- Since the distance between stars is so vast, ship travel duration can extend into many decades or even centuries, so crew reproduce and create future generations of crew while the ship is in transit.
- The two terms Sleeper Ship and Generation Ship are often, incorrectly, interchanged and used to refer to either type of ship.
- Since civilizations that use such ships generally have limited means and technology for producing NAFAL starships, most are used for colonization purposes.
A ship containing a full complement of personnel intended to make a sub-light journey across space. Since such journeys take years, or even decades, the crew and passengers of the ship expect to give birth, live and die naturally during the course of the journey. The subsequent generation of the original crew and passengers being the ones who actually arrive at their destination.
Generation Ships are sometimes referred to, incorrectly, as Sleeper Ships, which are similar, except that the majority, or all of the passengers and crew are put into low berths/hibernation for the duration of the journey.
The following species are known to use, have used, or posses the technology to manufacture generation ships: