This episode is sponsored by Brilliant We often talk on this channel about wonderous megastructures that will house countless billions
and factory complexes that will dwarf our planet’s entire industrial output. But it makes you wonder… Who’s going to maintain all that stuff? Something often overlooked in building projects
is that in general their maintenance and upkeep is rather staggering. Anything you build will cost you at least
as much to maintain for a generation as you spent building it, and even more if you are
lax on maintenance and something breaks. I’d imagine everyone here has experienced
that wonderful shock of getting a repair bill and groaning. Should you be a true glutton for punishment
the public and private sectors afford countless opportunities to stare down at a budget with
grim certainty the taxpayers or shareholders will not be best pleased with the news you
will be sharing with them. Left to themselves stuff breaks down, but
it does so a lot faster when being used and in practice just from being in proximity to
our civilization, and we’ll see that remains true even in space where by default you’d
expect the vacuum not to cause erosion and corrosion. There’s a popular myth that the Ancient
Roman roads were ultra-durable. But while the Romans were darn good civil
engineers, roads always have to be built cheaply because of the sheer volume of materials involved
and the distance they have to be transported. So while it’s practical to build comparatively
small critical structures like bridges ultra-strong, roads have to rely on the ground beneath them
for support. Heavy vehicles eventually crumble solid-surfaced
roads, and wheels cut dirt roads into pairs of soggy trenches. The truth is, the Romans built a huge number
of roads, and the ones that survived millennia were often the ones that fell into disuse,
a tribute to quantity as much as quality. While we have built many robust structures
that have weathered the centuries well, most of the buildings of the past are at best ruins
and in most cases buried under layers of dirt and ash until some archeologist finds them. Most of what remains has either required vast
amounts of repair down the centuries or is basically some rock, and usually that rock
only vaguely resembles what they built which typically had nice layers of colorful coatings
and ornamentation until decay, weather, erosion, or war stripped them down or later generations
cannibalized it for building materials. This gives us a short list of basic maintenance
strategies. First you can build from ultra-durable materials. Second, you can limit usage and exposure to
background decay factors. Third, you can keep things simple. Complexity almost always requires more effort
to maintain and is generally more costly for the components too. Fourth, you can engage in constant maintenance
and replacement. And fifth, which is beginning to become an
option as our technology improves, you can have things which repair themselves. That last is only a strategy in the effort
and economic sense of course, otherwise it’s the same as the fourth, constant maintenance,
it just doesn’t involve people as much, and makes the repairman more of a doctor or
programmer than a classic craftsmen. Each of these will likely be employed of course,
tailored to the object being maintained and what your tech permits, or your culture does. It’s important to understand that when we
discuss things like megastructures, you have vastly more to maintain not just in quantity,
but proportionally to your human population. This is true even for the smallest and simplest
of these, such as an O’Neill Cylinder, which contains hundreds of square kilometers of
internal living area and external hull, and which might house hundreds of thousands of
people. To give a comparison of a simple material
we build, our own modern highways usually need about a hundred people per square kilometer
to maintain them, we normally discuss them in terms of linear length, where it is more
like a person per kilometer or mile, but that’s the approximate zone for area, and for building
artificial habitats, all that land area needs maintenance. Indeed it’s more three-dimensional too,
as you’ll have layers to maintain. We don’t really have to maintain our air
and sea and dirt and all beneath it rests upon – they do. Indeed they have more metaphorical layers
to maintain too, they have to look to their weather – inside and out - their ecology
– possibly also inside and out, and their electronic and digital layers too. To a degree we already have to do this, and
to be fair our ancestors did more of it than folks often realize, carefully if clumsily
shepherding their lands. When you’re dealing with a megastructure,
you need to master these skills and use all the automation you comfortably can just to
make them plausible. And to give an idea about this, let’s take
a hypothetical O’Neill Habitat – again the smallest and simplest of megastructures
– and look at what is likely being maintained. We’ll start from the inside. First we have the lighting itself, some versions
call for big windows to let light in, others light is concentrated and bounced in through
small ports by mirrors, others we generate it artificially by massive power plants and
light bulbs. In the first case, windows, those are big
