What will it take to get 1,000,000 people living in space habitats?

Sure, land is expensive here in downtown Metropolis, but lots of cheap land to build on even a few dozen miles out, never mind in the backwoods, or in flyover agricultural lands that rich, self-important and sophisticated people like me scoff at. Then you have deserts, taigas, the arctic, shallow seas... even cheaper land there. I hear they have free air and nice 1g gravity and stuff there too.

Moreover, all our construction firms, materials and construction staff are here, on the planet. I am told we live in something called a deep gravitational well, so moving the aforementioned materials and crews off-world is going to be more expensive than driving them 50 miles on the interstate.

I've heard of solar arrays for power and space mining for mineral as entry points into a space economy. Leaving aside the somewhat dubious economics/physics, those intuitively sound more like the equivalent of oil rigs in the North Sea: nasty industrial places where you go for 6 months for a lot of dinero, and then come back to shore and spend it all on booze and whatnot. Not a place you'd settle anytime.

So, how does it ever make any economic sense to build & eat the costs of operating space habitats and for 1,000,000+ people to choose to live in them?

• thanks to @JBH for blackpilling me on this :( – Serban Tanasa Apr 1 at 18:59
• plenty of people on earth want to volunteer for colonization right now, costs are almost no problem at all for those motivated enough, and besides, why cant you just get about 1500 people to come and then just... wait for reproduction. besides, if not enough people are motivated you can just say its an "unexplored new horizon, a land of opportunity and untapped potential, waiting for you to take a chance!" and plenty of people will start coming in. – zackit Apr 1 at 19:13
• @chasly-supportsMonica I think all those locations you mention are in space. I go by the assumption that we're more likely to have Earth and moon-orbiting habitats than Mars colonies (they tell me Mars is far and has little air) or Moon colonies (why be on the moon when you can be in orbit around it at a similar cost?) – Serban Tanasa Apr 1 at 19:55
• They tell me that LEO has no building materials to hand (unlike Mars or the Moon). Also Elon Musk seems dead set on reaching Mars and given his track record is likely to achieve it. Jeff Besos wants to build in LEO but has not even launched anything into orbit yet. – Slarty Apr 1 at 22:19
• @Slarty reaching Mars is one thing, establishing a viable self-sustaining permanent outpost, quite another. Not to say it won't be done -- it's just a lot harder. By contrast, a LEO habitat doesn't need to be self-sustaining at all, it's right here, can drop in to borrow some sugar if they run out. And so, since it's easier, I assume they'll pop up in larger numbers sooner. Regarding the unsurprising lack of material lying around in LEO (aside from old satellites), I would assume that it would be sent there from some place that has materials. Like a factory. – Serban Tanasa Apr 1 at 23:12

A FEW THOUGHTS:

I can think of a few reasons people would want to move into space if they had the resources to do it.

