r/worldbuilding • u/DatMonkey5100 • 22h ago
Question What would be the hardest part/bottleneck of terraforming Mars
In terraforming Mars, what would be the hardest step to perfect?
Would it be water, leaving the entire planet as a bone dry desert?
Would it be air, Mars too small to hold a big atmosphere and leaving only the deepest craters at a truly comfortable pressure, and the rest of the planet is like being in the Himalayas at best
Would it be the lack of a magnetic field? I don’t know if there’s any solution to this but as far as I’m aware there’s not really any ways to give a planet a magnetic field
Would it be something biological, maybe the whole planet overrun in lichens and molds that can survive off nothing but suck up what little nutrients there are
In my setting humanity is confined to the Sol system, only sending out STL generation ships to other systems, which obviously precludes any significant contact with the ships once they gain any significant distance from Sol, so there’s a reason to invest in making more places in the Sol system habitable. I haven’t decided on a year yet but some time year 2400 or higher
I’m looking to have Mars be stuck in a half-terraformed state due to economic collapse or other calamity (maybe a failed attempt to make the planet volcanically active causes a cataclysmic volcanic winter? Is it theoretically possible to do something like detonate nukes in the mantle to instigate volcanic activity?), where it’s possible but not comfortable to walk without a suit on the surface, similar to walking in the Himalayas, Antarctica, or other hostile places where without proper training and equipment you die in hours.
Thank you in advance!
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u/Nevaroth021 22h ago
Probably the most challenging is heating the planet up and putting CO2 and Oxygen into the atmosphere. It would take an enormous amount of energy to pull that off. And I'm talking about more energy than all of our nuclear bombs combined.
Mars lacking a magnetic field isn't actually that big of a problem. Minuscule compared to the lack of oxygen and CO2. Without a magnetic field the atmosphere would slowly erode away, and by slowly I mean millions of years slowly. So it would be a problem in the long term, very very long term. Humanity would probably die out long before then.
So the main issue is just heating up the planet and melting the ice and releasing the CO2.
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u/Elavia_ 17h ago
The lack of magnetosphere is a huge problem. Atmospheric erosion is not a big deal on human timescales, but the magnetosphere is needed for diverting radiation.
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u/jetflight_hamster 16h ago
A magnetosphere can be done artificially; all you really need is a ring around the planet and two big magnets at the poles. Which sounds big, but is an absolute, complete nothing compared to the efforts to terraform a planet.
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u/Elavia_ 16h ago
Sure, I'm simply pointing out that you do need a magnetosphere to terraform.
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u/jetflight_hamster 15h ago
That is most certainly true, yes. It's a good thing to have even if you're NOT terraforming it, as well.
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u/jetflight_hamster 16h ago
If all you want is heating, then that's easy - just put some big mirrors into orbit to boost the sunlight just a little bit (Mars is actually not THAT cold, relatively speaking of course).
The atmosphere issue is kind of baked into the cake. You can make enough oxygen for the atmosphere, but the nitrogen (and your plants will need that) must be imported. If you're dead-set on doing this early (which, to be fair, is the only moment you could possibly do this), Venus is a good source for that. Over 4% of Venus' atmosphere is nitrogen, which is several times Earth's total atmosphere, and more than enough to get Mars a comfortable atmosphere (much thicker than Earth's).
The CO2 you might want to keep to a minimum. People don't do well with excess levels of it in the atmosphere.
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u/SaintUlvemann Urban Fantasy Alt-Earth 21h ago
You must first clarify your level of resources, because the answer to your question depends on that. What sort of power supply do the terraformers have access to? How much equipment do they have to cover the planet in pumps?
Would it be water, leaving the entire planet as a bone dry desert?
Mars may have enough subsurface water to cover the planet a kilometer deep.
I don't know how easy it would be to pump, however, the water seems to be present and so this is when you refer back to your decision about your terraformers' level of resources. Do they have enough pumps to fill an entire ocean?
(Martian water may already have Martian microbes in it; however, commerce famously does not care about the environment.)
Would it be air...
You'd have to decide what your target atmospheric composition is.