structural weaknesses, even segmented into panes, that you must constantly maintain as
they get scratched up and cracked from outside space dust and debris, and more so from inside
dust, which must be swept out, and the windows polished, and likely replaced as they take
UV damage, which is worse in space. Second, small windows with concentrated light,
have these same problems but reduced, but need large mirrors and dishes outside too. The third requires those artificial lights
be maintained and replaced and the wiring kept up, and maintenance of either the solar
panels or internal power plants that fuel them. Then there’s temperature, not too hot, not
too cold, and hot is likely to be the big problem, as it’s hard to get rid of heat
in space. That wraps into weatherman… not guys who
try to predict the weather, but guys who decide what the weather will be. Such habitats are big enough for natural weather
and small enough not to get extremes that we’d see on the larger super-sized megastructures,
but will likely be fairly planned and artificial regardless. On the ecology side, we examined that more
in “The Environment of Space Habitats” and it’s where we also introduced the idea
of tweaking and tailoring life not just to that environment but to help maintain it,
as an alternative to robots. Work smarter not harder is humanity’s slogan. If you can get your critters in the habitat
to do some of the work for some supplemental food, like squirrels or raccoons picking up
trash or weeding gardens, in exchange for tasty treats, then it lets you also supplement
how many critters you have in your garden worlds, as they have an additional food source. This allows more top-heavy food chains too
which could not naturally exist, as your auxiliary space farms can add to the food supply at
any level of that food chain. We talked about that and concerns about genetic
diversity more in that episode, but a point we noted was that you might even be able to
get them to help with your landscaping, like a modified coral that kept your shorelines
intact against erosion, or some self-healing concrete. Land on Earth is old and natural and deep,
yet it erodes a lot faster from our activity. On our habitat, all those hills and valley
and beaches and fjords need a lot more work to make and maintain. And since rock isn’t free, you’re probably
not that thick down to your outer hull that’s spinning around, and the inside of that might
be damaged by erosion too and would be hard to get at to maintain. Now I said outer hull but in fact it probably
isn’t. As we’ve often noted when discussing rotating
habitats, while we typically depict them as a cylinder spinning in the void, in all probability
they’d be a cylinder spinning in a superstructure. That cylinder hull is built for tensile strength,
not absorbing micrometeor strikes or abrasion from space dust, all of which will be worse
because they spin, often quite fast and faster the wider the rotating habitat. It’s worth remembering what the biggest
source of space dust and debris is likely to be – ships leaving the habitat, spraying
it with whatever propellant they use, be it rocket flames or charged ions or even just
reflected concentrated light. That last is a lot less of an issue, and one
of the reasons I often tout the benefits of laser propulsion in space. So a space habitat is less likely to be a
cylinder than a big orb with a cylinder and other facilities inside it, mimicking the
asteroid mining era where they’d probably be built into excavated shafts on asteroids. That outer lay is likely to be a sandwich,
maybe a foam metal or ideally some thin outermost layer with liquid beneath that hardened over
when exposed to vacuum to scab over punctures, and to which a micrometeor can fly through
and lose energy. You might do several layers too, with deeper
ones being places where you had many thin membrane compartments full of your reserves
of water and air and fuel, ideally hydrogen or deuterium for fusion, though you might
slap solar panels and radiators all over the outside instead. All of this of course needs maintenance, and
different kinds likely need different robots. Some might magnetically crawl along the outside
polishing solar panels or welding cracks or acting like the metal equivalent of a Zamboni
machine, polishing, smoothing, melting, or laying new layers down on the outside. In fact, ice might be used as a cheap exterior
shield too, instead of metal. You might have more drones flying around with
wide spectrum cameras looking for cracks and weaknesses. Inside that thick shell you might have that
liquid and drones that swam around in there, or even tailored lifeforms, fixing the inner
layers. They might fly around in layers of gases. Indeed you might have a thin atmosphere inside
that superstructure too, from everything leaking, you want to gather that back up, waste not
want not, and higher pressures leak faster anyway, but you’re likely to have a low
pressure fog in there between the various pressurized facilities, especially the ancillary
ones where you’re building cheap and thin because it’s just some big hydroponic facility
or mostly automated factory where people don’t actually live. Other organisms might, things might easily
adapt to living on leak cracks venting air, and as we saw in Void Ecology and Space Whales
