What is the minimum number of working individuals that would be necessary for the survival of a settlement on Mars?
Hillary Shaw
Newport, Shropshire, UK
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The 50/500 rule you would need 500 people to prevent genetic drift, although 50 might be sufficient to prevent inbreeding. Genetic drift is an insidious process within small populations that can cause certain variations to be lost. For example, just 2 per cent of the world’s population have green eyes, so this variant could be lost over time in a small population if the few green-eyed people have less offspring. Then we tend towards a monogenetic pool, with all the perils of inbreeding.
The good news is, humans have a long period of fertility, around 25 years (age 15 to 40), so you wouldn’t need to send all 500 out to Mars at once. The bad news takes us into legal/jurisprudential territory: humans should never be forced to procreate, and they may have more propensity than animals not to, through sexual orientation, personal choice or even mental breakdown.
Living in a Martian colony, especially in its first few decades, would be extremely stressful. You would need to save everything, there would be no chance of an outside walk in the forest and there would be constant dangers we don’t face on Earth with little chance of timely emergency aid from there either.
So we have a situation where radical new laws might be needed because even small “misdemeanours” could imperil the survival of the entire colony. Would we penalise individuals who chose not to reproduce? What of those whose expertise was valued, but who didn’t procreate?
How would we deal with “non-conformists”, from the lazy to the criminal, maybe even creating new “criminalities” such as not having children? What penalties would we have? Prison is simply a drain on scant resources, after all. Maybe even vandalism and theft would carry the death penalty?
This makes for an interesting student discussion in jurisprudence. You would probably need a very draconian, dictatorial regime until the colony grew into the thousands.
Toor Khan
Ouch, Pakistan
The minimum number of working individuals that would be necessary for the survival of a settlement on Mars is estimated to be 110. This number is based on a published in the journal Scientific Reports in 2020.
The research considered the following factors in determining the minimum number of settlers: the need for a diversity of skills and expertise to maintain the settlement’s infrastructure and systems; the need to account for illness, injury and other unforeseen events; and the need to allow for some degree of specialisation and division of labour.
The study also found that the minimum number of settlers could be reduced if the settlement was able to rely on a high degree of automation or if it was located in a particularly favourable environment. However, the research cautions that these factors shouldn’t be overestimated, as Mars is a very hostile environment and any settlement would be vulnerable to a variety of risks.
It is important to note that the minimum number of settlers isn’t the same as the optimal number of settlers. A larger settlement would be more resilient to shocks and would have a wider range of options at its disposal. However, it would also be more complex and more difficult to manage.
Michael Paine
Sydney, Australia
Not sure how many workers in total, but, according to , at least one should be an engineer. I attended a talk by Walter in 2001 when he was asked what essential item he would take to Mars. His response: a mechanical engineer!
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