• ESCAPING THE RIFF-RAFF: Rich folks who want to lord it over mere normal people can't get more OVER than moving to space. No one is going to sneak up on your house to rob you when the world can watch the thief sneak up on you. Rioting underlings can't ever overthrow you if your habitat is it's own independent country. This combines neatly with the "getting away from crappy Earth" scenario, so even if the little folks are dying of cancer at 50, you are in a perfect, climate-controlled paradise. Not to mention that the little people will simply be incapable of becoming your neighbors - they can't afford it, and in space, you can be neighborly with someone a hundred kilometers away (about how close you uber-rich want to be to the lesser folks).
• INDEPENDENT COUNTRIES: If you are a group of people fed up with how things are on Earth, the folks that already own everything and the governments claiming everything aren't going to let you set up your Tamil state/Mormon fundamentalist state/White purity state/whatever. The clear solution is that if you can get the funds, MAKE your own country in orbit. Unconstrained by the petty morality of grounder nations, you can make your own social experiment in orbit free from prying authorities/eyes.
• READY TO COLONIZE: The first step to colonizing other planets is to get your colonists up in space. There, you can build ships to take you to other planets or eventually even other star systems (fingers crossed). The habitats could even be built in such a way that they can be the solar-system equivalent of generation ships. If you have a self-sustaining habitat with a thousand people on it, are you that concerned if it takes you three years to get to Mars? Once you're there, you have a habitat in orbit for breeding colonists, having pre-built industry to make the things you want a lot closer than Earth, and a place to retreat to when things go all crappy and half your colonists die of something unexpected.
• TECHNOLOGICAL ADVANCES IN ZERO-G: People have been hoping that they could find new and exotic things they can make in space that they can't make on Earth. So in ten years when they discover the newest computer chip can only be made in zero-G, the people who make that discovery are probably already there. Entrepreneurs will build in space and do research in space looking for new opportunities. Sure, mining by itself isn't enough. Research isn't enough. Manufacturing isn't enough. Maybe tourism isn't enough. But put all those things together, and that's starting to sound like a city. Maybe even a society.
• A GENERATION OF KIDS GROW UP IN SPACE AND HAVE KIDS OF THEIR OWN: Once you have people who are living in space, even in small numbers, you have a culture and society that grow up. Then you have kids born in that culture, and to them space is the reasonable place to be - it's home. If you can make more homes and more "land," then people are people, and they'll have more kids and more kids until you have as many or more people in space as on Earth. After all, there is no shortage of room...
• PENAL COLONIES (to the extreme): What do you do when people don't want to live in space but the cost has come down enough to make it economical? Prisons are actually really expensive to run, so for a little more, you can get rid of those folks for good! Botany Bay station is full of criminals or genetically undesirable folks who are politically difficult to just KILL, but that you don't want to deal with any more. Last year's genetically engineered super-soldiers are this year's awkward, violent and freaky-looking problem, and they are precluded in the arms agreement you signed that ended the war. Set them up in their own habitat where they can't cause anyone else problems. Nothing could go wrong with that plan, right?
• SURPRISE REASONS: The newest treatment for aging is developed, but it works MUCH better on people in Zero G. Suddenly, the rich and old want to live in space to keep living. A chef invents a zero-G soufflé that is the most amazing thing anyone has ever eaten, and it has to be made and eaten in zero G (it can't survive reentry). Plant genetics advances and suddenly people can actually GROW new habitats in space that are dirt cheap (pun intended). A way of using the Venusian atmosphere to make cheap carbon nanomaterials is invented, but the round trip is really hard to make affordable, so you set up a permanent large colony in orbit around Venus.
• Thank you for a thorough answer (+1). I like the lordly mansion of eternal spring idea, but I'm not sure that gets me to a million people, even including the serving staff (if human). Independent countries floating a few hundred miles over the sovereign territory of places like China and the USA seems wildly unlikely, since these dinosaurs have, you know, guns and stuff. A few of the latter ones seem more like wishful thinking than concrete reasons. I agree that once you have a permanent population in space it'll grow naturally, but that's a big ONCE to accept. – Serban Tanasa Apr 1 at 23:23
• @Serban Tanasa The territoriality will likely follow rules about satellites at first, and get complicated from there. You always have the Lagrange points to work from, and the moon for those that still want a bit of gravity (but I didn't include moon reasons since you wanted strict space). It is intended as an "all the above" set of reasons, each piece getting you part way. – DWKraus Apr 1 at 23:27
• interesting, I simply chose "strict" space because it seemed the more plausible, it seemed like there's useful stuff to do in LEO, the L points, or moon orbit that Earth folks might pay for -- do you think we'll have 1m people on the moon or on Mars before we do in space habitats? Why? The problem with being close to Earth is that the Chinese and Americans will want to tax you, and they have armies and space forces to make you. Seems like that would make independence hard. Aditionally, in space habs (assuming rotation) you don't have to worry about low-g effects on health. – Serban Tanasa Apr 1 at 23:38
• @Serban Tanasa The effects of low gravity are likely to make permanent habitation more, not less likely. We'll probably develop therapy for the significant negative effects, but lower gravity is a plus otherwise. Elders retire to orbit and half gravity, where it's easy to get around, falling doesn't injure as much, work (meaning almost any activity) is easier, high oxygen environment. Kids don't have muscle mass, so going back to Earth is hard and unpleasant. Moon settlements are familiar to grounders, and moon bases provide mass for construction. – DWKraus Apr 2 at 0:35
• I am convinced some parts of this answer are articulated well in the movie Elysium. – Nuclear03020704 Apr 2 at 6:47

