Terraforming Mars — Nerd Fantasy or NASA’s Next Target?

The barren landscape of Mars. Credit: NASA
Will this be Mars in a few millennia? Credit: http://kingofwallpapers.com/

The famous physicist, Pierre van Schumacher, once said:

“The ultimate act of playing God is not to create life, but to create a planet.”

He was of course referring to terraforming; the deliberate alteration of a hostile, dead planet so that it becomes Earth-like, creating a possibility for human colonization.

Now you might be thinking that I made that quote up just because it sounds cool… and if you were you’d be correct! I mean come on, a French first name, a Dutch prefix, and a German surname… Nevertheless, “playing God” is a phrase I like, because it conveys the right level of magnitude to this idea: If we were to successfully terraform a planet — the would-be pinnacle of human engineering — it would represent humankind truly having control over its environment. It would be a feat of epic, godlike proportions.

The current planet on the surgeon’s table is Mars: A hostile wasteland of rock, dust storms, and more rock. If we are to see life flourish there we’ll need an intensive surgical operation, beginning with heating the planet, giving it an atmosphere, seeding it with organisms, and generating a magnetic field similar to the one on Earth. Although a difficult task, it’s one with tantalizing prospects. The creation of a new Earth-like planet would mean new species of plants and animals, free to evolve their own path on a different world. In Mar’s low gravity — which is 38% of Earth’s, flora and fauna could grow to massive sizes. Humans would be faster, stronger, quicker. Perhaps we would even see a world like the one in the movie Avatar, where gigantic trees reach up to the sky, and floating mountai……

Yeah, maybe no floating mountains. Nevertheless, with the world’s population projected to reach 9 billion by 2050, new real estate is becoming a major concern. There is also, you know, nuclear wars, extinction-level asteroid impacts, and pineapple on pizza… The point is: it’s the next step for humanity. And with the Sun growing ever-larger, its one we will ultimately have to take.

An artist’s impression of the terraforming of Mars. By Daein Ballard — The original image was uploaded on en.wikipedia as en:Image:MarsTransitionV.jpg, CC BY-SA 3.0

Unfortunately, Mars really is quite hostile. Positively shit in fact. It’s the Sahara desert and Antarctica rolled up into one, with raging planet-wide dust storms and a freezing -60C climate. It has an atmosphere 100 times thinner than Earth’s, with virtually no oxygen, and is bombarded by charged particles that would ravage any life there.

But we do know there was a time when water flowed on Mars. Frozen up in its ice caps and subsurface, Mars holds enough water to cover its entire surface in a 35 meter deep ocean. The ice caps also hold huge amounts of frozen carbon dioxide, which could provide an atmosphere if melted. Mars is also at just the right distance from the sun — aka the Goldilocks zone. There may have even been a time when it held life…

Essentially, there’s hope. We’ve already begun significantly changing Earth’s climate, so why not Mars’? In fact, many leading scientists have proposed we ship several CEOs from Exxon to Mars, in the hope that they’ll release enough carbon dioxide pollution to warm the planet to acceptable levels. Other (more ethical) possibilities include redirecting gas-filled comets to hit Mars, seeding it with organisms, and focusing sun rays on it with giant orbiting mirrors. Ambitious stuff for sure — so it’s important to ask the question: Do we have a realistic shot at this?

Artificial Magnetosphere

One of the biggest problems is that Mars lacks the planet-wide magnetic field (aka magnetosphere) we have on planet Earth. Here, our magnetosphere acts as the first line of defence against energetic charged particles streaming from the sun (solar wind), deflecting them around the Earth. On Mars without this protection an astronaut would receive more than a 100 times more radiation per year than on Earth. This would be fairly lethal to plants and sunbathers alike. It is also the prime culprit in why Mars originally lost most of its atmosphere several billion years ago — the solar wind eroded away the atmosphere like a river eroding away it shores. Creating an artificial magnetosphere is a big priority.

