Overview
Terraforming just means: to make another world (i.e. Mars) Earth-like and, thus, habitable. In order to make Mars Earth-like, it needs an atmosphere with both breathable oxygen and a thick layer of greenhouse gases to trap heat, human colonists and other life forms (i.e. edible plants, trees, or cyanobacteria) must be "shielded" from solar and cosmic radiation, and there must be large pools of liquid water to grow food hydroponically and for other purposes which we'll cover. In the earliest stages of terraforming Mars, the stupendous quantities of radiation blasting Mars would force any martian humans to live in either underground settlements or in habitat modules covered in Mars’ regolith. But as the terraforming process progressed, so to would Mars’ infrastructure and human colonization of this planet. In this article, we’ll discuss terraforming and colonizing Mars by describing a plausible future timeline of humanity's presence on Mars.
First Martians
Shortly after humanity transitioned to a Type 1 civilization and colonized the Moon and built some small homesteads within and along asteroids in the asteroid belt between Mars and Jupiter, humanity set their sights towards Red Mars. At this stage in human history, the aim is no longer to maximize profit but, rather, to optimize the wellbeing of societies and the efficiency of industrial processes—including everything related to the business of building space ships, traveling across space, and eventually staying somewhere in space. Like in Michio Kaku's Physics of the Future, humanity now constructs all spacecraft in Earth-orbit or on the Moon—as long as it is far away from any big gravity well, then manufacturing spacecraft and launching them away to other far off places in the universe is done so with a minimum expenditure of energy and resources.
Artist's depiction of the Ares spaceship from Kim Stanley Robinson's novel, Red Mars.
The very first brave men and women to go to Mars would necessarily have to be a crew of experts in various fields of engineering and science including physics, chemistry, biology, botany, genetic and chemical engineering, and so on. In the mid-21st century, a brilliant group of 100 scientists climb the Earth-based space elevator up into orbit and board the Ares—a spaceship and a triumph of human engineering. It simulated the Earth's day/night cycle and even the seasons—the travelers began their voyage in Spring and reached their final destination in Winter. The Ares also contained biodomes which resembled real habitats and ecosystems found on Earth. Just as we earthlings rely on our planet's ecology for survival, the 100 astronauts aboard the Ares relied on these biodomes not just for food but also comfort and psychological wellbeing. (Indeed, studies prove that plants have a calming effect on us humans; hence, they are crucial for scientists conducting research in remote regions of Antarctica and Siberia.) Eventually, the Red Planet appeared as a great red orb above the large transparent dome in the Ares and as they descended towards Mars, they split up into several different groups. Like in Kim Stanley Robinson's Red Mars, one group landed on Mars' moon Phobos and built a moon station there. To nullify any health hazards associated with the ultra-low gravity in this place, they built a rotating habitat which simulated Mars' gravity which was about a third of Terran gravity. It had been well understood by scientists of the 20th-century that the copious quantities of black dust on Phobos could be "blown" onto Mars, something that the famed astronomer Carl Sagan was a big proponent of. When all of the black dust eventually settled on Mars' surface, the decreased surface albedo would cause more solar energy from sunlight to be absorbed thereby heating the planet. A good first step in warming Mars and, thus, a good first step in terraforming the place.
The rest of the astronauts landed on Mars itself. Satellite images have had revealed great lava tube and cave systems located on the top of Olympus Mons and Pavonis Mons which were two enormous volcanoes whose heights dwarfed that of Mount Everest. All of the rock and regolith surrounding these big holes would act as a shield blocking any solar or cosmic radiation from penetrating through and, it was for this reason, that two other groups split up and went into the caves of Olympus Mons and Pavonis Mons where they eventually built the first martian settlements. Yet another group arrived near Vastitas Borealis—a vast series of plains which encircled Mars' north polar cap at just above 60° latitude. After that, habitat modules were assimilated and robots began to cover the habitat modules with Martian regolith to shield them from harmful radiation.
For a long time, humans were forced to live in caves and these habitat modules in order to avoid radiation hazards. But if humanity's presence on Mars was confined to being underneath heaps of dirt, this would be very dissatisfying indeed. Science fiction has instilled a popular vision of humanity, one day, reengineering Mars’ surface to resemble a kind of Earth 2.0 containing expansive cities, transportation systems, and massive skyscrapers. But to achieve this, we must first change Mars by terraforming it.