Because 'Oil Rigs' are just the beginning

Wikipedia's Asteroid Mining article states that in the next 50 to 60 years, we will run out of phosphorus, antimony, zinc, tin, lead, indium, silver, gold, and copper. A lot of that is available in various asteroids in space, so that's where we'll begin.

And sure, asteroid mining will start as a thoroughly unpleasant high-pay job, where you do a tour and then spend six months home before going back up. However, hauling raw materials out of orbit slowly enough to avoid extinction events is expensive. It'd be much cheaper to process the stuff in orbit and haul a smaller amount of more valuable, refined material. This goes on, until your space rigs are dropping cargos of the latest iThing back to Earth.

Now, we're not going to be shipping Flat Pack space stations up if we can avoid it, because that's expensive, so instead we'll be sending up the machinery necessary to build up there. Soon, mines, solar collectors, factories and habitats are being build in space using space-based materials.

At that point, there's quite a lot of industry up in orbit, and thus quite a lot of workers who all need places to rest and relax. Someone, eventually, will realise they can use that industry thats already up there to refine the materials that are already up there into clubs, pubs, non-spartan housing, and other accoutrements. Eventually, they'll get to a point where paying $100/kg to get to and from Earth ain't worth it for some people. After all, once you're in orbit, you're already halfway to anywhere. • only comment I have is that we have these things called "mines" on Earth, so why go to space to get it, since you can likely get it from the Earth-based "miners" for cheaper? Unless you want to build stuff in space, that is. But why would you want to build stuff in space? Your labor force, raw materials, physical plants, and most importantly customers, they're all here and transportation costs to and from space are pretty steep, I hear. – Serban Tanasa Apr 1 at 20:08 • @SerbanTanasa because negative externalities still have a cost, even if you aren't paying cash for them right now. Out there you can find more materials than a human civilisation could reasonably need, along with all the energy you might want, and you don't have to worry about poisoning any biospheres when exploiting either. – Starfish Prime Apr 1 at 20:38 • @SerbanTanasa There are certain rare metals that human technology uses in such abundance that we are expected to run out of economically viable reserves here on Earth within the next few decades. These same metals are relatively common in certain kinds of asteroids. In our children's life times, there will probably be several elements that are cheaper to mine in space than here on Earth. – Nosajimiki Apr 1 at 22:00 • @SerbanTanasa I've expanded further. Does that cover your concerns? – Kyyshak Apr 2 at 9:06 • The one thing I disagree with in this analysis is that that space industry is going to require a lot of workers. On earth, workers can be (relatively) cheap, and robots are therefore not competitive in a lot of places. But in space, human workers will be much more expensive than a robot that doesn't require air, water, food, housing, and other expensive things, only electricity. So expect basically all the work to be done by robots. For stuff that is hard to have a computer do, it will still be cheaper to have an operator on earth directly control a robot in space. Not many humans needed. – JanKanis Apr 5 at 15:33 Option 1: It becomes cheaper to build luxury space habitats than luxury apartments in New York City You want it to make economic sense to build space habitats and for people to get in them, so the first option is that it somehow becomes cheaper to build space habitats than expensive apartments in an expensive city. This is notionally possible because completely automated construction projects in space won't have to worry about pesky things like environmental impact, so they MIGHT be able to overcome the costs of construction on earth by building the habitats out of asteroids or some such nonsense. Option 2: It becomes objectively better to live in a space habitat We're doing a pretty good job of ruining the Earth. If we keep it up, then a space habitat might look pretty inviting. If we accelerate the process significantly, we could make it dangerous to stay on Earth and then everyone would want to move to a space habitat regardless of the expense. Option 3: There is no option 3 That's it. To make economic sense, it has to be cheaper than living on Earth or demand for it has to exceed the