The movie Pandorum is a sci-fi-horror movie. The gist is that a generational space ship traveling from Earth to another planet turns into a 1000 year trip where some of the passengers have been accidentally released to fend for themselves. The rapidly evolve into fierce primitive cannibals, that are clearly intelligent but only make roaring noises before they jump on you and eat you alive.
This would have been an awesome place for a toki-pona-like language, which is simultaneously modern and has a primitive-hunter-gatherer feel to it, despite the science being poorly thought out. If this were real, the humans would probably have evolved to be very short, slow moving and energy efficient, since a spaceship is a harsh place for hunter and gatherers. And I'm not sure cannibalism is a good long term survival strategy-- the ecosystem needs external energy to keep going.
A space ship has such a limited environment, probably even more so than an island, it would only need a small vocabulary-- no need for a short root word for "road", when all you have is are halls. The word for road/hall would mean the same as "a tube-like structure." In this case, no need for plant or animal words, since the only species that was available for food was other humans. Speaking of that, "jan" and "moku" would collapse into one word!