Going Interplanetary – How Can We Build a Colony on Mars?

By Matt Williams | 22 September 2020

(Credit: SpaceX)

Welcome back to our series on “Going Interplanetary!” Today, we take a look at “Earth’s Twin,” the Red Planet, and the God of War – Mars! Given its proximity to Earth, similarities to Earth, and the possibility that life once existed there, Mars remains one of the most popular destinations for proponents of interplanetary colonization.

This is a subject that was explored extensively in a previous series, titled “Making the First Martians.” However, for the purposes of “Going Interplanetary,” the colonization of Mars is something that deserves another look. And this time around, we’ll be brief! Well, brief as we can considering the size and significance of the topic. Ready? Here goes…

“Earth’s Twin”

Mars is often referred to by this nickname, and for good reason. Like Earth, it is a terrestrial (rocky) planet composed of silicate minerals and metals. Like Earth, it is differentiated between a core and a mantle and crust. Like Earth, it has a tilted axis that leads to seasonal changes. Like Earth, it has polar ice caps and a considerable amount of water locked away in its ice sheets.

Based on data from numerous rovers, orbiters, and landers, it has also been concluded that Mars once had flowing water on its surface in the form of rivers, lakes, and even an ocean that covered much of the northern hemisphere. This was billions of years ago when Mars also had a thicker and warmer atmosphere, not to mention a protective magnetic field (like Earth).

However, due to its smaller size, mass, and density, Mars’ interior cooled rather rapidly (compared to Earth’s) and all geological activity coming to a stop. This also resulted in all action in the core ceasing as the outer core solidified and the inner core remaining in a liquid state. Since this is what drives magnetic fields, Mars lost this protective barrier and its atmosphere was slowly stripped away.

As a result, the landscape of Mars changed drastically over the course of eons, resulting in the freezing, desiccated surface and thin atmosphere we see there today. So while life may have once existed on the surface of Mars (like Earth), it certainly doesn’t look like there’s anything there today!

However, those similarities that Mars has retained make it an attractive option as far as colonization is concerned. There are even ideas for how we could live there long-term that would involve fixing up the place again, thickening up the atmosphere, and getting its waters flowing again! But one thing at a time…

Dry, Cold, and Irradiated

As already noted, the surface of Mars is a hostile environment and has been that way for billions of years. The atmosphere is predominantly composed of carbon dioxide and is about one-two-hundredth (0.5%) as dense as Earth’s atmosphere. In other words, the air on Mars is both toxic to humans and too thin to breathe.

At the same time, the atmosphere experiences extreme ranges in temperature, in part because it’s so thin and cannot retain much heat. During the winter at the poles, surface temperatures can get as low as -143 °C (-226 °F); during summer at midday, they can get as high as 35 °C (95 °F). However, since the atmosphere is so thin, the temperature drops rapidly with even minimal distance above the surface.

Another consequence of the planet’s thin atmosphere is the fact that water cannot exist in liquid form. Most of the water on Mars exists as vapor or as ice, rapidly freezing when it’s cold and sublimating when it’s warm. While it is believed that water could exist underground in the form of aquifers, reaching that water would require drilling.

Yet another consequence of the thin atmosphere (and lack of a magnetosphere) is the amount of radiation the surface is subjected to. During an average year, Mars is exposed to about 24.45 rads (244.5 mSV) worth of radiation, and even more when a solar event occurs. Compare that to Earth, where people are exposed to an average of 0.62 rads (6.2 mSv) per year (2.5% as much).

Location, Location, Location

For these reasons, choosing your location carefully is a must. As much as possible, the location should afford natural protection to the Martian colonists and have natural formations that would accommodate structures. For instance, many habitat designs developed specifically for living on Mars propose using Martian regolith or ice as natural shielding against radiation.

For instance, there’s the ALPHA 3.0 habitat concept submitted by Mars City Design as part of the 2019 NASA 3D Printed Habitat Competition. Their design involved building habitats directly into Barchan Dunes, a common feature on Mars, so that the inhabitants would be protected by Martian sand several meters deep. An added benefit is that the structure would be able to move with the dunes themselves as storms drove them on.

Around the polar regions, water ice is plentiful and temperatures are perpetually belowing freezing. This allows for concepts like the Mars Ice House, a structure build from locally-harvested ice, fibers, and aerogel. This kind of structure would provide natural protection (since ice is a good radiation shield) while also providing clear views of the Martian environment (which is essential to preventing feelings of isolation).

Around the mid-latitudes, habitats could be built underground in stable lava tubes, especially in the once-volcanically-active Tharsis plateau region. These tubes could be accessed through “skylights,” spots where the surface has caved in above the tube. Uncollapsed sections could then be closed off and pressurized to create a livable environment.