cost. There are other reasons than economic reasons why we might put 1 million people in space habitats, but they aren't economic ones. Edit: Explanation of Why/How Space Habitats are the Same or Better than living in Cities For starters, we should clear one thing up about space habitats, and that's their size and layout. A long-term space habitat MUST be a rotating ring or cylinder to provide artificial gravity (unless we invent magic artificial gravity). It MUST then rotate slow enough that no one faces adverse effects from the rotation (likely lower than 1 RPM). It is also then highly likely that a second cylinder be attached at close proximity to the first to stabilize the orientation of the cylinder. If such a cylinder rotates at 1 RPM or less, it must have a radius of around 900m spincalc. The designs for the O'Neill cylinder assume a length 4 times the diameter, so I'll use that to give these habitats a minimum area of 20 km2 per cylinder. Since it's actually 2 cylinders attached to each other, that's 40 km2. For population density, US metropolitan areas range from 200 persons per km2 (unless you could Anchorage Alaska, which I don't) all the way up to 10,000 persons per km2, and I suspect the population density on these cylinders might vary similarly. Let's pick a lightly populated cylinder with 40,000 people now. How does such a cylinder compare to a city in the real world? 1. In a city of that size, food is imported, so virtually all types of cuisine are available. A cylinder of that size would need to either import its food as well or use some advanced technology to grow food in a way we haven't fully realized. My money's on the technology because they're doing some really fantastic things with lab-grown products these days, but that's not important. What is important is that the food is similar. 2. In a city that size, many people born in the city will never leave that city. People make fun of folks never leaving small towns a lot, but the same is true of cities. A space habitat will be largely the same because leaving the habitat during your lifetime will be prohibitively expensive. 3. A population group that size can support just about any form of entertainment facility you can think of short of major sports arenas. An O'Neill cylinder, additionally, would be built from the ground up with the interests of its residents in mind, and with every facility using state of the art technology. Quality public transportation would be built into the cylinder by default because no one is going to be bringing personal transports into space. All in all I suspect that living in a city your entire life is very much the same as living in a space habitat your entire life, and plenty of people do the former. Heck, with the increasing popularity and advancements in home delivery and VR, I suspect there's a large number of people who will never willingly leave their homes, let alone their home city. • I have questions. Re 1) why would I move out of my expensive condominium to a space station if the spaceplane ride there and back costs$100/kg (and I have lots of kilograms), when I can move to the exurbs and build me a palace for a fraction of the cost? Re 2), Earth is pretty big. I am a rich bastard. If we get Florida to sink (a great idea imo), I can just move to some other place on Earth, maybe plop in an AC and an air filter if needed. Re 3) I would love to hear some non-economics reasons why folks might choose to live on spinning caves in space. – Serban Tanasa Apr 1 at 19:18
• @SerbanTanasa let me answer your first question with a question: why would I (a rich person) live in New York City when I could build a palace in the exurbs? As to your 2nd, I did mention "objectively better", so it's got to be THAT bad on Earth. A great non-economic reason is "because it sounds cool" and there are definitely more than 1 million people on Earth who think it sounds cool. Another great one is "because it is necessary for the survival of the human race". Spinning caves in space are no different than square stone caves on an island in New York – SirTain Apr 1 at 19:26
• well, Metropolis has Culture and Decent Food. Also it might have Interesting People to Have Lunch With. Again, not clear how a BYO-Air cave in space would be better than an exurban palace. I mean, even if traffic is horrible, i expect it's easier to host a party there. – Serban Tanasa Apr 1 at 19:31
• @SerbanTanasa you seem to underestimate life on a space habitat, so I've added some more details – SirTain Apr 2 at 12:05

The way that Virgin Galactic, Musk, and Boeing expect to get people into space.

Tourism.