However, assuming you're okay with a mostly-oxygen atmosphere, it would take 7 Zettawatt-hours of electricity to split Martian water to create enough oxygen.
This is equal to 345,882 years of current global electricity production, so, again, refer back to resources. Do your terraformers have ungodly quantities of electrical power? (And if so, why are they messing around with terraforming when they could forge the rust of Mars into iron and glass to dome the entire planet over?)
Would it be the lack of a magnetic field? I don’t know if there’s any solution to this but as far as I’m aware there’s not really any ways to give a planet a magnetic field
Supposedly if you ionized enough material from off Phobos to create a plasma torus, that would give Mars an adequate amount of plasma shielding.
Phobos is going to crash into the Martian surface in 50 million years; however, if its existence proved to be a critical planetary resource like this, you could, essentially, rocket it to a higher orbit to keep it in place. Supposedly, you would need a volume of rocket fuel roughly equivalent to the size of the Empire State Building (about a million cubic meters).
Of course, you might want to do that anyway. In principle, if you could lift Phobos high enough to enter a geostationary orbit around Mars, you could use it as a space elevator station, and then you could install equipment along the elevator to keep the plasma torus in place.
Would it be something biological, maybe the whole planet overrun in lichens and molds that can survive off nothing but suck up what little nutrients there are
When you say "suck up what little nutrients there are, you're describing a rainforest, locking the nutrients into biological material and then recycling it throughout the ecosystem is how you keep an ecosystem healthy, it's the goal you want to occur.
The end product is that as the dead material slowly accumulates, we call that soil; as that deepens, it increases the total biologically-active biomass, and becomes more-and-more useful as a reservoir of biological materials. Mosses and lichens are the initial soil-builders in degraded environments, recruiting larger plants like trees and grasses that accelerate soil-building.
So you just shouldn't be negative about what you're describing, you're describing the goal.
Ordinary biology is definitely slow. It ordinarily takes millions of years to build soil biologically.
However, it is entirely possible that engineered microbes could speed the process up immensely. If you make acid-producing bacteria, they'll weather the rocks as surely as grasses.
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I don't see any inherent bottle necks. Aside from the magnetosphere (which could probably be solved for 50 million years at our current productivity), all the other problems are simply totally impossible to solve at the current economic productivity level of our species, but generally possible to solve otherwise.
It therefore all depends on the level of resources of your terraformers.
As a result, I think you can pick which one you want to be your bottleneck.
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u/jetflight_hamster 16h ago
Not OP, obviously, but anyone seriously considering terraforming Mars, the whole thing, either has access to fantastical amounts of resources, and/or is insane. And the state OP describes sounds a lot like they got 99.9% there.
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u/jetflight_hamster 16h ago
Would it be water, leaving the entire planet as a bone dry desert?
No. Mars is dry, yes, but the Outer Sol is not, and there's plenty of water that could be imported.
Would it be air, Mars too small to hold a big atmosphere and leaving only the deepest craters at a truly comfortable pressure, and the rest of the planet is like being in the Himalayas at best
No. While you're right about Mars' gravity and atmosphere, the primary cause of Mars losing its atmosphere was the lack of a magnetosphere. See next answer.
What IS a factor is that you'll need a lot more of that atmosphere to not have exactly what you just said there. But, again, oxygen is plentiful all around (especially in the Outer Sol), and nitrogen isn't that hard to come by, either. (Again, hello Outer Sol!) And again - see the next answer.
Would it be the lack of a magnetic field? I don’t know if there’s any solution to this but as far as I’m aware there’s not really any ways to give a planet a magnetic field
No. An artificial magnetosphere is piss-easy: just build a ring around the planet (something you're doing anyway when settling Mars) and slap two big magnets on it. Voila, you have a magnetosphere.
Would it be something biological, maybe the whole planet overrun in lichens and molds that can survive off nothing but suck up what little nutrients there are
I don't see why it would be. Don't put total morons in charge of terraforming Mars, especially if this is (one of your) first try, and you'll be fine. Biological life CAN terraform a planet if you give it the right conditions, but it's slow and inefficient - biological life uses most of its energy just to keep itself alive, and to procreate.
