to cherry-pick a tiny part of your comment: > What happens when more people than expected get pregnant in your space colony? i'm assuming "more than expected"

to cherry-pick a tiny part of your comment: > What happens when more people than expected get pregnant in your space colony? i'm assuming "more than expected" means "too many people to support given the circumstances". the answer of what to do in this situation is pretty obvious if there are no other options -- do a necessary unpleasant thing: abort the pregnancies or have a few other people volunteer to die [0]. people have figured this out in other societies. for example, people on the isolated island of Tikopia developed a society that was able to self-regulate population [1]. to be clear: i do not think this sounds like a wonderful state of affairs. but if you are in such a situation, and there are no other options left, what else can you do? to get back to the more general point -- sure, it seems like a reasonable idea to have a colony on another planet, if we can figure out a way to do that sustainably and resiliently, to reduce risk if we "lose" the Earth somehow. But let's think that through: how hard would it be to establish a colony on another planet that could support itself, and recover/flourish, without external support, in a scenario where the Earth was lost? Probably pretty hard! I guess it depends upon the scenario. If some virus kills off the human population of a planet without otherwise doing too much damage, maybe it is possible to re-settle it, which allows some of the people from your colony a chance at restarting life in a kinder environment. If somehow you lose the whole ecosystem on earth that supports human life, then perhaps resettlement is not an option. Then there are risks that might wipe out both earth and the colony in one hit [2]. [0] edit: or, maybe in this hypothetical future technologically advanced spaceship society people have figured out contraception and family planning and this is situation that will not happen. [1] https://expandyourbrain.wordpress.com/2011/05/23/we-the-tikopia-isolated-island-chiefdom/ https://expandyourbrain.wordpress.com/2011/05/23/we-the-tiko... [2] e.g. a really lucky close shot from a gamma ray burst? some kind of coordinated multi-planet misanthropic terrorist plot?