last month, you could end up with a fairly rich near-vacuum ecology even if you weren’t
intentionally engineering it. There’d be a lot trash floating around in
that inevitably too, needing picked up and recycled, but also in habitat areas in general. A solar system is a big place, but when we
think about the sheer quantity of megastructures we might build in one, potentially trillions
of O’Neill Cylinders alone, it’s not so empty anymore. Especially around hubs, as most planets would
likely be swarming with orbital habitats. Trillions of habitats mean even more trillions
of ships, and if each was losing only say one random nut or bolt or wrench or soda can
out into a space every week or so, you’d have quadrillions of hypervelocity bullets
flying around the solar system. This is likely to be even worse near dense
population areas as losses of trash are most likely when a ship is first taking off or
arriving, meaning it’s close in distance and velocity. This also means that part of being a space
janitor is writing up tickets for littering, and getting to operate giant laser cannons
to vaporize trash or the offenders themselves if space littering became a capital crime. Seems extreme, but remember, throwing a soda
can out your airlock is like throwing a bomb, and at relativistic speeds, an atomic bomb. So there are quadrillions of random nuts and
bolts floating around at tens of thousands of meters per second. You can add a lot more rubbish coming off
the hull of the megastructure itself, and while it would be slow moving locally, once
it drifts away from the immediate area it’s only moving slow relative to anything that
just happens to be on an identical orbital path. We’ve talked about Kessler Syndrome before,
a chain reaction of collisions in Earth’s orbit spraying debris and shrapnel around
to hit other objects which in turn spray out more debris, potentially shrouding a planet
in a swarm of razor sharp hyper-velocity bullets. A civilization that’s building in orbit
a lot, wrapping their world in thousands upon thousands of orbiting habitats, docks, and
industries, has to deal with this constantly. Indeed they probably don’t worry about Kessler
Syndrome happening because they probably exist in a constant state of it. Odds are someone will have run a massive cost
analysis on how much detection gear, how many point defense or laser broom ablation systems,
and how much armor to absorb hits various ships and stations need, how much extra energy
and fuel and propellant that costs, and compared it to clean up. I’d just guess that it would probably mean
they did a lot of debris clearance but that your typical inhabited planet still had millions
of tons of millimeter sized junk floating around. So there’s going to be a lot of folks who
make their living cleaning up that trash and others issuing citations and fines for making
it. And the same applies to a full blown Dyson
Swarm only scaled up a billion-fold. I don’t want to imply such civilizations
are constantly living in a swarm of their own junk and hypervelocity shrapnel, or that
this isn’t manageable, but rather that it is exactly that – manageable – and given
that it’s being managed by humans, odds are it will be managed rather haphazardly
and sloppily. And someone is going to be managing it. A recurring point on this channel is that
while such civilizations will doubtless employ a lot of robots, they will probably tend to
be fairly stupid robots requiring some oversight. This is not because such a civilization can’t
make something smarter, but because odds are the cost of having people provide that oversight
will be viewed as cheaper than purchasing tons of security and weapons to prevent or
contain a machine rebellion or pay for all the public relations management and spin doctors
you’d need to justify what is pretty much slavery. Build something as smart as a human and you
either need to give it rights, in which case you’ve just created another citizen paying
taxes and complaining about how much infrastructure maintenance costs, or you spend all your time
fending off attacks, verbal or literal, about how you’re either overtly enslaving an intelligent
mind or essentially created an entire brainwashed species that loves its job. Keep it simple, keep it dumb, or else you’ll
end up under Skynet’s thumb… or being processed in its recycling center. Besides, the other big problem always facing
post-scarcity civilizations is what to do with all the people going nuts from a lack
of purpose. Speed of reflexes isn’t necessarily an issue
either, computers mostly excel at doing simple tasks hyperfast, but there are options even
there. I mentioned earlier that in terms of layers
of infrastructure maintenance, you would also have the electronic and digital one, and it
might be quite big, metaphorically speaking, as you might have a lot of uploaded digital
people, cyborgs, transhumans, or folks who mostly live in virtual worlds. Don’t assume just because someone wanted
to move to a classic habitat cylinder – which again is not the only type of megastructure
– that they are a regular baseline human. Or that their kids would be. Just because your parents wanted to live on
some orbiting garden park, doesn’t mean you do. Or that their AI would be, again it’s not
