Terraforming Mars involves changing the surface and climate of the planet to make large areas hospitable to humans. There are many reasons why permanent human habitation on Mars is being planned for: population growth, demand for resources, and runaway climate change. Of course, if and when we terraform Mars, it would be ludicrous to repeat these mistakes a second time round. Firstly, though, we have to make sure we, and future generations, can survive on the red planet.
Yes, trying to live in an environment which can kill you is a bit problematic. Without a pressure suit, the low pressure on Mars will cause a human to die within a few minutes. Exposed bodily liquids, such as saliva, tears, urine, blood and the liquids wetting the alveoli in the lungs will boil away. One astronaut was exposed to pressure below the Armstrong limit (1). He survived. But his “last conscious memory was of the water on his tongue beginning to boil”. Scary stuff indeed.
If we can raise the atmospheric pressure to a certain level, then pressure suits will no longer be necessary (although oxygen masks still will be). British physicist Martyn Fogg wrote in his book Terraforming: Engineering Planetary Environments (1995) that there are five challenges when it comes to terraforming Mars. And increasing atmospheric pressure is one of them.
It can be done by increasing the temperature of the polar caps. These are mostly made out of dry ice (solid CO2). By warming them by just a few degrees, we can make the solid CO2 into gas CO2. The gas will then cause a greenhouse effect, warming the planet and causing the ice beneath the surface to melt. This will cause Mars to have nearly 100% the atmospheric pressure of Earth. It will also create a suitable temperature for life, and create oceans and lakes.
But how do we warm the polar caps in the first place? There are a few ways this can be done. In Technological Requirements for Terraforming Mars, Chris McKay and Robert Zubrin suggest using giant orbital mirrors to reflect sunlight to the caps (2). Another solution is to heat them with nuclear reactors. Or we can create greenhouse-producing factories on Mars. There are all kinds of challenges posed by each of these solutions. But given the rate of technological advancement, meeting these challenges may be within our reach in the near future.
What’s promising, though, is that heating the polar caps would also tackle another one of Fogg’s challenges: increasing the surface temperature of the red planet.
Image credit: Wikipedia
Making the air breathable
Canadian geneticist Robert Haynes coined the term ecopoiesis, which is the process of making a planet more hospitable for primitive microbial life. Raising the atmospheric pressure and surface temperature of Mars will help achieve this. As well as make the Martian climate easier to explore by humans. But the remaining challenge of making the atmosphere breathable is a lot trickier.
The problem is that the air on Mars consists of 95% carbon dioxide, 3% nitrogen, 1.6% argon, and trace amounts of oxygen and other gases (3). On Earth, oxygen accounts for about 21% of the air that we breath, with nitrogen accounting for 73%.
Mars simply doesn’t have enough nitrogen to support large-scale life. So we will need to increase the amount of nitrogen. However, Mars’ nitrogen is all stored in mineral form as nitrates in the regolith (4). It will require a massive amount of energy to free these reserves. It may be possible to introduce significant atmospheric nitrogen from ammonia-rich asteroids. But again, hurling these asteroids (in a controlled way of course) at Mars would be expensive in terms of energy.
Turn down the UV, please
Another one of the challenges presented by Fogg is reducing the amount of UV radiation on the surface of Mars (5). One way of reducing this harmful radiation is to introduce highly UV-resistant lifeforms, such as lichen, directly onto the surface. These organisms would release oxygen which would form ozone in the upper atmosphere, and in turn reduce the amount of UV radiation reaching the Martian surface. But as mentioned previously, the lack of nitrogen makes it difficult for large-scale organisms such as lichen to be able to survive in the first place.
We may never be able to fine tune Mars’ climate to make it exactly like Earth’s. So the red planet may never support human life as we know it today. But that doesn’t mean a permanent human population can’t be sustainable. It just means we have to figure out ways to tolerate whatever conditions we create by terraforming Mars.
About the author: Sam Woolfe @samwoolfe
I’m currently a Writer at The Canary, covering issues relating to the food industry, drugs, health, well-being and nutrition. I’m also a Blogger for Inspiring Interns, where I offer careers advice for graduates. If you have a story you want me to cover, drop me a message on Twitter (@samwoolfe). You can also check out my travel blog (samreflectsontravel.com) and personal blog (www.samwoolfe.com) to read my articles on philosophy, psychology, and more opinion-related content.