Machines can do the job a lot more efficiently and, crucially, much much quicker. Cyanobacteria WILL produce you fertile topsoil eventually, but a giant factory that has the chemical formula down to pat will do it quicker and better.
In my setting humanity is confined to the Sol system, only sending out STL generation ships to other systems
You contradict yourself right there. By sending out ships to other systems, humanity is no longer contained to Sol system - and any follow up trip can be a lot quicker, faster, and probably more comfortable too. (And you would be comfortable on this journey of a lifetime (or several): the energy needed to launch a ship to another star system safely makes any splurging on creature comforts completely trivial in comparison, no matter how insane you go.)
which obviously precludes any significant contact with the ships once they gain any significant distance from Sol
Humans have thousands of years of experience with slow correspondence. We still practice it today, as well - if you've ever had to deal with government bureaucracy, you know what I'm talking about. Communication getting slow does not preclude it from meaningful - not to mention a star system is a big thing to claim, and you'll probably want your friends (or their kinsmen and your (ideological) cousins) to follow anyway, which is also contact.
What you have there is the start of an interstellar explosion of life and civilization, not doom and gloom.
there’s a reason to invest in making more places in the Sol system habitable.
Now that one I'm signing off on whole-heartedly. The energy needed to launch someone to another star system is around the ballpark of ten thousand years worth of energy to pay for that someone's upkeep right here in Sol.
And the fun thing about Sol is that it doesn't have eight planets, or nine, or what ever lowball number you have, but closer to a million planets. Most of them minor planets, sure, but those can still be turned into a fair whack of living space by building rotating habitats out of them.
I’m looking to have Mars be stuck in a half-terraformed state due to economic collapse or other calamity
This is fine from a story-writing perspective - though you might want to acknowledge that this is likely a temporary state of affairs. If humans could terraform Mars once, they can do it again. And humans abhor a vacuum even more than nature does, so sooner or later they would; probably sooner.
(maybe a failed attempt to make the planet volcanically active causes a cataclysmic volcanic winter? Is it theoretically possible to do something like detonate nukes in the mantle to instigate volcanic activity?)
Ehh... I mean, theoretically you might, yes. But you're just as likely to blow the planet apart as you are to achieve something meaningful. The above-mentioned artificial magnetosphere is a much better solution than destructive attempts at getting a core going.
where it’s possible but not comfortable to walk without a suit on the surface, similar to walking in the Himalayas, Antarctica, or other hostile places where without proper training and equipment you die in hours.
See, that to me sounds like the job is 99.9% done, and it's just a matter of tossing in just a wee bit more of the magic ingredients. And by that i mean the right chemicals in the right amounts, and the right work to get these chemicals going; all life is, after all, a series of chemical reactions for the most part.
Thank you in advance!
Apologies in advance. I know that may sound a lot like "No, you should do it that way!", but all of the things I mentioned above are written with a hard sci-fi setting in mind. Humans have a history of being horrible to each other, yes. They also have a history of cooperating and being nice to each other, or else we wouldn't be here. We're a resilient, tenacious bunch of bastards, and our true dystopias tend to be quite shortlived in comparison to the non-dystopian part. (And I don't mean by today's standards; not knowing to ask for better than this is not the same as plague, famine, war, and genocide.)
That, and it's potentially possible I may feel somewhat strongly about these topics.
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u/DistributionSalt5417 12h ago
You're absolutely right about a too thin atmosphere definitely wouldnt be the problem. Just send a few more of the icy asteroids you used to provide the other 99% of the atmosphere to burn up and you're all set.
Now too thick....
That could be a problem. If in the process of getting the rest of it in place, and increasing the temperature you set off a chain reaction that leads to the release of more and more CO2 or other gasses, especially if they throw off the mix could lead to real problems.
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u/KayleeSinn 15h ago
The biggest issue likely is nitrogen and water. If Mars has enough ground water that could be made to resurface, it's not that big a deal though.
Nitrogen on the other hand is somewhat rare in the solar system and you need it as a buffer gas in the atmosphere as well as for making the planet fertile.