that you don’t have AI, it’s just if you plan on making it as smart as a human, you
best tread carefully about not thinking of it as a person, and that might mean it wants
a home and time off too. Sub-human AI modeled on intelligent animals
might be a popular approach too, and if your big mechanical hull inspector drone had a
brain modeled after a bloodhound, you might be giving it a virtual dog world to hang out
in when Rover’s not fixing your hull. This represents a sort of shadow ecology. You might have thousands of different species
of critter, from slightly tweaked normal life to massively artificial mechanical and digital
life, from amoeba dumb to human smart, and all points in between, all employed maintaining
that megastructure. All probably mutating and being altered and
patched and upgraded, all likely increasingly unique to each place, as each has its own
special needs and diversification is a good strategy against sabotage or attack too. So I always assume people are building and
maintaining these things, even if the definition of people might need to be expanded, or if
the building and maintaining mostly involves shouting at welding drones too stupid to realize
they’re trying to seal an airlock not a leak, and sending angry emails off to the
programmers about the newest software patch causing your debris clearance drones to open
fire on the ones tasked with inspecting the hull because they now thought they were debris. Then got themselves shot to smithereens by
the station defenses that identified them as hostile after getting a distress call from
the debris-collectors shouting about being under fire. Incidentally, this is another reason why I
always describe space habitats not as a fragile shell but probably massively armed and armored
facilities that would be deathtraps for an invasion force. Partially because you really do need to have
some thick hulls swarming with anti-debris lasers if you expect folks to feel safe living
there. And partially because that invasion force
needs to be kind of careful going in, even assuming all those trillions of neighboring
space habitats don’t care about you blowing that place up, they are not going to appreciate
ten billion tons of flaming wreckage and debris flying around the solar system. Amusingly probably being chased by any remaining
maintenance drones, a gathering swarm of salvage drones who identified it as valuable fair-game
assets, and merrily getting shot to pieces by all those neighbors trying to take out
the flaming wreckage with whichever of their defensive batteries aren’t currently busy
retaliating against the invasion fleet that caused the problem. And yeah they probably will have those giant
anti-ship guns because having a megaton space freighter get hijacked or sabotaged and crash
into your habitat is a bad time to wish you’d invested in heavy artillery. Possibly not on individual O’Neill Cylinders,
but as I said, those are on the small side of megastructures under discussion and you’d
probably also tend to see them clustered in packs anyway. Even if they’re as big as you can build
for engineering limitations or economic viability, you can lash a ton of them together with tethers
for easy transport to and fro and proximity has value, so they’re likely to be clustered
up like islands in an archipelago rather than evenly distributed, possibly with a superstructure
all around all of them. Neat thing about most space habitats, they’re
all basically spaceships too, albeit rather clumsy and slow ones, so it’s kinda like
a giant houseboat you can move around to be on its own or park in clusters to share ancillary
facilities, which presumably include giant defense guns. But it could easily be that those would evolve
as some leviathan equivalent of RV parks, where instead of an RV going to a place that
has hookups and support for lots of recreational vehicles, they have them for entire space
stations. Again a space habitat it basically a somewhat
clumsy spaceship, and also more like the gardener ships we discuss for interstellar colonization. An interstellar ship needs to be totally self-sufficient
except for raw materials and fuel, so they can replace any components or colonial gear
damaged or decayed in century long voyages. This effectively makes them mobile factories
and colonial farms since instead of parking at their new world forever, they can stop,
drop off half their colonists and colonial gear, restock on raw materials from some asteroid,
and make new gear and breed more colonists on their way to the next star. Possibly also new ships, since they need to
be able to manufacture every part for their own ship anyway. A similar philosophy applies to space habitats,
they don’t have to be entirely self-sufficient if they live in built up solar systems able
to supply them, but they will need to be constantly engaging in repair, and possibly growth too. This could result in cylinder habs that constantly
grew in length like some coil of sausage links, occasionally detaching sections for major
repair or retirement, or some big circle of a rotating habitat, a small version of a Topopolis,
that had a manufacturing center that just slowly rolled through it at a glacial pace
replacing sections, like the Ouroboros, the snake eating its own tail. So long as the hoop is far wider in diameter
