Editing Openai/691a2d9f-c044-8012-bccf-942bfce6334d (section)

===== Even if you did find a comet at, say, 4 light-years out (which is already basically Alpha Centauri’s territory), a “return” for humans at any realistic sub-light speed is: =====
* centuries to millennia back home
* generations spent just shuttling resources out and in
* you’d be better off sending uncrewed logistics probes instead of human crews.

So the “go forward, seed comet, come back on remaining supplies” pattern makes sense inside a stellar system (Solar System, Alpha Centauri system, Kuiper Belt, Oort region), but not across most of the star-to-star gap.