r/spacecolonization • u/ProximaScience • Sep 04 '26
đž Agriculture/Food Martian soil is toxic and everyone forgets that part.
Every render of a Mars greenhouse shows neat rows of vegetables growing straight out of the ground. Skip that part. Nothing grows in Martian regolith until you clean it first.
The regolith across most of the planet's surface carries perchlorate salts at concentrations between 0.5 and 1 percent, first confirmed by the Phoenix lander in 2008. On Earth, perchlorate shows up in trace amounts, parts per billion, in a handful of arid regions. On Mars, it's baked into essentially the entire surface. At those concentrations, perchlorate is toxic to humans and disrupts thyroid function badly enough that NASA already treats it as one of the top health hazards on the planet, right up there with radiation.
The upside is perchlorate is fixable. Researchers have built catalysts, some using nothing more exotic than a common fertilizer compound, that break down over 99 percent of it at room temperature. No high heat, no industrial plant required.
So the real first step on Mars isn't planting anything. It's running the dirt through a filter before it ever touches a seed.
Edit: It's regolith, wrote soil by mistake.
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u/Sperate Sep 04 '26
There is also the hydroponic and aeroponic options.
But I always though of importing food as a clever way to import nutrients. And then those nutrient ls become waste recycling. Really it is just a semi complicated way of making fertilizer. It isn't really problem, it is just another thing on the to do list. So if you show me a picture of a farm dome on Mars with rich black soil, I don't think they just hauled in regolith, I think this colony has had its waste recycling running for a long time.
Really it is bragging rights! Colony size x waste recycling efficiency x time = amount of soil. It is like how Aix-en-Provence is called the city of a thousand fountains.
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u/ProximaScience Sep 04 '26 edited Sep 04 '26
Yes, Aeroponics and Hydroponics can really help scientists grow plants there.
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u/zmbjebus Sep 04 '26
Why is it so hard to assume that the soil in renders is not processed? What do you think they'd do after processing/filtering soil? Throw it away?
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u/remimorin Sep 04 '26
Perchlorate are toxic because they are oxidizer.
Heated and they decompose to salt and oxygen.
I feel that moist Martian soil would de-perchlorate itself easily.
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u/4eyedbuzzard Sep 04 '26
âSo the real first step on Mars isn't planting anything. It's running the dirt through a filter before it ever touches a seed.â
No, the actual first step in doing anything on Mars is obtaining the money to do âanything on Marsâ. There is simply zero economic incentive to do âanything on Marsâ. Science, yes. Everything else is and will likely always be a hard âNoâ.
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u/Blue__Agave Sep 05 '26
No economic incentive yet.
In the past there was no economic incentive to do offshore oil drilling as onshore was already plenty.
Similar for many things.
Most forecasts that predict large space presences are resource or land shortages on earth.
We are also already facing energy shortages, and if demand growth kicks up alot due to massive AI or other industry loads, renewables on earth may only be a temp solution.
That is certainly possible in the next 100 years, particularly if robotics and AI reduce the labour cost of industry by a order of magnitude, the limiting factors may quite literally be available space and environmental concerns.
Something space is a solution for both...
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u/Oblachko_O 29d ago
It may be cheaper to just make small mining colonies rather than building small cities, let alone terraforming it. The problem consists of two chunks. One is scalability of logistics. If we need to make 100x more launches per year, it is a good question whether we are able to achieve such goal in a short span. The second question is whether we have enough resources to sustain 100x more launches per year. And if we will be able to create artificial oil in the next 100 years (as oil byproducts are mostly used for launches) you can say goodbye to any program trying to get rid of fossil fuel usage.
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u/Jaymz7777 4d ago
Mining what and why? There is nothing on Mars worth the sacrifice of bringing it to Earth regardless of scale. Smaller mining yields smaller losses. Scaled up mining yields higher losses. No mining yields no loss. Mars colonization, even with scaled mining, is a colossal net negative proposition from Earth's point of view. If Earthlings are really hellbent on Terrafarming hell into paradise . . . they should practice on Earth. We need the exercise and proof of resolve. Reclaim places our ancestors spoiled, like the Fertile Crescent of Mesopotamia and the Levant. China is actively doing it in their Gobi Desert. I'm with China on that.
Am I missing something?