Phase 1 of terraforming: creating a martian magnetosphere
About 4.1 billion years ago, Mars partly resembled Earth containing a thick atmosphere and immense oceans of liquid water. But around that time, the planet somehow lost its protective magnetosphere. After this happened, the Sun's solar winds stripped away the planet's atmosphere and the Martian oceans evaporated. Without a protective magnetosphere, it would be impossible to sustain an atmosphere and oceans. NASA scientists proposed placing an artificial magnetosphere at the Mars L1 Lagrange point. A planet's lagrange point is like a "cosmic parking lot": the satellite would remain stationary at this location relative to Mars throughout its orbit. With this protective "shield" against solar winds and cosmic rays surrounding Mars, the planet's atmosphere, ocean, and surface, and any human visitors or settlers living there, would be protected from those solar winds and cosmic rays. This technique was employed shortly after the first humans settled Mars and Phobos. After the artificial magnetosphere was set up, the first hundred no longer had to worry about radiation and they proceeded to build domed, martian cities.
First expeditions on Mars
Shortly after the construction of Mars' new magnetosphere, a group from the first 100 abandoned the sedentary life of living in caves and dirt-covered settlements and embarked on their first expedition: the group that landed in Vastitas Borealis trekked many kilometers until they eventually arrived at Mars' north pole. When they arrived, they encountered vast white cliffs of ice. They mined this ice for water, hydrogen and oxygen. They imagined using the water for drink and to cover Mars' surface with immense oceans; they wanted to use the oxygen to create a breathable oxygen atmosphere and also to fill cities covered by large transparent domes with oxygen so that people could walk in these cities without oxygen tanks or pressurized space suits; and they foresaw using the hydrogen as rocket fuel.
Everyone who was living their on the Red Planet knew that Mars was very rich in resources and that if those resources could be transported to elsewhere in the solar system, they would be very valuable indeed. But how to get those resources from Mars to elsewhere in the solar system was the question. Around the year 2061, they sent a robotic probe to a metallic meteoroid and moved it into Mars' orbit. Then, the metals contained within the meteoroid were used to construct a cable tens of thousands of kilometers long which descended down to the Martian surface and attached to the summit of Pavonis Mons. The first space elevator on Mars. By simply applying classical mechanics, researchers as far back as the late-20th century understood that a world's (in this case, Mars) rotation could impart rotational energy into the space elevator. And this Martian space elevator would have enough rotational energy to send a payload to anywhere in the solar system with the use of hardly any fuel. All of the energy used in sending a payload up the length of the cable in a cab could be recovered in the cab's descent back down to the ground. Very economical, indeed.
"This shot follows the cabin of a space elevator descending on a cable towards the northern parts of the Terra Cimmeria highlands on Mars. A large settlement, hinted as glowing lights in the dark, can be seen far below on the ground. One of Mars' two moons - Phobos - is seen above the cabin to the left of the cable in the beginning of the shot." This image was produced by Erik Wernquist.
Poster by SpaceX
Because of Mars' thin atmosphere, without the space elevator in operation it would be very difficult for a spacecraft to land on its surface. But another one of the big advantages of the space elevator was that it made getting to Mars a lot easier. And so, during the 2060s, many thousands and eventually millions of earthlings started going to Mars and living in all of the newly constructed domed cities. During this time, scientists and engineers made the long trek from the northern latitudes of Mars to Valles Mariners—a great system of canyons and escarpments that extended for thousands of kilometers across Mars' equator and whose lowest depths were several kilometers down. They constructed cliff dwellings which were magnificent monuments of mostly glass overlooking the canyons—glass cities built into cliffs on Mars. Residents of this region got around mostly by using zip line and gliders which also became very popular recreational activities.
Phase 2: creating a Martian atmosphere and oceans
After creating a magnetosphere, phase two of terraforming Mars will be to melt large quantities of frozen ice and methane on Mars: vast quantities of greenhouse gasses, locked inside of this frozen matter, will get released and begin to accumulate in the atmosphere. While a thick layer of greenhouse gasses gets built up in the atmosphere, at the same time, all of that melted ice will begin to form large oceans of liquid water. Much of the ice that we need is stored on Mars' polar ice caps, in the Martian regolith, and underneath Mars' surface. The rest of the ice that we'll need would come from icy comets in the outer solar system.
