Generation ship dynamics A researcher in Florida has calculated the optimal population for a generation-ship on a 200-year-plus interstellar voyage.
For a space trip of 200 years, perhaps eight to 10 generations, his calculations suggest a minimum number of 160 people are needed to maintain a stable population.
This would produce around 10 potential marriage partners per person, he says, and if this seems a small number, “think about how many people you dated before you got married”.