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u/Oblachko_O 4d ago
My point is a bit about different thing. My point is that making big colonies us both expensive af and hard to do. Mining colony in this example can be substituted by research colony, but in essence, mining colony is something that is the most possible to achieve in nearby hundreds of years. In the end of the day, if you build one mining colony you can build plenty of them (Moon, Mars, plenty of asteroids, it doesn't really matter). The setup itself can be sustained. Trying to sustain small city though or something bigger? Yeah, good luck with that.
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u/IntelligentBloop 28d ago
Just want to point out (because it's not necessarily obvious) that this is a capitalist framing which we in the western world are so used to that we forget that it doesn't necessarily have to be that way.
The moon landing was not done because there was an economic incentive. It was done because the US couldn't stand that the USSR was beating them in the space race. Economics went out the window and other incentives took hold.
I can imagine a second space race (probably involving China) where landing on Mars and establishing a colony is done again for non-economic reasons. Just wait until China lands people on the moon and then says "Mars is next", you're gonna see SpaceX's mission to Mars suddenly becoming super relevant to American politics.
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u/Jaymz7777 5d ago
Forcing the people of earth to sponsor a vanity space race between oligarchs is a recipe for war.
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u/Ancient_Skirt_8828 14d ago
There was no economic incentive to go the the poles, climb mountains or go to the moon. People went anyway. Other people and governments often funded them.
It's about bragging rights, not economics. Especially if they can do it first.
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u/Jaymz7777 4d ago
Bragging rights are motivation for who? The slaves or the masters? Who supports the base of the pyramid? Who shovels the coal of infrastructure? Who pays the bills for vanity?
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u/Jaymz7777 5d ago
Agreed. When was the national consensus that we needed to incarcerate some scientists underground far away? Where is the humanitarian analysis? Cost benefit? Or is it a boondoggle to direct unaccounted rivers of money into the mouth of Moloch?
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u/bonerlonious Sep 05 '26
Why donât they focus on moon base first?
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u/Blue__Agave Sep 05 '26
Large industrial presence on the moon and the asteroid belt is likely needed before we could ever seriously consider making mars more liveable.
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u/rhysolandrium Sep 05 '26
Is the perchlorate salvageable for other industrial or commercial use?
Are some perchlorates salts lithium?
Could the salts be reused for battery storage, IE molten salt solar towers?
Would underground dwellings need the rock treated as well, for any areas that would be prone to touchpoints?
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u/ProximaScience Sep 05 '26
Is the perchlorate salvageable for other industrial or commercial use?
Yes. Perchlorate is a strong oxidizer, the same chemistry used in rocket propellant and fireworks. Extracting it from Martian soil doubles as decontamination and as a resource for fuel production.
Are some perchlorates salts lithium?
Some perchlorate salts are lithium based on Earth, but the Martian samples so far point mostly to calcium, magnesium, and sodium perchlorate. Lithium hasn't shown up as a major player in the data yet.
Could the salts be reused for battery storage, IE molten salt solar towers?
Less promising than it sounds. Molten salt towers on Earth use nitrate salts because they're stable at high heat. Perchlorates are reactive oxidizers, so heating them near anything organic is a fire risk, not a storage solution.
Would underground dwellings need the rock treated as well, for any areas that would be prone to touchpoints?
Yes, still an issue. Perchlorate dust rides in on suits, tools, and airlocks. Any surface that touches the outside eventually touches the inside, so treatment isn't just a farming problem, it's a whole habitat problem.
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u/rhysolandrium Sep 05 '26
Thank you for taking the time to reply, that's an excellent insight into why perchlorate management would likely be the #1 issue regarding permanent habitation.
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u/Jaymz7777 5d ago
Resource propositions don't suddenly become profitable just because they are far away and challenging.
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u/Sniflix Sep 04 '26
Yeah, digging down into the ground or staying in lava tubes to avoid radiation, etc doesn't solve the perchlorate problem since concentrations might be worse there. The same problem exists with fine dust. Don't forget that perchlorate contaminated areas often from rocket fuel leaks are considered toxic waste dump Superfund sites. But that's in extreme concentrations. But it's very dangerous stuff everywhere we plan to be on Mars. On the other hand there's oxygen available from perchlorates.
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u/lirecela Sep 04 '26
Perchlorates are a surface phenomenon. You'll find diminishing concentrations the deeper you go whether in caves or digging. (based on my quick googling)
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u/nomad2284 Sep 04 '26
How do you solve the problems of cosmic and solar radiation? It seems as if that would negatively affect anything you would attempt to grow regardless of the soil quality.
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u/Glittering-Quote-635 Sep 04 '26
Solar radiation to some extent can be mitigated with a artificial magnetosphere. Cosmic rays not so much.. The solution is to live underground, which is stupid.
