Generation Ships in Science Fiction

The answer was the Generation Ship. Build a gigantic ship (in orbit, since it would be too heavy to launch) and stock it with the necessities of life, including the ability to grow food to support the crew. Then staff it with several hundred crew personnel, and allow them to form family units. Then launch towards the most likely star system and wait hundreds of years.

The descendents of the original crew will reach the star system, and disembark to begin their new lives back on a planet again, always assuming that they survived the trip.

Orphans of the Sky

Robert Heinlein's classic Orphans of the Sky might almost be the archetype of the Generation Ship story. In it, mutineers take over a generation ship, and knowledge that the ship is, in fact, a ship, is lost to succeeding generations, as inhabitants grow up thinking that their one ship is the entire universe.

As generations pass, mythology and religion form, and as the ship loses its way, mutations create a subspecies that menace the ship's inhabitants. Can the 'crew' who thinks they are a tribe rather than a ship's crew overcome their own upbringing and engrained beliefs when it is necessary to save the ship?

Book of the Long Sun

The whorl in Gene Wolf's Book of the Long Sun is a giant cylindrical vessel, and yet to the inhabitants, it is all they know. An Olympus of sorts is maintained, a priesthood exists to speak to the gods, and ask for their assistance, which often is quite successful. And yet the vessel is decaying, and things are beginning to break down. Can the 'gods' - surely the long-dead engineers who created the whorl - come through this time? Have they left enough of themselves in the computer systems of the starship, and can they stop their intramural fighting long enough, to rescue the troubled civilization? This multi-volume sci-fi series is epic, almost high-fantasy in feel.

Modern-day Work-arounds

The Generation Ship can work for a single novel, but you can't build a universe out of it, except one that evolves in exceedingly slow motion. Modern sci-fi just throws out the speed of light as a limiting factor, plugs in a term like 'hyperspace' or 'warpspeed', and the need for Generation Ships is overtaken by events.

They can be popular plot-devices still, however. Some Generation Ships are discovered, still in progress towards their destination, by faster-than-light ships, either with crew intact or crew all dead/missing, and perhaps a mystery to solve.

There's still a few plot-twists left in the old device.