It's a common feature among science fiction franchises: the idea that we will colonize Mars someday and make it an outpost of human civilization. It is also common to speculate that over time, the colonists will develop their own culture and traditions and even become a separate political entity. For the first time in history, there actually will be a people known as "Martians".
A neat idea
It is a neat idea, but the reality of colonizing the Red Planet is actually very challenging, and the long-term effects of living on another planet are not well understood. And with plans ramping up to send astronauts to explore the surface of Mars, or establish a permanent human presence there, there is a growing urgency to learn more.
So what are the likely effects of spending an extended amount of time on the Martian surface? What will astronauts experience after spending a few months of exploration there? And perhaps more importantly, what will potential colonists experience and how long will it take for human beings to acclimate to life on Mars?
Simply put, is there a way to make the Red Planet livable? Or is the dream of creating the first true "Martians" just that: only a dream? The short answer is that we don't know for certain if it can be done. The long answer is that it could be, but that it presents some rather serious unknowns and will probably take many generations.
So what exactly are our plans for creating a civilization of Martians and what is needed to make those happen?
Current Plans to Visit Mars:
At present, NASA is still planning on sending crewed missions to explore the surface of Mars sometime in the 2030s. This plan was outlined in the NASA Authorization Act of 2010 and in the U.S. National Space Policy that was issued that same year. Among other things, the Act directed NASA to take the following steps:
"In developing technologies and capabilities... the Administrator may make investments in space technologies such as advanced propulsion, propellant depots, in situ resource utilization, and robotic payloads or capabilities that enable human missions beyond low-Earth orbit ultimately leading to Mars;"
Intrinsic to this plan are studies into the long-term effects of microgravity on the human body since astronauts will be spending months traveling between Earth and Mars. It also calls for the creation of infrastructure and several key systems, such as a rocket powerful enough to send crews and supplies beyond Low Earth Orbit (LEO) and a spacecraft capable of taking them to Mars.
Meanwhile, there is no shortage of luminaries and entrepreneurs who are hoping to see a colony built on Mars within their lifetimes. These include the late Stephen Hawking, Elon Musk, Buzz Aldrin, Jeff Bezos, Robert Zubrin, Bas Landorp, and many more...
Currently, the most detailed and high-profile plan is the one offered by SpaceX founder Elon Musk. While he has been vocal about his desire to create a human colony on Mars for years, it was at the 67th Annual Meeting of the International Astronautical Congress in 2016 that he offered a comprehensive look at what his plan for a Martian colony would look like.
The presentation was summarized in an essay titled “Making Humans a Multi-Planetary Species“, which was published in the June 2017 issue of the journal New Space by Scott Hubbard (New Space's editor-in-chief). The objectives it detailed included the development of the Starship/Super-Heavy (formerly BFR) launch system and the beginning of crewed missions to Mars in the 2020s.
The purpose of these missions are also spelled out on SpaceX's website:
“The objectives for the first mission will be to confirm water resources, identify hazards, and put in place initial power, mining, and life support infrastructure. A second mission, with both cargo and crew, is targeted for 2024, with primary objectives of building a propellant depot and preparing for future crew flights. The ships from these initial missions will also serve as the beginnings of the first Mars base, from which we can build a thriving city and eventually a self-sustaining civilization on Mars.”
In September of 2018, Musk provided an updated look at what his proposed base (named Mars Base Alpha) would look like and indicated that he hoped to have it built by 2028. Most recently, Musk estimated that the cost of a one-way ticket to Mars would probably run between $100,000 and $500,000 (an optimistic assessment, to say the least).
Regardless of how realistic these timelines or appraisals are, it is clear that establishing a human presence on Mars comes with some serious challenges and risks. It's also clear that the strategies required to mitigate them will need to involve some highly advanced technology and very creative thinking!
What We've Learned About Mars:
Mars has been the subject of fascination long before the modern era. However, it was with the birth of modern astronomy and space exploration that it has become the focus of considerable research. At one time, many scientists speculated about the possibility of there being life on Mars and even a civilization.
However, surveys performed in the past half a century have put any notions of their being a species of native Martians to rest. Speculation about a possible Martian civilization is attributed to Italian astronomer Giovanni Schiaparelli, who studied Mars when it was at perihelic opposition (closest to Earth) in September of 1877.
While observing the surface to create the first detailed map of Mars, he noted the presence of what features he called "canali" - long straight channels mistranslated as "canals". These features were observed by other astronomers using the improved telescopes of the late 19th century.
By this time, astronomers also began to notice seasonal changes, like the diminishing of the polar caps and the formation of dark areas during the Martian summer. Combined with the observed "canals" (which were later shown to be an optical illusion), scientists began to wonder if Mars could support life like Earth.
