There is no shortage of people today who have an opinion on whether or not humans should colonize Mars. On the pro side, there are those who think that a Martian settlement will serve as a "backup location" for humanity in case some cataclysmic event happens here on Earth.
On the con side, there are those who feel that focusing on Mars will steal focus away from efforts to save planet Earth. There are also those who think the natural hazards make it a bad idea, while people on the flip side think it is these very things that make it an exciting challenge.
But when you look past the arguments for and against colonization, there is the inevitable question of if we can settle on Mars and what that settlement would look like. The question goes beyond mere aesthetics and embraces everything from architecture and construction to food, transportation, and general health.
So what exactly would a colony on Mars look like, and how would it operate?
Making a Go of Life on Mars:
To be fair, there is no shortage of ideas for how human beings might establish a colony on the Red Planet. They are also quite detailed, ranging from different kinds of structures that could be built, how they would be built, what they would be built from, and how they would be protected from the elements.
Then again, they would have to be in order to address the many challenges that living on Mars would present. These include (but are not necessarily limited to):
Extreme Distance from Earth
Increased Exposure to Radiation
Planet-Wide Dust Storms
Taking all of this into account, it becomes clear that any efforts to build a civilization on Mars will have to take into account a lot of specific needs. And meeting these will necessitate that colonists rely pretty heavily on some pretty advanced technology.
Habitats will need to be sealed and pressurized, heavily-insulated and heated, shielded against solar and cosmic radiation, self-sufficient in terms of water, power, and other essentials, and built (as much as possible) using local resources - aka. In-Situ Resource Utilization (ISRU).
Getting to Mars:
Using current methods, the journey to Mars is long and potentially dangerous and can take place only when Earth and Mars are at the closest point in their orbit to each other. This is what is known as a "Mars Opposition," where Mars and the Sun are on directly opposite sides of Earth. These occur every 26 months, and every 15 or 17 years, an opposition will coincide with Mars being at the closest point in its orbit with the Sun (aka. perihelion).
On average, Mars and Earth orbit at an average distance of 225 million km (140 million mi). But during an Opposition, the distance between Earth and Mars can drop to as little as 55 million km (34 million mi). However, since it is not exactly a direct flight, the travel time involved is not a simple matter of calculating the distance divided by average velocity.
This is because both Earth and Mars are orbiting around the Sun, which means you can’t point a rocket directly at Mars, launch, and expect to hit it. Instead, spacecraft launched from Earth need to account for the moving nature of its target to be pointed at where Mars is going to be, a method known as ballistic capture.
Another factor to consider is fuel. Again, if you had an unlimited amount of fuel, you’d point your spacecraft at Mars, fire your rockets to the halfway point of the journey, then turn around and decelerate for the last half of the journey. You could cut your travel time down to a fraction of the current rate – but you would need an impossible amount of fuel.
Because of this, a mission to Mars can take between 150 and 300 days (five to ten months) to reach the Red Planet. This all depends on the speed of the launch, the alignment of Earth and Mars, and whether or not the spacecraft will have the benefit of slingshotting around a large body to pick up a boost in velocity (aka. a gravity-assist).
Regardless, crewed missions invariably require spacecraft that are larger and heavier than robotic spacecraft. This is necessary since human beings require amenities while in space, not to mention the amount of supplies and equipment they'll need to carry out a mission.
The challenges posed by long-distance and natural hazards on Mars have led to some creative suggestions of how to build habitats that will shield against the environment and can be built in-situ. Many of these ideas have been proposed as part of an incentive challenge sponsored by NASA and other organizations. Some examples include:
The MakerBot Mars Base Challenge:
This joint competition, which ran from May 30th to July 12th, 2014, was hosted by NASA JPL and MakerBot Thingiverse - a Brooklyn-based 3-D printing company. For the sake of the competition, entrants were given access to MakerBot 3-D printers and tasked with designing bases that were utilitarian, capable of withstanding the elements, and providing all the amenities of home.
Of the over 200 ideas that were submitted to the competition, two were selected as the contest winners. These included the Mars Pyramid, a design that was inspired by the Pyramid of Giza. This particular structure was designed to withstand the worst of the elements while also being configured for science and engineering activities and experiments.
