realistic number of people for an Earth Colony

Well, having lived in only small cities, I'd say 50.000 would be more than enough. You wouldn't know everyone but you'd bump into familiar people regularly.

Some interesting thoughts along these lines over at Charlie Stross's place. He thinks a self-sustaining colony operating at our current level of civilised society would need a LOT of people. ("How many people does it take to design and build a space suit?" is an interesting question he asks.)

If ypu are thinking about how many people would be in the initial colony ship sent to start a colony, then oyu should also consider the time, distance, and size of the ship. The matter of moving enough food to feed even a thousand people on a space ship for any long period of time demands a huge amount of energy, which is why we usually put them to sleep for the trip. The colony would have to increase population to many thousands as quickly as possible, but it would take multilpe ships and multiple ships to send that many people Do you have faster than light travel? If so, then use it.

Torgo said:

Some interesting thoughts along these lines over at Charlie Stross's place. He thinks a self-sustaining colony operating at our current level of civilised society would need a LOT of people. ("How many people does it take to design and build a space suit?" is an interesting question he asks.)

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Everything he says is exactly right -- about the complexity. He's 180° out on the political stuff he put in there (in my opinion), but that's just an aside.

Society is the division of labor for the betterment of all. In other words, through specialization, we reach a much higher potential because people do the things they are best suited to do and can concentrate on getting really good at a very narrow discipline. In order for a society to survive at a specific level, one needs the appropriate degree of specialization. You can't make a space suit without a seamstress or a chemist. Therefore, you do need a large number of people in order to do that at a self-sustaining level.

A colony can have smaller numbers than general society because people can be hand picked for the exact specialties that are needed. But it's still going to be a lot of people. Millions of them.

If the colony is only a year away, it is possible to get help with specific tools and items that the colony won't be able to do on their own. This is dangerous to an extent if the supply line is cut.

Without enough specialists, society will regress to a simpler level because the technology can't be maintained. People will become generalists and therefore won't be as efficient as they were before. Think of a mid-1800's doctor who also cuts your hair vs a 21st century neonatal surgeon.

In one of my current works in slow progress, I debated this number issue and came up with what I hope works to START a colony.

1...The planet has to be able to support life, water, air, and basic food products (edible plants and or animals), have to already be there and our genetics have to tolerate this new food.

This new world would also have the basic building elements in order for a new colony to survive. Trees for lumber to build houses and use for fuel, furniture, and basic equipment like plows and carts. Also, coal, iron and other metals to be mined to make crude instruments for mining, building, farming, etc. Crude forges could be built fairly early, but the minerals have to be there and somewhat easy to get to.

2...Because it will take a large gene pool for any colony to survive without developing genetic DNA line problems, my colonist have more women than men. Everyone understands that monogamy is out for several hundred years so the colony line can be established. Of course, saying monogamy is out and actual practice will be difficult and no will be forced into relationships they do not agree with.

3...Obviously not everyone involved is going to be a specialist of some sort. The colony will need not just the scientist, doctors, veterinarians, engineers, technicians and so forth, but will also need specialized skills in farming, fishing, building anything from houses to boats, craftsmen to work in metals, and even specialized laborers for building and food production. Some type of military or police members will also be needed just to keep the peace in the colony as well as protect the colony.

4...Politics. Yes there will be politics, but before the ships ever leave earth, a set of laws for the colony will have to have been drawn and everyone will have had to agree to them. Once the colony is established in twenty years, then new laws can be written, added, or even old laws removed. A single leader will be needed for the first five years and then the colony can vote on a new leader and elders or senators to represent them. As new villages form, leaders in those villages will play into the political scene as they represent their village needs to the main colony city. If that makes sense...

5...What I came up with is 15,000 colony starters, minimum, with no children. All adults. The children can come in a few years after the basic colony has been established. The first generation should more than double the colony in the first twenty years, excluding any massive plagues or die offs. The Second generation would then double again in another 20 years and the colony could start spreading out and establish additional towns and villages. By the fourth generation, 80 years after the first generation arrived, trade between the different towns and village will start progressing and we end up with the start of a new world as each generation spreads out.

