If humans ever decide to colonize a planet outside the solar system, they will need a spaceship of incredible size. A new study has shown that the colony for long-distance interstellar flights should number 20-40 thousand people.
That is how many people will be able to provide the genetic and demographic diversity necessary to survive during and after long space travel.
Researchers previously believed that a few hundred people would be enough to establish an interstellar settlement on or near an alien planet. However, they later decided to revise this figure. After all, the death of a large number of crew members in the event of an unforeseen disaster can threaten the entire mission, writes the Space edition.
In April, the journal Acta Astronautica published a study in which anthropologist Cameron Smith of Portland State University in the US state of Oregon looked at an interstellar travel of about 150 years.
The timing is consistent with the calculations of the non-profit organization Icarus Interstellar, which, together with DARPA, Nasa and the Foundation for Enterprise Development, is planning flights to distant stars. The Starship Project, announced in January 2012, aims to achieve manned interstellar travel by 2112.
To achieve this goal, a number of technologies will be required, including the space-time curvature technology, which allows in a short time to overcome interstellar distances at speeds higher than the speed of light. The project also involves the construction of an autonomous colony spacecraft. To date, NASA and DARPA have separately invested $ 100,000 and $ 1 million in this project, respectively.
Colony of people on a spaceship - illustration
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Smith's calculations, which he cited at a recent NASA Future In-Space Operations (FISO) event, are based on the theory of population genetics and computer modeling. The ideal ("safe"), according to the scientist, is the figure of 40 thousand people, of which 23 thousand are men and women of reproductive age.
This figure may sound large, but it is fully justified. Such a number will allow avoiding inbreeding, ensuring high genetic diversity, taking into account demographic changes and surviving at least one serious disaster, the article says. 40 thousand people can guarantee the health of the population in five generations.
Smith gives an analogy from the real world: to preserve vertebrate species on Earth, you need to start from 7 thousand individuals. A decrease in this figure leads to the gradual disappearance of the species. There are genetic reasons for this.
As a fallback, the researcher proposes to send frozen eggs and sperm along with the ship for the subsequent growth of people in space. However, this option was not seriously considered in his article.
Similar considerations apply to the colonization of Mars. The more people fly to the Red Planet, the greater the chance of its successful settlement.
Interstellar travel will require entirely new technologies. An increase in the speed of a modern spacecraft a thousand times, according to the scientist, will allow us to reach the closest star to Earth, Proxima Centauri, in 140 years.