than the thickness of it, it can be bent and rotate for gravity just fine, same as even
steel can be used like a rope if long and skinny enough. Obviously you automate anything you can, your
limitation being how smart and sophisticated you’re comfortable with that automation
being. And it can be human level or smarter too,
just depends on what your civilization is comfortable with ethically, and smart enough
to avoid killing themselves with. For instance, one of the more obvious maintenance
pathways is to go the quasi-biological route, as we’ve discussed before and most recently
in Space Whales & Bioships. If your megastructure is basically a big animal,
biological or not, with various organs overseeing repairs and clean up, it need not be too smart,
and certainly many of the parallels for microorganisms living in it doing work need not be, but it’s
plausible you might find it advantageous to make something pretty smart. Needless to say you circumvent a lot of problems
by designing something that likes what it does. You’ve essentially gone and made a big Space
Turtle whose shell you live on or inside, and you’d prefer it not minding you doing
so or actually felt happy as the home to a prosperous civilization there, rather than
regarding you as some sort of mold living on it or cruel taskmaster hurting and compelling
it. Incidentally when talking about artificial
or engineered intelligence of human level or higher I generally mean that in regard
to its capacity for reasoning, abstraction, creativity and so on. Raw processing power is mostly irrelevant
unless it turns out that such things inevitably become sentient and sapient above a certain
threshold. You are going to generally want that fairly
often though, as while some megacomputer able to track a quadrillion objects simultaneously
need not be even vaguely sentient, if it isn’t it is very vulnerable to something stupider
but smarter, as it were. And of course if you’ve gone the heavy artificial
intelligence route and your various megastructures are quite smart themselves, even if they generally
like their jobs, some might want things changed up a bit or become bad eggs. You don’t want to be living on a space turtle
that’s decided you’re all a parasitic mold and it needs to fly by the Sun for some
cleansing UV rays, or regards you as its precious but unwise children deeply in need of brainwashing
or it’s played the long game and subtly influenced everyone to breed for stupidity
or complacency toward it. Add to that, outside of one of these megastructure-minds
going entirely homicidal, folks would probably be very hesitant to kill one, which might
be rather tricky to safely do anyway, but good odds are if you’re going this pathway
you do regard it as inhuman but still a person or honored critter. I could imagine folks opting to evacuate such
a place and leave it be or try to talk it into some new task. A habitat becomes a nature preserve instead
or some massive warship foundry that decided each ship was it’s child and is panicky
about where they’ve all gone or gotten destroyed gets repurposed into an uncrewed observational
array or one with a skeleton crew, even if it’s not terribly good at the job. Another fun possible story there, tons of
abandoned crazy derelicts that were still quite functional but only the brave, desperate,
or equally crazy wanted to visit them. Which offers another sort of maintenance,
psychologists for disturbed megastructure-minds. And again while you might have a single mind
for a single place, the equivalent of the mythical Genus Loci, you’re just as likely
to have several for many different functions, with many layers of complexity and oversight,
that shadow or machine ecology I mentioned earlier. You might possibly have a single overmind,
the Space Turtle, but more likely some equivalent to an ecosystem rather than a single organism. I don’t use the ecosystem parallel casually
either, as we noted in Void Ecology, even ignoring that biological versus mechanical
is a rather vague and arbitrary thing, and a bit of a false dichotomy, such things are
likely to take on the characteristics of an ecosystem even if it’s designed rather than
evolved. It’s also worth keeping in mind that most
of these have ecosystems on board them too, which we mentioned earlier probably need maintenance
in terms of things like genetic diversity, though the bigger megastructures can potentially
be as stable as Earth in that regard, indeed some are artificial planets or larger than
planets. Those usually also would need Active Support
to keep them from falling in on themselves, like orbital rings, and those are going to
need maintenance too. Not all megastructures have anything to do
with humans habitation either, but we generally focus on those, partially for the obvious
reason and partially because many things you need to do at a big scale don’t require
big objects, I don’t need an asteroid sized mining facility to disassemble an asteroid,
many smaller ones might do the job as well. See the various megastructure and generation
ship series for more discussion of those. Similarly raw energy abundance can help with
debris and maintenance, if you’ve enough juice everyone just vaporizes any debris right
down to atomic dust and can go heavy-handed on the forging and recycling by just using
