Generation ship

A generation ship, or generation starship, is a hypothetical type of interstellar ark starship that travels at sub-light speed. Since such a ship might require hundreds to thousands of years to reach nearby stars, the original occupants of a generation ship would grow old and die, leaving their descendants to continue traveling. Rocket pioneer Robert H. Goddard was the first to write about long-duration interstellar journeys in his "The Ultimate Migration" (1918). In this he described the death of the Sun and the necessity of an "interstellar ark". The crew would travel for centuries in suspended animation and be awakened when they reached another star system. He proposed to use small moons or asteroids as ships, and speculated that the crew would endure psychological and genetic changes over the generations. Konstantin Tsiolkovsky, considered a father of astronautic theory, first described the need for multiple generations of passengers in his essay, "The Future of Earth and Mankind" (1928), a space colony equipped with engines that travels thousands of years which he called "Noah's Ark". In the story, the crew had changed so much over the generations at so many levels that they did not even acknowledge Earth as their home planet. Another early description of a generation ship is in the 1929 essay "The World, The Flesh, & The Devil" by John Desmond Bernal. Bernal's essay was the first publication to reach the public and influence other writers. He wrote about the concept of human evolution and mankind's future in space through methods of living that we now describe as a generation starship, and which could be seen in the generic word "globes". According to Hein et al., a "generation ship" is a spacecraft on which a crew is living on-board for at least several decades, such that it comprises multiple generations. Several sub-categories of generation ships are distinguished: sprinter, slow boat, colony ship, world ship. The Enzmann starship is categorised as "slow boat" because of the Astronomy Magazine title "Slow Boat to Centauri" (1977).