Without faster-than-light travel, reaching another star means building a ship where the people who launch it never see the destination and the people who arrive never see Earth. This episode explores the generation ship from Robert Goddard's 1918 essay on hollowed-out asteroids and suspended animation, through Konstantin Tsiolkovsky's 1928 vision of a Noah's Ark colony whose waking crew evolves over millennia, to J.D. Bernal's 1929 warnings about biological and psychological change in isolation.

We then turn to modern engineering: the 2012 framework in the Journal of the British Interplanetary Society that classifies sprinters, slow boats, colony ships, and world ships built from four stacked Stanford torus habitats, the fusion propulsion of Project Daedalus, and the trade-off between a light fast ship and a heavy one with a stable biospher ...