| In science fiction, a generation starship, is a type of starship where the colonists who reach their destination are the descendants of the original long dead crew who began the voyage.
Konstantin Tsiolkovsky in "The Future of Earth and Mankind" (1928) was probably the first to present the idea of the colonization of other worlds by use of a generation starship.
Don Wilcox is probably the first science fiction author to use the idea in "The Voyage that Lasted 600 years" published in Amazing Stories in 1940.
Robert A. Heinlein's "Orphans of the Sky" (1963) first published as "Universe" (1940), and "Common Sense" (1941) in Astounding Science Fiction is the classic generation starship story. In this story the crew have forgotten that they are aboard a starship, until the prototypical Heinlein hero rediscovers the truth.
Other authors to use this meme were Brian W. Aldiss in "Non-Stop" (1953) Clifford D. Simak in "Spacebred Generations" (1953), Chad Olivers "The Wind Blows Free" (1957), and Fritz Libers "Ship of Shadows" (1969), among many others.
There was even a television series based on the idea of the generation starship, "The Starlost" from a script by Harlan Ellison. (Ellison disclaimed the series and used his Cordwainer Bird pseudonym in the credits.)
The generation starship idea has also been used as a minor subplot in at least two Star Trek episodes that I can recall.
The generation starship remains the only known "technically feasible" (maybe) method for us to reach another star. Technically feasible in the sense that we currently have the technology to build such a starship given the time and effort to do so. Unfortunately technically feasible does not mean economically feasible. Just guessing here but the world economy would need about a three orders of magnitude increase before we could afford to build one of these things.
Other starship variants are those that use Faster-Than-Light (ftl) drives, Jump ships, ram scoop drives, light sails, and ships that use relativistic time contraction.
Variants of the generation starship, include the use of suspended animation and sending just the information of the human ether genetically encoded, or recorded as digital data.
3/20/2002
mblase points out that:
"Footfall" (by Larry Niven and Jerry Pournelle) featured a generation starship used by aliens to (attempt to) colonize Earth. An interesting reversal of the norm."
| 
