The idea of colonizing space within science fiction tends to suffer from a certain bias,
as famously noted by Isaac Asimov many years ago.
He stated that he was a planet chauvinist, tending to focus on colonizing planets rather
than thinking about space itself.
But in reality, there may be more advantages to colonizing space using habitats rather
than large-scale colonies on other planets.
While we will no doubt colonize planets and moons within the solar system, the vast majority
of these places are either very distant or very harsh, though the moon is an exception
due to it’s convenient close proximity.
Mars on the other hand is a very harsh place that you can only easily get to during certain
launch windows.
Gravity is one major issue here.
Both the moon and Mars have significantly lesser gravity than earth.
We know zero gravity can be detrimental to human health over long periods, but what of
low gravity?
That is still ultimately still unclear.
But the biggest advantage to colonizing space itself using habitats is that you can both
simulate something close to earth gravity through centrifugal force, and locate them
conveniently close to earth for easy access.
And the technology to build habitats in space is not as far off as you might think.
In a sense, we’ve already started to explore this concept.
For decades space agencies have had people living, at least temporarily, on space stations.
We have one active right now, the International Space Station currently has 3 people on it.
And while people on that station tend to only stay for a matter of months, time spent in
space will no doubt become increasingly extended as we continue to explore.
But the ISS is small potatoes compared to what we could eventually do.
It’s possible to use the raw materials of the moon and asteroids to build much, much
larger habitats that could conceivably host millions of people.
In principle, these habitats could become self sufficient and support entire branches
of human civilization on a permanent basis.
As Jeff Bezos recently laid out in his vision for Blue Origin, this could dramatically alter
the equation for earth and tackle problems such as overpopulation and environmental issues
by moving the manufacturing base to space to make earth a sort of ecological park, and
as Elon Musk points out, colonization will broaden the scope of humanity to make us less
susceptible to extinction.
Regardless of what one thinks of billionaires with dreams of space, their rivalries, their
companies and the viability of their respective visions; their core ideas about the future
are sound.
And, generally speaking, it’s not a great idea to rely solely on the politicians of
the world to make human colonization of space a reality, there must be a private component
if it is to happen.
That said, what are our options for constructing space habitats that can permanently support
entire new branches of human civilization?
The key to all of this is availability of materials to build the habitats.
Currently, almost anything we do in space is ultimately launched from earth.
This is a very expensive process that holds back human colonization of space.
There are ways to make this cheaper, such as building things like space elevators.
But even then, it makes more sense to use materials that are already available in space
itself by mining the moon and the asteroids.
Take for example water.
There is no shortage of water ice in the solar system.
Evidence mounts that an average asteroid is loaded with it, and very large asteroids may
contain more freshwater than earth has.
And, indeed, the asteroid Ceres may even have a slushy liquid ocean beneath its surface.
If you have water, you can extract oxygen, and hydrogen.
Also present in asteroids are huge amounts of iron and nickel, but also things like carbon
compounds.
In fact the murchison meteorite was so loaded with organic materials that when it fell in
1969 it smelled like an organic chemistry lab.
It was subsequently found to even contain amino acids, the building blocks of life..
So there are a wide variety of materials present in the solar system accessible to us to eventually
build space habits without the need to launch much from earth.
But say we built the infrastructure to gather these materials, exactly what would we build?
There are actually a number of conceptual habitats that could be used to build giant
space-based colonies.
The first is the O’Neill cylinder.
The idea goes back to physicist Gerard K. O’Neill back in his 1976 book The High Frontier:
Human Colonies in Space.
He proposed that through extracting and using raw materials launched from the moon via a
mass driver, and eventually mining asteroids, you could construct a several types of space
habitats.
The largest of these is the O’Neill cylinder and could be built literally on a scale of
5 miles wide and 20 miles long that could be home to a very large number of people.
It would consist of two counter rotating cylinders.
This has the effect of providing artificial gravity through centrifugal force, but having
them counter-rotate would cancel out gyroscopic effects that would interfere in keeping the
habitat pointed towards the sun.
Inside the cylinder would be strips of land alternating with giant windows.
The windows would allow sunlight into the cylinder, but with modern technology it’s
easy to envision power generation through solar energy running very efficient lights
that mimic sunlight, or eventually fusion energy.
O’Neill further laid out that you could add agricultural and industrial rings the
cylinder that might rotate at different rates optimal for their use, for example near zero
gravity for the industrial section to facilitate easier manufacturing at low gravity.
For the living area, O’Neill calculated that such a habitat would need to rotate 28
times an hour to simulate earth gravity.
But it’s important to remember that it’s simulated gravity through centrifugal force,
and would feel and behave a bit different from what you’re used to on earth.
One thing that would happen is if you dropped your keys as they fell they would deflect
slightly due to the motion of the cylinder.
You’d also be able to detect the spin of the habitat while turning your head.
But that’s you, you’re from earth.
Anyone born in the cylinder would find this to be normal, and visiting earth and its gravity
would seem off to them.
One interesting side effect of the O’Neill cylinder is that the internal volume is large
enough for weather systems to form, albeit ones very different from those of earth.