All-expense-paid vacations to the usual tourist spots are getting so ho-hum. Over-crowded, ridiculously expensive, and poor quality.

"Dear, just EVERYBODY has been to that resort. Let's go somewhere the Jones' have not been. They are getting so boring, they just go on and on about their last vacation. So frightfully pedestrian."

If you look at the numbers, 1% of the world population has 99% of the wealth, or whatever trope you want to use.

But 1% of the population is 72 million people. That is a lot of potential space tourists. Recall that it usually takes ten service providers (waiters, room cleaners, grounds keepers) to serve just one luxury guest.

There is so much money out there in very big bubbles, just looking for some place to be spent on.

• Tourists can to to the peak of the Everest mountain. Doesn't mean they settle there. A tourist kinda by definition does not live there. So I assume you mean the support staff. But why would they live there? Why not go North Sea oil rig on that too - folks doing tours of a few months? – Serban Tanasa Apr 1 at 19:23
• @SerbanTanasa im pretty sure the idea is that if they go there and see how nice it is they'll be more willing to settle down. as long as people want to go somewhere enough they will try to go there, doesn't really matter how much it costs people will still try. – zackit Apr 1 at 19:39
• @zackit, you assume it will be possible to make it nice enough cheaply enough for it to be attractive to the fraction of rich enough people who are also crazy enough to do it. I guess folks may do it for fun once or twice (like they do skydiving), but to choose to actually settle in a pressurized spinning can ... seems like it'd get old pretty fast. – Serban Tanasa Apr 1 at 19:58
• @SerbanTanasa its an investment, space is full of valuable resources. even if they themself dont move there, they may begin hiring others to go work on resource mining out in space, getting paid significantly higher amounts to do so thanks to the quantities of these resources and the required commitment. other people come to be with their family in these stations and begin setting up more of a society beyond the workers. in the end, whether or not these billionaires actually stay to live there, it can still result in a human colony from just money motivation alone. – zackit Apr 1 at 22:06
• Why would the service staff go there? Because someone hired them to go there. Same reason people go to North Sea drilling rigs. It's a job. You get paid. Once there, easier to live there than to keep readjusting to earth and space. Once you adjust, your spacer skills become very valuable. Stay long enough, you can never come home. Why did the first aboriginals cross the Bering Straight and stay in Canada? Comparatively, wasn't any worse than going into space. That's why the Sherpas took climbers to Mount Everest. Because they could. They got paid. They had adjusted. – Justin Thyme the Second Apr 1 at 23:04

Escaping an apocalypse!

The Earth is going to be hit by a giant asteroid. It is so large that it can be seen a hundred years away.

Scientists calculate that a concerted effort over those hundred years will allow a maximum of 1 million people to be housed indefinitely in space.

When the time comes for evacuation, the world leaders will have the difficult task of deciding who shall leave and who shall die. Part of the plan is to try to reduce the entire world population to this size so that everyone still living can go. Of course it will miraculously turn out that the the descendants of the world leaders are part of that population.

The Earth will eventually become liveable again so some preparation must be made for The Return.

• Someone will have left the password to the life support softare on a postit on a monitor on earth - giving rise to The Premature Return And Subsequent Bargaining – bukwyrm Apr 7 at 8:51

I don’t think that many space habitat projects are going to be constructed for financial gain at least not initially. They will cost a lot and the people who build them will do so mostly for ideological reasons not economic reasons. As is the case with having a baby, babies eat a lot, cr*p a lot, want a lot and are a general money pits with no economic payback. Similarly the Pilgrim Fathers did not travel to America with the intention of making a quick buck.

Governments might build habitats because it’s a good place for some science research and they need to provide habitation for the workers (ISS like), they might also build them because the Chinese are building them and they don’t want to be seen to fall behind or miss the boat.

Individuals and companies might eventually build habitats to make money via space tourism or industry, but the cost to get to Space needs to come down a lot to incentivize that option on anything other than a very small scale. Individuals and companies might also build habitats for their own ideological reasons.

