Minimum number of humans for viable space colony?

Minimum number of humans for viable space colony?

What is the minimum number of humans, both male and female, that would be required (with a strict breeding program) to ensure a viable, long-term human colony on another planet?

Thank you for allowing me an opportunity to answer your interesting question. The answer of course is not proven so it would depend largely upon who one asks, but the question has been given some thought in the past relative to certain hypothetical situations. I was unable to find anything even remotely reliable in terms of outlining or describing a ?strict breeding program? but I did find that some research (as you suggested alternatively) had been conducted and theorized by a reliable source, who speaks of various plans related to the number of travelers necessary to accomplish a long-term mission in space:

Anthropologist John Moore of the University of Florida has studied this issue extensively and while others have considered scientific ways of procreation (cryogenics, artificial insemination, etc) he has focused primarily on propagating new inhabitants, new sojourners and new pilots during the flight duration by way of common mating and natural selection. WHITLEY STRIEBER?S UNKNOWN COUNTRY outlines some of Moore?s theories:

?Researchers are trying to figure out the ideal number of people needed to create a viable population for multi- generational space travel. They?ve decided it needs to be 160 people. But with some social engineering it might even be possible to reduce this to 80.?

?Moore has previously studied small migrating populations of early humans and has developed simulation software called Ethnopop that analyzes the reproductive viability of small groups. A space trip of 200 years would perhaps take eight to 10 generations, and for this, his calculations suggest a minimum number of 160 people are needed to maintain a stable population. This would produce around 10 potential marriage partners per person??

Moore goes on to say that there are more options than just the obvious. Imposing significant self-control could expand each generation by a dozen or so years, thereby stretching out the periods of new births over a much longer period of time and reducing the minimally necessary population to roughly 80 inhabitants instead of the 160 in the earlier scenario:

?Moore suggests two ways to accomplish this. The first is to begin with young childless couples, the way Polynesian seafaring colonists once did. The second is to ask the space crew to postpone reproduction until the woman is 35 to 40 years old, creating longer time gaps between the generations. This results in a stable population of just 80 but the consequences of the increased medical risks of late childbirth have to be considered.?

WHITLEY STRIEBER?S UNKNOWN COUNTRY http://www.unknowncountry.com/news/?id=1270

?What would be a good number to start with? An expedition of between 150 and 180 people could sustain itself at the same rate over many generations, Moore calculates.? CNN ?Report: Make deep space travel a family affair? http://www.cnn.com/2002/TECH/space/03/09/family.spacetravel/

While Moore suggests that 150-180 initial inhabitants would be optimal to insure and sustain a healthy population for more than 20 centuries without significant inbreeding, he stated in 2002 that such a mission could theoretically be carried out by as few as two females, taking with them a large number of frozen embryos from Earth and the medical knowledge and experience to implant the embryos into one another to begin their traveling ?family?.

In 2002, the anthropologist Dr. John Moore estimated that a population of 150-180 would allow normal reproduction for 60-80 generations--equivalent to 2000 years. A much smaller inital population of two female humans should be viable as long as human embryos are available from Earth. Use of a sperm bank from Earth also allows a smaller starting base with negligible inbreeding.

Of course Moore must discount certain potential problems with this place where human emotions intervene. Issues such as infighting, the inhabitants developing their own government and breaking away from the Earth bound government, or self-destruction through disease or civil war or some things that would certainly seem necessary to factor into the mission. Having said that, Moore?s theory is obviously based in a best case scenario and assumes that all generations over the 500 or so year journey will remain loyal to a government and a planet they have never visited and a cause that they did not willingly embark upon themselves.

Your question is indeed a fascinating one and one that many of us have considered in the past. What I find to be an even more fascinating concept however, and one that I guess I never considered before, is that the charter group must accept the fact that they are leaving the earth forever, never to return or to see the final destination. This would truly be the ultimate sacrifice for science. The second issue, which of course is not related to the breeding program at all, is that the decedents, should they ever return to earth, would have developed their own language during their 500 year journey for which there will be no earthly interpreter. They will, in effect, be ?coming home? to a planet populated by extraterrestrials with whom they have nothing in common and cannot communicate.

And it is entirely possible that if these humans remained in reproductive isolation for long enough, they could evolve into another species altogether.?