This is all based on limited interaction between the mother planet and the colonies as supplies will be costly and take a long time to get. So the colony has to be self sufficient and that means basic fuels and energy is going to be limited until what they brought is gone. Sure, we can bring a lot of solar stuff, but when that stuff starts breaking down, you have to have the ability to repair or replace parts which a new colony will not have. Paper will once again become a necessity because tablets and lap tops will break down, or just become useless with the power to run them. Same with all electronics unless you want your colony to develop nuclear energy, or some other such energy form. Wind of course would be a blessing for small scale energy.

I see my colony almost starting out much like Europe did during the first century. My colonist for all purposes would start out in the first century of their new world and a lot of exploring will occur, especially once they realize they are not alone...

Now, if the colony is on a world with limited natural resources, then you will have to figure out what is the value of settling on a world that has limited resources. A mining colony would be far different from a colony sent to populate a new world.

I hope some of this makes sense...

It can be as big or as small as you like, depending on your imagination. You could send one man with big vats of sperm and eggs and something to grow them in and a way of turning them into instant adults once hatched. (Although I would send 2, one man as a spare).

Alternatively, look at the various first fleets that colonized around the world. How many people were on the mayflower or in Sydney's first fleet. That had 1000 people with 2 war ships, 6 passenger ships and 3 supply ships. That was enough to establish a colony but it was still very dependent on supply from England since the crops they took with them did not grow using traditional agriculture techniques. It also took a year to get supplies from England. With the different ships, not everyone would know everyone else.

If it is a totally independent colony (with no support from Earth) see other peoples postings above. They are excellent.

A finished novel of mine (submitted and hoping) dealt with the idea of colonization in a slightly different way than what the OP proposes. My novel had the MC and the supporting cast (seven others at first and then more later on) abducted by an alien force to another world. This place had already been set up for them, so there was no need to world-build per se, but the very size of the colony was small which means in the long term, they'll have to breed or die. I never mentioned monogamy or polygamy in my work, mainly because it's a non-factor, for reasons which shall go unmentioned for the moment.

The "50000 to start with" idea is good. Have you thought about how many starships that will take and how long they're going to travel in space for? Other things to consider would be manpower to build the ships, length of time (is there a deadline for this kind of colonization?) equip the crew, train others and so on. Fifty thousand, though, would certainly be a good start.

sassandgroove said:

what is a realistic number of people for an Earth Colony ship to another planet? I want it to be enough that my character won't know everyone on the voyage even though it took over a year.

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A planet where? How far away? Mars? I could see a large ship (where you can't carry a large amount of fuel so you can't do a large delta-vee, thus it has to go slow and take a long time to get anywhere) taking a year from Earth orbit to Mars, similar to how NASA's Messenger probe got to Mercury:
http://www.nasa.gov/mission_pages/messenger/timeline/index.html

There will be a LOT of information exchange with Earth. They will carry with them computers that have substantial portions of the Internet (much like the Watson computer that won on Jeopardy having its own copy of Wikipedia and many other databases), and much of that (news sites, additions and changes to Wikipedia, sites the colonists "subscribe" to such as the forums on absolutewrite.com) will be continuously updated, with the information being only a half hour behind. General websurfing will be hindered, however, by it taking an hour round-trip for whatever random webpage (such as joe's blog) to load. They'll have whatever expert help they need from Earth, as long as they don't need an answer in less than an hour.

J.S.F. said:

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The "50000 to start with" idea is good. Have you thought about how many starships that will take and how long they're going to travel in space for? Other things to consider would be manpower to build the ships, length of time (is there a deadline for this kind of colonization?) equip the crew, train others and so on. Fifty thousand, though, would certainly be a good start.

