
World Ships: Feasibility and Rationale [pdf] - molp
https://zenodo.org/record/3747333
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echelon
Why are we so certain we'll be sending human bodies?

All of sci-fi is steeped in interstellar transportation of human bodies, each
with human brains and human biological needs and handicaps. I just don't get
it.

There's no forcing function to make us go to the stars, establish permanent
habitats on Mars, etc. They're not very hospitable or profitable enterprises.

I see us evolving human biology before we attempt this seriously. Genetically
modified bodies that have different metabolisms, different mechanical gaits,
changed oxygen metabolism.

Or perhaps we'll have brain uploads, and exist ephemerally. Living matter
isn't ideal in outer space. We can always turn on biology again when we reach
the destination - if we even want to.

Or maybe AGI just kills us.

In any case, I don't see human forms doing any of this nonsense. I think
people fantasize about the familiar things they can relate to. I see a
fundamental mismatch between the human body and outer space that would be
served by optimizing humans for the environment.

~~~
airstrike
It's simple. However unsuitable we may be for life in outer space, we do need
a plan B, _any_ plan B, in case life on this planet gets obliterated by an
asteroid, war or runaway climate change.

One would think the frailty of human life on this world would be top of mind
right now, what with the once-in-a-century pandemic we're living through.

~~~
coderintherye
It's an interesting question though: Is plan B of succeeding in interstellar
travel actually easier than a plan in which we figure out how to change our
biological construct to survive in harsher climate-change or post-war
conditions?

~~~
airstrike
It is interesting indeed, and meant to add to my comment that it feels like
finding a way to have a permanent settlement in Mars seems more near-term than
changes to our biology.

I think the consensus is we generally "know" what to do to figure out a way
out of this rock (so not necessarily interstellar travel), whereas modifying
our biology seems magical in comparison.

Living outside of Earth, in a different gravity well, with different doses of
radiation and likely in confined spaces is challenging, but at least you can
put those things into comprehensible words. I wouldn't even know where to
begin describing how we'd modify our biological construct, as you put it.

~~~
cousin_it
Human engineering can be put into words. It's just very scary. Genetic
modification, cyborgification or mind uploading could give us any bodies we
want, but also create new terrifying possibilities of control: imagine you've
been genetically modified by a tyrant, or your brain lives in a robot body
built by a tyrant, or your uploaded mind is in a computer controlled by a
tyrant. Humanity isn't politically ready for human engineering tech - in other
words, I wouldn't trust any of today's governments with it - but it's coming
one way or another, and probably sooner than starships.

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sillywalk
I find Techno-Utopianism vaguely amusing.

We are currently residing on a better "Worldship" than we could ever engineer,
and we've been knowingly destroying our life support systems in the face of
ever-growing warnings from scientists. Ignoring the other planetary crises we
face - biodiversity and ecosystem collapse - our continued existence on our
planet depends on somehow sucking billions of tons of CO2 out of the
atmosphere and storing it somewhere, somehow, forever. This is trivial
compared to colonies in our solar system, much less interstellar travel.

Ignoring the question of technological and engineering feasibility I propose
the hypothetical World Ship _Thought Exercise_ ( 100,000 people (on average),
10k year journey, each individual lives around 100 years). How would the
population be structured? Would it be democratic? How would crime be dealt
with? How would people decide who does what? Would there be castes? An
underclass? Would there be rationing? Could there be homeless? What about
birth control? What if a portion of the population simply didn't want to have
kids or didn't have enough to replace the population? How would religion be
dealt with? Would, could and/or should a 10k long civilization remain static?

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russfink
Deep in, one study suggested 10,000 to 14,000 individuals are needed to ensure
a diverse and sustainable population when the destination is reached.
Elsewhere in the paper, it discusses models of childbearing, ages, etc.
However, is there any model that captures the possibility that many of these
10,000's can be frozen embryos, gestated at intervals within live females, to
achieve diversity without having to build egregious (vs just plain large)
ships?

~~~
shrubble
Didn't the current population of Iceland come from some 360 or 400 people?

~~~
eesmith
[https://science.sciencemag.org/content/360/6392/1028](https://science.sciencemag.org/content/360/6392/1028)

> Settlers in Iceland are thought to number ~8,000 to 16,000 individuals, with
> the population rarely exceeding 50,000 until 1850 (3), after which there was
> a rapid expansion to its current size of 330,000.

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goda90
> The emergence of alternative, less costly modes of crewed interstellar
> travel at an earlier point in time might render world ships obsolete.

An interesting scenario would be the emergence of considerably faster travel
after sending these ships. There could be ships catching up and even beating
the old world ships to their destination.

~~~
all2
This scenario is explored in an old pulp scifi novel I read.

World ships are sent, in the interim time-bendiness of the universe (100 years
on Earth an 5 years aboard ship) FTL travel is developed and the occupants of
the world ships are rescued and repatriated.

No clue who wrote the book.

~~~
eesmith
"Time for the Stars"?
[https://en.wikipedia.org/wiki/Time_for_the_Stars](https://en.wikipedia.org/wiki/Time_for_the_Stars)
Not quite a worldship, but a large exploration vehicle.

~~~
all2
Yes, that's it! I may just go buy it and read it again.

Thank you!

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eesmith
> "Studies in closed-system ecology are underway or have been demonstrated to
> some extent with Biosphere-2 or BIOS-3."

And so far demonstrated that it's not feasible.

> It can be seen that regarding biological feasibility, in particular
> genetics, population sizes in the 10^3 - 10^4 range are required

There is no mention of education. The assumption is that neolithic villages
are a good model, but neolithic villagers didn't operate an interstellar ship.

Do all children in the ship need the equivalent of, say, a high school
education? If so, the time needed to educate them takes away from time needed
to raise food, manage sewage treatment systems, etc.

In Biosphere-2, the staff spent all their time on the biosphere, with no spare
time for raising and educating children.

~~~
macintux
> Key roadblocks ... the development of a maintenance system capable of
> detecting, replacing, and repairing several components per second.

~~~
eesmith
Biosphere 2 had ecosystem failures which don't fall under that category. Like
carbonatation of the concrete.

~~~
macintux
Well, hopefully in 200 years we’ll have sorted out a few more details.

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LatteLazy
I am a physicist but I think most of the questions around colonising other
planets belong to biologists. Why send a world ship when you can send 20,000
frozen embryos? Or enough biological precursors for that, a database of genes
and an AI smart enough to engineer humans to survive on this new world with
different gravity/atmosphere/light etc? Why maroon people on a barren world
with no other life when a machine in orbit can seed it with life but by bit
for 10000 years and only print humans when there is a lush biosphere?

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roca
Seems to me much more feasible to ship frozen embryos, artificial wombs, and
android foster parents. Good artificial wombs might be a very difficult
technology but they sound a lot easier (and certainly much less expensive)
than building a reliable world ship.

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mleonhard
I can't figure out how to view the PDF full-screen without downloading it.
This is frustrating.