A rather extravagant depiction of Earth’s magnetosphere protecting it against solar wind

So how would one accomplish such a feat? One idea is to melt the outer core of the planet by detonating a series of buried nuclear bombs. Once liquid, swirling of the outer core — which contains charged atoms/molecules, would create a magnetic field. This is how Earth produces its magnetosphere. The problem is, intentional nuclear explosions have never been everybody’s idea of fun, so not much attention has been paid to the idea so far. Another suggestion is to pass a huge electric current through the outer core in order to melt it. Both ideas seem a little like wild speculation however, and it’s hard to take them seriously without any proper research having been done.

Luckily, a study in 2008 from the Japanese scientists Motojima & Yanagi has given us a ‘more solid’ possibility: The construction of planet-encircling superconducting cables, which transport electric current with extreme efficiency. The movement of the charges in the current directly creates a magnetic field. Specifically, the study showed that 12 cables only 60 cm wide would be enough to produce 10% of Earth’s magnetic field. This could easily be scaled up (extra, larger cables etc.) on Mars to produce a full magnetosphere, with only a ‘modest’ strain on resources.

Verdict: Laborious, but doable.

A proposed method of creating a magnetosphere is with a series of superconducting rings. Reproduced image

Creation of an Atmosphere

Perhaps the most important step in making Mars habitable is creating a much thicker atmosphere. Currently the Martian atmospheric pressure is about 1 kPa (Earth is 101 kPa at sea level), which is below the Armstrong limit of 6 kPa, meaning exposed bodily liquids such as saliva, tears, and liquids wetting the lungs boil away. In these conditions, life cannot be sustained for more than a few minutes. Constructing shelters and buildings is also difficult due to the pressure difference between outside and inside; as Matt Damon will tell you, pressurized things on Mars have a tendency to explode.

Dat south polar ice cap tho. Credit: NASA

We do have trick up our sleeve though. Raising Mar’s temperature enough will melt its north and south polar ice caps, releasing enough carbon dioxide to form an atmosphere of about 30 to 60 kPa. A warmer Mars is a goal in itself, so there’s a chance to kill two birds with one stone here.

There are several possible approaches to do this, one of which being the pumping of “super-greenhouse gases” into the weak atmosphere. There are several types of gases we can use for this, including small fluorine compounds, hydrocarbons, and ammonia. The most potent of these gases are the fluorine compounds (aka CFCs). One option could be to send rockets full of compressed CFCs to crash on the surface of Mars, releasing their payloads upon impact. There’s a problem though: a mere 39 million tons would be needed to do a proper job. And that’s not even accounting for the annual replenishing of 0.17 million tons needed because the CFCs decompose in the presence of sunlight! It does seem excessive, but keep in mind that around 13 million tons of the stuff was produced on Earth in only 20 years. And if Mars has similar levels of fluorine-containing minerals, we could mine it there as much as we want.

The main caveat with CFCs is that they could destroy any ozone layer present. On Earth, our ozone layer protects us from 97–99% of UV sunlight. If we want to have any exposed life on Mar’s surface, this layer of protection will be needed.

Interestingly, the introduction of dark-coloured organisms such as lichens, algae, and bacteria has been proposed as a method for heating the planet (dark colours absorb more heat energy). Scientists have collected organisms that can exist in extreme conditions e.g. no oxygen, and subjected them conditions similar to those on Mars. The results are remarkable in some cases (they survived for several weeks) and show that this approach may be of use, albeit not a complete solution.

An orbiting array of reflective balloons focusing sunlight onto Mar’s surface (Illustration: Rigel Woida)

This leaves us with the giant orbiting mirrors. This idea has piqued a bit of interest because it would actually be pretty effective. The idea here is to reflect light that misses Mars back onto its surface. One proposed configuration is a circular mirror with a radius of 125 km focusing on Mars south pole. This could raise the entire region by 5 degrees, which could be enough to trigger a runaway greenhouse effect. Such a mirror could not be launched from Earth, and would need to be built in space from asteroids. As you can imagine, this presents a serious challenge: How would we mine those asteroids? Are there enough accessible resources in space? How would we construct the mirrors?

