How many people are needed for a space colony?

Shifting Reality is set in a space station orbiting Epsilon Eridani b. The planet, which my characters call Sarasvati, is a gas giant which I have given rings, and the station’s main industry is the harvest of ice from these rings for the production of water, oxygen and fuel. The station is one of four human settlements in the solar system, three of them mining stations. These four settlements survive as independent communities, if not entirely from each other, then certainly from Earth, 10.5 lightyears away.

All of which raises the question: just how big does a community need to be to be truly independent, while maintaining the standard of living we’re accustomed to?

Let us take a few steps back and ask a question that will probably sound stupid, and variations of which make up many jokes: how many people does it take to change a lighbulb.

Duh, I hear you say. Changing a lightbulb is so easy, that’s why the jokes exist. I totally just googled “lightbulb jokes” and there is an entire site devoted to them, from which this beauty: How many porn actresses does it take to change a light bulb? A: Well, it looks like 2 of them are really doing it, but the real answer is actually none. They’re just faking it. Mwahahaha! Lightbulbjokes.com

Anyway, the point is, changing a lightbulb is an extremely easy task.

Or is it?

Think of all the assumptions underlying the word lightbulb: that we know what it is, what it does and how it works. That there is a reliable supply of electricity. That there is a company that makes ladders. That we have a house that has a ceiling for a lightbulb to hang on.

So, how many people does it really take to change a lightbulb? How many people does it take to make sure that lightbulbs can exist and work so that the Irishmen, or Canadians, or porn actresses, can change them?

There’s the manufacturing: the glass, the metal, the factory that puts it together and puts it in a box. There is the mining. There is the power stations and the industry associated with making them work (coal mining, hydro-power and dams, wind farms, whatever). None of those industries will work without buildings or other places to house them. People make these buildings. Those places need to be cleaned and maintained and you need people to do this. None of those companies can survive for very long without an influx of new workers, so there are places for the new generation to be trained. Looking further into the future, each of those companies needs to make provisions to allow their workers to look after the very young. None of any of these people do well without food, so there are the people who cook, and they, or course will need something to cook, so you need agriculture, after all those people have used transport to get to their work, and would like to flush the toilet after they’re done, and would also very much like to buy all the items they need in a shop. And doing all of this naked could get rather embarrassing, not to mention cold. I have not yet mentioned the internet, or medical care.

By the time the insignificant light bulb is screwed into its insignificant fitting, many people have made contributions to it. Yes, many of those contributions are exceeding fleeting, but in terms of our question–how many people would a truly independent human colony need–by no means insignificant. All those things need to work and need to be in place before someone can climb up the ladder and change that lightbulb.

Medieval humans spent a hideous amount of time simply surviving: chopping the wood, hunting the game, toiling in the fields. They might have been smart, but only the very rich ones had the time to do something with it, by buying labour to do their domestic work. When technology lifted, the growing of food was one of the first things to be large-scale outsourced to other parts of the population. Ditto with the building of houses, the very basic level of health care, the making of clothes, the raising of farm stock. Then: transport. Many people who first bought cars still did a lot of their maintenance themselves. The cars, of course, were manufactured, but these days very few people maintain their own cars. Your car might even need a computer technician. The making of clothes has gone the same way. Of course none of us, barring people in remote areas, ever produced our own electricity or looked after our own water and sewerage.

Each time living standards jump, we add an extra level of service, with associated necessary people to maintain it. If you are astonished by how many people’s efforts have touched the humble light bulb, you will be blown away by the number of people who have breathed over the space program.

I wanted to know what the web says about minimum population requirements, and if you google “how many people are needed for a space colony” the number that’s most quoted is ten thousand. I haven’t discovered the source of this number. Will quote it here when I find it.

Ten thousand is a large-ish village. My husband’s family lives in a town roughly that size. It’s very agricultural, so food isn’t a problem. There is a council that maintains roads and sewerage. But no one makes washing machines. And if someone is sick, you have to go to the hospital in the city. There is also no high school, and I’m not even speaking about a university.

Picturing that village with the people in it, it is my guess that if the rest of the world disappeared, they’d survive fine, but it would be accompanied by a very sharp drop in living standards.

Yeah, yeah, I can hear the protests. You train the people. And they multi-skill. Yep. Sure. And the people starting the colony could decide to only include smart people, and not take loafers, and expect everyone to put in their very best effort. But you know what? That will only work for so long. Loafers, disagreers and political stirrers are born. We’re in space 10 lightyears from Earth. What are you going to do? Execute them? And the last time a society as a whole tried to give everyone jobs and be hyper efficient, we called it communism. Ain’t gonna work.

What is more, society needs a fairly large proportion of people who are happy to just consume stuff. A lot of the above services will only work well at large scale. Ten thousand might be a nice number for a seeder population or might be a genetically justified number (it gets quoted in this respect), but it’s not a long-term viable population.