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If you're going to one of the the nearest stars, four or five light years away, the trip will take 20 years with super-good rocket engines and antimatter-fuel technology (we're talking major, MAJOR engineering breakthroughs in rocket engine technology), or with lesser technology more likely for the first interstellar starship, centuries. Thus it will be a generation ship(s) and the people who arrive at the distant planet will be descendants (great, great grandchildren) of the people who start the trip, else a "suspended animation" technology is used to put people in a sleep that keeps them alive for hundreds of years.

Furthermore, they will only be able to have good radio contact with Earth for the first few years or decades of the journey. At some point the distance may be too great to have any contact at all. At that point the ship(s) will truly be on their own. At least if they're all going to the same destination, they should have good radio/TV/Internet contact with each other. It would cost less to make one big ship, but there might be good reasons to have several ships (the possibility of a ship hitting a rock which would destroy it at interstellar speeds, or something 'going wrong' socially on one ship).

A colony could be self-sustaining with a lot fewer than 50,000, if the population has enough genetic diversity and they have technological mens for producing many goods. The logistical problems of transporting people to the nearest stars that might support a colony are huuge, unless one had ftl transportation. Even the genetic diversity isn't important, as long as there are nogenetic diseases among the colonists.

Inbreeding wasn't all that bad for humans. Nearly all marriages were between cousins until a few hundred years ago. For hundreds og thousands of years people inbred with a occasional addition of foreign genetic material, and most tribes had no more than a few hundred members.

Lots of questions would go into answering this. How big are the ships? How many ships? How long is the journey? Are they awake for the journey? (you can stack a lot more in stasis). And how many waves are they arriving in?

Genetically I have heard of some very small numbers, 50-150 needed for enough diversity.

As far as population, my high school had 1200 and I never did see or meet everyone, even in my own class of 400.

How the population size relates to ship size depends on your level of technology. Are you going to have replicators for food, like Star Trek, or are you going to have pre-prepared meals like the shuttle or the army, or are you going to use hydroponics or greenhouses to grow the food, or just store in enough for the whole voyage. Plus, after they arrive, if they are going to grow crops, they have to have enough food until they can reliably grow their own. As far as the people go, you can cram a lot of people into a small area. US aircraft carriers cram in 6000 people into that space. Replicators require power, the rest of the food sources require ever increasing space up to growing it in a green house.

I'm probably over thinking this, but sometimes I find it helpful to have all the questions out there.

Personally, I'd go with small numbers on each ship and if you want a larger colony, have multiple ships, trips, or have some time pass. Or have them in stasis and pulled out as needed until the colony is functioning. Or an advance expedition to get the colony going and ready for the rest of the arrivals. I think using stasis and about 1000 people per ship, a total of maybe 5 or 6 ships, total colony population when they are all revived would be about 6000.

Sass:

Why are they there? I mean, it's entirely possible that they might be a group seeking to "get back to nature" or to "rediscover God," to farm, to establish the universe's best university.

The motivation for settling would also affect what they build, and maybe even how many people such a colony would need for self-sufficiency.

You can only know about 50 people anyway.

sassandgroove said:

I was going to assume that in the future they found a way around that and though it would still take some time, it was more like a year rather than 20 or a generation.

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Yes,, there wuill be a way to drop out of this space-tie continuum and drop back in at a different place. I expect that to be available within the nex firty years, so travelling to another star system will be relatively easy.

What about tech there in the colony? I thought that at first they could use the power from the ship for a few things, when they first landed, they could each send one message home to say there were ok, that kind of thing. When I start the story, she says they just finished building the power station. But then they'll have to build a grid, etc. And what about sewage (yuck) and theywouldn't have cars and cell phones would be useless and things like that. I am tyring to work things out in my head. They would only have the food they brought with them at first. They would have to find native edible plants and animals and plant their own seeds and hope they grow right away.

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You will have to decide what level of technology they will have, If they sidestep space-time, then they will be able to import anything at reasonable prices. If they used generation ships to get there, then they will have to do things the hard way. Humans don't need much technology to survive, if the climate is reasonable, and there is adequate food.