An interstellar ark or Generation ship is a conceptual space vehicle designed for interstellar travel. Interstellar arks may be the most economically feasible method of traveling such distances. The ark has also been proposed as a potential habitat to preserve civilization and knowledge in the event of a global catastrophe.
Such a ship would have to be large, requiring a large power plant. The Project Orion concept of propulsion by nuclear pulses has been proposed. The largest spacecraft design analyzed in Project Orion had a 400 m diameter and weighed approximately 8 million tons. It could be large enough to host a city of 100,000 or more people.
Another concern is selection of power sources and mechanisms which would remain viable for the long time spans involved in interstellar travel through the desert of space. The longest lived space probes are the Voyager program probes, which use radioisotope thermoelectric generators having a useful lifespan of a mere 50 years.
One propulsion method for a crewed spacecraft could be a fusion microexplosion nuclear pulse propulsion system, like that proposed in Project Daedalus that may allow it to obtain an interstellar cruising velocity of up to 10% of the speed of light. However, if the ship is capable of transits requiring hundreds of thousands of years, chemical and gravitational slingshot propulsion may be sufficient.
Specific proposals and research projects
The Enzmann starship proposed in 1964 is a large fusion-powered spacecraft that could function as an interstellar ark, supporting a crew of 200 with extra space for expansion, on multi-year journeys at subluminal speeds to nearby star systems.
In 1955 Project Orion considered nuclear propulsion for spacecraft, suitable for deep space voyages.
In 1973-1978 Project Daedalus was conducted by the British Interplanetary Society to study unmanned interstellar spacecraft.
The 1933 novel When Worlds Collide is one of the earliest examples of an interstellar ark. To save humanity from extinction when a star is about to destroy Earth, a group of astronomers construct a massive spaceship to carry forty humans, in addition to livestock and equipment, to a new planet.
Jack Williamson's 1934 story "Born of the Sun" is another early example, in which planets are revealed to be no more than eggs for immense creatures. A steel magnate and his geologist-astrophysicist uncle create an "ark of space" to preserve the human race in the six months left in the Earth's existence. The ark is designed to hold two thousand people, be powered off of cosmic rays, and to recycle water and waste to create synthetic food and air, thus providing for an unlimited survival of its crew in space.
Brian Aldiss' 1958 novel Starship (published as Non-Stop in England) describes a modified human civilization whose members do not realize they have been on a four-and-a-half century inter-stellar trip.
A group of three large arks served as the homes and battleships of the space-faring Thraki race in William C. Dietz's Legion of the Damned series.
The concept of an interstellar ark was used humorously in the cult sci-fi classic The Hitchhiker's Guide to the Galaxy, in the form of the B-Ark of the Golgafrincham Ark Fleet, filled to capacity with cryosleeping advertising executives, management consultants, telephone sanitisers, and other "undesirables" whom the Golgafrinchams wanted to expel.
The Starlost is a television series about a generation ship lost in space, whose inhabitants had forgotten that they were on a ship.
In the PC game Outpost series, an interstellar ark named Conestoga was used to evacuate a population of humans from the impending destruction of Earth.
The PC game Alien Legacy features "seedships", used to spread mankind due to an interstellar war that might wipe out the Earth.
The SS Botany Bay was a sleeper ship used by Khan Noonien Singh in the Star Trek first season episode "Space Seed".
A Star Trek third season episode entitled "For the World Is Hollow and I Have Touched the Sky" takes place on a hollow asteroid generation 'ship' called Yonada.
The Centauri Princess is a cylindrical interstellar ark peopled with humans, depicted in elaborate detail in the novel First Ark to Alpha Centauri by A. Ahad
The cylindrical generation ship Vanguard serves as the centerpiece of Robert A. Heinlein's 1963 novel Orphans of the Sky, a combination of two shorter 1941 works.
In the animated Disney-Pixar film WALL-E, the space vessel Axiom, originally intended as a temporary dwelling for humanity for a 5-year period during which robots were to clean up an environmentally devastated Earth, becomes a de facto ark housing multiple generations of humans over a period of 700 years.
In Stargate Atlantis third season episode "The Ark", Colonel Sheppard's team discovers an ark in orbit about a planet. It was built to preserve the planet's people, in stasis, after they were defeated in war.
Episode 30 of the radio drama Dimension X, "Universe", featured a seed ship whose human population had split into the lower deck inhabitants and the upper deck inhabitants. The upper deck inhabitants were mutated by radiation leaking through the ship's hull. The inhabitants were not aware they were on a ship and believed the vessel contained the entirety of the universe. The episode was written by Robert A. Heinlein.
In the Warhammer 40,000 fictional universe, the Eldar race live and travel aboard interstellar arks, Craftworlds
In Rendezvous with Rama, by Arthur C. Clarke, and later, followed by three more books, this time, co-written with JPL Space Director and novelist, Gentry Lee, an alien interstellar ark transits through Earth's solar system. When a second ship flies round the Earth, (or is it the first ship again?), a trio of humans are “ensnared” by happenings inside the city-sized ship, who then ride the giant craft to the far reaches of the galaxy.
1994 Sega Genesis game Generations Lost is a side-scrolling adventure game whose protagonist discovers that his "world" is a generation ship sent from Earth, sent to colonize a distant world. The ship was designed to sustain life for at least 700 years.
New Zealand author Ken Catran's Deepwater novel trilogy is a science fiction adventure for young adults about a massive generation ship Deepwater Black created by the dying population of a virus stricken Earth. The main inhabitants are teen clones all created from gene donors, all of which contributed to Earth society in phenomenal ways. As they travel on, they must survive the unknowns of space as well as the insecurities of being clones with the genetic memories of their dead donors constantly resurfacing in their heads. The novels were made into a 13 episode series for Yorkshire Television and SciFi Channel in 1997
In Hull Zero Three, by Greg Bear (2010), an interstellar ark is equipped with a library of biological forms and generates customized individuals as needed during its voyage.
The 2005 novel Building Harlequin's Moon by Larry Niven and Brenda Cooper follows the story of one of three arks that flee a dying solar system (due to A.I. and nanotechnology that has gone bad). Most of the inhabitants are in suspended animation, but they are forced to stop and build a society to create enough anti-matter to continue the trip.
The 2009 film Pandorum is set on an interstellar ark called Elysium. Originally sent into space to seed a new world since Earth was overpopulated, the ship has fallen into disarray and is largely overrun by a cannibalistic humans subspieces who evolved from passengers who went insane after Earth had mysteriously disappeared.