This is an effect already noticed with very large building interiors on earth, such as
NASA’s Vehicle Assembly Building.
The internal volume of this building is so large that it has to have moisture control
systems in place to keep things dry, and that on humid days, rain clouds of sorts can reportedly
form under the ceiling.
O’Neill Cylinders can also be connected together to form double habitats, or as many
as you want really and could support tens of millions of people.
And, best of all, they can be built close to earth, allowing easy travel to and from
the home planet.
In Jeff Bezos’ vision, earth would become a kind of park, and all of the manufacturing
and industrial activities done in space.
Perhaps even a majority of the human population will live in O’Neill Cylinders at some point,
with space humans vastly outnumbering earth humans.
But the gargantuan O’Neill Cylinders aren’t the only option.
There will no doubt be a need for something smaller, at least initially, but larger than
common visions of space stations.
This leads us to the Stanford Torus, which could support up to 140,000 people.
This option is much like a scaled up ring type space station, and once again rotates
to provide artificial gravity through centrifugal force.
Like the spokes of a wheel, the ring is connected to a hub, which provides a natural place for
ships to dock.
Yet another possibility is the Bernal Sphere, or a modified form of it.
Here you have a much smaller cylinder than an O’Neill Cylinder, with a window at one
end admitting sunlight, but again, this concept dates to 1929, so with modern technologies
the need to admit sunlight into the habitat is basically marginalized or eliminated.
There are larger options as well, though these lay in the far future and represent extremely
advanced and difficult engineering and materials.
Assuming carbon nanotube technology is employed, a habitat much larger than an O’Neill Cylinder
could, in principle, be built.
This is termed a Bishop Ring, and effectively represents a similar idea to the O’Neill
cylinder, a rotating ring that produces simulated gravity, but on a much larger scale, Forrest
Bishop’s original idea being for a ring 620 miles in radius, and 310 miles in width.
This is some serious living space, it’s essentially the landmass of India.
And there’s one slightly disconcerting aspect, it wouldn’t need to be enclosed.
It would be large enough to hold an atmosphere effectively without the need to have a roof,
essentially leaving the structure open to space.
But, if you think about it, earth doesn’t have a roof either, so we already live like
this, though you would need walls to retain the atmosphere.
But, things can be scaled up from the Bishop ring as well.
Here we get into science fiction.
Actually engineering megastructures of this size may be impossible in practice, but they’re
worth a mention.
Next up is Iain M. Banks’ Orbital, which is a much larger ring on which there are continent
sized plates each supporting billions of people.
Bigger than that is Larry Niven’s Ring world, which is yet another ring, but one so huge
it’s encircling a star.
Stepping up from there is the idea of a Dyson Sphere, which actually goes back to sci fi
author Olaf Stapledon’s 1937 book “Star Maker” where a star is entirely encased
in a solid sphere allowing for the civilization living on the interior surface within to take
advantage of the entire energy output of their star.
But in the case of the smaller, more doable habitats like the O’Neill Cylinder, which
could lie hundreds of years in our future rather than thousands or millions like a Dyson
Sphere, one has to wonder what such an arrangement might be like.
Three scenarios come to mind.
As shown in the movie Interstellar, life in such habitats could be idyllic, governed by
a humanity that did alright in solving the differences of earth’s nation states.
It would be a world of peaceful trade between habitats, all connected to a paradise earth
managed and kept in a largely natural state.
But it may not be that nice, as depicted in the Expanse.
It may be a case of a “meh” future where life is relatively hard for some folks, rivalries
exist as they do currently here on earth, and everyone generally lives in an all too
human future where we’re still solving very human problems all while spreading out into
space.
Or, it could get much worse.
It’s very likely possible to have wars between O’Neill Cylinders, where entire populations
could be instantly wiped out using anti-Cylinder weaponry, such as a directed asteroid, bombs,
crashing cylinders into each other, lasers, and so on.
These differences could well be some of the same that plague earth today, or new ideologies
where the Cylinders become like self-contained nation states, or confederations of cylinders
based on political ideologies creating a cold war scenario.
Or even a war between the cylinders and earth, where the home planet is ultimately destroyed
by cylinders of people that no longer have any connection to it, or even a need for it.
I hope that future never comes to pass.
Thanks for listening!
I am futurist and science fiction author John Michael Godier currently ending on a less
gloomy note, or maybe more gloomy.
If we play our cards right and are careful with transporting our seeds to the cylinders,
we may conquer garden weeds.
No seeds, no weeds.
If SETI ever detects a system with a perfectly habitable planet, but with no technosignatures
associated with it, but plenty in the space around it, we might ask why they abandoned
their planet.
They might answer “We got sick of all the weeds”.
It might be that all habitable planets in the universe end up left back to nature on
that basis that cylinders are nicer.
But then a new species eventually evolves intelligence on the home world and tries to
take your cylinders.
I’m already eyeing the dolphins suspiciously and on that note, be sure to check out my
books at your favorite online book retailer and subscribe to my channels for regular,
in-depth explorations into the interesting, weird and unknown aspects of this amazing
universe in which we live.