After the first human have had colonized parts of Mars and after creating a magnetosphere, the next step towards terraforming Mars would be to create an oxygen-rich atmosphere with a thick layer of greenhouse gases and also to create oceans. But the question is: how do we do this? We can accomplish all three of those tasks by melting frozen bodies of ice and methane: this includes the ice covering Mars' polar caps, the ice stored in Martian regolith and beneath Mars' surface, and even in icy comets in the outer solar system. Greenhouse gasses, which were initially trapped in the ice, get ejected into Mars' atmosphere. The greenhouse gases trap the Sun's radiant heat energy causing the planet to warm. At the same time, as the ice melt, meltwater for large bodies of liquid water. But at this stage in the terraforming process, average Martian surface temperatures are still far below freezing and it will take several more decades of heating Mars before average temperatures rise above freezing and large bodies of liquid water and oceans can form.
But a question arises: how do we melt the ice? Let's start out by thinking about how to melt the ice that is already on Mars. Elon Musk proposed that we detonate thermonuclear bombs in regions of the Martian atmosphere which are above both of Mar's poles. These explosions would release quantities of electromagnetic energy so stupendous that it could melt the polar caps and get all of those greenhouse gases into the atmosphere. Billions of years ago, our entire home planet Earth was a giant ice ball; when some of that ice began to melt, this lead to a runaway greenhouse effect. Although not on a scale of epic proportions like the Snowball Earth event, an analogous unfolding of events would occur if we began melting ice on Mars. If we had took Musk's advice and melted some ice with nukes and then allowed a runaway greenhouse effect to take over from there, nearly all of the frozen permafrost, glaciers, and polar caps would get melted. According to estimates, there's a lot of frozen ice on Mars—so much, in fact, that if it all were melted, there would be enough liquid water to cover 20 percent of the Martian surface with oceans. Since we'd be able to melt a considerable fraction of the total amount of Martian ice using our "nuke/greenhouse strategy," we would be able to cover a considerable portion of the Martian surfaces with oceans and, in the process of all that melting business, liberate a lot of greenhouse gasses into the atmosphere.
But both Martian and Terran civilization decided to take a slightly more conservative approach. Instead, they attached rockets and mass drivers onto two meteoroids and maneuvered them into Mars' orbit. Robots used the materials contained in those meteoroids to construct a vast array of orbital mirrors which they called the soletta after the prophetic novel Green Mars. The soletta acted as a giant magnifying glass which concentrated sunlight and increased the amount of solar insolation incident on Mars' surface. The soletta directed sunlight to the polar caps causing the ice to gradually melt. As the ice melted, greenhouse gasses were ejected into the atmosphere causing Mars to get warmer.
Phase 3: we need to melt more ice for Mars’ atmosphere
To get Mars to be Earth-like, we need to make sure that that atmosphere is so heavy that the atmospheric pressure is similar to Earth's. We want to get that atmospheric pressure up to about 14 PSI which is the same as the Earth's atmospheric pressure at sea level. Only at a high atmospheric pressure close to 14 PSI would the Martian atmosphere be able to retain a breathable atmosphere. But the problem is that even if we melted nearly all of the frozen Martian ice, the resulting atmospheric pressure would only be about ~7 PSI.
The obvious problem then becomes: is there anyway to transport enough frozen ice to Mars which could then be melted to get an atmosphere heavy enough to have an atmospheric pressure of about 14 PSI? Yes, there is. As I discussed in my article on Colonizing the Asteroids and Comets in our Solar System, the asteroids and comets are abundant with all the resources that human travelers and settlers need: such as water and metals. In the far reaches of our solar system is the Kuiper comet belt. Here, there is more than enough frozen ice in all of these little worlds to create the heavy atmosphere that we want. In my article on colonizing asteroids and comets, the spacecraft we discussed there could be used to move icy asteroids and comets to Mars. So getting these little worlds to Mars isn't much of a problem.
Once we get our icy worlds to Mars, there are two different strategies we could use to melt the ice. The first is that we could let these worlds collide head on with Mars. This would generate enough energy to melt all of the ice stored in these worlds and release it into the atmosphere. But the people living on Mars opted for the second option which was to whirl those ice worlds into a stable orbit around Mars. The Martian atmosphere would exert frictional forces on the ice which would eventually melt it thereby releasing greenhouse gases into the atmosphere.
