Multigenerational colony ships

There's a movie called Mission to Mars (or something like that) with Timothy Bottoms where a group lands on Mars and takes a hydroponic green house with them - a tent filled with plants, a water source (don't recall what it was) and the ability to generate power. INside the tent the astronauts can remove their masks because of the oxygen generated by the plants. FWIW

I looked at population size for a lost colony setting. While that doesn't have all the same issues as a generation ship, the population situation is similar.

Here are the only links I still have (I thought I had more):
http://www.newscientist.com/article.ns?id=dn1936
http://en.wikipedia.org/wiki/Small_population_size

My mind boggles at the number suggested in that first article (also, I think it's counting breeders only, without taking into account the possibility that some individuals may die before reproducing), but I never found much else that gave any numbers at all.

Another breeding tip- google 'line-breeding' and horses. It's like well thought out inbreeding (in theory). Very popular in the Quarter Horse circles, among others. (He's got X on top and bottom! He's sure to win the futurity!)

You only really need like a 100-200 people to found a colony, IF strict breeding procedures are followed.

rosemerry said:

My WIP deals with a colony ship that will take around 4,000 to get to the planet they want to colonize. I have 1400 people going on the trip. My plot consists of once they reach the planet should they stay on the ship (don't fix what ain't broke) or leave the ship and colonize the planet (finish the original mission). This is why cryo won't work cause then my plot is just shot to hell.

I'm still working with the numbers but is anyone else working on a similar story that deals with this type of ship. I know Pthom is. That one of the biggest problems is population numbers.

As far as food, I was going to have them using hydroponics so they would be mostly vegetarian. Although I did read an article in Discovery where scientists are growing meat in petri dishes so colonists could get meat that way.

Click to expand...

You might want to read these books. They're fiction.

Orphans of the Sky, by Robert Heinlein. A multigenerational colony ship on which there's been a disaster. The descendants of the original colonists have forgotten they're on ship.

Methuselah's Children, also by Heinlein. A persecuted minority is forced to flee the Solar System. They grow meat from a heart muscle, by the way. The ship wasn't designed to carry them all. And there's a little discussion of the consequences of inbreeding.

These were written about fifty years ago.

Alexei Panshin used the multigen ship in his novel Rite of Passage.

There was also a thoroughly screwed up '70s TV series called The Starlost. (Harlan Ellison wrote a savage essay about what went on behind the scenes.)

For the necessary colony size to prevent inbreeding, google the words "Exogamy" and "Endogamy."

ETA - James Blish wrote a novel called The Seedling Stars, about ships that modified human gene plasm to craft colonists designed for their new worlds.

And they could always carry frozen sperm and eggs to liven up the gene pool if it gets too stagnant.

Or make the original folk all women with frozen sperm to create the first generation...

And have no male role models for the children?

Horrifying.

The term to know and understand is Minimum Viable Population Size (MVP).

In the abstract of a study I found, scientists estimated MVPs for 102 vertebrate species. (Humans are, despite some spineless individuals, vertebrates.) They define a MVP as “one with a 99% probability of persistance for 40 generations.” The estimate for MVP was more than 7000 adults. Once they doubled the duration of the study, the MVP increased by 67%. Yet they warn that “a habitat capable of supporting ... 7000 adult vertebrates is in order to ensure long-term persistance.”

I suppose that in a generation ship, it's conceivable to have fewer adults, as long as there was a bank of genetic material (as suggested above) to draw from in order to stave off genetic drift--and possible extinction.

Also, just to screw things up- there are wild cards. How many animals on the Galapagos started with an MVP? Though, there is evidence that one species also turned to many, just to complicate matters further.

Still, it might be fun to have a small/medium bottleneck and maybe the population splits and then....

OMG! I couldn't stop interpreting MVP as 'Most Valuable Player'. Which is hilarious when we are talking about reproduction in a relatively small population.

Yes, Bahamut, but the populations on the Galapagos had a significantly longer time to evolve than any of the proposed generation ships. There, species evolved. In a generation ship, the only concern is that your descendents remain intelligent enough to not only establish the colony (or perform whatever else they're going to wherever for), and hopefully to perpetuate the species.

