A successful flight to Proxima b, the closest exoplanet to Earth, will require a crew of at least 98 people, according to an article accepted for publication in the journal JBIS (preprint available at arxiv.org). This number of participants will allow to give birth to healthy children during the 6300-year-old expedition.
In 2016, astronomers discovered Proxima b, the closest exoplanet to the solar system. It orbits the red dwarf Proxima Centauri and could potentially be habitable. It is believed to be a rocky planet the size of Earth with an equilibrium temperature of about −39 degrees Celsius. Since it is only 4.22 light years distant from us, this makes it a potentially attractive target for future interstellar missions.
Scientists at the University of Strasbourg, Frederic Marin and Camille Beluffi, decided to calculate the minimum crew size required to successfully fly to Proxima b. The researchers determined the duration of the mission based on the capabilities of modern technologies. As a basis, the authors took the Parker solar probe - NASA's automatic spacecraft for studying the outer corona of the Sun. Its launch is scheduled for summer 2018. It is assumed that the ship will approach the outer layers of the star at a distance of about 6 million kilometers and will move at a record speed of 724 thousand kilometers per hour, which is about 0.067 percent of the speed of light. If the first crew flies to Proxima b just as quickly, it will reach the planet in 6300 years. In the future, the flight period may be significantly reduced, up to 42 years,however, Maran and Beluffy decided to proceed from the current possibilities.
The researchers then conducted a computer simulation based on various principles of social engineering. They used the HERITAGE code of the Monte Carlo algorithm, which is used to simulate random processes. The simulation took into account the accidental and natural deaths of the expedition members, possible infertility, restrictions due to incest and the level of probability of becoming pregnant.
It turned out that for the colonization of Proxima b, at least 98 people are needed - 49 men and 49 women. It is this number of astronauts that will allow the crew not only to survive, but also to produce healthy offspring and completely eliminate incest (with the exception of the early stages of flight). The optimal fertile window turned out to be the age of 32-40 years - giving birth to children during this period, people will be able to ensure a stable increase in the ship's population and maintain a balance between young and old crew members. In addition, in this case, the epidemic that occurs in the middle of the trip will not lead to the complete death of all members of the expedition.
In the future, Maran and Beluffy plan to include genetic factors in their model - the effects of mutation, selection, drift and transfer. In addition, it will be necessary to take into account the impact of cosmic radiation on human health.
Astronomers today argue about the suitability of Proxima b for life. The red dwarf Proxima Centauri too often experiences powerful outbreaks, so radiation can lead to the death of living organisms. Scientists recently registered a flare that increased the brightness of a star a thousand times in 10 seconds. To survive such events, Proxima b must have the same powerful magnetic field as Earth and a dense atmosphere.
Christina Ulasovich
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