Generation Ship

[GussieFinknottle]

I'm currently writing a story set in a sci-fi world I'm building. It's hard science.

Basically, humanity has developed 10% of lightspeed travel. Having mostly used it to send spaceships to asteroids and mine them, or to planets in the Solar System (which they can all reach in under a day).

However, several countries decide to set off on "Colonyships", what has also been called a Generation ship in other fiction. They can fit about 20,000 people comfortably, and the population is maintained at that level. One of these countries is heading to Alpha Centauri, which will take about 43 years. The ship is artificially pressurised and has artificial gravity. I'm currently designing the ship and I'm trying to figure out what they'd need.

So far, I've got this on it. Note that there are several floors to the ship, including several recreation ones, two cargo ones, sixteen residential ones and one administrative one:

Recreational Floor:

-Planetarium

-Cinemas

-Cafés

-VR Café (VR of being on Earth, which most people have not seen)

-Libraries

-Bookshops

-Shopping Centers (with robot/hologram vendors instead of real human beings)

>Musical Instrument Shop

>

Clothing shops

>

Etc...

-Apartments (Residential Area/Grid)

-School

-Gyms

-Zero Gravity rooms (for admiring the view, sensation or sports)

 

Administration Floor:

-Lab (Frozen embryos of four of each Earth Animal, male and female)

-Hospital

-Cockpit

-Supercomputer running the ship

-Hologram interface handler/server

-Wifi server

 

Cargo Levels:

-Drone Bay

-Weapon(s) depot


What more could be put on it?

 

[PB666]

So whats wrong with your story, alot.

1. you don't need weapons (unless multiple cultures that are in conflict have sent ships, unlikely very expensive)

2. you don't need or even want 0.1 speed of light to get to asteroids. Fusion driven generational ships do not accelerate fast enough. They do provide power to reach the outer solar system, it would still take weeks to get there with the most optimistic fusion drive. The pulse plate nuclear drives are somewhat faster, again, not really suitable for mining, alot of latent radioactivity. Probably best to stick with speeds of 0.001c to reach those asteroids. You don't really need a generation ship to go to alpha centuri at 0.1c, the generation ship would come later, the ship you sent would be a seed ship, it would do the most rudementary terraforming assuming you found a terraformable planet that did not already have competitive life on it.

You need a stock pile of raw materials (Primarily at the front of the ship that will absorb the cosmic radiation your ship produces) but also can be used to make LEDs and other electrons, you also need an engineering bay. In addition you need a science and telescopy bay and lab for searching out materials, and a ship building bay that can allow you to build the hulls of extensions and place them around your ship or attach them to asteroids. The ship needs an INRU, Bookshops obsolete, library since most are scientist you need a feed to Earth and its all electronic now.

3. Frozen embryo's, problem you need wombs, which could be cultured in a lab, the problem is that you don't have enough lab space, and you wont need it till you arrive, so you really really need and engineering bay. The a husbandry bay cause there aint no place for animals on alpha centuri, beta, or proxima. Even if you found a suitable planet, first you need things like bacteria, cyanobacteria, water plants, brine shrimp and other sea-life, seeds for trees, etc. It would take you 1000 years at this rate, then you could ship in animals along with at least a few wombs of immune neutral animals.

[sevenperforce]

Four of each animal is also not nearly enough to create any sort of sustainable population, either. If you want a small temporary breeding population of tasty or useful animals, a few hundred embryos per desired species might be enough. But if you want a permanent sustainable population you will need 100,000 individuals minimum in order to have enough genetic diversity for the population to survive in the wild, and that is if you have already achieved 95%+ terraforming on the target world. 

If the trip only takes 45 years, why would most of the passengers have never seen Earth?

Is artificial gravity based on linear acceleration, centrifugal acceleration, or handwaved? Handwaved selectable artificial gravity is technology on a level with Alcubierre FTL drive.

[kerbiloid]

They obviously had decided to eliminate any existing biosphere, replacing it with terrestrial lifeforms.

Then, in advance of this fleet of intrusion, they must send a vanguard of huge uncrewed eradicator ships, with huge amount of the terrestrial

5 hours ago, PB666 said:

bacteria, cyanobacteria, water plants

(especially chlorella), and pulverize this biological stuff onto the desired planets.

[Nibb31]

7 hours ago, GussieFinknottle said:

It's hard science.

Basically, humanity has developed 10% of lightspeed travel. Having mostly used it to send spaceships to asteroids and mine them, or to planets in the Solar System (which they can all reach in under a day).

lol.

 

Why would you need robot hologram/vendors when you have a whole population of people doing nothing? Why do you need shops if nobody works ? Does your ship have an economy ? What is it based on ? What wealth can be created in a closed loop environment ?

