After mind-melting experiences in Copenhagen I needed to change channels for a little while. I spent the last week reviewing and revamping my paper on the genetics of multigenerational interstellar voyaging. Humanity isn't ready to do this, but that's fine, it will take a long time to get ready. This is part of my effort in Icarus Interstellar's Project Hyperion, an international team laying the groundwork for a 100-year study of the physics of interstellar flight for human populations; the idea is to provide humanity with the physics and propulsion needed to make such voyages, if we want to do so, 100 years from now...pretty 'out there' stuff! I'll present this paper at a NASA-DARPA conference in Houston later this year. Abstract below. I think it;s ready for publication and am now massaging it for submission to
Acta Astronautica;
Estimation of a Genetically and Demographically Viable Founding Population for Multigenerational Interstellar Voyaging
Cameron M. Smith
Department of Anthropology
Portland State University
August 2013
9,237 words, discounting references
ABSTRACT
Designing interstellar starships for human migration to exoplanets requires establishing the starship population, which factors into many variables including closed-ecosystem design, architecture, mass and propulsion. I review the central issues of population genetics (effects of mutation, migration, selection and drift) and demographics (population size, age, and sex structure on departure) for human populations on such voyages, specifically referencing a roughly 5-generation (c.150-year) voyage currently in the realm of thought among the Icarus Interstellar research group. I present several formulae as well as concrete numbers that can be used to help determine populations that could survive such journeys in good health. I find that previously-proposed multigenerational voyage populations, on the order of a few hundred individuals, are significantly too low to consider based on current understanding of vertebrate (including human) genetics and population dynamics. Population genetics theory, calculations and computer modeling determine that a properly-screened and age- and sex-structured total founding population (Nc) of anywhere from roughly 14,000 to 44,000 people would be sufficient to survive such journeys in good health. A safe and well-considered Nc figure is 40,000, an ‘IMP’ or interstellar migrant population composed of an effective population [Ne] of 23,400 reproductive males and females, the rest being pre- or post-reproductive individuals. This number would maintain good health over five generations despite (a) increased inbreeding resulting from a relatively small and isolated human population, (b) depressed genetic diversity due to the founder effect, (c) demographic change through time and (d) expectation of at least one severe population catastrophe over the 5-generation voyage.
