A Mars colony is necessarily a technological society, as it is incapable of surviving without technology due to the hostility of the environment. A technological society requires a high level of education in its individual members. High levels of education are correlated with low birth rates. It is therefore likely that a Mars colony or settlement will have a low birth rate, and may have no birth rate at all if there are serious problems with gestation in low gravity.
So population growth is likely to be done mainly through immigration. And the colony will need to limit emigration to retain the skill set required for an autonomous colony. Population growth is limited by the availability of resources, in particular the availability of energy on Mars. It is also limited by the transportation system available from Earth to Mars.
Population growth rate is a variable that is highly dependent on conditions on both Earth and Mars.
There are many different tasks for the colonists to carry out. Mars is an alien world and bears imponderable conditions. People will need to improvise. The following skills are vital:
- Profound knowledge and experience in technical matters and engineering
- Scientific expertise in Geology, Biology, Medicine and Radiology
- Agricultural knowledge
- Capabilities for Education, Health, Nursery and Psychology
- Production skills in both low and high complexity fabrication, from glass blowing to 3D printing.
The size of the human population must not be too big due to the risk of overpopulation, causing lack of food and resources. It must also be high enough to maintain the required skill set necessary for maintenance and expansion. As colony growth is likely to be mainly through immigration it should be possible to regulate immigration in order to control population. Illegal immigration to Mars is unlikely to be a significant problem due to the difficulty of procuring adequate transportation. At least for the first century or so.
The size of the human population must not be too small due to the risk of inbreeding depression. However Mars is not isolated from Earth, baring catastrophe, and immigration should solve this issue. Eventually, as one of the aims of the colony is self sufficiency, the size of the population will need to be significant, both for genetic diversity but also for skill diversity. A martian culture cannot allow itself to loose too many technical skills or it will collapse through technological failure.
A group of male individuals tend to be more aggressive than a mixed group of males and females. The mix in age of the individuals has an effect, too. An entirely male colony is hardly a colony, in the sense that it has no possibility of self perpetuation, unless significant progress is made in artificial gestation. The same could be said for an entirely female population, although in that case there already are technological solutions to the absence of males.
While the first Martian settlers, who grew up on Earth, will be full of enthusiasm, the next generation might have a different attitude. This has to be taken into account. An initial population of mixed age can reduce the effect of division into groups with different interests.
Living on Earth will always be an alternative to living on Mars. So a martian society will need to provide sufficient opportunities to its members, in particular to younger individuals, to keep them interested in living on Mars.
- What is the minimum size of a human population to avoid inbreeding effects?
- Criminality in a highly technological society. When an action against the technological support system of the colony can imperil the entire population, what is the proper response to criminality?
- A Martian Society is likely to be a high energy society, with high individual productivity. What can be done with less productive individuals, including the young, the elderly and the physically limited individuals?