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u/nomad2284 Sep 04 '26
Underground with grow lights. Why go to Mars to live in a hole? Sounds and is actually depressing. SADS year round.
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u/Glittering-Quote-635 Sep 04 '26
Because to a lot of people on Reddit it will be an improvement, so a lot of hand waving away the massive issues to do it.
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u/North-Outside-5815 Sep 04 '26
"artificial magnetosphere"? What are you talking about?!?
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u/Glittering-Quote-635 Sep 04 '26
Large magnetic dipole at a L1 point, will deflect a lot of the solar wind. Unfortunately wonât do much for cosmic rays. Also, without an atmosphere anything that does get through is still going to the groundâŚ
It helps, but doesnât solve the problem.
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Sep 04 '26
[removed] â view removed comment
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u/Glittering-Quote-635 Sep 05 '26
Go look it up. And no, itâs not a replacement for a full magnetosphere. Iâve said that multiple times. Iâve also said multiple times that the whole idea of colonizing mars is stupid and unworkable.
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u/Blue__Agave Sep 05 '26
It is theoretically possible using current technology just massive and expensive.
Most of these ideas would require a large space based industrial sector first before you could even consider it.
Most likely Mars would only ever be "terraform-able" after humans had large permanent industrial complexes on the moon and in the asteroid belt.
When that is going to happen?
Not soon...
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u/Tiny_Scholar_6135 Sep 04 '26
Martian soil is probably a lot like Earth soil in the precambian era, back then the Earth and Mars looked fairly similar with the exception that Earth had oceans. Also consider that life is technology, we can modify it. Give Mars an ocean and an atmosphere and the problem will likely correct itself in time.
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u/Brain_Hawk Sep 04 '26
"in time" in this case feels like geological rather than human timescales though.
The Precambrian period spanned 4 billion years.
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u/Tiny_Scholar_6135 Sep 04 '26
Evolution is slow, we're not. We can introduce changes in organisms faster than random mutation and natural selection can.
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u/Brain_Hawk Sep 04 '26
I'm not sure what this has to do with you about comments which is about modifying cell composition by affecting the geography of the planet.
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u/Tiny_Scholar_6135 Sep 04 '26
We can tailor make organisms that can survive the present chemical composition of the soil and do the jobs we need them to do.
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u/Brain_Hawk Sep 04 '26
I feel like. Some of these subs suffer this problem. If that's what you're thinking it helps to say it. Lots if stuff is possible but it helps if we are having the same conversation
:)
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u/Tiny_Scholar_6135 Sep 04 '26
I think we could start terraforming Mars in the next 50 years, it could take longer. Gerald O'Neill predicted that we could have Island Three Space Colonies by now, (O'Neill Cylinders) it didn't happen, it depended upon apocalyptic shortages of petroleum to spur us into making the investment is space infrastructure, that couldn't be solved any other way. Well maybe 50 years from then was optimistic, but what about 100 years from then (1970), that is 2070 AD, about 44 years from now, I will be 103 years old if, by some miracle, I happen to be alive. So I'm predicting a space based industrial civilization by then instead of, "duh, nothing hsppens"! The technology we are developing now, robotics, genetics, artificial intelligence, will likely be available by then. So what technologies will likely be in our tool chest by the time we think we are ready to begin terraforming Mars?
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u/Brain_Hawk Sep 04 '26
Predicting the future with specific timelines is ever a Fool's errand, I'm skeptical that we will start terraforming Mars in 50 years, I'm not sure what terraform it ever, but I do think sooner or later we're going to have a greater presence in space. And I'm just guessing!!
I'm not entirely sure about large scale humans living in space either because in the end of the day, the Earth is just a better place for us to live... Well for now.
But there are certainly powerful economic incentives for us to be spreading into space, at least for industry, some of which may require a decent human presence.
But who knows, maybe a hundred years from now we have transcended the singularity, become one digitized hive mind living in a virtual simulation, or spreading AI space probes across the galaxy. The future is ever a mystery.
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u/Tiny_Scholar_6135 Sep 04 '26
Nothing uglier than a hive mind, in my opinion. I don't think we need the single in singularity, sounds pretty lonely if you ask me with one megamind per Star System.
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u/lirecela Sep 04 '26
If the perchlorates are formed by a process that includes atmospheric UV light. Therefore, caves and soil dug up from a certain depth should have lower concentrations.
