We could start a settlement on Mars with just 22 people, scientists say

New research suggests that a settlement on Mars could get up and running with far fewer settlers than previously predicted. The study also looked at what personality types are best adapted to long-term stays on the Red Planet.

The research conducted by scientists from George Mason University, Fairfax, Virginia, and other institutions, looked at the challenges that would face Mars settlers as they build and maintain a self-sustaining human presence. The research comes as space agencies across the globe begin planning future long-stay space missions on the moon and eventually on the Red Planet.

The researchers’ goal was to answer questions such as: What conditions are needed to maintain a stable outpost on Mars? What combination of personality types would do best in this hostile environment? How many resources are needed for two years between resupplies and assuming occasional accidents? As the study has it, under two dozen people are needed to start a future Mars settlement.

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“From our multiple simulations and scenarios (up to 28 Earth years), we found that an initial population of 22 was the minimum required to maintain a viable settlement size over the long run,” the authors wrote in a paper detailing their findings, which has not yet been peer-reviewed, published on the research repository site arXiv. “We find, contrary to other literature, that the minimum number of people with all personality types that can lead to a sustainable settlement is in the tens and not hundreds.”

A model Martian settlement

To answer these questions and better determine the behavioral and psychological interactions of future Martian settlers, the team employed a computer modeling approach called Agent-Based Modeling (ABM) simulation.

ABMs are commonly used to study the interactions between people, things, and places, over time. The researchers also considered data regarding groups of humans in other high-stress remote situations, including aboard the International Space Station (ISS). This allowed them to test the minimum number of people needed to keep a Mars outpost running, sometimes for as long as almost three decades.

The model used by the team assumed that the Mars settlement has already been constructed and that food, air, and water are being produced in situ on the Red Planet. That means that the simulated Martian base doesn’t require start-up time.

The ABM settlement also has a nuclear generator established that has a steady source of electricity for a minimum of 7 years. The purpose of this simulated settlement is to mine minerals from the Red Planet to be sent back to Earth.

Running the test five times for 28 years, the outpost population sizes were varied from 10 to 170 to find the stable population size.

In addition to finding that a Mars base could operate over long periods with just 22 people, the team determined that the settlement could survive if its population dropped as low as 10 settlers, but only if it was built back up within 1.5 years — which was the time the simulation set between supply missions from Earth.

The team went beyond this, however, also testing what type of person seems to be best suited to long stays on the surface of Mars.

What personality types function best on Mars

The ABM simulations used by the team allowed them to account for the interactions between settlers by considering four basic personality types based on resilience and coping ability. These four types were defined as agreeable, sociable, reactive and neurotic.

The team defined agreeables as “individuals with the lowest degree of competitiveness, low aggressiveness, and not fixated on stringent routine,” while socials were “individuals with a medium degree of competitiveness, extroverted, require social interaction, but are not fixated on stringent routines.” People with a medium degree of competitiveness and competitive interpersonal orientation and who are fixated on stringent routines were classed as reactives. The final group, “individuals with a high degree of competitiveness, highly aggressive interpersonal characteristics, and challenged ability to adapt to boredom or a change in routine,” were classed as neurotics.

In the models, Red Planet settlements started with an equal number of these four personality types. In all the tests, the researchers pointed out that the agreeable personality types were the only Mars settlers to last the duration of every single run.

“We also found that the agreeable personality type was the one more likely to survive,” the team wrote. “The stress caused by accidents, as well as from interacting with other settlers, takes a toll, and agreeable personality types were assessed to be the most enduring for the long term, whereas neurotics showed least adaptation capacity.”

As well as modeling events at an individual level, such as the interactions between settlers, the team also used the ABM simulations to account for global challenges. This means looking at the potential impact of events such as accidents and disruptions to the Martian base’s supply chain with Earth on the outpost as a whole.

The team said their research “demonstrates that team and individual psychological success in extreme environments can be broadly attributed to coping capacity, which we define as the ability of people, organizations, and systems, using available skills and resources, to manage adverse conditions, risk or disasters.”

For future studies, the team suggests varying the proportions of personality types among the settlers, suggesting that a team of all agreeable types could make the most cohesive and successful Martian settlements.