Also, having a single floor for work, another for shopping, another for work, etc... means that you get traffic jams between each area on shift rotation hours. Have you never played Sim City ?

4 of each animal ? That's just as silly as Noah's ark's 2 of each animal. That's not enough to develop a viable population of anything. And every animal on Earth ? There are 8.7 million species on Earth, and we only know about 10% of them.

Edited April 24, 2016 by Nibb31

[PB666]

You actually could create a viable population now with the new insitu technique. The deal is that you would need the genetic blue print, you could replace key genes within the brood stock, as the population expands you introduce new genes and combinations. But again that requires infrastructure. You need keystone species in each ecosystem. Similar animals can use a single species as a womb species.

 

[Nuke]

6 hours ago, sevenperforce said:

Four of each animal is also not nearly enough to create any sort of sustainable population, either. If you want a small temporary breeding population of tasty or useful animals, a few hundred embryos per desired species might be enough. But if you want a permanent sustainable population you will need 100,000 individuals minimum in order to have enough genetic diversity for the population to survive in the wild, and that is if you have already achieved 95%+ terraforming on the target world. 

If the trip only takes 45 years, why would most of the passengers have never seen Earth?

Is artificial gravity based on linear acceleration, centrifugal acceleration, or handwaved? Handwaved selectable artificial gravity is technology on a level with Alcubierre FTL drive.

id imagine they would use stored sperm and embryos and just use the 4 as breeders. they would be all female. when one gets to old or dies then another is impregnated with a female embryo. embryos would be pre-sexed and sourced from genetically diverse stock. this allows you to maintain a high genetic diversity without needing to keep a large population going. upon arrival all 4 are impregnated with female embryos, and this goes on until a large genetically diverse population of breeders is established. they they are all artificially inseminated and are allowed to procreate naturally from that point onward. 4 is probably just the minimum number at which the odds for total failure are sufficiently small, issues with pregnancy, disease, infertility, even issues with the environment like depressurization events.

Edited April 24, 2016 by Nuke

[insert_name]

you need some sort of lander, and a place to maintain it unless you only want to visit asteriods

[shynung]

Rather than 4 of each animal (there's about 8.7 million of them, and that's the ones we already know, there's probably more), it's more useful to carry 100-150 embryos of only the useful species, like livestock(cattle, pigs, chicken), beasts of burden(horses, mules), and companions(cats and dogs).

Or, better yet, cut down the species count by striking out livestock species, and grow synthetic meat. That, or have the beasts-of-burden species do double-duty as livestock.

Also, you'd need something to keep the population busy while en-route. A bored population is can be very easily incited to do something drastic, like rioting and breaking stuff. This means it might not be in your best interest to automate almost everything inside the ship (no robot workers), so that the population has something to do.

In addition, you might want to have some sort of manufacturing capability on board. Everything from simple tools to high-tech machinery breaks down no matter how robust they are built, so it's a good idea to be able to manufacture spare parts from raw materials found en-route (or carried on board; lightly-processed stuff like steel plates are denser than ready-made items like gears). Not just a stash of ready-made spare parts, mind you; different equipments needs different spare parts (you can't fix a mechanical transmission with a processor chip), and there's no sure way of knowing how much of which part will break more. This will also be another way of keeping the populace occupied.

[radonek]

I don't think frozen embryos will make it. Freezing stop intracellular DNA repair mechanisms and they will accumulate radiation damage, which would be pretty severe on 0.1c. 

[shynung]

Good point.

At that point, it may be cheaper to store the DNA sequences of said embryos' species in a storage/archive system, and use this to clone them when needed using blank ovum cells and synthetic wombs.

Though, if we already have that, it's a step away from simply storing a bunch of sequences from different humans, and cloning them at the destination using the same tech used to clone the animals. The problem then comes down to a reliable automated parenting system to raise enough humans for them to continue procreating the old-fashioned way.

[HebaruSan]

8 minutes ago, shynung said:

The problem then comes down to a reliable automated parenting system to raise enough humans for them to continue procreating the old-fashioned way.

Is that a humane thing to do to your colonists? Wouldn't it be confusing and traumatic to grow up in isolation from all others of your species with only a computer to give you any kind of education or culture? I doubt you could even test that system on Earth (as you surely ought to before relying on it at a distance of light years!) without violating laws about ethical experiments on humans.

[shynung]

1 hour ago, HebaruSan said:

Is that a humane thing to do to your colonists? Wouldn't it be confusing and traumatic to grow up in isolation from all others of your species with only a computer to give you any kind of education or culture? I doubt you could even test that system on Earth (as you surely ought to before relying on it at a distance of light years!) without violating laws about ethical experiments on humans.

Not necessarily in complete isolation; they could have social interactions with each other.

Though, that's a good point.