For example SpaceX has a mission statement to the effect that they want to make humanity a multi-planetary species. And that is not just a throw away sound bite as it is with most company statements, that is what SpaceX is all about. The only way that is going to happen is if it’s a lot cheaper to get to orbit and we stop throwing hundreds of millions of dollars worth of precision engineering into the Atlantic Ocean at every launch. And that is why SpaceX are building a totally reusable spacecraft.

Large scale human habitats beyond the Earth will take a vast amount of money and time to establish. The human exploration of Mars is probably at least a decade away and a 1000,000 person city on Mars might take very many decades to centuries to complete. But once a certain critical mass of beyond Earth infrastructure has been built it will start to build a momentum of its own.

• Human settlement on (almost) any part of earths surface is not an apt analogy - you need negligible initial investment per traveller, and then you can stone-age your way ahead. Any continued provision from established settlements is just a bonus. And even that expansion was only economically viable because we can simply send a mutton-to-be out to get fat on the land without charge, while picking berries without charge , breathing air from trees without charge while being warmed to +-20 of body temp without charge and shitting into the woods without charge. None of this is free in space. – bukwyrm Apr 7 at 9:07
• Most of this is true but irrelevant. My comment with respect to the Pilgrim Fathers was one concerning motivation. Their motivation was ideological not financial. The same will be true on Mars even if the costs are orders of magnitude greater. – Slarty Apr 7 at 16:34

Slavery.

1-100 people living off the toil of 999900 people is currently achieved by arcane trade agreements and property laws - this could be handled much more efficiently by going to space, where you would have complete practical freedom (sure, there is space legislation - but what are they gonna do, tow you?). You also have much less hassle with runaways.

You'll have to trade with earth, and you'll have a workforce that cannot be used for high-tech endeavors (and selling your slaves out as a call-center is not profitable enough) - so you'll need to go the raw materials way - they mine* something, which is slingshotted back to earth, who in turn provides you with space-station essentials**. It will have to be something so essential to earths way of life that it stymies any coordinated effort to stop you, like oil. There is no oil in space, but maybe there is an asteroid with a mineral that forms crystal lattices which can be used as seeds in a blockchain? You'd need to lead earth down a path where the continuation of that blockchain is just that important, and the adoption of alternatives just that bit too much hassle for all involved, then announce your heroic going-to-space in an effort to sustain it.

Hey presto! You+1M slaves in orbit***

* You cannot invest in 1g environments, or even exercise yards for your slaves, it would be just too costly - you'll have to make do with them being electroshocked once in a while to retain minimally viable muscle mass, so the mining itself will be done by drones that are remote-operated by them****

** Like more slaves. Face it, there will be some attrition, and somebody on earth is always spare

*** 1M in orbit will take an insane amount of investment, in no way shape or form will that ever be economically viable if they are all in luxury habitation (read: more than coffin-enclosures). Your space palace, on the other hand, will be a negligible overhead on the infrastructure to keep the other 1 000 000 people alive-ish.

**** Come to think of it, remote-operating a vehicle does not need all that body mass - there might be cost-cutting in limb-cutting - three fifths should be more than enough remainder

• Even leaving the horrible ethics issues aside, why would I use slaves when I can use robots? Robots don't need any life support, & can could be (mostly) produced in-situ from mined materials (save for the light but more complex parts like control chips). – Serban Tanasa Apr 7 at 13:27

Make it easy to get there.

If you have enough space elevators, or cheap powerful spacecraft and rotating skyhooks at least, or physically viable warp drives, then the weak call of sightseeing, minerals, isolation, pioneering and so forth becomes strong enough to pull people out of the gravity well for a day or a week. Some stay for years. The rest is just ... entropy. More ways to be off the Earth than on it.

See Stine's "The Third Industrial Revolution", Heppenheimer's "Colonies in Space" Savage's "The Millennium Project" for serious economic handwaving.

Historical parallels:

Mining towns until recently were a family affair. Lots of old west examples. More recent, Uranium City, SK, Faro, YK

Mining town form when the cost of bringing people in and out get to be too much.

