Colonizing Mars — The First Steps to Becoming a Multiplanetary Species
Mars has been getting a lot of hype with companies like SpaceX and Virgin Orbit all wanting to go to Mars, NASA launching Perseverance, and the thought of terraforming Mars. All of these are steps to actually colonizing Mars.
Just want to add we won’t see colonies on Mars in the next 20+ years, but let’s play with the idea.
If we were to go out on Mars right now, we would die in 3 minutes of arriving there. Needless to say, we can’t really say will figure it out once we get there. We need to plan ahead.
Let’s pretend colonizing Mars is like baking a cake. Our baker will be the engineers and scientists researching Mars. Let’s first establish the ingredients needed for any human to survive. We need water, food, and shelter. Also, since we are going to another planet we will need oxygen.
Water
While this main sound counterintuitive, water is the leavening agent to our cake. Water is such an important necessity for survival. The average person can only last 3 days without water. On Mars, not only do we need water to drink but we also need water to water our crops as there won’t be a nearby Chipotle to pick up some food.
It was recently discovered that Mars has frozen water at the poles of the planet. We are going to need to utilize the ice and turn it into drinkable water. One proposed method is basal melting. Let’s first break down what is basal melting. Basal melting is melting occurring at the bottom of the ice caps. To achieve basal melting, salt, and geothermal heat flux, the flow of heat under Mars’ surface, is utilized.
Salt can be used to lower the freezing point of water. Similar to the idea of how salt is poured on the roads before a snowstorm to prevent the roads from being piled up with snow by causing the snow to melt. Salt will be extracted either from the soil or local brine pools. Salt can also be extracted from Mars’s atmosphere. The specific salt used will be perchlorates, as they are the most effective in lowering the freezing point. This salt solution will not be enough to lower the freezing point of the ice as we need a heat flux of 72 mW/m2, which is leading to the use of geothermal heat flux.
The geothermal heat flux will be used to further melt the ice, but since Mars doesn’t produce enough heat to melt the ice, a magma chamber can be utilized to enhance the output of heat. A magma chamber would be placed 10 km below the ice region, the South Polar Layered Deposits. The SLPD is the largest water-ice reservoir on Mars. Previous studies have confirmed that there is subglacial volcanic activity, so it is a matter of finding the right crater to find the right chamber.
Once we are able to turn the water into ice, the water will need to go through further purification as the ice also contains Martian dust.
Check out this article for more information about this.
Food
The next ingredient is food, which will be the sugar in our cake. The average human being can survive between 8 to 21 days without food. While this may seem a lot, it is actually pretty little if we want to set up a permanent base on Mars.
Obviously, there are options of just bringing freeze-dried or can goods to Mars, but this will end up being costly and a waste of resources as the Mars colony becomes a permanent base. Therefore, we need to look into growing crops on Mars.
Before I get to how we grow crops on Mars, let’s cover the basics of growing crops on Earth. We are going to need to take a field trip back to bio class and revisit plant biology. One of the main nutrients crops need is Nitrogen. Nitrogen plays a role in the growth of a plant by assisting in the photosynthesis process to create energy to grow. The main source of nitrogen is in soil. Through nitrogen fixation, we get the nitrogen in the soil.
On Mars, hinted by its desert surrounding, there is no nitrogen due to there being no organic matter on Mars. The soil, also known as regolith, does contain carbon though, which plants require for making energy and in return produces oxygen.
A study done examined whether plants could grow in conditions similar to Mars. They found that plants grown in Mars’ soil stimulant, soil with similar properties that would reflect the growth of plants on Mars on Earth (the Earth’s soil was nutrient-poor and is not what we use to grow crops normally), were all able to germinate. Mars’s soil stimulant also had the highest number of plants surviving after 50 days compared to the Earth’s and the Moon’s soil stimulant. The biomass increment — the amount of organic matter produced by the plant — was the highest on Mars. After further analysis, they found that Mars’ soil had a better capacity to hold water similar to European soil.
Overall, through the use of nitrogen fixers — plants that add nitrogen to the soil — we can see a possibility in growing crops on Mars with regolith to sustain life. Another possible idea of growing crops includes hydroponic farming.
Hydroponic farming eliminates the need for soil and instead grows crops in nutrient-rich water. We would need to utilize the water harvested from the ice, to grow the crops. One of the drawbacks of hydroponic farming is that not all crops can be grown in the setup. Some examples include strawberries, corn, and potatoes.
