  The survival of a genetically healthy multi-generational crew is of a prime
concern when dealing with space travel. It has been shown that determining a
realistic population size is tricky as many parameters (such as infertility,
inbreeding, sudden deaths, accidents or random events) come into play. To
evaluate the impact of those parameters, Monte Carlo simulations are among the
best methods since they allow testing of all possible scenarios and determine,
by numerous iterations, which are the most likely. This is why we use the Monte
Carlo code HERITAGE to estimate the minimal crew for a multi-generational space
travel towards Proxima Centauri b. By allowing the crew to evolve under a list
of adaptive social engineering principles (namely yearly evaluations of the
vessel population, offspring restrictions and breeding constraints), we show in
this paper that it is possible to create and maintain a healthy population
virtually indefinitely. A initial amount of 25 breeding pairs of settlers
drives the mission towards extinction in 50 +/- 15% of cases if we completely
forbid inbreeding. Under the set of parameters described in this publication,
we find that a minimum crew of 98 people is necessary ensure a 100% success
rate for a 6300-year space travel towards the closest telluric exoplanet known
so far.