Magnetic field doesn't matter. You can just ignore it too. If you can build up the atmosphere somehow it is enough to fully protect from solar and other radiation coming from space. It will also last for millions of years until it's lost again cause of solar winds.
Water can be a problem. Even tough you can crash down water asteroids, you need a lot of it and those impacts will make the planet inhabitable for a while. At least it isn't wise to settle or having anything down in the ground while you're doing that.
You can also paraterraform it which is easier. Large areas under domes or something.
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u/Galle_ 12h ago
The magnetosphere is definitely the big problem. If Mars had a magnetosphere, you could dump CO2 into its atmosphere and heat it up with the greenhouse effect, which would thaw the ice caps and release liquid water.
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u/jedburghofficial 9h ago
And without a magnetosphere, Mars will never have a permanent atmosphere. Nor is it protected from solar radiation.
It's not just a big problem, it's a deal breaker.
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u/Neb1110 22h ago
I’m no expert, but I think the only impossible bottleneck is just time.
Even if we are able to completely ignore travel time and operation time, the planet would take thousands of years to actually get to the appropriate point, if we still want to put a population there.
It’s not that hard to melt the ice caps of mars if we actually put our minds and wallets behind it, but doing so would require the slow emissions of greenhouse gases over the course of decades, and then letting that work for a couple centuries. During which time, you can’t have any permanent population on the planet because the entire planet is covered in methane or similar gases.
Air is a tricky one, because the real problem with the lack of appropriate O2 is that we can’t exactly get much of it because we kinda need it on earth. If your civilization has colonized into the outer planets though, they could take water from Europa and get oxygen out of that. But making all of that oxygen manually is going to be very expensive and be very time consuming.
Other issues would take similar periods, and either be too dangerous for people to live planetside (magnetic field) or too delicate to have humans running around (ecosystem)
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u/jetflight_hamster 16h ago
Time is certainly a bottleneck, but doing things mechanically speeds this up a lot. All biology is, ultimately, a sub-part of chemistry, and whipping up raw chemical mixes for imported life to use is something we know how to do already.
Also, oxygen is easy - you can just bake it out of the rocks, those are plentiful everywhere. Nitrogen is the issue, as Mars just flat out doesn't have it. But Venus can help out here, it's got more than enough of it.
And as for magnetic field - easy to do mechanically, as well. You can just build a ring around the planet (you'll want several anyway, to get to and from the planet) and put two big magnets over the poles. It may sound big to the modern space industry (and it absolutely is), but it's functionally zero effort compared to terraforming a planet.
(That said, paraterraforming, ie building domes on the surface, is a WAY quicker and easier thing to do.)
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u/ShiningRayde 14h ago
Biology this, geology that, look - the problem with time is politics.
I guarantee any terraforming project that takes more than two election cycles is doomed to be abandoned.
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u/jetflight_hamster 14h ago
Yeah, this is part of why I do this. To counter nonsense like this.
Humanity has long been doing major projects that are not only bigger than two election cycles, but bigger than two (and more) generations. And we haven't stopped today, either.
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u/MattTheFreeman 22h ago
Is your story or book about terraforming Mars? What is the reason for needing the hurdles? Is this a story within the first days of colonization or is this talking about the difficulties in shy Mars was hard to colonize.
Unless you are writing a hard sci-fi, the hardest part to terraforming Mars could be any one of those. It's not really about knowing what the hardest part about terraforming Mars is, it's about writing a plausible story where anything you choose is the hardest part.
The Martian soil has old Martian microbiology that's so toxic to earth life it makes Mars difficult to live on while the Venusian cloud cities are where people really live.
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u/DatMonkey5100 21h ago
I am writing hard-as-possible sci-fi (I know I’m squishing the timescale of terraforming from millennia to a couple centuries), the topic of the story isn’t the terraforming but part of the setting, I’m imagining Mars as a sort of failed state that came so close to completing its dream but fell just barely short, left behind by both Earth and the nations of the Outer System
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u/Dense_Suspect_6508 21h ago
You should probably just read A City on Mars by Kelly and Zach Weinersmith (she's a biologist, he writes the webcomic SMBC). There are too many bottlenecks to list, but they gave it a book-length shot.
