In 2004, then-President Bush was expected to announce a new space initiative. There would be a manned mission to Mars and our first moon base would be up and running by 2020. It was set to cost between $40 billion and $80 billion. More recent estimates suggest the cost would be around half a trillion dollars. One proposed plan to save money would be to send older astronauts who would just never come back. They would establish a base and live the rest of their lives on Mars.
NASA conducted over 1000 studies on the potential of a Mars mission between 1950 and 2000. At one point, NASA was actively looking into having a manned mission to Mars or, inexplicably Venus, by 1975 or 1977.
Obviously, humanity is not moving quickly toward Mars, but it will happen one day. When it does, is it just going to be a quick trip or something more? It’s almost a waste of resources to go there just to plant a flag. The idea of setting up a base and even colonizing the planet has long been a dream. Elon Musk has a plan to get there and populate the planet by the 2040s. He believes one million people will be living there by then. NASA is less optimistic and believes a manned mission by the 2040s, not an entire city, is more realistic.
But the question is, can we do it at all? How do we overcome the many obstacles that make populating Mars far harder than populating some random new corner of the Earth?
The atmosphere on Mars is thin and inhospitable, about 95% carbon dioxide. The pressure is so low that, without protective gear to wear, a human’s blood would boil. Mars used to have a magnetic field like Earth, but it faded away about 4 billion years ago. That means it is no longer able to hold an Earth-like atmosphere because solar winds stripped it all away with no atmospheric protection. The gravity on the planet is about 38% of Earth and thus it can’t hold a thick atmosphere.
There is water on Mars but it’s not free-flowing on the surface like it is on Earth. We’d have to land near some of the known resources and work to harvest it. Likewise, growing plants on Mars would require special conditions. You can’t just plant a potato in Martian soil. The planet is colder than Earth with temperatures that barely top 70F at the hottest but plunge to -80F at the coldest. It also gets far less light to aid in photosynthesis. Plants would need to be grown in greenhouses which require more resources and care.
Most concerning is that, because Mars has no atmospheric shielding like Earth, it’s constantly being bombarded by cosmic radiation. Anyone on the surface would be hit by it all the time, risking cancer and other diseases. That problem needs to be solved before any long-term settlement can be established.
So how do we solve these problems? Lucky for us, and more lucky for the first people to go to Mars, we do have a few solutions.
Building Shelter
Before anything can happen on Mars, it needs to have a place to happen. Humans on Mars need shelter. SpaceX has been working on plans for dome shelters for some time now. Future Martians can’t just use lumber or concrete, and there are only so many heavy supplies that can be brought from Earth.
One idea for Martian shelters is chitin. You can find this material in fungus as well as exoskeletons of insects and things like fish or lizard scales. Astronauts could bring insects for protein and extract the chitin, then mix it with Martian soil to make a construction material. Using only materials found on Mars or that are byproducts of things the astronauts have with them, the result is a compound very much like concrete but much lighter.
Not only can you make building materials out of it, but you can fashion it into just about anything, even tools. It’s sturdy, lightweight, and easy to make.
Other plans that have been submitted to NASA make use of 3D printing. Printers can be sent ahead of manned missions and set up by robots. One company has already proposed a design for five-story structures, and their 3D printing on earth has shown they know what they’re doing.
Taking advantage of Martian geography has also been proposed as a method of doing a lot of the hard work of shelter building. Why build a whole structure when you can use a cave? Several caves have already been identified as potential sites.
In a similar vein, the idea of building underground has been proposed. Subterranean structures also offer the benefit of protection from the cosmic radiation that bombards the planet.
Producing Oxygen
Humans can only survive a few minutes without oxygen so that is the most important thing we need to have on Mars. Oxygen tanks on a space shuttle weigh over 1.3 million pounds and that’s just the air they need to survive travel. There would be little room for “extra” oxygen on a Mars mission, rather just enough to get them established before they started making their own.
NASA created a machine called MOXIE (Mars Oxygen In-Situ Resource Utilization Experiment) that extracts oxygen from the Martian atmosphere. They tested it on the Perseverance rover and it proved successful throughout many tests. The machine strips oxygen molecules from the CO2 in the Martian atmosphere to make breathable air by way of electrolysis. This oxygen can also be used as fuel.
In the tests, it made enough air for a small dog to survive. In reality, more powerful machines can be deployed to ensure all astronauts have air to breathe for the duration of their stay.
There are other ways to make breathable air on Mars, however. If the briny water full of chemicals called perchlorates found on Mars probes is an indication of more abundant water supplies, astronauts could land near these rivers and extract abundant oxygen and hydrogen from the solution also using electrolysis. It would make more oxygen with less power, too.
A third method involves doing much the same as what MOXIE does only, in this case, low-temperature plasma is used instead of old-fashioned electrolysis. The benefit to this is that it’s far more energy efficient.