Another option is to build habitats in low-lying regions, like Valles Marineris or Hellas Planitia. Both of these features (a massive canyon and the largest impact crater on Mars, respectively) are up to 7 km (23,000 ft) in depth and have atmospheric pressures as high as 1.158 kPa and 1.2 kPa (respectively), which is almost twice the average on the rest of the surface.

These higher pressure conditions would mean less of a pressure difference between the habitat’s interior and exterior and allow for water to condense during certain times of the day – making the colonists less reliant on underground or distant sources of water.

That Bloody Gravity!

Compared to Earth, Mars is less massive and less dense, which means the local gravity is lower. In fact, Martian gravity weighs in at 3.711 m/s², compared to 9.8 m/s² here on Earth, which works out to 0.379 or 38% of Earth gravity. Why is this a problem, you ask? Well, because the human body (like all life here on Earth) evolved entirely in a 1 environment.

And as studies conducted on the International Space Station (ISS) have shown – in particular, NASA’s Twin Study – long periods spent away from a 1 environment can take a drastic toll on your health. This includes the loss of muscle tissue, bone density, weakening of the cardiovascular system, diminished eyesight, and the deterioration of the liver, kidneys, and other organs.

For this reason, astronauts aboard the ISS put themselves through a rigorous exercise regimen, but these only limit the effects. Readjusting to Earth’s gravity is also very difficult, as NASA’s Twin Study and the experiences of astronaut Scott Kelly can attest!

While the effects of living in a low-environment like Mars (as opposed to a microgravity environment like space) are not well known, it’s a foregone conclusion that they will be comparable. For this reason, people living on Mars will have to engage in regular and strenuous exercise, but more drastic measures may still need to be adopted.

One idea is to create rotating stations in orbit that are spun up to simulate 1 g. Martian colonists could then travel to these stations regularly to be exposed to Earth-normal gravity and strengthen their bodies. Pregnant and nursing women would also benefit from these stations, allowing their children to develop in a familiar gravity environment.

Beyond that, the only option is to trust in medical science to provide treatments that would prevent the human body from atrophying over time (like gene therapy or “miracle drugs”). Otherwise, future Martians will have to rely on a combination of regular check-ups, lots of exercise, and centrifugal force to ensure their health!

Terraforming Mars

Here is a concept we explored in more depth in a previous article. As we established there, the possibility exists to transform Mars into a more Earth-like planet where humans could live indefinitely. Doing so, however, would require a massive investment in time, energy, resources, and a multi-generational commitment.

Even after that process was complete, and there’s no telling how long it might take (possibly thousands of years), the planet would still not be up to Earth standards. Since Mars has only about 38% of Earth’s gravity, it would only be able to retain an atmosphere of about 0.38 bar – that’s equivalent to what the air pressure is like at elevations of 8,000 m (26,250 ft) here on Earth – and temperatures would still be very cold by Earth standards.

In other words, the air on Mars would be about as thin and cold as it is in the Himalayan Mountains. And the gravity would still be roughly 38% of what our bodies consider to be normal and the long-term health effects remain unknown. On top of all that, without a magnetic field in place (or some artificial magnetic shielding), the atmosphere would be slowly stripped away and Mars would eventually revert to what it’s like there today.

But with countermeasures to address the effects of lower gravity, magnetic shielding, and warm clothes and bottled oxygen, people could live on the surface of Mars and be out in the open. Over time, flora and fauna specific to Mars would emerge and the term “Martian” would apply to an entire biosphere, rather than just humans.

Colonizing Mars. Straightforward in theory, very difficult in practice, but ultimately doable. And as the old saying goes, “where there’s a will, there’s a way.” If the past few years have taught us anything, it’s that there is no shortage of entrepreneurs, luminaries, academics, organizations, and average janes and joes willing to make it happen.

Between Elon Musk (SpaceX), Richard Branson (Virgin Galactic), The Mars SocietyExplore MarsMars City Design, James Lovelock, Robert Zurin, Buzz Aldrin, Stephen Hawking, and the roughly 200,000 people who volunteered for a one-way trip with MarsOne, it seems clear that the colonization of Mars is not so much a matter of “will it happen?” as “when will it happen?”

Reprinted with permission from the author.

Matt Williams is a professional writer, lecturer, and science fiction author whose articles appear in Universe Today, Interesting Engineering, HeroX, Popular Mechanics, and other publications. His first collection of novels is available through Amazon, Audible, and Castrum Press. He lives in Esquimalt, BC, Canada. For more info, check out:⁣⁣⁣⁣⁣⁣⁣⁣⁣ https://storiesbywilliams.com⁣⁣⁣⁣⁣⁣⁣⁣⁣, https://www.universetoday.com/author/mwill/⁣⁣⁣⁣⁣⁣⁣⁣⁣ and https://interestingengineering.com/author/matthew-s-williams. Follow him at Twitter.

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