Artist's impression of the terraforming of Mars, from its current state to a livable world. Credit: Daein Ballard
The idea of terraforming Mars, making its atmosphere and environment more Earth-like for human settlement, goes back decades. During that time, many proposed methods have been considered and put aside as “too expensive” or requiring technology well in advance of what we have today. Nevertheless, the idea has persisted and is often considered a part of long-term plans for establishing a human presence on Mars. Given the many plans to establish human outposts on the Moon and then use that infrastructure to send missions to Mars, opportunities for terraforming may be closer than we think.
Unfortunately, any plans for terraforming Mars suffer from unresolved hurdles, not the least of which are the expense, distance, and the need for technologies that don’t currently exist. Triggering a greenhouse effect and warming the surface of Mars would take massive amounts of greenhouse gases, which would be very difficult and expensive to transport. However, a team of engineers and geophysicists led by the University of Chicago proposed a new method for terraforming Mars with nanoparticles. This method would take advantage of resources already present on the Martian surface and, according to their feasibility study, would be enough to start the terraforming process.
For decades, we have seen Mars as a desolate landscape devoid of any signs of life. Attempt to identify ways of growing plants and food on the red planet have focussed on greenhouse like structures to enable plants to survive, that is, until now! A desert moss called ‘Syntrichia caninervis’ has been identified and it can grown in extreme environments like Antarctica and the Mojave Desert. A new study revealed the moss can survive Mars-like environments too including low temperatures, high levels of radiation and drought.
Astronauts on Mars will need oxygen. There's oxygen in the atmosphere, but only small amounts. But there's lots of subterranean water on Mars, and that means there's lots of oxygen, too. (Credit: NASA)
Throughout the 20th century, multiple proposals have been made for the crewed exploration of Mars. These include the famed “Mars Project” by Werner von Braun, the “Mars Direct” mission architecture by Robert Zubrin and David Baker, NASA’s Mars Design Reference Mission studies, and SpaceX’s Mars & Beyond plan. By 2033, two space agencies (NASA and the CNSA) plan to commence sending crews and payloads to the Red Planet. These and other space agencies envision building bases there that could eventually lead to permanent settlements and the first “Martians.”
This presents several major challenges, not the least of which have to do with exposure to radiation, extreme temperatures, dust storms, low atmospheric pressure, and lower gravity. However, with the right strategies and technology, these challenges could be turned into opportunities for growth and innovation. In a recent paper, a Leiden University researcher offers a roadmap for a Martian settlement that leverages recent advancements in technology and offers solutions that emphasize sustainability, efficiency, and the well-being of the settlers.
A scientific visualization of the electromagnetic currents around Mars. Credit: NASA/Goddard/MAVEN/CU Boulder/SVS/Cindy Starr
Terraforming Mars is one of the great dreams of humanity. Mars has a lot going for it. Its day is about the same length as Earth’s, it has plenty of frozen water just under its surface, and it likely could be given a reasonably breathable atmosphere in time. But one of the things it lacks is a strong magnetic field. So if we want to make Mars a second Earth, we’ll have to give it an artificial one.
Artist's conception of a terraformed Mars. Credit: Ittiz/Wikimedia Commons
For almost a century now, the concept of terraforming has been explored at length by both science fiction writers and scientists alike. Much like setting foot on another planet or traveling to the nearest star, the idea of altering an uninhabitable planet to make it suitable for humans is a dream many hope to see accomplished someday. At present, much of that hope and speculation is aimed at our neighboring planet, Mars.
But is it actually possible to terraform Mars using our current technology? According to a new NASA-sponsored study by a pair of scientists who have worked on many NASA missions, the answer is no. Put simply, they argue that there is not enough carbon dioxide gas (CO2) that could practically be put back into Mars’ atmosphere in order to warm Mars, a crucial step in any proposed terraforming process.
The study, titled “Inventory of CO2 available for terraforming Mars“, recently appeared in the journal Nature Astronomy. The study was conducted by Bruce Jakosky – a professor of geological sciences and the associate director of the Laboratory for Atmospheric and Space Physics (LASP) at the University of Colorado, Boulder – and Christopher S. Edwards, an assistant professor of planetary science at Northern Arizona University and the leader of the Edwards Research Group.
The study was supported in part by NASA through the Mars Atmospheric and Volatile EvolutioN (MAVEN) and Mars Odyssey THEMIS (Thermal Emission Imaging System) projects. Whereas Professor Jakosky was the Principal Investigator on the MAVEN mission, Professor Edwards is a participating scientist on the Mars Science Laboratory Curiosity Rover (MSL), and worked on the Mars Odyssey THEMIS mission (among other Mars missions).
