I can’t imagine just how much space and equipment will be needed for all of the manufacturing processes, as well as the need for raw material stores. Star Trek obviously waves this away with a “replicator” but without a real one, it’s not going to be easy.
Presumably 3-d printers would handle most manufacturing, cutting down on the space and mass needed for making stuff. I’ve heard suggestions that the first Mars mission include some.
I think it’s obvious that humanity is nowhere near ready for a generation ship. We need at least another century of learning how to live in space. There are so many things we know that we don’t how to do yet, and even more things we don’t know we don’t know how to do.
Definitely. If a space station in near-Earth orbit can survive a decade or a century without needing any resupply, it might be time to consider a generation ship.
I find the idea of a generation ship that couldn’t afford to lose several tons of mass in the form of bodies to be a bit hard to credit - that’s just too thin a margin of error to base such a (I would assume) important project on. I’d expect a robust ship design that could handle that kind of loss without its entire ecosystem failing.
Wrong Wikipedia article…
There is another problem with a generation ship: The odds of starting a succcessful colony with the number of people you could put in such a ship is approximately zero.
The likely outcome of a generation ship would be for everyone to die before arrival. On the off chance that they survived, AND the planet was hospitable, the likely outcome is a small outpost that slowly dies as they run out of critical equipment and lack the capacity to replace it. Technological capacity is highly constrained by population size.
We might one day solve this with AI and robotics, but that leads to wondering why you’d send people at all, at least at first. I’d rather have AIs scouting out other systems, building necessary infrastructure on our new planet, stockpiling food and water and generally prepping the place for humans befor pe they arrive.
Yes but… The biggest difference is the size. No one has postulated just how many people would be on one of these ships - 5,000. 10,000 more? Considering that even a small town in most Earth countries has 50.000 or more residents, that is a very small pool.
Not only that. If you don’t like the street/town/state/country you live in, there is at least the possibility of moving somewhere better. On a ship, this will be difficult. If the people in the living unit next to yours are obnoxious, you might apply to admin to be relocated. There are no spare units, so you can’t move. You confront your neighbour and… consequences.
It’s not so much that they couldn’t afford to lose this, it’s more a matter of design philosophy. We know that no system built by humans will be 100% sealed and recyclable. There will always be some degree of loss, and we’d design every system to minimize that loss. And there’s also the expectation of accidents. If something hits you and you lose a lot of atmosphere, you’re going to need a large reserve capacity to survive that. What if there’s more than one accident? At that point, yeah, maybe those bodies would have made the difference between success and failure.
We can’t predict how many accidents we might have, so the safest bet is to conserve as many resources as possible. Hopefully we wouldn’t need them in the long run, but if the shit hits the fan, we’ll be damn glad we have them.
Any plan for colonization using a generation ship would be predicated on establishing a lower-tech society on the planet. That’s one reason you’d take actual animals with you (at least in cryostorage or the like). Give me 100 tractors, and in 100 years I’ll have zero tractors. Give me 100 horses, though, and I could start breeding new ones.
So part of the plan would be to have people on the ship practicing old-timey techniques like blacksmithing and such. If European colonies in the 1600s could set up such societies, the generation ship could as well.
Hmm. Humans don’t like environments with high levels of carbon dioxide; plants do. Perhaps humans might be augmented so they tolerate high levels of carbon dioxide (this might help with the terraformation of Mars, for example), but it would be better to artificially adjust the atmosphere inside the generation ship to avoid CO2 poisoning. I expect humidity would be a problem too.
There are lots of failure modes possible for a generation ship biosphere; some of these are described in Kim Stanley Robinson’s Aurora. The artificial biosphere in Biosphere 2 failed because of an imbalance in the soil bacteria; we need bacteria and fungi to decompose organic waste, but they are awkward customers.
Colour me pessimistic, but I doubt very much that there is a single planet within hundreds of light years that could support horses outside on its surface, or provide anything suitable for them to eat. Horses are much more likely to be dead weight.
Sure, maybe, but then, why would we be colonizing that place with a generation ship?
Colonies in hostile environments make sense if you have FTL capabilities, because then you can have actual commerce between stars, so maybe there’s critical resources you can mine and sell, and use the profits to support the colony.
