Generation ship

O'Neill cylinder
A generation ship is a slow colony ship whose colonists are the yet to be born n-children of the original crew. Because the voyage takes more than a human lifetime to reach its destination, the crew is supposed to reproduce as normal, so their descendants can continue the journey.

A generation ship tends to be very large as it needs to act as a colony itself, providing Earth-like comforts to its initial generations, and gradually adjusting to the destination environment until the last generation lives in an environment almost exactly like their destination.

Upon landing, the ship effectively becomes the colony’s first city, but the colonists start surviving with what they can take from their environment.

Generation ship

Grasshoppers i_am_a_speckle