Assuming that air is not going to be an issue by the time we get to Mars, what do we do about food and water?
Harvesting Water and Food
Mars has an abundance of ice on the surface and below the surface. This ice can be used to make drinkable water. As it is, the water would be toxic so it would need to be treated before consumption, but NASA has plans for that. One includes introducing helpful bacteria to consume dangerous perchlorates and make the water drinkable.
To make water for a whole colony, ideas like creating a giant, microwave water extractor that can operate inside a borehole in the ice have been proposed.
Once the water situation has been handled, astronauts can move on to worrying about how to grow food. The Martian soil is fairly toxic, so things like hydroponic gardens are going to be the solution. But that doesn’t mean the soil has no use. Cyanobacteria can grow on Martian soil. This will remove dangerous perchlorates but also provide organic material needed for farming. Essentially, it would make fertilizer in which astronauts can start growing food.
With fertilizer being provided by bacteria, or even from astronaut waste, farms can exist in Martian structures. Hydroponic gardens, vertical farms, and anything that offers space to grow plants can be used. While it seems like it might be hard to grow plants on an inhospitable planet, agriculture experts have likened it to growing crops in a city. It may not be set up in a way conducive to that, but you can adapt. As a bonus, the plants can also be used as part of water recycling and oxygen production.
NASA is working on genetically modified plants that could survive Mars’ more harsh conditions in the hopes of boosting food, oxygen, and even medicine production for future Martians.
Radiation Protection
So we can get to Mars, we can build a base, fill it with oxygen, and grow some salads while we’re at it. What do we do about the dangerous radiation hitting the planet non-stop? It’s estimated astronauts heading to Mars will be exposed to radiation levels 700 times higher than on Earth. Particle radiation, the most dangerous type, comes from distant stars and is made up of protons stripped of their electrons and traveling at near-light speed. Most are hydrogen but some are much heavier elements like iron or uranium.
These particles pass through nearly everything they hit, including spacecraft and astronauts. On their way through your body, they can damage DNA and cells. You can shield against them with very thick lead, for instance, but that’s impossible to bring to Mars. Other options may be using something like hydrogen in the form of water or plastics. Another option is hydrogenated boron nitride nanotubes which are light enough to be woven into fabric. More work is required to determine feasibility, though.
One potential method to protect astronauts from these dangerous particles is to basically create a force field. Even though it sounds like science fiction, this is something we could generate with a magnetic field. Superconducting electromagnets set up around a Martian base would stop particles from entering and causing damage. The major drawback to this idea is the power required to keep it running isn’t practical.
So far, coming up with a practical way to overcome the radiation issue has proven to be one of the most difficult challenges for a mission to Mars. There are some solutions, but it’s not known how effective they would all be over the long term.
Can we Terraform Mars?
Thanks to science fiction, the idea of terraforming is something many of us are aware of but the logistics in real life are far from clear. No one has ever done it before or even tried, so we’re flying blind on a lot of this and there are major hurdles to overcome.
If you want to terraform Mars, it needs an atmosphere. How do you provide that if nothing holds it in place? Escape velocity on Mars is three miles per hour, so it’s very hard to keep anything bound to the planet.
One plan to make it hospitable involves releasing iron and aluminum nanorods into the atmosphere to act as greenhouse agents. This plan would raise the temperature to nearly 80 degrees Fahrenheit and melt Mars’ ice caps, releasing greenhouse gasses. This would take years and still only make the planet warm, not make air or usable soil, but it’s a step.
To make oxygen on Mars would be a monumental task. On Earth, cyanobacteria evolved billions of years ago when our own atmosphere was mostly carbon dioxide. They began performing photosynthesis to produce oxygen and made our world hospitable for life. That could theoretically happen on Mars but the process takes thousands of years and needs brighter light than Mars has. To counter this, some low-light bacteria alternatives have been suggested.
Melting the ice caps on Mars may not provide the atmospheric pressure needed to allow liquid water to remain on the surface. Even if we use nuclear weapons to melt them, as some have proposed. It’s believed that there simply is not enough CO2 on Mars for this to work.
The lack of a magnetic field means any atmosphere we make will vanish again. That means either kickstarting the magnetic core of the planet again, which is beyond any known technology or establishing an artificial magnetic field in space. But that is also beyond current technology.
If Mars could be terraformed, the process could very well take generations. Those who lived there would have to adapt to a world with different pressures and gravity. Daily exercise would be required to maintain muscle and bone mass. Over time, those on Mars would adapt to their world and likely never be able to return to Earth without serious health issues.
But none of that matters at the moment because we have almost none of the technology needed to properly terraform the planet. We can go there and build, yes, but living on the surface is not something we’ll see for centuries, if ever.