As we explored in a previous article, “How Do We Terraform Mars?“, many methods have been suggested for turning the Red Planet green. Many of these methods call for warming the surface in order to melt the polar ice caps, which would release an abundant amount of CO2 to thicken the atmosphere and trigger a greenhouse effect. This would in turn cause additional CO2 to be released from the soil and minerals, reinforcing the cycle further.
According to many proposals, this would be followed by the introduction of photosynthetic organisms such as cyanobacteria, which would slowly convert the atmospheric CO2 into oxygen gas and elemental carbon. This very method was suggested in a 1976 NASA study, titled “On the Habitability of Mars: An Approach to Planetary Ecosynthesis“. Since that time, multiple studies and even student teams have proposed using cyanobacteria to terraform Mars.
However, after conducting their analysis, Professors Jakosky and Edwards concluded that triggering a greenhouse effect on Mars would not be as simple as all that. For the sake of their study, Jakosky and Edwards relied on about 20 years of data accumulated by multiple spacecraft observations of Mars. As Edwards indicated in a recent NASA press release:
“These data have provided substantial new information on the history of easily vaporized (volatile) materials like CO2 and H2O on the planet, the abundance of volatiles locked up on and below the surface, and the loss of gas from the atmosphere to space.”
Scientists were able to gauge the rate of water loss on Mars by measuring the ratio of water and HDO from today and 4.3 billion years ago. Credit: Kevin Gill
To determine if Mars had enough gases for a greenhouse effect, Jakosky and Edwards analyzed data from NASA’s Mars Reconnaissance Orbiter (MRO) and Mars Odyssey spacecraft to determine the abundance of carbon-bearing minerals in Martian soil and CO2 in polar ice caps. They they used data from NASA’s MAVEN mission to determine the loss of the Martian atmosphere to space. As Prof. Jakosky explained:
“Carbon dioxide (CO2) and water vapor (H2O) are the only greenhouse gases that are likely to be present on Mars in sufficient abundance to provide any significant greenhouse warming… Our results suggest that there is not enough CO2 remaining on Mars to provide significant greenhouse warming were the gas to be put into the atmosphere; in addition, most of the CO2 gas is not accessible and could not be readily mobilized. As a result, terraforming Mars is not possible using present-day technology.”
Although Mars has significant quantities of water ice, previous analyses have shown that water vapor would not be able to sustain a greenhouse effect by itself. In essence, the planet is too cold and the atmosphere too thin for the water to remain in a vaporous or liquid state for very long. According to the team, this means that significant warming would need to take place involving CO2 first.
However, Mars atmospheric pressure averages at about 0.636 kPA, which is the equivalent of about 0.6% of Earth’s air pressure at sea level. Since Mars is also roughly 52% further away from the Sun than Earth (1.523 AUs compared to 1 AU), researchers estimate that a CO2 pressure similar to Earth’s total atmospheric pressure would be needed to raise temperatures enough to allow for water to exist in a liquid state.
Artist’s rendering of a solar storm hitting Mars and stripping ions from the planet’s upper atmosphere. Credits: NASA/GSFC
According to the team’s analysis, melting the polar ice caps (which is the most accessible source of carbon dioxide) would only contribute enough CO2 to double the Martian atmospheric pressure to 1.2% that of Earth’s. Another source is the dust particles in Martian soil, which the researchers estimate would provide up to 4% of the needed pressure. Other possible sources of carbon dioxide are those that are locked in mineral deposits and water-ice molecule structures known as “clathrates”.
However, using the recent NASA spacecraft observations of mineral deposits, Jakosky and Edwards estimate that these would likely yield less than 5% of the require pressure each. What’s more, accessing even the closest minerals to the surface would require significant strip mining, and accessing all the CO2 attached to dust particles would require strip mining the entire planet to a depth of around 90 meters (100 yards).
Accessing carbon-bearing minerals deep in the Martian crust could be a possible solution, but the depth of these deposits is currently unknown. In addition, recovering them with current technology would be incredibly expensive and energy-intensive, making extraction highly impractical. Other methods have been suggested, however, which include importing flourine-based compounds and volatiles like ammonia.
The former was proposed in 1984 by James Lovelock and Michael Allaby in their book, The Greening of Mars. In it, Lovelock and Allaby described how Mars could be warmed by importing chlorofluorocarbons (CFCs) to trigger global warming. While very effective at triggering a greenhouse effect, these compounds are short-lived and would need to be introduced in significant amounts (hence why the team did not consider them).