Between all the various different techniques used, by the early 22nd-century Mars had gradually warmed until its average temperature was above freezing. And so much ice had been melted that great bodies of liquid water filled the canyons of Valles Mariners and the depths of Vistitas Borealis.
Life on Mars
Back in the early days on Mars shortly after the protective satelite reached L1 and encompassed Mars with a protective magnetosphere, some of the scientists and engineers decided to stay in the whereabouts of Vastitas Borealis where they built research centers which used a technique known as CRISPR/CAS9 gene editing—an advent of the early 21st-century—to genetically engineer and alter the genomes of photosynthetic cyanobacteria to be resistant to radiation and extreme cold. Autonomous planes circumnavigated Mars depositing this cyanobacteria and many miniature, carbon-dioxide producing factories to help increase global temperatures. But there was a great deal of solar radiation, within a certain range of wavelengths, that bounced off of Mars' surface and penetrated right through the CO2 haze. Thus, there had been a problem with trapping the solar radiation within this range of wavelengths. This was somewhat bothersome since a lot of heat was being lost this way. And so, some of those miniature factories produced a cocktail of chemicals and halocarbons which effectively trapped that otherwise lost heat.
But now, Mars had immense oceans and a thick layer of greenhouse gases composed of primarily carbon dioxide. Mars was much warmer at this point—a good thing of course—but the problem still remained that the atmosphere, while congenial for some forms of biota, was a poisonous carbon dioxide haze that was inhospitable to anima life. As a first step towards tackling this problem, Martian scientists created immense algae blooms of cyanobacteria in the Martian oceans which oxygenated the world—a little at least. I discussed in some of my other lessons two major oxygenation events in Earth’s early history where large algae blooms of cyanobacteria converted immense quantities of carbon dioxide into oxygen. This was the prelude—the necessary first step—for the emergence of large, multi-cellular organisms and a rich biodiversity of fauna and flora. Perhaps that same is also true for Mars? Large colonies of cyanobacteria could suck up all of the carbon dioxide in the Martian atmosphere and produce enormous amounts of breathable oxygen. Then, perhaps after that, Mars could be populated with many plants and animals. But animals require plant life in order to thrive. Even just going from microbes to a rich biota of forests and plants is a project that took millennia to complete.
The researchers realized that these microbes could, after millennia, create arable land for large trees, each hundreds of meters tall, to grow in. These trees would be as enormous and tall and maybe even as alien as the trees comprising the first Tarran forests during the Carboniferous period. They imagined these great rain forests covering the plains of Vistitas Borealis. Mars' atmosphere was dominated by mostly carbon dioxide; all those trees, each hundreds of meters tall, could soak up all of that CO2 and pump out large quantities of oxygen into Mars' atmosphere. In Earth history, there were two great oxygenation events, both caused by immense algal blooms of cyanobacteria. In the case of Mars history, a somewhat similar series of events unfolded. Cyanobacteria kicked off the first oxygenation event and, gradually, portions of Martian terrain transformed into fell fields with small communities of lichen and moss and then into kromultz with small dwarf trees shielded by massive boulders and then, finally, into mighty forests and rich ecosystems containing diverse biota. After a long time, most of the envelope of poisonous carbon dioxide gasses had been sequestered from the atmosphere. At last, animals could be introduced into the environment and humans could walk along certain portions of Mars in their bare clothing without spacesuits.
After Mars was colonized with millions of people and after the planet was fully terraformed, it is plausible that this hypothetical futuristic humanity would go on to colonize the skies of Venus or perhaps Saturn's moon Titan which we'll discuss in the next few lessons.
This article is licensed under a CC BY-NC-SA 4.0 license.
References
1. Kaku, Michio. Physics of the Future: How Science Will Shape Human Destiny by the Year 2100. Anchor, 2012. Print.
2. Robinson, Kim S. Red Mars. London: HarperCollins, 1992. Print.
3. Robinson, Kim. Green Mars. Bantam Spectra, 1994. Print
4. Wernquist, E. Terrarium - (Mars). Retrieved from http://www.erikwernquist.com/wanderers/images/gallery/WANDERERS_mars_elevator_02.jpg.