Approaching the problem from the other side, and forgive the macabre-ness of the following: if a quarter of the world population disappeared overnight, would our standard of living drop?

Yeah, yeah, I hear you, it depends on which ones. You could argue bluntly that the world could well do without the poorest people, but don’t go telling me that the rest of the people could just go on living as before. For one, who made that shirt you’re wearing?

A quarter isn’t that much, so what about if half the world population vanished, and let’s be fair and distribute the vanishing evenly over the entire population. Three and a half billion people, and you’d miss half the people who normally share your table at dinner. Don’t tell me worldwide standard of living wouldn’t be affected.

OK, still, it’s a matter of choosing the right people, and training. But, in order to have the same standard of living, those supposed ten thousand colonists will need the same access to extremely specialist medical care that we have. We have this care because people are allowed to specialise–because they outsource everything else. Forcing fewer people to do the same work means unspecialising them. A jack-of-all-trades will not do the same job as a specialist. End of story.

But, you can automate tasks.

Yes, and each level of technology you jump will require more dedicated specialists to maintain it. Dog, meet tail.

You need more than ten thousand. Substantially more. You need something the size of a decent city, just to maintain our current western standard of living.

Oh, I forgot, we expect these folk to maintain an interstellar space service as well…

Words and worlds: about my SF fiction worlds


The marshes of Barresh seen from the direction of the great esscarpment, as in Watcher’s Web.


As I heard today that my novella The Shattered World Within will be published in Giganotosaurus (and I’m extremely happy about his; last year they snatched two Nebula nominations out of twelve stories published, so it’s a well-read magazine), I made some comments about relationships between this novella and published work. Facebook and Twitter are not the most ideal venues to explain those things, so here we go.

In my Science Fiction worlds, I use (not exclusively, but rather a lot) two different worlds. One, I refer to as “the space opera world”. It has, space opera-like, different types of humans who have evolved like Darwin’s finches, and we–the humans we’re familiar with–are only a small branch. In this world, there is FTL travel, which is a network of custom-made wormholes, a network that relies on technology and politics outside the control of Earth humans.

This is the world I’ve used in Shattered World, but also in The Far Horizon and Watcher’s Web. Shattered World is set about 100 years in the past, Watcher’s Web in the present, and the novel Ambassador (Ticonderoga Publications 2013) is set about 200 years into the future. Due to the Darwin-finch effect, it is a rich world, with many different corners that don’t need to (and often don’t) overlap. But you may recognise some names. Barresh (where most of Watcher’s Web is set) is the locality of the above picture-doodle in Bryce–although the buildings need to be lower. Other names will we Asto, the Coldi people, Aghyr, and Miran, or Hedron, the locality of Shattered World, although it doesn’t yet have a name in the story.

The other world is the one I call the ISF/Allion world. This world has one human starting point (Earth), and spends a lot of time without FTL travel. It is developed eventually, but it’s not easy, as in space opera. In this world, Allion Aerospace Ltd was a company that boldly went… er, no… boldly bought the ISS off the various contributing nations when they wanted to let it infall and developed it commercially.

(Seriously, I made this up before all this GFC and private space flight business started)

They built a self-sustaining habitat, supplying the station from their base in Indonesia. They scouted workers amongst brilliant postgrad students at western universities, disgruntled by their lack of prospects in their home countries, and their inability to secure a working visa for their home countries. By far the majority of their recruits are women.
They also put the first human (Chandra Lee–non-white, non-male, non-American) on Mars, started a settlement there, and the company became fully space-based.

The rest of the–more traditional–world has been playing catchup since, and both Allion and the official, government-sanctioned International Space Force have made mistakes, fought skirmishes and one all-out war.

This world is limited to hard SF. It encompasses a much narrower range of environments and stories, and most stories fit after the other (although you can read them as stand-alones). There are also a lot of short stories in this world, such as Trassi Udang (Belong), Poor Man’s Travel (Anywhere but Earth), and Charlotte’s Army. All of these are seen from ISF perspective. His Name In Lights: a novella is from Allion perspective. Watch out for a longer work, tentatively called Shifting Reality, that follows where Poor Man’s Travel left off, and involves Ari from Trassi Udang when he is four years older.

Oof, I don’t think I would have fitted all of that in 140-character Twitter posts.

Technology in society and worldbuilding–an ode to the washing machine

In one of the free-access halls of the Art Gallery of New South Wales you can find this painting. It’s called The Widower, and was painted by Joseph Tisott in 1877. I cannot go to the Art Gallery without looking at this painting, and I cannot do so without tears in my eyes.