The sides of the pyramid would be composed of solar panels to collect energy and provide the inhabitants with vistas to combat feelings of isolation. A nuclear generator would provide backup power, water would be stored near the main power center and heated as needed, and food would be grown with a sustainable aquaponics system at the top of the pyramid.
The second winner was the Mars Acropolis, a futuristic design that incorporated carbon fiber, stainless steel, aluminum, and titanium into the main structure while a combination of concrete, steel, and Martian soil formed the outer protective wall. The main structure would consist of a foundation and three levels that accommodated different functions and facilities.
On the ground level, decompression chambers would protect against a loss of air pressure, while a series of greenhouses would produce food and help filter the air and produce oxygen. Level one would house the water purifier, while level two is where the living quarters, labs, and a landing dock would be placed.
Meanwhile, level three would act as the nerve center, with flight operators and observation posts and the colony's water reservoir. This reservoir would be situated at the very top of the settlement where it could collect atmospheric water, condense it for use by the inhabitants, and use the sun's energy to warm it.
Journey to Mars Challenge:
Announced in May 2015, this NASA-sponsored incentive competition sought to inspire creative ideas from the public that would allow for continuous habitation on Mars. According to the guidelines, NASA was looking for ideas that would address issues of "shelter, food, water, breathable air, communication, exercise, social interactions, and medicine."
In addition, all of the submissions needed to focus on resource efficiency, feasibility, comprehensiveness, and scalability in order to facilitate missions that are longer in duration and greater in distance from Earth, eventually approaching “Earth independence.” A total prize purse of $15,000 was awarded to the three concepts that best met all of these criteria. By October 2015, the winners of the competition were announced.
They included the Mars Igloo: An ISRU Habitat, which was submitted by aerospace engineer Arthur Ruff of Toronto; the Starch from the Micro-Algae Chlorella as the Main Food Source for a Self-Sustaining Martian Colony, submitted by Keck Graduate Institute alumni Pierre Blosse from Iowa; and the Mars Settlement Concepts, submitted by chemical engineer Aaron Aliaga and geophysicist Maleen Kidiwela of California and Texas (respectively).
The 3-D Printed Habitat Challenge:
This competition was a joint venture between NASA's Centennial Challenges, the National Additive Manufacturing Innovation Institute (aka. America Makes), and Bradley University in Peoria, Illinois. It was divided into three phases, each of which had its own prize purse that would be divided among the three winning teams.
In Phase I, the Design Competition, teams were required to submit architectural renderings. This phase was completed in 2015, and a prize purse of $50,000 was rewarded. The winning entries for this phase included the Mars Ice House by Space Exploration Architecture (SEArch) and Clouds Architecture Office (Clouds AO).
The concept was inspired by recent missions that have shown just how prevalent water ice is in our Solar System, especially on Mars. This particular design relies on the abundance of water and the perennially cold temperatures in Mars’ northern latitudes to create a habitation for explorers.
The construction would be handled by autonomous robots that would harvest ice on site and combine it with water, fiber, and aerogel, which would then be printed as layered rings. This method and choice of building materials would provide insulation, radiation shielding, and a view of the surrounding environment to potential Martian settlers.
Regolith Additive Manufacturing (RAM) by Team Gamma, which also won the People's Choice Award. This concept calls for the use of three inflatable dodecahedral modules to form the basic shape of the habitat, while a series of semi-autonomous robots then use microwaves to melt and distribute regolith (aka. "sintering") over these to form the habitat's protective outer layer.
Third place went to the Entry, Descent, and Landing (EDL) concept, which was submitted by Team LavaHive. Their design called for the use of repurposed spacecraft components and a technique known as "lava-casting" to create the connecting corridors and sub-habitats around a main inflatable section.
In Phase II, the Structural Member Competition, focused on material technologies, requiring teams to create structural components. It was completed in August of 2017 with a prize purse of $1.1 million.
This phase was divided into three levels, where teams were tasked with printing samples of their structure, subjecting them to compression and bending tests, and then printing scale models of their concepts.
In Phase III, the On-Site Habitat Competition was also divided into levels, where each team was subjected to a series of tests designed to measure their ability to construct a habitat autonomously. This phase culminated in a head-to-head habitat print in April 2019, with a $2 million prize purse awarded.
Throughout this phase, several teams stood out for their creative concepts, which merged ISRU and unique architectural designs to fashion highly-functional habitats out of the Martian environment. But in the end, the top prizes went to team AI. SpaceFactory of New York for their MARSHA habitat.