Even by the early 1960s, articles were published about possible life forms on Mars and the existence of a Martian ecosystem (complete with oceans and vegetation). These notions would be shattered by the robotic exploration of Mars during the mid-1960s and 1970s.
While the Soviets reached Mars before NASA with the Mars 1 probe, it was the Mariner 4 mission (which made a flyby of Mars on July 14th, 1965) that provided the first close-up photographs of the surface, as well as far more accurate data on its atmosphere and magnetic environment.
While the pictures showed impact craters, the probe's other scientific instruments revealed a surface atmospheric pressure of about 1% of Earth's and daytime temperatures of −100 °C (−148 °F). In addition, no magnetic field or Martian radiation belts were detected (similar to what Earth has), which indicated that life would have a very difficult time surviving there.
But it was the Viking program, which launched the Viking 1 and Viking 2 spacecraft and lander missions to Mars in 1975, that convinced the scientific community that there was not likely to be any life on the Martian surface. However, the landers also revealed evidence of past liquid water and rainfall on the planet.
Further evidence gathered by other robotic missions - such as the Opportunity and Curiosity rovers, and the Mars Reconnaissance Orbiter (MRO) and Mars Atmosphere and Volatile Evolution (MAVEN) orbiters - has indicated that these conditions existed roughly 3.8 billion years ago, at a time when Mars had a thicker atmosphere and warmer average surface temperatures.
The presence of warmer, wetter conditions on Mars in the past has led to speculation that Mars may have once supported basic life forms (most likely single-celled microbes). Several current and future missions (like the Mars 2020 rover) will continue to look for evidence of past (and maybe even present) life.
However, roughly 4.2 billion years ago, Mars' lost its magnetosphere as a result of its outer core cooling and solidifying. Convection in the core ceased as a result, where the outer core rotates in the opposite direction of the planet's rotation and creates a dynamo effect (which is believed to be what powers Earth's magnetic field).
As a result, Mars' atmosphere began to be slowly stripped away over the course of the next 500 million years. This led to the surface becoming the dry, frozen landscape we know today, but also allowed for the preservation of the ancient landscape - and all the evidence of past rivers and lakes.
Conditions on Mars Today:
To break it down, Mars has a few things in common with Earth that make it attractive as far as exploration and colonization are concerned. For starters, time works much the same on Mars as it does on Earth, with striking similarities between seasonal changes and the length of a single day.
A Martian day is 24 hours and 39 minutes, which means that plants and animals – not to mention human colonists – would be able to have a diurnal cycle (day/night cycle) that is almost identical. Mars also has an axial tilt that is very similar to Earth’s - 25.19° versus Earth's tilt of 23.5° - which means it has the same basic seasonal patterns as our planet.
Basically, when one hemisphere is pointed towards the Sun, it experiences summer while the other experiences winter – complete with warmer temperatures and longer days. The only difference is, with a year lasting a total of about 687 days (668.6 Martian days), the seasons last about twice as long.
There's also the abundant supply of water ice on Mars, which is largely concentrated in the polar ice caps. However, studies of Martian meteorites, its atmosphere and surface conditions have suggested that significant amounts of water may also be locked away beneath the surface. This water could be extracted and purified for human consumption easily enough.
Additionally, Mars is closer to Earth than the other Solar planets, with the exception of Venus (which is way too hot and acidic to colonize!) In fact, every 26 months, the Earth and Mars are at opposition – at the points in their orbit where they are closest to each other – which would make for regular “launch windows” to send colonists and supplies.
Unfortunately, that's where the similarities end. When it comes right down to it, Mars is a cold, desiccated, irradiated, and inhospitable environment for life as we know it. In terms of temperature alone, its average surface temperature during the course of a year is -63 °C (-81 °F), compared to Earth's comparatively balmy 14 °C (57 °F).
The atmosphere is also incredibly thin and unbreathable. Measured on the surface, the air pressure on Mars averages at about 0.636 kPa, which is roughly 0.6% that of Earth's at sea level. And whereas Earth's atmosphere is composed of 78% nitrogen, 21% oxygen, Mars' atmosphere is a toxic plume composed of 96% carbon dioxide and some water vapor.
Then there's the small matter of all the radiation people would be exposed to. On Earth, human beings in developed nations are exposed to an average of 0.62 rads (6.2 mSv) per year. Because Mars has a very thin atmosphere and no protective magnetosphere, its surface receives about 24.45 rads (244.5 mSV) per year - more when a solar event occurs.
NASA has established an upper limit of 500 mSV per year for astronauts and studies have shown that the human body can withstand a dose of up to 200 rads (2000 mSv) a year without permanent damage. However, prolonged exposure to the kinds of levels detected on Mars would dramatically increase the risk of acute radiation sickness, cancer, genetic damage, and even death.