In a study done to see if it were possible to grow plants in hydroponic farms, they were able to successfully grow Moringa oleifera, also known as Drumstick tree in conditions that reflected Mars. They replicated the Mars environment by replicating the reduced sunlight Mars gets. This study didn’t replicate the effects of the radiation on Mars nor the difference in temperature on Mars. These factors would need to be created in an artificial environment which will go into more in the shelter section.
Shelter
Humans need shelter to protect against any hazards or problems found outside. The shelter is like the flour to our cake as it provides our structure to the mission. On Mars, we will need shelter to protect against radiation. Due to Mars’ thin atmosphere and lack of magnetic field, this results to there being an increase in radiation compared to Earth. This radiation can be deathly to humans. Here we are going to list a few ways to protect against radiation.
SITU Concrete
Concrete is known for its radiation shielding properties. That is why it is used on nuclear power plants to shield them from radiation. The SITU concrete will be made out of Mars’s local soil, regolith, and sulfur. Mars is abundant in sulfur, therefore the concrete will be made from 50% of regolith to 50% of sulfur. To protect from radiation, the concrete will need to be between 91–182 cm thick. Due to the difference in temperature, the engineers will also have to account for thermal expansion on Mars, which may affect the design. The concrete homes can also be built under the surface to protect against radiation, eroding materials in the air, and to account for thermal expansion.
When building the homes, the Plaster of Paris can be used to bind the concrete as it is simple and doesn’t use a lot of energy to produce or harden. PoP will be made out of a sulfur material found on Mars such as bassanite or gypsum. Water may also be used as a binder as it will freeze due to the cold temperatures on Mars. The concrete will be mixed, transported, cast, and compacted in either a pressurized area.
A shell design will be utilized to protect against Mars’ extreme environment. Some of the factors included the difference in gravity, air pressure, thermal bands, and support of the building material’s own self-weight.
The goal is to create a habitat interior that will be pressurized to allow the astronauts to wander around in a shirt-sleeve environment (aka no unique clothing). Therefore making it is easier to adjust and set a permanent base on the red planet.
SITU Ice
I’m actually serious, ice is an option to building a Mars home. While the homes may not look as pretty as Elsa’s castle, ice found on Mars will be used to create domes and tall structures.
H20 is a great building material for radiation sheltering and it is a cheaper alternative. Another benefit to using ice is that it allows for light to transmit through. This is beneficial in terms of the mental health of astronauts as sunlight as it improves mood. The idea of seasonal depression comes from not getting enough sunlight.
The ice used to build these homes will need to be first extracted from the Mars ground. Robots equipped laser will be used to extract ice by cutting the ice with a laser. The ice collected with then be exposed to Mars’ radiation to melt it into liquids, therefore allowing us to extract any impurities.
When building homes out of SITU ice, we will have to utilize 3D printing. A pressurized interior volume will be created to keep the ice frozen, while a pressurized exterior volume will also be created to support the weight of the ice while building. The ice will be printed in layers to avoid brittleness. Fibers and salt will also be added to increase the strength of the material. One example of fiber is pykrete, a wood pulp, that can increase the strength of the ice 3x. It will be printed at a higher temperature allowing for more ductility and letting the ice repair itself. Then, an aerogel will be added to the interior to keep the heat in while allowing the light to still come into the Mars home.
Link to a paper to find out more, Link to another paper to find out more
Linked below is a proposed design by NASA. The design is called the ICE Home. Features inside the home include bunks, greenhouses, libraries, food prep areas. Basically, all the features are needed to make a comfortable and liveable space. The house is made of a pressure vessel which is the main structure, that is surrounded by a layer of water ice on the exterior for protection against radiation.
Link to Paper to find out more
Magnetosphere
While we can use materials like ice and concrete to protect against radiation, an alternative is creating an artificial magnetosphere, a planet’s magnetic field. A magnetosphere is basically a shield that protects a planet from cosmic radiation and solar winds.
Mars lacks a magnetosphere due to the iron core being shut down. If were to possibly restart Mars’s magnetosphere, we could possibly terraform mars. Terraforming is the process of making a planet’s surface resemble Earth making it liveable to humans. Therefore we don’t have to venture outside with heavy equipment to protect ourselves and we could plant plants into Mars soil.
While this may be a bit far out, creating an artificial magnetosphere can play a key role in the future for creating a permanent settlement on Mars. It is a bonus to our cake, like adding in some chocolate chips.
