Eu também estava procurando por este ótimo livro e encontrei o seu post durante a minha pesquisa. Se você não encontrou, The Return por Richard Maynard.
‘The Return’ starts with a voyage into interstellar space by a team of seven British astronauts. Their goal is to travel faster-than-light to the Alpha Centauri system and back, a journey which should take the equivalent of sixteen years of Earth-time. Unfortunately the ship encounters navigational problems and goes off-course; by the time the crew corrects the error, they have been traveling for 15 years ship-time. The crew must confront the awful fact that perhaps as many as 60 years...or as many as 400 years.... have passed on Earth since their departure.
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And the humans that populate these landscapes are semi-literate savages wrapped in animal furs and toting spears. And they are not friendly, as the starship crew soon discovers….