According to the team, their cone-shaped design is not only the ideal pressure environment but also maximizes the amount of usable space while taking up less surface space. It also allows for a structure that is vertically-divided based on different types of activity and is well-suited to 3-D printing thanks to its bottom-up design.
The team’s also designed their habitat as a flanged shell that moves on sliding bearings at its foundation, the purpose of which was to deal with temperature changes on Mars (which are significant).
The structure is also a double shell, consisting of an inner and outer layer that are completely separate, which optimizes airflow and allows for light to filter in from above to the entire habitat.
Hawaii Space Exploration Analog and Simulation (aka. Hi-SEAS):
Using an analog for a habitat on Mars, located on the slopes of the Mauna Loa volcano in Hawaii, this NASA-funded program conducts research missions designed to simulate crewed missions to Mars. At an elevation of 2,500 meters (8,200 feet) above sea level, the analog site is situated in a dry, rocky environment that is very cold and subject to very little precipitation.
Once there, crews live in a habitat where they carry out tasks that would be similar to a Mars mission, which includes research, missions to the surface (in spacesuits), and being as self-sufficient as possible. The habitat itself is central to the simulated mission, consisting of a dome that is 11 m (36 ft) in diameter and has a living area of about 93 m² (1000 ft²).
The dome itself is airtight and has a second level that is loftlike, providing a high-ceiling to combat feelings of claustrophobia. The six people in a crew sleep in pie-slice-shaped staterooms that contain a mattress, a desk, and a stool.
Composting toilets turn their feces into a potential source of fertilizer for the next mission, an exercise station provides for regular exercise, and email communications (with a simulated time lag) allow for contact with the outside world.
Other ideas include the Mars Ice Home, an idea put forth by NASA Langley Research Center in conjunction with SEArch and Clouds AO. After winning the Mars Centennial Challenge, NASA partnered with these architecture and design firms to help expand on their prize-winning proposal.
The updated concept relies on an inflatable dome and detachable decompression chamber, which are lightweight and can be transported and deployed with simple robotics. The dome is then filled with locally-harvested water to form the protective main structure.
The Ice Home also doubles as a storage tank that can be refilled for the next crew. It can also be potentially converted to rocket fuel at the end of the mission if needed.
One of the more difficult questions to answer about Martian settlement has to do with the number of people involved. In short, what is the maximum number of people that could be sustained in a single colony? And if these people were effectively cut off from Earth, how many would there need to be to keep a self-sustaining population going?
In this case, we are indebted to a series of studies conducted by Dr. Frederic Marin of the Astronomical Observatory of Strasbourg. Using custom-made numerical code software (known as HERITAGE), Marin and his colleagues managed to ascertain how large a multi-generational spaceship crew would need to be.
What they determined was that a minimum of 98 people would be needed in order to sustain a healthy population where the risks of genetic disorders and other negative effects associated with inter-marrying would be minimized. At the same time, they tackled the question of how much land would be needed to sustain them.
Given that dried food stocks would not be a viable option since they would deteriorate and decay during the centuries that the ship was in transit, the ship and crew would have to be equipped to grow their own food.
Here, they found that for a maximum population of 500 people, at least 0.45 km² (0.17 mi²) of artificial land would be needed. From this amount of land, the crew would be able to grow all the necessary food using a combination of aeroponics and conventional farming.
These calculations can be applied to a Martian settlement very easily since most of the same considerations apply. On Mars, much as with a spacecraft, the issue is how to ensure sustainability and self-sufficiency over long periods of time.
Knowing how many people can be supported using a certain amount of land is also invaluable since it allows planners to place constraints on how large a settlement can (or needs) to be.
The issue of transportation is another big one and applies to both getting to Mars (spacecraft) and getting around once you are there (infrastructure). In the case of the former, there are a few neat ideas that have been floated, plus some really interesting concepts that are being developed.
On the public side of things, NASA is developing a new breed of heavy-launch rockets and spacecraft for the sake of its proposed "Journey to Mars." The first step in that is the development of the Space Launch System (SLS), which will launch astronauts to cislunar space (around the Moon) in the coming years.
Once there, they will rendezvous with an orbiting station known as the Lunar Orbital Platform-Gateway (LOP-G). Attached to this station will be the Deep Space Transport (DST), a vessel that relies on Solar Electric Propulsion (SEP) to make the months-long journey to Mars when it is at opposition.
