Interstellar ark

An **interstellar ark** is a spaceship designed for interstellar travel. This can be used for long-term space missions as a generation or sleeper ship. This is also a potential habitat to preserve civilization and knowledge in the event of a global catastrophe.

### Proposals

Later studies indicated that a nuclear pulse drive starship powered by fusion-antimatter catalyzed nuclear pulse propulsion units would be in the 10% range and pure Matter-antimatter annihilation rockets would be theoretically capable of obtaining a velocity between 50% to 80% of the speed of light. At 0.1*c*, Orion thermonuclear starships would require a flight time of at least 44 years to reach Alpha Centauri. Carl Sagan suggested that this would be an excellent use for current stockpiles of nuclear weapons.

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.

It used nuclear electric propulsion to generate electricity which would then be used to run ion engines. If the project continued it could have been been the basis for a possible interstellar journey.

A generation ship would have to be entirely self-sustaining, providing energy, food, air, and water for everyone on board. It must also have reliable systems that could be maintained by the ship's inhabitants over long periods of time. Systems could also be enhanced by AI that would not require sustenance or sleep.

Generation ships would have to anticipate possible biological, social and morale problems, and would also need to deal with sociological matters of self-worth and purpose for the crews. Generation ships travelling for long periods of time may see breakdowns in social structures.

It would have to be large enough to support a community of humans and a fully recycling ecosystem. However, a spacecraft of such a size would require a lot of energy to accelerate and decelerate. A smaller spacecraft, while able to accelerate more easily and thus make higher cruise velocities more practical, would reduce exposure to cosmic radiation and the time for malfunctions to develop in the craft, but would have challenges with resource metabolic flow and ecologic balance.

See also: Generation ships

Sleeper and generation ships could be improved by the addition of AI systems or androids that could maintain systems and take over in cases of emergencies that could affect the humans on board. In *Raised by Wolves*, two androids escape a war-ravaged Earth, taking with them twelve human embryos. Their spacecraft reaches the planet Kepler-22b where the "mother" android hooks herself up to artificial umbilical cords to allow six fetuses to grow.

Examples:
* The Discovery in Space Odyssey is an interplanetary sleeper ship
* In Mass Effect Andromeda, humans and other races travel to the Andromeda Galaxy aboard a series of arks, with the aim of colonizing a series of new home worlds. The travel time is only 600 years due to the discovery of a form of faster-than-light travel that cuts down the time to traverse the 2.5 million light years between galaxies.
* In the Alien Universe, the Hypersleep Chamber on the Nostromo is where people are cryogenically frozen (in cryosleep or hypersleep) to survive the very long trips. It is capable of suspending the body’s autonomic functions while maintaining the health of each individual cell during stasis.
* The Hunter-Gratzner in the Riddick Universe transports a number of its passengers in cryostasis.
* SS *Botany Bay* is a sleeper ship from Star Trek
* Sleeper ship from Star Wars