This painting encapsulates so much emotion. The little girl is happy; the father worries. The year is 1877. His wife has died leaving him to look after his children by himself. He works a back-breaking job on the land or doing some trade. He cannot stop work or work less to look after his children. There is no worker protection or insurance. There is no 9 to 5. There is no one to look after the children. If he doesn’t already know how to cook, sew or clean, he could learn to do this without a doubt, but, the thing is… merely doing the laundry is a major backbreaking task, and so is cooking and cleaning, and there is no time in the day for him to do this. Not while he is alone. He’ll need a housekeeper, or he’ll need to re-marry.

This post is not about gender issues. It is about how much technology has liberated us from doing menial tasks whose only function it is to keep ourselves fed and clean.

I read an article in the newspaper a while back that the greatest technological invention that has made the most profound difference on our daily lives is not the internet, or the car. It is the humble washing machine.

My paternal grandmother was born in 1897, and she grew up in a fairly backward place, where there was no electricity. Their pre-contraception household had 13 people, and doing the washing was a huge, hard and relentless task. They surely didn’t wash clothes as often as we do, but they did change one sheet on the bed every week, and washed, bleached and ironed all their clothes. Pre-electricity.

Our family has only five people, but the contraption I fear breaking down the most is the washing machine. At our place, I do the washing. If I had to hand-wash our clothes, or even half of them, I would spend a couple of hours a day doing this. I would have no time to work. Moreover, I would not be able to leave the house for more than a day, because my family, lovely and able as they all are, would not have this kind of time in their day to do this either.

So, consider that next time you design a low-technology world.

SF writers having fun with seasons

As a writer, you can do all sorts of fun worldbuilding stuff with seasons. The English-language concept of Spring-Summer-Autumn-Winter is based on the European seasons. Even on Earth, it doesn’t hold everywhere.

In northern tropical Australia, where I used to live, you have two seasons:
A dry season, when–surprise, surprise–it doesn’t rain, and a wet season, when it’s supposed to rain but often doesn’t, and if it does, it does so in quantities no drainage system could possibly be built to cope with, and in between these bouts of liquid air, it’s just horrible and humid.

Even in Sydney, we have only three seasons. Autumn very slowly morphs into spring, as the European benchmarks for winter–long nights, bare trees, and snow–just don’t hold. Many trees never lose their leaves at all, and some only do so well into spring, and even some of the European trees appear mightily confused.

On your imaginary world, you may choose to adhere to the basic four-season model, but if your setting has a dry or tropical climate, the seasons will be different.

But why not do something more challenging. Let’s go back to what causes seasons. Two things:
1. the inclination of the planet’s axis of rotation compared to the plane of rotation.
2. physical distance of a planet to the star.

Factor 1 is by far the most important on Earth. It is why we have summer while the northern hemiphere has winter. Factor 2 requires an elliptical orbit. No planet has an orbit that’s 100% circular. Earth’s orbit is pretty darn circular, but still, Earth is closest to the Sun in January and furthest from it in July. Therefore, the summers in the southern hemisphere are slightly warmer than summers at similar latitude in the northern hemisphere, and the winters slightly colder. Still, when you consider other factors of topography, this effect is so small as to be meaningless.

Supposing you were on Mars, the facts would look very different. Mars has both an inclination and an elliptical orbit. Therfore, the winters on the southern hemiphere of Mars are noticeably colder (and longer, since a planet moves faster the closer it is to the sun) than those on the northern hemispere and the summers noticeably warmer. However, the inclination of Mars is still similar to Earth’s.

Now imagine if you were on a planet rotating perpendicular to the plane of orbit. We have such a planet in the solar system: Neptune. If you stood on the north pole of Neptune in the northern summer, you’d have the sun not only permanently above the horizon, but straight overhead, as in the tropics on Earth. In winter, the sun would disappear for months. The sun would only rise and set every day on the equator. How would plants and animals survive on a world like this?

Worldbuilding assistance

When I’m doing worldbuilding, I find it helps if I can find images of landscapes, items or technology that resembles what I’m trying to describe, but sometimes that doesn’t work, so I’ve gotten out the paints and pencils after a long retirement and started to dabble in art again.

I’ll be talking about some of the results.

A key location in a number of my fiction works is the city-state and surrounding enclave of Barresh. The picture above is what I first knew of it when Jessica in Watcher’s Web unwittingly stumbled into the territory after having crashed in the rainforest on top of the cliffs. Getting down to water level is a matter of falling down a rock slide. She ends up in the place shown here. In the lagoon that lies inland from the mouth of the river is a village where natives live. To the left is a huge expanse of marshy ground with little islands, reeds, water plants, thermal springs and geysers, and BIG fish. The large island with the city is way to the left. That’s where she needs to go, but she doesn’t have a boat (remember the BIG fish with BIG EVIL teeth?).

Anyway, while the place was always in my head, I’ve found that trying to put it on paper forced me to think about some of the logistics. How deep is the water (about waist deep in most places)? How far does this cliff go for (a long way)? Is there an ocean anywhere near (yes, on the other side of the city)? Things like that. It’s a very useful exercise.