Once the DST reaches Mars orbit, it will rendezvous with the Mars Base Camp, another space station that will provide access to the surface via a reusable lander (the Mars Lander). Once crewed missions to Mars have been completed, this transportation infrastructure could be retooled for civilian use.
Provided people have a way of getting to cislunar space, the DST could ferry people from the Earth-Moon system to Mars every two years, allowing for a gradual buildup. That's where private aerospace companies will come could into play.
For instance, crews could be transported to cislunar space using any number of private launch providers. A good example is the New Glenn rocket, a heavy-launch vehicle under development by private aerospace company Blue Origin.
As indicated by CEO Jeff Bezos (founder of Amazon), this rocket will allow for the commercialization and settlement of Low Earth Orbit (LEO). But with its heavy-lift capabilities, it could also send people on the first leg of their journey to Mars.
In a different vein, SpaceX and its founder Elon Musk have been pursuing the development of a super-heavy rocket and spacecraft known as the Super Heavy and Starship. Once complete, this system will allow for direct missions to Mars, which Musk has indicated will culminate in the creation of a Martian settlement (Mars Base Alpha).
As for transportation on the Red Planet, there are numerous possibilities, ranging from rovers to mass transit. In the case of the latter, a possible solution was suggested by Elon Musk in 2016 during the first Hyperloop Pod Competition.
It was at this time that Musk expressed how this concept for a "fifth form of transportation" would work even better on Mars than on Earth. Ordinarily, the Hyperloop would depend on low-pressure tubing to allow it to reach the very speeds of up to 1,200 km/hour (760 mph).
But on Mars, where the air pressure is naturally less than 1% of what it is on Earth, a high-speed train like the Hyperloop would not need any low-pressure tubes at all. Using magnetic levitation tracks that transport people to and from different settlements in very little time could criss-cross the planet.
Of course, any habitat or settlement on Mars has to take into account the very real threat posed by radiation. Due to its thin atmosphere and lack of a protective magnetosphere, the surface of Mars is exposed to considerably more radiation than Earth is. Over long periods, this increased exposure could result in health risks among settlers.
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. As such, any settlement on the Red Planet will either need to be hardened against radiation or have active shielding in place.
A few concepts for how to do this have been suggested over the years. For the most part, these have taken the form of either building settlements underground or constructing shelters with thick walls fashioned from local regolith (i.e., 3D-printed, "sintered" shells).
Beyond that, the ideas get a little more fanciful and a lot more technologically advanced. For example, at the 2018 American Institute of Aeronautics and Astronautics (AIAA) SPACE and Astronautics Forum and Exposition, civil engineer Marco Peroni proposed a design for a modular Martian base (and spacecraft that would transport it to Mars) that would provide artificial magnetic shielding.
The settlement would consist of hexagonal modules arranged in a spherical configuration under a toroid-shaped apparatus. This apparatus would be made of high-voltage electric cables that generate an external magnetic field of 4/5 Tesla to shield the modules from cosmic and solar radiation.
Peroni's plan also called for a vessel with a sphere-shaped core measuring about 300 meters (984 ft) in diameter - known as the "traveling sphere" - which would transport the settlement to Mars. The hexagonal base modules would be arranged around this sphere or alternately housed within a cylindrical core.
This spaceship would transport the modules to Mars and would be protected by the same type of artificial magnetic shield used to protect the colony. During the journey, the spaceship would provide artificial gravity by rotating around its central axis at a rate of 1.5 rpm, creating a force of gravity of about 0.8 g (thus preventing the degenerative effects of exposure to microgravity).
Even more radical is the idea for an inflatable artificial magnetic shield that would be placed at Mars' L1 Lagrange Point. This location would ensure that the giant magnetic shield would remain in a stable orbit between Mars and the Sun, providing it with artificial magnetic shielding against solar wind and radiation.
The concept was presented at the “Planetary Science Vision 2050 Workshop“in 2017 by Jim Green - the Director of NASA's Planetary Science Division - as part of a talk titled "A Future Mars Environment for Science and Exploration."
As Green indicated, with the right kind of advances, a shield capable of generating a magnetic field of 1 or 2 Tesla (or 10,000 to 20,000 Gauss) could be deployed to shield Mars, thickening its atmosphere, raising average temperatures on the surface, and making it safer for future crewed missions.