But there’s no interstellar trade in a universe without FTL. You go, and plan to stay there essentially forever, a new branch of humanity isolated from all the others, except maybe for radio contact spread out over years, decades or centuries. In that case, you’d only aim for planets that have the potential for supporting human life without massive technological support, and if it can support humans, it can support other animals.
Otherwise, why even colonize a planet? You’re already in space, and have the technology to build self-sustaining environments. Build a bunch of O’Neil habitats instead.
This is probably the only sensible strategy. Ships carrying AI systems, mechanical replicators and large databases of solutions to problems, (but no humans) would almost certainly be significantly smaller and lighter than a generation ship, and arrive first. Robert Freitas has described this strategy in some detail.
These autonomous ships should be able to build sufficient habitats to support the humans in comfort upon arrival. One drawback is that the AIs might be sensible enough to decide not to accommodate humans after all, since humans are also the source of numerous ‘failure modes’.
This is a good point. The ideal might be to build an ark in Earth’s orbit that is set up to allow an engine to be docked to it at a later date. That way you could be designing/refining the interstellar engine while perfecting the closed system of the ship itself.
Probably because that is all there is. The universe is not like Star Trek; in that universe nearly every planet they visit has an Earthlike atmosphere ( planets in Trek resemble the deserts near the Desilu studios for some reason).
In the real universe Earth-like planets are incredibly rare, and we haven’t found one good one yet. If we do find a planet with a respectable biosphere, it is likely to have plants that are inedible or otherwise incompatible with the requirements of a horse-powered economy. Biospheres that are significantly different to Earth will be toxic, and biospheres which closely resemble Earth will almost certainly have pathogens of various unknown kinds.
The only way to colonise the universe in any significant way is to go out there and build your own habitats - this is true of every other planet, moon and asteroid in the Solar System, and will be true of practically every other system in our galaxy and beyond. Colonising the Final Frontier with horses and appleseeds is a non-starter.
But then you run into the problem discussed above - can you build a modern technological society with the number of people you can fit on your ship? How many different careers are there that are essential, and can you guarantee enough people in each generation are good enough at each one to keep these skills alive over hundreds or thousands of years?
If you don’t send humans, why make the effort with a generation ship? The thinking I always hear about is that we need to preserve life, as ours might be the only one. And another asteroid might hit, solar flairs, nuclear war, etc might wipe us out. At 10% c the nearest possible exoplanet is over 40 years away. Maybe that would work, but it seems like a lot of extra work when for aprox the same effort we could send humans.
There are some designs and considerations on the new world that an AI couldn’t make for humans.
We have eight planets, hundreds of moons and thousands of asteroids in this system to practice self-sufficiency on. It would not be a good idea to travel to other systems until we can condense all useful human knowledge down to a portable form; databases are getting smaller all the time, and the entire literary output of humanity should fit on a generation ship at a data density that should be achievable by the time we are ready to launch. You might need a bit more room if you are going to include instructional videos as well.
It won’t be worth going until there are machines capable of replicating a very wide range of tools and prospecting successfully for necessary resources; this will all be attempted on the planets and moons of the Solar System first, and if it can’t be done there we won’t be able to go to any other stars successfully.
The problem of retaining and transferring skills in a small population is another big stumbling block. I’m optimistic about the use of brain-computer interfaces to augment human capability. The use of competent AI advisor systems is another, related possibility, and it seems entirely possible that skills and technological capability need not be lost in a successful extrasolar colony. Possible, but not guaranteed.
Telephone handset sanitisers are essential.
Animals ecolved in an Earth ecosystem, as did the plants they eat, their gut biomes, etc. The odds that we can form a ‘low tech’ society on another planet, even one with temperate conditions, are probably close to zero.
Or maybe we’ll find that evolution selects for similar things, and any planet like Earth will have plants and animals similar enough that we can survive there. But I wouldn’t bet on it. Ther are lots of places on Earth itself where low-tech civilizations cannot thrive.
I meant you wouldn’t send humans at first. Too much risk. You’d send AIs, and only send people after the machines have found a suitable planet, checked it for dangers, built enough infrastructure for humans to survive there, stockpiled food and fuel, etc.