If humans are ever to colonize the galaxy, we will need to make the trip to a nearby star with a habitable planet. Last year, astronomers raised the possibility that our nearest neighbor, Proxima Centauri, has several potentially habitable exoplanets that could fit the bill.

Proxima Centauri is 4.2 light-years from Earth, a distance that would take about 6,300 years to travel using current technology. Such a trip would take many generations. Indeed, most of the humans involved would never see Earth or its exoplanet counterpart. These humans would need to reproduce with each other throughout the journey in a way that guarantees arrival of a healthy crew at Proxima Centauri.

And that raises an interesting question. What is the smallest crew that could maintain a genetically healthy population over that time frame?

Today, we get an answer thanks to the work of Frédéric Marin at the University of Strasbourg and Camille Beluffi at the research company Casc4de, both in France. They have calculated the likelihood of survival for various-sized missions and the breeding rules that will be required to achieve success.

First, some background. Space scientists and engineers have studied various ways of reaching nearby stars. The problem, of course, is the vast distances involved and the comparatively sedate speeds that human spacecraft can manage.

That's "human spacecraft." ;-) To read more, click here.