I'd worry about whether they'd be culturally capable of colonizing a planet after 4000 years on a space barge. I mean thats like the pyramid builders to us. Smartness aside, could you imagine the terror they'd feel leaving a ship for the first time ever.

And wouldn't the interior of the ship wear out? I mean the keyboards, the walkways, the beds, and all that stuff. Maybe they can grow bamboo, and constantly make new flooring material, chairs and stuff.

Sarpedon said:

... imagine the terror they'd feel leaving a ship for the first time ever.

And wouldn't the interior of the ship wear out? I mean the keyboards, the walkways, the beds, and all that stuff. Maybe they can grow bamboo, and constantly make new flooring material, chairs and stuff.

Click to expand...

This is precisely the theme of a story of mine which involves a million or so people in a space habitat. (It isn't going anywhere...it's waiting to take its inhabitants back to Earth...long story.) They resist the idea of leaving the safe interior of their world. After 50 generations or so, that one concept is terrifying. "Won't we fall off?" "What keeps the air from flying out into space?" "No, we're much better here inside where we're protected from ... well, from everything."

And yeah, the habitat in my story is definitely falling apart, having been designed to support the population for only one millenium (not 4). Lots of fun talking about things that don't work--especially the leaky sanitation/recycling system .

Bahamutchild said:

Or make the original folk all women with frozen sperm to create the first generation...

Click to expand...

Sarpedon said:

And have no male role models for the children?

Horrifying.

Click to expand...

This reminds me of a very old short I read years ago. I think the title was "The Twenty and the Four", although Google fails to turn up anything by that name. It's about a group of 24 people departing on a one-way trip to colonize a new planet. (The backstory may have been that Earth was about to be destroyed, and there was only enough time and resources to build and equip this one ship. If not that, then something very fraught about how they were expected to produce lots of babies.)

There's a big build up about how their identities are kept secret and they're referred to by nick-names. It also goes on about how the Twenty are experts in various fields, while the Four were selected for their, umm, breeding attributes.

The revelation at the end is that it's twenty women and four men.

rosemerry said:

I'm still working with the numbers but is anyone else working on a similar story that deals with this type of ship. I know Pthom is.

Click to expand...

I'm working on something like this for this year's NaNo. Mine aren't trying to get anywhere; they're on "world-ships" that were designed as permanent living spaces after large-scale disasters (and some other factors) on several worlds left a refugee population that nobody wanted in their back yard. (That means I have to think of some good disasters for backstory.) They're still periodically in contact with the other ships and with some of the original worlds (with bolognium-tech to make the time-scale manageable), and are proud of their role as wanderers, as opposed to those "planted" on the planets.

I figure the voyagers will take it for granted, and so will I (but mind, I don't typically read SF- just watch it some)

I don't know if I'll explain it in the story, but mine works off of the force that moves the ship, ie not according to known physics.

I did want to know generally how it worked for myself, more than just the black box idea.

Don't Reinvent the Wheel!

AnnieColleen said:

I don't know if I'll explain it in the story, but mine works off of the force that moves the ship, ie not according to known physics.

I did want to know generally how it worked for myself, more than just the black box idea.

Click to expand...

Centrifugal force can substitute for gravity. Spin your ship around its long axis, and you'll generate pseudo-gravity. Outward from the center of the ship will become "down," and gravity will seem higher as you climb away from the axis toward the surface of the ship.

Or your ship can be powered by a constant-acceleration drive, like a Bussard RamJet, which would generate a continuous g-force.

Folks, this is really, really basic info. Sci-Fi 101, if you will - stuff every SF writer should know.

Try The Starflight Handbook: A Pioneer's Guide to Interstellar Travel by Eugene F. Mallove and Gregory L. Matloff.
And Arthur C. Clarke's Rendezvous With Rama.
And again, Bob Heinlein's Orphans of the Sky.

The more plausible, the more powerful.

Yeah, I know; I thought about those. That's not the direction I want to go, though.

Sarpedon said:

And have no male role models for the children?

Horrifying.

Click to expand...

Actually with advances in parthenogenesis there'll be no need for men on our colonies ever.

And with artificial "wombs" there won't be any need for sex(es).

As long as we can still have sexytime!