Resource towns: I know of two communities that exist only to provide staff to run a power dam, plus the staff to support the community.

Lumber towns.

Research stations. See Antarctic bases.

Military bases.

There is an island in the Canadian Archipelago that has iron ore deposits of the same quality and size as the Minnesota Mesabi range. As of the 1970s it wasn't economical to mine because the best you could hope for was a 6 week shipping season. That may change with global warming. But if the deposit is big enough it's worth creating a ocmmunitiy instead of work camp.

Ultimately people do things for economic reasons. New England whalers went to sea for 3-5 years at a time.

Unless you have an earth killer type threat, getting 1,000,000 people living space in a short time for one big reason is probably never going to happen. So getting them out there is going to happen because of a combination of things over a longer period of time.

Things on Earth will already provide you the reasons why: Climate change, food shortages, financial collapse, overpopulation, wars, persecution, lack of opportunity.

There's tons of refugees here on Earth already, right? So if there were corporations that were willing to foot the initial bill to take some of them to work in space they might just go. Couldnt be any worse than sitting in an internment camp just waiting to be sent back to the rotten place you tried to leave.

Things in space will give you the way how: The first trips could be only a hundred or so people to mine out a spot on the moon or an asteroid. They would build an infrastructure to support themselves and a few hundred more, while simultaneously starting an economy based on what they're mining. Later a few hundred more come.

After a few trips you have a few thousand people, living in space, mining the moon, asteroids, mars, or even on the surface of some of the other moons that we wont immediately freeze to death on (with suits or inside vehicles of course).

Later, they start making the habitats more nice and inviting. Trees and grass, parks with lakes and playgrounds, entertainment venues. etc. Not just cold mechanical tubes like the first few (those guys had it hard). Hype the places up to be accepting of everyone, regardless. Free training. Free home. Get right to work.

Before you know it the whole things pays for itself and it grows exponentially. After a while they wont even need Earth at all anymore.

The overwhelming elephant in the room about everything connected to space travel is radiation shielding.

Everything else is: nothing, a non-issue.

Note that if we invented faster than light travel we could do .. nothing much. Because Radiation Shielding.

All of scifi just a thing where we pretend Radiation Shielding isn't a thing. The whole Elon Mars Etc notion is nonsensical because Radiation Shielding.

So in your story there has to be a handwave about some miracle radiation shielding material or system.

• Ok, add one meter of frozen water on top. Or one meter of lunar regolith. Or one meter of steel, if cheap enough. There, solved it for you. – Serban Tanasa Apr 2 at 12:24
• You know I'm not sure a meter does it (we should ask about that on another site, maybe physics or space exploration). But that is an enormous amount of weight and that becomes the whole engineering/social-political issue. The rest is easy. Note that this doesn't solve the problem for moon/mars/etc bases. (Sure, "deep underground") – Fattie Apr 2 at 13:06
• Radiation isn't too bad in low Earth orbit, might even be completely acceptable. If you can get some people living in orbit, then you can some fraction of them to work in lunar or asteroid mining. Now you have cheap access to the material needed for radiation shielding. NSS's take on the issue: space.nss.org/wp-content/uploads/… – Harabeck Apr 2 at 19:08
• You better call Elon Musk that he missed this one important thing, after he spent years thinking about what was needed to colonize Mars and is disrupting the space industry in bringing those ideas to reality. I remember him saying something about 'radiation' in one of his many talks over the years, you should try looking it up. 🤣 – JanKanis Apr 5 at 18:13
• @JanKanis , it's really normal in life that people (even "Great People") make huge and ridiculous basic mistakes. There's some handwaving crap here .. mars-one.com/faq/health-and-ethics/… Which simply says "Living on Mars means living underground" Oh, you can go outside for a very short time each day. But there's no protection at all against SPEs. (Other than the proposed faster than light warning system :) ) And there's no protection, at all, against cosmic rays. So you can theoretically go outside, but you can't. ... – Fattie Apr 5 at 18:47