Dust storms are a relatively common occurrence on Mars and take place when the southern hemisphere experiences summer, which coincides with the planet being closer to the Sun in its elliptical orbit. Since the southern polar region is pointed towards the Sun during the Martian summer, carbon dioxide frozen in the polar cap evaporates.
This has the effect of thickening the atmosphere and increasing the air pressure, which enhances the process by helping suspend dust particles in the air. In some cases, the dust clouds can reach up to 100 km (62 mi) in elevation.
Due to increases in temperature, dust particles are lifted higher into the atmosphere, which leads to more wind. The resulting wind kicks up yet more dust, creating a feedback loop that can lead to a planet-wide dust storm when conditions are just right.
These take place every 6 to 8 years (roughly three to four Martian years) and can reach speeds of over 106 km/h (66 mph). When such dust storms hit, they can reduce the amount of sunlight reaching the surface significantly, which can play havoc with solar panels.
This is the reason why the Opportunity rover ceased being operational in the summer of 2018. However, the Curiosity rover managed to ride this storm out, owing to the fact that it is powered by a Multi-Mission Radioisotope Thermoelectric Generator (MMRTG).
In this respect, any future settlements on Mars should have a backup power option. In the event that dust storms become too prolonged or severe, it would be handy to have nuclear reactors that can service a settlement's power needs until dust storms clear.
Another big issue of living on Mars is the challenge of producing enough food to sustain a colony of humans. Given the distance between Earth and Mars and the fact that supply missions would only be able to arrive once about every two years, there is a strong need for self-sufficiency when it comes to things like water, fuel, and crops.
To date, multiple experiments have been conducted to see if food can grow in Martian soil. In the early 2000s, experiments were conducted by researchers from the University of Florida and NASA's Office of Biological and Physical research. This consisted of seeing how plants would grow when subjected to Martian pressure conditions.
Another experiment involved using Earth bacteria to enrich Martian soil - specifically, cyanobacteria Chroococcidiopsis. This bacteria is known to survive in extremely cold and dry conditions on Earth and could help convert the Martian regolith into soil by creating an organic element.
In 2016, NASA teamed up with the Lima-based International Potato Center to test if potatoes could be cultivated using Martian soil analogs, which were created using Peruvian soil. This experiment was conducted for three reasons: on the one hand, the arid conditions in the region served as a good facsimile for Mars.
In parts of the Andes, precipitation is similarly rare, and the soil is extremely dry - just like on Mars. In spite of that, the Andean people have been cultivating potatoes in the region for hundreds of years.
But perhaps the greatest draw was the fact the experiment calls to mind the scenes in The Martian where Matt Damon was forced to grow potatoes in Martian soil. In short, it was a spectacular PR move for NASA at a time when it is looking to drum up support for its proposed "Journey to Mars."
In recent years, MarsOne, the non-profit that recently declared bankruptcy, also conducted experiments to see which crops would grow best in Martian soil. This took place between 2013 and 2015 in the Dutch town of Nergena, where teams from the Wageningen University & Research Center planted crops in simulated Martian and Lunar soil provided by NASA.
Over time, the teams tested different kinds of seeds (along with organic nutrient solution) to see which ones would grow in a Lunar and Martian environment, with the same seeds growing in Earth soil as a control. The team confirmed that rye, radishes, garden cress, peas, tomatoes, and potatoes could all germinate nicely and produce more seed for the next harvest.
From these many proposals and ideas, a picture of Martian settlement begins to appear. This is in keeping with our growing interest in Mars and evolving plans to explore the planet. And while the challenges may be great, the proposed solutions are both innovative and potentially effective.
Whether or not we should colonize Mars, the fact remains that we can, given the right commitment and enough resources. And if and when we do, we already have a pretty good idea of what Martian colonies might look like.
- NASA - HI-SEAS
- NASA - Greenhouses for Mars
- Mars One - Mission Feasibility
- NASA - Mars Space Pioneering
- NASA - Greening of the Red Planet
- Thingiverse - Mars Base Challenge Winners
- NASA -NASA's Centennial Challenges: 3D-Printed Habitat Challenge
- Innocentive - NASA Challenge: Space Pioneering – Achieving Earth Independence