
(Score: 2) by PiMuNu on Tuesday December 01 2020, @05:27PM (3 children)
Good point, although Hydrogen does react with CO2...
https://en.wikipedia.org/wiki/Sabatier_reaction [wikipedia.org]
(Score: 2) by JoeMerchant on Tuesday December 01 2020, @06:18PM (2 children)
If I'm reading properly, it's an endothermic reaction: ∆H = −165.0 kJ/mol - now, if you want water and methane and have spare energy to pump into it...
🌻🌻🌻 [google.com]
(Score: 2) by PiMuNu on Wednesday December 02 2020, @10:20AM (1 child)
The text says:
> described by the following exothermic reaction
but I am no chemist!
(Score: 2) by JoeMerchant on Wednesday December 02 2020, @01:16PM
Hmmm... don't doubt your reading of the text, but water and methane would seem, intuitively, to have more energy in their bonds than CO2 and H2.
🌻🌻🌻 [google.com]
(Score: 2) by Immerman on Wednesday December 02 2020, @06:18PM
Not necessarily - hydrogen is one of the leading candidates for the basis of pre-oxygen cellular metabolisms here on Earth. If cells can fuel themselves with hydrogen in the absence of free oxygen, presumably a fuel cell can as well.
In fact, the sabatier reaction, which they plan to use as part of the fuel refinement process on Mars, produces heat while converting hydrogen and CO2 to oxygen and water. A very useful sort of fuel cell to have where water and oxygen are scarce. Why carry all that heavy water and oxygen with you in your Martian expedition RV when you can drink and breathe the exhaust from your hydrogen fuel cell?
(Score: 2) by oumuamua on Tuesday December 01 2020, @05:56PM (4 children)
You've got potatoes growing in the hydroponics/greenhouse that as a by-product produce oxygen. Someone really needs to calculate the efficiencies of all the different processes.
(Score: 2) by oumuamua on Tuesday December 01 2020, @07:06PM
someone calculated it here:
https://medium.com/@candidegardening/how-many-plants-would-it-take-to-produce-enough-oxygen-for-one-person-7312743ed70b [medium.com]
They should have used food producing plants like corn, wheat and potatoes for better realism.
(Score: 3, Insightful) by Immerman on Wednesday December 02 2020, @03:57AM (2 children)
Better yet, do away with complex organisms in your initial ecology. On Earth, all complex life combined is outmassed by about 30:1 by single-celled organisms. If life is a thin soup on the surface of this rock, multicellular life is a sprinkling of pepper in that soup.
Seems to me if you want to export an Earthlike ecology to another world, your first step should be establishing a similar microbial foundation. Microbial growth rates would also mean your ecology could grow as fast as you could provide it raw materials and a suitable environment, and could recover very rapidly from any ecological disasters. Make the ecology big enough that the colonists are a minor component.
We even have a fairly comprehensive selection of dietary microbes to draw on thanks to NASA's research in the 60s, which identified a selection of easily cultivated hydrogen-eaters to provide food for long-term space missions. Technology which at least one company is currently looking to commercialize right here on Earth. Now, I love meat and potatoes as much as the next guy - but you're going to have a lot more ecological excess to grow those if you harvest your staple ingredients like flour, sugar, palm oil, and protein powder directly from microbes instead of growing an entire stalk of wheat in order to eat the scant handful of seeds it eventually produces. A microbial diet can get a lot more interesting than algae cakes, and with staples taken care of and plenty of excess, you can focus more temperamental multicellular farming efforts on foods that will boost morale instead of worrying if your wheat harvest will be enough to avoid famine. Herbs and spices, delicious fruits and vegetables, maybe even a pig farm or two... though you might want to keep that in a completely separate recycled atmosphere.
(Score: 0) by Anonymous Coward on Wednesday December 02 2020, @05:39PM (1 child)
Germs, let's remember, are bad.
(Score: 2) by Immerman on Wednesday December 02 2020, @06:08PM
If you believe that I have a sterile bubble to sell you. Hope you like serious chronic health problems, because without the bacteria that digest your food for you, you're going to have lots of them.
(Score: 2) by kazzie on Tuesday December 01 2020, @07:58PM
I first came across the word "Moxie" when reading Bored of the Rings. I inferred that it too was a drink, but I don't think it's ever been sold east of the pond.
(Score: 3, Funny) by Phoenix666 on Tuesday December 01 2020, @11:21PM (3 children)
If Mars is full of brine the obvious play is to build the solar system's largest pickle factory.
Washington DC delenda est.
(Score: 2) by Immerman on Wednesday December 02 2020, @04:02AM (2 children)
Something tells me that magnesium perchlorate brined pickles would have a very limited audience... in fact, if they proved popular the audience would rapidly limit themselves right out of existence. If you want to eat lots of perchlorates, you'd better be one of the many microbes that have evolved to do so.
(Score: 4, Funny) by Phoenix666 on Wednesday December 02 2020, @02:15PM (1 child)
TRANSLATION: Earthman too weak for strong Martian pickle.
Washington DC delenda est.
(Score: 0) by Anonymous Coward on Wednesday December 02 2020, @05:40PM
They said I couldn't drink methanol what do they kn
(Score: 2) by donkeyhotay on Wednesday December 02 2020, @04:49PM
"Harness the Mars Brine" would make a good name for an alt band.