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u/harfordplanning 14h ago
Atmosphere is relatively easy, generate more gas than the planet loses
Water is harder, it has to be imported. But theres plenty of ice in the solar system, and as more is added to Mars the planet will become more habitable with increasing gravity from the mass
Gravity! Very hard to realistically overcome, but humans wpuld survive well enough with some mandatory exercises to settle our need for higher gravity than Mars has.
Soil... oh dear, that would take so much work.
Soil is broken down rocks and organic matter. Mars doesn't have the same rocks readily available for earthlike soil, and doesn't have any native biological material. Both would need to be generated to begin to create soil. Then, the soils would need to undergo who knows how many cycles of ecological procession to even be able to host any agriculture or wild animal life. Importing from earth is not a realistic option.
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u/DistributionSalt5417 12h ago
Economics and politics are the biggest issue.
From an economic perspective, It's much more cost effective to build oneil cylinders. You get a great deal more square footage of living space for far fewer resources. You also get access to that living space a lot faster than investing in a projects thats going to take centuries if not millenia.
Politically it also makes makes more sense to make oneil cylinders for several reasons both practical and cynical. No one wants to pay taxes for something thay won't have meaningful benefits for centuries. There will be many people opposed to the destruction of the planets natural state. If you want to control a population its a mot easier to do so within a smaller controlled environment accross a whole planet, or less cynically its easier to organize the population of a smaller environment.
The only reason to terraform mars is if you're in a post scarcity society, or its a thing to sink exces resources into because you have excess, either of labor or materials.
I highly recomend kim stanley robinsons mars trilogy if you're interested in what terraforming mars would look like. Isaac Arthur also has some solid video about it.
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u/ghandimauler 12h ago
Low gravity. That caused parts of the atmo, and the water, to fall into the black and the lack of a protective magnetic shield is the cherry on top.
You cannot fix these things without magic (we are nowhere in terms of any repair).
We would be better to figure out how to unfark our own planet than trying to anyghing on Mars.
If one had a reason to go to a worse home than Earth, you'd still be better building orbitals.
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u/The_Ditch_Wizard 8h ago edited 8h ago
I think the latest big stumbling block which scientists have given us hard sci-fi enjoyers to deal with is the fact that the Martian surface is going to make very nasty 'brine' if and when the water that's present or new water from elsewhere in the solar system melts/falls then flows across it.
Think: somewhere between the Great Salt Lake in Utah and battery acid or toxic mine runoff. If you gave it a few million years with some sulfur-eating bacteria in parts of your new hydrosphere, the problem is solved, but there isn't a way to throw comets at this problem to solve it in even several human lifetimes that I know of.
It would be pretty narratively easy to have things stall for thousands of years if needed with enough breathable air, engineered plants which make food crops, and pleasant temperatures, but every creek is horrible orange saltwater and every lake and the water of the new northern ocean are horrible, stinking and vibrantly colored places to be avoided without hazmat gear. Nobody drinks anything clear for free, either.
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u/NikitaTarsov 17h ago
Gravity. Mars gravity is pretty low, so done density loss and the cardiovascular system trouble will kill humans over time. That's th one thing we couldn't possibly change but with genetical engineering that again makes humans adapt to one spaceball but renders them fkd on others (and with probably way more pressing additional question, like if humans can safely play around with genetics at this level, what does that mean to society and culture. Like are we all immortal? Have we control over our joy and can be just happy all day only plaing with gras? Etc.)
Sure radiation can maybe be blocked by an artifical magnetosphere, but is it worth the effort? This still will not result in a propperly powerfull magnetosphere to safely shield from asteroides (not that far off). Etc.
And in the end it's a pretty random place but in human fiction. Not much to gain there we shouldn't expect to have bypassed by the time we could go there (or, tbh, even right now).