And then there's the matter of Martian gravity, which is roughly 38% that of Earth's (3.72 m/s2 or 0.379 g). While scientists do not yet know what effects long-term exposure to this level of gravity would have on the human body, multiple studies have been conducted into the long-term effects of microgravity - and the results are not encouraging.
This includes NASA's seminal Twins Study, which investigated the health of astronauts Scott and Mark Kelly after the former spent a year aboard the International Space Station (ISS). In addition to muscle and bone density loss, these studies showed that long-duration missions to space led to diminished organ function, eyesight, and even genetic changes.
It is fair to say that long-term exposure to over 1/3rd of Earth-normal gravity would have similar effects. Like astronauts serving aboard the ISS, these effects could be mitigated with a robust exercise and health monitoring regiment. But the possibility of living under these conditions, and children being born in them, raises a whole lot of unknowns.
How Do We Adapt to Mars?:
Between all of these hazards to human health, life on Mars doesn't exactly seem inviting, does it? And yet, there is no shortage of people willing to make the journey and become the first generation of "Martians". Part of the appeal is the challenge that settling on a new planet presents, especially one that requires some hard work to make it livable.
And in the short term, there appear to be many possibilities for making life on Mars work. Whoever chooses to do so will be forced to lean on their technology rather heavily and will have to be as self-sufficient as possible. That means building materials, food, water, air, and all the necessities of life will need to be produced on-sight, or what is known as in-situ resource utilization (ISRU).
This is especially true when it comes to the creation of habitats. In recent years, NASA has sponsored a design competition intended to spur innovative ideas on how local resources can be used to build settlements on Mars. This is known as the 3D-Printed Habitat Challenge, which is hosted by NASA’s Centennial Challenges program.
For the challenge, which began in 2015, multiple teams were tasked with using recent advances in 3D printing, robotics, modeling software, and material development to design and build large-scale structures using recyclables and/or materials found on Mars. Proposals ranged from structures printed from regolith to ice, which would offer natural protection against the elements and radiation.
Other proposals involve stable lava tubes that run beneath the surface as natural shielding. Basically, if the surface is exposed to dangerous levels of radiation, then habitats should be built underground. Efforts to develop this idea include NASA-funded Hawai’i Space Exploration Analog and Simulation (Hi-SEAS).
As part of an exercise that has been taking place since 2013 on the Hawaiian mountain of Mauna Loa, Hi-SEAS is dedicated to training crews for long-duration missions on Mars. In recent years, training efforts have included exploring local cave systems, which are the remains of extinct lava tubes.
The European Space Agency (ESA) also created the Planetary ANalogue Geological and Astrobiological Exercise for Astronauts (PANGAEA) program to teach astronauts about geology and cave exploration. A few years ago, the Pangaea-X campaign created the largest 3D map of a cave system (La Cueva de Los Verdes in Spain) in order to test mapping technology that could be used on Mars.
Some more radical suggestions for mitigating the radiation involve creating a magnetic field for Mars. At the less adventurous end of things, you have suggestions for creating artificial magnetic shields around colonies. A good example is a plan for a modular base that would be protected by an electromagnetic torus that generates an artificial field.
Another comes from a 2008 study conducted by researchers from the National Institute for Fusion Science (NIFS) in Japan. Based on continuous measurements that indicated a 10% drop in Earth's magnetic field over the past 150 years, they advocated how a series of planet-encircling superconducting rings could compensate for future losses. With some adjustments, such a system could be adapted for Mars.
More ambitious solutions include a proposal made by Dr. Jim Green (Director of NASA's Planetary Science Division) for an artificial magnetic shield that would be deployed to Mars' L1 Lagrange Point - which was presented at the Planetary Science Vision 2050 Workshop in 2017.
Even more ambitious suggestions include reactivating Mars' outer core, which could be done one of two ways: The first would be to detonate a series of thermonuclear warheads near the planet’s core, while the second involves running an electric current through the planet, producing resistance at the core which would heat it up.
Alas, the gravity is still a problem, mainly because the long-term effects are not yet fully understood. However, there are still possibilities, such as long-term health monitoring and regular medical intervention. Here on Earth, bone density loss (in the form of osteoporosis) is mitigated by the use of medications, hormone therapy, vitamin and calcium supplements.
Regular exercise that includes weight training is also helpful, and would also help maintain muscle mass. Artificial gravity is another possible means of addressing muscle and bone density loss, which could be generated by centrifuges, or rotating space stations in orbit. If transportation becomes a regular feature, Martians could also visit Earth periodically as a form of therapy.
How Do We Adapt Mars to Us?:
In the long-term, there is the possibility of altering the Martian environment to suit human needs. This process is known as "terraforming", where changes to the atmosphere and surface of the planet will result in a more "Earth-like" environment. This presents some major challenges; but again, meeting them is not beyond the realm of possibility.