NASA’s MAVEN spacecraft is depicted in orbit around an artistic rendition of planet Mars, which is shown in transition from its ancient, water-covered past, to the cold, dry, dusty world that it has become today. Credit: NASA
The idea of importing volatiles like ammonia is an even more time-honored concept, and was proposed by Dandridge M. Cole and Donald Cox in their 1964 book, “Islands in Space: The Challenge of the Planetoids, the Pioneering Work“. Here, Cole and Cox indicated how ammonia ices could be transported from the outer Solar System (in the form of iceteroids and comets) and then impacted on the surface.
However, Jakosky and Edwards’ calculations reveal that many thousands of these icy objects would be required, and the sheer distance involved in transporting them make this an impractical solution using today’s technology. Last, but not least, the team considered how atmospheric loss could be prevented (which could be done using a magnetic shield). This would allow for the atmosphere to build up naturally due to outgassing and geologic activity.
Unfortunately, the team estimates that at the current rate at which outgassing occurs, it would take about 10 million years just to double Mars’ current atmosphere. In the end, it appears that any effort to terraform Mars will have to wait for the development of future technologies and more practical methods.
These technologies would most likely involve more cost-effective means for conducting deep-space missions, like nuclear-thermal or nuclear-electric propulsion. The establishment of permanent outposts on Mars would also be an important first step, which could be dedicated to thickening the atmosphere by producing greenhouse gases – something humans have already proven to be very good at here on Earth!
Project Nomad, a concept for terraforming Mars using mobile, factory-skyscrapers from the 2013 Skyscraper Competition. Credit: evolo.com/Antonio Ares Sainz, Joaquin Rodriguez Nuñez, Konstantino Tousidonis Rial
There’s also the possibility of importing methane gas from the outer Solar System, another super-greenhouse gas, which is also indigenous to Mars. While it constitutes only a tiny percentage of the atmosphere, significant plumes have been detected in the past during the summer months. This includes the “tenfold spike” detected by the Curiosity rover in 2014, which pointed to a subterranean source. If these sources could be mined, methane gas might not even need to be imported.
For some time, scientists have known that Mars was not always the cold, dry, and inhospitable place that it is today. As evidenced by the presence of dry riverbeds and mineral deposits that only form in the presence of liquid water, scientists have concluded that billions of years ago, Mars was a warmer, wetter place. However, between 4.2 and 3.7 billion years ago, Mars’ atmosphere was slowly stripped away by solar wind.
This discovery has led to renewed interest in the colonizing and terraforming of Mars. And while transforming the Red Planet to make it suitable for human needs may not be doable in the near-future, it may be possible to get the process started in just a few decades’ time. It may not happen in our lifetime, but that does not mean that the dream of one-day making “Earth’s Twin” truly live up to its name won’t come true.
Artist's concept of a terraformed Mars (left) and an O'Neill Cylinder. Credit: Ittiz/Wikimedia Commons (left)/Rick Guidice/NASA Ames Research Center (right)
The idea of terraforming Mars – aka “Earth’s Twin” – is a fascinating idea. Between melting the polar ice caps, slowly creating an atmosphere, and then engineering the environment to have foliage, rivers, and standing bodies of water, there’s enough there to inspire just about anyone! But just how long would such an endeavor take, what would it cost us, and is it really an effective use of our time and energy?
Such were the questions dealt with by two papers presented at NASA’s “Planetary Science Vision 2050 Workshop” last week (Mon. Feb. 27th – Wed. Mar. 1st). The first, titled “The Terraforming Timeline“, presents an abstract plan for turning the Red Planet into something green and habitable. The second, titled “Mars Terraforming – the Wrong Way“, rejects the idea of terraforming altogether and presents an alternative.
The former paper was produced by Aaron Berliner from the University of California, Berkeley, and Chris McKay from the Space Sciences Division at NASA Ames Research Center. In their paper, the two researchers present a timeline for the terraforming of Mars that includes a Warming Phase and an Oxygenation Phase, as well as all the necessary steps that would precede and follow.
Artist’s impression of the terraforming of Mars, from its current state to a livable world. Credit: Daein Ballard
As they state in their paper’s Introduction:
“Terraforming Mars can be divided into two phases. The first phase is warming the planet from the present average surface temperature of -60° C to a value close to Earth’s average temperature to +15° C, and recreating a thick CO² atmosphere. This warming phase is relatively easy and quick, and could take ~100 years. The second phase is producing levels of O² in the atmosphere that would allow humans and other large mammals to breath normally. This oxygenation phase is relatively difficult and would take 100,000 years or more, unless one postulates a technological breakthrough.”