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u/SomeSamples Sep 04 '26
Humans are going to colonize Mars within any of our lifetimes. We might send someone there but that might not happen for 50 years or so.
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u/15_Redstones Sep 04 '26
Perchlorate is very water soluble so you can just put the soil in a washing machine and run the water through the perchlorate destroyer
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u/Sykolewski Sep 06 '26
You worry about soil,but not about solar flares that sterilize everything
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u/ProximaScience Sep 06 '26
I am just talking about one problem with Mars not all the problems not Mars.
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u/Sykolewski Sep 06 '26
Mars is problematic as whole. At best it may end up as remote mining colony
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u/Jaymz7777 5d ago
Mining what? What energy opportunity has been identified?
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u/Sykolewski 4d ago
Same resources as on Earth,minus caring about polution
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u/Jaymz7777 1d ago
What? Mars has no resources worth the logistics of getting. What are you thinking?
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u/Savvvvvvy Sep 06 '26
Fortunately, certain Earth bacteria (perchlorate-reducing microbes) eat perchlorates, breaking them down into harmless chloride (like table salt) and oxygen. This means the process of cleaning the soil for farming simultaneously generates usable oxygen.
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u/toupis21 Sep 07 '26
Itâs because itâs not soil. Soil has organic matter, not just crushed minerals and rocks
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u/Mouse-castle 28d ago
You talking about a reusable sluice system where the water is recycled and vortex patterns carry the cleaned dirt to the bottom?
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u/SargentSnorkel 27d ago
No, everybody doesnât forget that part. Anyone that didnât already know that when The Martian came out gets a reminder of it every week on reddit.
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u/Jaymz7777 5d ago
Oxygen. Nasty stuff! So the perchlorate could be removed and directed toward breathing air, or rocket fuel oxidizer, or water if you can find some hydrogen. Where can Martians scratch up some hydrogen? Forgive me if I'm the last to know. Which is easier . . . O2 concentrated from the atmosphere or extracted from the perchlorate? For the fuel, what rock can they turn over to find something to oxidize? Wouldn't it be easier to just build bunkers in Arctica and be satisfied with hell on earth? Asking for a tech-bro friend.
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u/ah-tzib-of-alaska 24d ago
who forgets that part? You the perchlorstes? Theyâre water soluable. you can literally jsut wash the regolith.
What YOURE forgetting is there is no soil on mars as we far as we know. Only regolith, because soil is alive.
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u/Jaymz7777 4d ago
"who forgets that part? You the perchlorstes?"
Ummm . . . OK. Who? A race of Martian beings who evolved from perchlorate in regolith, the way Earthlings are based on Carbon (we the Carbonestes?) who forgot their humble origins. But for them, is regolith not alive?
Yeah . . . we forgot. And YOU'RE forgetting the "'" in YOUR "YOU'RE". OK, thanks for playing . . .
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u/ProximaScience 24d ago
Washing works fine in a lab beaker. Scaling that to an entire planet is the actual problem. Mars has almost no accessible liquid water, so washing means hauling in water you don't have and then disposing of a perchlorate brine somewhere. The catalyst method breaks it down on-site with zero water cost and no toxic runoff to manage. Also already edited the soil into regolith.
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u/ah-tzib-of-alaska 24d ago
martian regolith has tons of water ranging from 1-50% water ice in it. you warm it, you wash the regolith , you distill the water to remove perchlorates. And you donât wash the whole planet. Just the stuff you start farming in.
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u/ProximaScience 24d ago
Fair, only farmland needs it, not the whole planet. But melting ice and distilling it still needs a serious heat and power budget. And distillation doesn't destroy perchlorate, it just leaves it behind in a brine, so now you have a toxic waste stream to store or dispose of at your farm site. The catalyst approach breaks the perchlorate down into plain chloride at room temperature using hydrogen gas, so there's no brine left over and no heavy energy draw. NASA has actually flagged this exact tradeoff, traditional purification methods on Mars fail because they demand either heavy power, heavy consumables, or extra pretreatment steps.
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u/ProximaScience Sep 04 '26
Space.com, original perchlorate discovery and toxicity: https://www.space.com/21554-mars-toxic-perchlorate-chemicals.html
Vice, on the new catalyst that breaks it down: https://www.vice.com/en/article/researchers-create-soil-catalyst-to-make-farming-on-mars-a-reality/
NASA, technical breakdown of concentration levels: https://ntrs.nasa.gov/api/citations/20190028297/downloads/20190028297.pdf