To terraform Mars, three things need to be done: warm the surface, thicken the atmosphere and create a biosphere similar to Earth's. Luckily, these three tasks are all interconnected. By thickening the atmosphere, the planet would be warmed and the amount of radiation reduced. By introducing Earth plants and vegetation, the atmosphere would be converting to something breathable.
The first step would be to trigger a greenhouse effect on Mars, which could be done any number of ways. For one, ammonia, methane, or chlorofluorocarbons (CFCs) could be introduced into the Martian atmosphere. Since all three are powerful greenhouse gases, their introduction would thicken the atmosphere and raise global temperatures.
There's the also the possibility of melting the polar ice caps, which would release a significant amount of water vapor and carbon dioxide (from the dry ice at the south pole) and have the same effect. Many of these ideas were proposed by NASA in a 1976 study titled “On the Habitability of Mars: An Approach to Planetary Ecosynthesis“.
There's also the possibility of using orbital mirrors to warm the Martian surface directly - an idea proposed by Mars Society founder Dr. Robert M. Zubrin and Christopher P. McKay of the NASA Ames Research Center. Positioned near the poles, these mirrors would be able to sublimate the CO2 ice sheet and contribute to global warming.
Once the atmosphere is thickened and the surface warmed, liquid water would once again be able to flow across the surface. This would also lead to precipitation, which would allow for photosynthetic organisms, plants, and vegetation to be introduced to the surface. Over time, these would be able to convert the CO2-rich atmosphere into one rich in oxygen gas.
However, there are limits to how much we can alter Mars to suit our needs. With only 38% of Earth's gravity, Mars would only be able to retain an atmosphere of about 38.44 kPa (or 38% of Earth's atmosphere). This would not be enough for humans to breathe comfortably, so people would still need to carry oxygen tanks with them when wandering around outside (though pressure suits would no longer be necessary).
And without a magnetosphere or artificial magnetic field, the atmosphere would be slowly stripped away over time and exposure to radiation would still be an issue. And of course, the effects of Martian gravity would still be an issue and there is no foreseeable way to alter that.
What About "Areoforming"?:
All of this raises an important point: why commit to the lengthy and expensive process of changing Mars at all? Why not alter Earth organisms to make them more compatible with Martian conditions? Inevitably, life will change once it is introduced to Mars, so why not meet it halfway?
Whereas altering the Martian environment to suit our needs is known as "terraforming", altering life to suit conditions on Mars is often referred to as "areoforming" (from the Greek god Ares) or more simply as "marsiforming". The key to this is to find life forms that could survive the tough conditions on Mars and make ourselves more like them.
These would include lichens and methanogens, two types of terrestrial organisms that are capable of withstanding conditions within certain niche environments on Mars. With some genetic modifications, species of these plants could survive out in the open. The same is true of cyanobacteria, photosynthetic organisms that could convert atmospheric CO2 into oxygen gas.
Plants could also be modified that would be able to withstand perchlorates (which are common in Martian soil) and remove them, so that future generations of plants would be able to thrive. But the biggest challenge would be finding genetic modifications that would allow humans and animals to thrive in Martian gravity.
For example, there may be gene modifications that could allow humans to grow and remain healthy in Martian gravity, or to be able to withstand the higher levels of Martian radiation. If not, then shielding and artificial gravity are going to need to be a regular feature of life there.
At present, we still don't know what the long-term effects of life on Mars will have on terrestrial life forms. Astronauts conducting long-duration missions there will certainly have to contend the usual consequences of space travel: muscle atrophy, bone density loss, a high dose of radiation, and some tough times adapting to life on Earth again.
But for colonists, the consequences will be much more far-reaching and nebulous. Will animals and humans be able to carry a baby to term in 0.38 g, or will there be complications? Will Martian children suffer from mutations or changes at the genetic level? Will some genetic modifications allow them to live full and healthy lives or will they require regular medical intervention?
For this reason, extensive research is still needed, and treatment/genetic modification options addressed. In the end, though, it is clear that some form of adaptations will be needed before humans and terrestrial life forms can fully colonize Mars. This may involve altering the Martian environment to suit us, ourselves to suit Mars or a little from Column A and a little from Column B.
In the end, there is only so much we can do, and nature will have the final say!
- Wikipedia - Colonization of Mars
- Wikipedia - Terraforming of Mars
- NASA - The Human Body in Space
- NASA - Twins Study/The Research
- James Lovelock - The Greening of Mars
- NASA - How to Protect Astronauts from Space Radiation on Mars
- National Space Society - The Case for Colonizing Mars (Robert Zubrin)
- Space Safety Magazine - How Will Living on Mars Affect our Human Body?
- NASA - On the habitability of Mars: An approach to planetary ecosynthesis