Before these can begin, Berliner and McKay acknowledge that certain “pre-terraforming” steps need to be taken. These include investigating Mars’ environment to determine the levels of water on the surface, the level of carbon dioxide in the atmosphere and in ice form in the polar regions, and the amount of nitrates in Martian soil. As they explain, all of these are key to the practicality of making a biosphere on Mars.
So far, the available evidence points towards all three elements existing in abundance on Mars. While most of Mars water is currently in the form of ice in the polar regions and polar caps, there is enough there to support a water cycle – complete with clouds, rain, rivers and lakes. Meanwhile, some estimates claim that there is enough CO² in ice form in the polar regions to create an atmosphere equal to the sea level pressure on Earth.
Nitrogen is also a fundamental requirement for life and necessary constituent of a breathable atmosphere, and recent data by the Curiosity Rover indicate that nitrates account for ~0.03% by mass of the soil on Mars, which is encouraging for terraforming. On top of that, scientists will need to tackle certain ethical questions related to how terraforming could impact Mars.
Artist’s concept of a possible Mars terraforming plant. Credit: National Geographic Channel
For instance, if there is currently any life on Mars (or life that could be revived), this would present an undeniable ethical dilemma for human colonists – especially if this life is related to life on Earth. As they explain:
“If Martian life is related to Earth life – possibly due to meteorite exchange – then the situation is familiar, and issues of what other types of Earth life to introduce and when must be addressed. However, if Martian life in unrelated to Earth life and clearly represents a second genesis of life, then significant technical and ethical issues are raised.”
To break Phase One – “The Warming Phase” – down succinctly, the authors address an issue familiar to us today. Essentially, we are altering our own climate here on Earth by introducing CO² and “super greenhouse gases” to the atmosphere, which is increasing Earth’s average temperature at a rate of many degrees centigrade per century. And whereas this has been unintentional on Earth, on Mars it could be re-purposed to deliberately warm the environment.
“The timescale for warming Mars after a focused effort of super greenhouse gas production is short, only 100 years or so,” they claim. “If all the solar incident on Mars were to be captured with 100% efficiency, then Mars would warm to Earth-like temperatures in about 10 years. However, the efficiency of the greenhouse effect is plausibly about 10%, thus the time it would take to warm Mars would be ~100 years.”
Mars’ south polar ice cap, as seen in April of 2000 by the Mars Odyssey mission. Credit: NASA/JPL/MSSS
Once this thick atmosphere has been created, the next step involves converting it into something breathable for humans – where O² levels would be the equivalent of about 13% of sea level air pressure here on Earth and CO² levels would be less than 1%. This phase, known as the “Oxygenation Phase”, would take considerably longer. Once again, they turn towards a terrestrial example to show how such a process could work.
Here on Earth, they claim, the high levels of oxygen gas (O²) and low levels of CO² are due to photosynthesis. These reactions rely on the sun’s energy to convert water and carbon dioxide into biomass – which is represented by the equation H²O + CO² = CH²O + O². As they illustrate, this process would take between 100,000 and 170,000 years:
“If all the sunlight incident on Mars was harnessed with 100% efficiency to perform this chemical transformation it would take only 17 years to produce high levels of O². However, the likely efficiency of any process that can transform H²O and CO² into biomass and O² is much less than 100%. The only example we have of a process that can globally alter the CO² and O² of an entire plant is global biology. On Earth the efficiency of the global biosphere in using sunlight to produced biomass and O2 is 0.01%. Thus the timescale for producing an O² rich atmosphere on Mars is 10,000 x 17 years, or ~ 170,000 years.”
However, they make allowances for synthetic biology and other biotechnologies, which they claim could increase the efficiency and reduce the timescale to a solid 100,000 years. In addition, if human beings could utilize natural photosynthesis (which has a comparatively high efficiency of 5%) over the entire planet – i.e. planting foliage all over Mars – then the timescale could be reduced to even a few centuries.
Finally, they outline the steps that need to be taken to get the ball rolling. These steps include adapting current and future robotic missions to assess Martian resources, mathematical and computer models that could examine the processes involved, an initiative to create synthetic organisms for Mars, a means to test terraforming techniques in a limited environment, and a planetary agreement that would establish restrictions and protections.
Quoting Kim Stanley Robinson, author of the Red Mars Trilogy, (the seminal work of science fiction about terraforming Mars) they issue a call to action. Addressing how long the process of terraforming Mars will take, they assert that we “might as well start now”.