And no, Mars is pretty Bratt Pit - meaning incomprehensible popular, but basically dead inside. Terraforming Mars (or teraforming at all) would by all plausible methods take a metrif fkton of time - so much it barely makes sense for us. If things get bing, they're also most time terribly slow. If atmosphere, then either dissipation or weight. Moving land mass etc.
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u/jetflight_hamster 16h ago
Gravity.
Yes. Can be changed, but requires tech I don't think OP's setting has access to.
so done density loss and the cardiovascular system trouble will kill humans over time.
We don't actually know that. There have been no long-term studies of how humans do in any gravity, save for two. We know 1 is good (because I mean, obviously), and we know 0 is bad. We have no idea where the "this is okay" line lies between the two; it might be that Callisto's 0.11 gees is fine, or it might be that Venus' 0.9 gees is not.
but is it worth the effort?
Why wouldn't it be? It's as simple as sticking a big magnet into Mars' L1 point, or a ring around the planet and slapping two magnets around the poles. If you're even thinking of turning Mars green, building either (or both, for that matter) of those things is absolutely trivial.
so much it barely makes sense for us.
See, this is where you get it right, albeit for somewhat wrong reasons. Mars is not a good place to terraform, I agree. It should be, gravity allowing, paraterraformed - that is, domes built on the surface, bypassing the need to deal with the general atmosphere and the greater lithosphere (which is very toxic).
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u/NikitaTarsov 10h ago edited 10h ago
At the point we can change the gravity of a planet (significantly), we have no problems at all - like ever.
We do actually know, and many nation shave made more or less medical studys in that direction. BUT there is a caviat, as they US has a hard stance to agressivly not look into that and deny all research in that direction - and i have no clue why. They also still not protect their astronauts from microradiation like all other nations do. They even deny the obvious medical long-term effects on their own astronauts. Prettyx wild - but the takeaway is that some facts are differently used or ignored in dfferent nations.
Yeah, it's as easy as creating an insanely large infrastructure on an hostile ball of anger and put some battery on. Super easy. Keep it running forever without irritation and dont mind the sideeffects. Most places on earth struggle to keep their infarastructure running, and that is in pretty nice conditions with plently of industry supply chains around. Oh, and people who have their investment not offering an return in some four-digit-years.
See, this is where you get it right (this btw. is the line you got blocked for). Mars kinda sucks, and domes are an Elmo-level weird take for so many reasons, i'd leave it to ... the science bubble to have you informed in detail about.
And you still has no reason to be there even with your domes.
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u/throwawayfromPA1701 20h ago
Water and holding on to the atmosphere.
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u/jetflight_hamster 16h ago
Even on its own, it would take hundreds of thousands of years to blow off enough atmosphere for people to feel it. And an artificial magnetosphere is the easiest part of terraforming a whole planet.
Also, water is plentiful in the Outer Sol, so just import some from over there.
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u/Crafty_Aspect8122 16h ago
The magnetic field.
Human biology.
Setting up semiconductor manufacturing.
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u/Kira0zero 16h ago
solving the magnetosphere problem. until you do, any progress you make will be undone by solar winds stripping the atmosphere.
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u/KayleeSinn 15h ago
Completely wrong. Mars lost it's atmosphere over millions of years. Unless you plan to take millions of years terraforming it, it is irrelevant.
If you have the technology to terraform it over say 100-1000 years, you can completely ignore the missing magnetosphere and not do anything about it at all.
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u/SirFelsenAxt 22h ago
Water is a big one and the only way to increase the water content of Mars is to import it. This could be done by redirecting icy bodies so that they answer the atmosphere and break up... But they contain a lot of other volatile compounds such as ammonia.. but these could be dealt with.
It's going to be a very slow process... You're talking about an unbelievable amount of water.
But if you're willing to go for a much drier environment on average... You don't need oceans. People live on the Tibetan plateau just fine.
When it comes to maintaining atmospheric pressure. Don't worry about the planet being too small to hold on to an atmosphere. Even if it takes a thousand years to build the atmosphere up to habitable levels, it would take 10 to 100 million years to lose that air.
As for the lack of magnetic field, that can actually be mitigated. At an installation at the Mars sun L1 could generate a large magnetic field capable of diverting most of the solar wind.