Here is a possible way of how we might approach it:
To create a magnetosphere, we are going to have to create an artificially charged particle ring that is placed in Mars’s geostationary orbit. This is because the orbit will be stable. One of the prominent options in creating a magnetosphere involves a solenoid loop. Solenoids are electromagnets that resemble the properties of a magnet when an electric current is passed through them. The solenoid coils would be arranged in a hollow lattice pattern to reduce the mass. Nanotubes would then be utilized to enforce the structure. In order to cover all latitudes of Mars, either a giant wide solenoid loop with a lower magnetic field or multiple smaller solenoid loops with higher magnetic fields can be used to create the magnetosphere. While the wider loop may be a harder structural challenge, it would be much more efficient and safer for humans.
This ring will be formed by ejecting matter from one of Mars’s moons and using electromagnetic and plasma waves to create a net current in the ring, therefore creating a magnetic field.
Let’s back up to ejecting matter as it may sound kind of confusing. Ejecting matter is a process black holes do when eating away at the universe. The black holes end up spitting out some of this matter they envelop and it becomes highly charged particles. This can be used in our solenoid loop to send an electric charge, therefore, creating a magnetic field. Plasma waves will be utilized to control the intensity.
This process definitely sounds like it is going to need a lot of power to power it. It will need precisely 10¹⁷ J of energy. This energy can be created through nuclear fusion.
Oxygen
Our final ingredient of the cake, oxygen, let’s make it the eggs. With eggs, the cake out binds together to form the delicious goodness we love. With oxygen, we are able to breathe which keeps our heart pumping. The average human can only survive 4 minutes without oxygen. Unfortunately, Mars is not as abundant in oxygen as Earth. Luckily, Mars’ atmosphere is comprised of 96% of carbon dioxide. Through the process of solid oxide electrolysis, we can pass a current through 2CO2 molecules to create oxygen.
NASA is testing this process out through their Thermodynamic Model of Mars Oxygen ISRU (In-Situ Resource Utilization) Experiment. Their experiment utilizes three systems: compressor system, solid oxide electrolysis (SOXE) system, and process monitoring and control system. These systems work together to pull in the atmospheric gas, compress it, extract the oxygen from the gas, and monitor the properties of the gas. Their machine is able to extract 99.6% of oxygen.
Compressor System
The compressor system will be made up of a scroll pump. The pump will be fitted with a dust filter. This scroll pump will be used to compress the air. The compressed air will then travel through a “plenum” which is a buffer space to prevent any pressure spikes before entering the SOXE.
SOXE
Within the SOXE stack, there are stacks of cells. These cells are made up of an oxygen-permeable electrolyte which is in between a cathode — a negatively charged electric conductor — and an anode — a positively charged electric conductor. NASA utilizes an electrolyte membrane for a dry electrolysis process that doesn’t require water.
The anode and cathode are utilized to pass an electric charge through the CO2 molecule. The CO2 molecule flows down the porous cathode layer, where an electronic potential (aka electrons) is applied. This electronic potential causes the oxygen to be negatively charged and separate from the carbon molecule/move against the electric field, therefore flowing to the electrolyte. The oxygen ions, due to their negative charge, are attracted to the anode, since it is positively charged. The electrolyte acts as a buffer. The electrolyte contains free ions. This layer conducts the oxygen ions to the anode. In the anode, due to their positive charge, cause the oxygen ions to oxidize and release the electronic potential from the oxygen. The electronic potential then flows back up, while the O2 flows through the porous anode.
Thus, the final by-product is carbon monoxide and oxygen.
2CO2 → 2CO + O2
Experiment (MOXIE), illustrates the process.
Process Monitoring and Control System
The PMC subsystems' main purpose is to make sure everything is running smoothly throughout the system. They check the gases produced as a byproduct of the solid oxide electrolysis. They also check the pump health, state of the SOXE process, and the composition of the gas that exists in the MOXIE. The PMC utilizes sensors to measure pressure, temperature, voltage, and composition throughout the entire MOXIE.
Final Thoughts
Going to Mars is not going to be easy, but what will be even harder is establishing a human presence on Mars. This will include supplying water, food, shelter, and oxygen. By utilizing SITU resources, we can cut down the cost of transporting items and make the colonies self-sustainable. Features such as an artificial magnetosphere will be helpful in terraforming Mars, but these features are more far out.
Granted, it will probably be around 20–30 years before we see colonies on Mars but with companies such as SpaceX and Blue Origin having ambitious plans to go to Mars, we will see a Mars colony in our lifetime.
Plus, how cool would it be to say that I went on vacation at Mars?
Check out my previous article to see one of the ways we can get to Mars.