As a consolement, we do have one thing going for us: If we can release a little bit of carbon dioxide into the atmosphere through warming, this carbon dioxide would absorb more heat from the sun via the greenhouse effect, releasing even more carbon dioxide from the poles, trapping even more heat, and so on, triggering a runaway greenhouse effect.

Verdict: Really, really hard, requiring huge investments of money and resources. (But technically possible)

Where’s my water, oxygen, and nitrogen?

So let’s say we succeed in creating a magnetosphere, we succeed in warming the planet, and we succeed in raising the atmospheric pressure. If we take a trip to Mars we’re still lacking in a few essentials — and I don’t mean a Lynx Africa gift set. (Water, oxygen, and nitrogen to be exact)

The water part is actually kind of easy. As mentioned before, there’s tons of water frozen up in the ice caps, with plenty more in the subsurface —enough to cover Mars in a 35 meter deep ocean. In fact, Mar’s geological features suggest that it once had an ancient ocean covering 36% of its surface. Another estimate puts this at 19%. To get these oceans back, all we need to do is warm Mars up again.

The lack of oxygen is a little more troublesome. We do however have right ingredients: carbon dioxide and water. All plants on Earth use photosynthesis, where sunlight is used to convert carbon dioxide and water into oxygen and glucose. With our ever-increasing knowledge of genetics, eventually we should be able to design plants and microbes specifically suited to early Martian conditions. If they can reproduce successfully to cover large swaths of Mars, evolving as they do so to become more efficient, this will be a job well done. Additionally, a large proportion of Mar’s soil is comprised of rocks which have a high oxygen content, which may be released with intense heat. With these two sources combined, one estimate is that would take 900 years to release enough oxygen into the atmosphere to support advanced life.

The final piece of puzzle is nitrogen. Back on Earth, nitrogen makes up 78% of our atmosphere, playing an important part in diluting oxygen to make the air breathable. It is also a basic building block of life e.g. 3.2% of the human body is nitrogen. On Mars however, it only makes up 2% of the already much thinner atmosphere. Now we could extract nitrogen from the soil, but it’s unclear whether there would be enough for a proper atmosphere, whilst still keeping enough in the soil to support life. It may in fact be the overall limiting factor. A highly speculative remedy for this could be redirecting massive asteroids containing nitrogen to hit Mars. The idea would be to heat parts of the asteroid with nuclear energy, super-heating frozen gas on the asteroid, which would fire outwards like a popped balloon, propelling the asteroid towards Mars. The trouble is, we really don’t know if there are enough of these asteroids in the solar system — a lot of them would be needed to make any real difference. The other problem is controlling the trajectory: we all know how straight balloon’s fly.

So getting enough water and oxygen seems to be a manageable task, but a lack of nitrogen may turn out to be the one factor preventing Mars from fully becoming Earth 2.0.

So, we will be able to, right?

We’ve seen that Mars is a complex, interconnected system, with many changes needing to be made — nearly all affecting each other — before it will be habitable in the sense that Earth is. Whether or not we’ll get there completely is still up for debate —e.g. the lack of nitrogen may mean Mar’s open air will never be properly breathable. But for most of the current problems we do have feasible solutions, including superconducting rings, super-greenhouse gases, super-large orbital mirrors, and super-tough organisms. And a mostly habitable planet is still a lot easier to colonize than a hostile one. No, the limiting factor I suspect won’t be a scientific one, but a political one.

No Elon Musk, a few nukes will NOT do the job on such a complicated system as this.

Fully terraforming Mars will likely take over a thousand years, requiring literally astronomical amounts of resources, money, and research. A consistent effort will be needed; one that is immune to the evolving politics of its time. Without a doubt, it will be the greatest-ever feat of engineering attempted by humankind. We have a habit of pulling off such feats — The Pyramids of Giza, the Great Wall of China… So in my humble opinion, it’s not a fantasy cooked up by a few overzealous sci-fi writers; it’s an eventuality. Mars will be terraformed. (Just not for a while).

To finish, a few words from Alfred Einstein’s lesser known twin sister, Gertrude Einstein:

“We have the audacity, the willpower, and the technology; all we need now is some damn funding!”