lots of regular armor that’s just raw plain metal you detach and replace and smelt down
occasionally. It’s good to be experts at recycling and
repair in space but you can make up for that with just raw use of simple automation, raw
material, and tons of energy. There are no free lunches nor infinite stockpiles,
entropy wins out in the end, so civilizations should tend to want to be efficient even if
they don’t have to be, but you might also see many phases of approaches, much as we’ve
had here on Earth. Early energy-rich, high automation societies
might cheerfully build many super-armored, resource intense habitats that were surrounded
with space litter, that’s very easy to imagine in an early colonization of the Asteroid Belt
for instance, what with all the mining and likely many habitats built inside those asteroids,
then switch to other methods later. In all probability you pursue all these approaches,
simultaneously, or in phases, or certain factions of civilizations prefer one route over another. Lots of types of megastructures but I don’t
classify Dyson Swarms as one normally, because I never think of them as likely to be homogenous. At least civilization focused ones – there
are other Dyson Swarm and Stellar Engines types. Trillions of small artificial worlds all spread
out just never strikes me as a super-unified civilization or likely to remain one if it
began that way, especially since as we mentioned a couple weeks back in Threats to Interplanetary
and Interstellar Civilizations, diversification is a good survival strategy, and we saw a
few more reasons why this is so this time. Of course, unless your maintenance is truly
perfect, you’re likely to eventually hit a point of diminishing returns where you opt
to build a new one and abandon the old, and we mentioned other ways you might get derelicts
too, like one with an overmind that went nuts but was left be. In a system with trillions of these places,
even if they are built to last as long as civilization has been around, tens of thousands
of years, and even if they were only derelicts a little while, maybe a decade on average,
that still means at any given time you have billions of them sitting vacant and derelict. Waiting to be scavenged, repaired, hauled
off to the breakers, or just waiting miserably with a few stubborn hold outs hoping their
ghost town will flourish again one day. Such a tiny fraction, small compared to the
portion of vacant homes and buildings we have, and yet it’s still billions of derelict
megasturures, quite possible acting as temporary homes to trillions of roamers and scavengers
and pirates, a scifi author’s dream come true, and something we’ll look at more in
a couple of weeks. But for now, that’s Space Janitors and Megastructure
Maintenance, the gritty underside of our bright future, but still pretty awesome, I think. Civilizations like we were discussing today
are shaped by and critically dependent on technologies like metallurgy or physics or
automation, but then so are we even today, and more so every day as technologies like
robotics and computer science move more and more into our daily lives. An understanding of how all this math and
science works is no longer just valuable, but vital, and if you’d like to learn more
math and science, and have fun while you’re doing it, try out Brilliant. Their online courses and daily challenges
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challenges in the archives and access dozens of problem solving courses. I mentioned derelict space habitats and megastructures
probably being very common in the future, even in a civilization that’s pretty good
about it’s maintenance and clean up, and that’s a topic that seems worthy of its
own episode, so in two weeks we’ll head back to the Rogue Civilizations series to
look at such derelicts, space hulks, trash planets, and the sorts of civilizations that
might develop around them. But next week we will be celebrating our 200th
Regular Episode here on SFIA, where we look at so many awesome things that might one day
come to exist, and we’ll commemorate the occasion by turning things around and looking
at things which will never exist. For alerts when those and other episodes come
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website, IsaacArthur.net, all linked in the video description. Until next time, thanks for watching, and
have a great week!
Great episode Isaac! A topic I've had particular personal interest in since watching the classic hard sci fi anime "Planetes."
Thank you Isaac for one of the best episodes in a long time! So many cool ideas I'd never thought about.
Space Zambonis!
Great video. I never thought of the whole "life in a constant, Solar System-wide Kessler Syndrome" factor from all the space debris, but that makes sense - a solar system-spanning civilization is going to have a lot of debris drifting around, especially since it will probably take them a long time to finally coordinate on reducing it.
Getting rid of the heat in an O'Neill Cylinder is a real nightmare, especially if you have a big open interior. That's why I think for temperature and weather management, they'll just have an inner cylinder inside the outer cylinder that simulates the sky, to reduce the volume of air and pollutants that they have to cycle and remove.