To this, Valeriy Yakovlev – an astrophysicist and hydrogeologist from Laboratory of Water Quality in Kharkov, Ukraine – offers a dissenting view. In his paper, “Mars Terraforming – the Wrong Way“, he makes the case for the creation of space biospheres in Low Earth Orbit that would rely on artificial gravity (like an O’Neill Cylinder) to allow humans to grow accustomed to life in space.
Looking to one of the biggest challenges of space colonization, Yakovlev points to how life on bodies like the Moon or Mars could be dangerous for human settlers. In addition to being vulnerable to solar and cosmic radiation, colonists would have to deal with substantially lower gravity. In the case of the Moon, this would be roughly 0.165 times that which humans experience here on Earth (aka. 1 g), whereas on Mars it would be roughly 0.376 times.
Interior view of an O’Neill Cylinder. There are alternating strips of livable surface and “windows” to let light in. Credit: Rick Guidice/NASA Ames Research Center
The long-term effects of this are not known, but it is clear it would include muscle degeneration and bone loss. Looking farther, it is entirely unclear what the effects would be for those children who were born in either environment. Addressing the ways in which these could be mitigated (which include medicine and centrifuges), Yakovlev points out how they would most likely be ineffective:
“The hope for the medicine development will not cancel the physical degradation of the muscles, bones and the whole organism. The rehabilitation in centrifuges is less expedient solution compared with the ship-biosphere where it is possible to provide a substantially constant imitation of the normal gravity and the protection complex from any harmful influences of the space environment. If the path of space exploration is to create a colony on Mars and furthermore the subsequent attempts to terraform the planet, it will lead to the unjustified loss of time and money and increase the known risks of human civilization.”
In addition, he points to the challenges of creating the ideal environment for individuals living in space. Beyond simply creating better vehicles and developing the means to procure the necessary resources, there is also the need to create the ideal space environment for families. Essentially, this requires the development of housing that is optimal in terms of size, stability, and comfort.
In light of this, Yakolev presents what he considers to be the most likely prospects for humanity’s exit to space between now and 2030. This will include the creation of the first space biospheres with artificial gravity, which will lead to key developments in terms of materials technology, life support-systems, and the robotic systems and infrastructure needed to install and service habitats in Low Earth Orbit (LEO).
Artist’s depiction of a pair of O’Neill cylinders. Credit: Rick Guidice/NASA Ames Research Center
These habitats could be serviced thanks to the creation of robotic spacecraft that could harvest resources from nearby bodies – such as the Moon and Near-Earth Objects (NEOs). This concept would not only remove the need for planetary protections – i.e. worries about contaminating Mars’ biosphere (assuming the presence of bacterial life), it would also allow human beings to become accustomed to space more gradually.
As Yakovlev told Universe Today via email, the advantages to space habitats can be broken down into four points:
“1. This is a universal way of mastering the infinite spaces of the Cosmos, both in the Solar System and outside it. We do not need surfaces for installing houses, but resources that robots will deliver from planets and satellites. 2. The possibility of creating a habitat as close as possible to the earth’s cradle allows one to escape from the inevitable physical degradation under a different gravity. It is easier to create a protective magnetic field.
“3. The transfer between worlds and sources of resources will not be a dangerous expedition, but a normal life. Is it good for sailors without their families? 4. The probability of death or degradation of mankind as a result of the global catastrophe is significantly reduced, as the colonization of the planets includes reconnaissance, delivery of goods, shuttle transport of people – and this is much longer than the construction of the biosphere in the Moon’s orbit. Dr. Stephen William Hawking is right, a person does not have much time.”
And with space habitats in place, some very crucial research could begin, including medical and biologic research which would involve the first children born in space. It would also facilitate the development of reliable space shuttles and resource extraction technologies, which will come in handy for the settlement of other bodies – like the Moon, Mars, and even exoplanets.
Ultimately, Yakolev thinks that space biospheres could also be accomplished within a reasonable timeframe – i.e. between 2030 and 2050 – which is simply not possible with terraforming. Citing the growing presence and power of the commercial space sector, Yakolev also believed a lot of the infrastructure that is necessary is already in place (or under development).
“After we overcome the inertia of thinking +20 years, the experimental biosphere (like the settlement in Antarctica with watches), in 50 years the first generation of children born in the Cosmos will grow and the Earth will decrease, because it will enter the legends as a whole… As a result, terraforming will be canceled. And the subsequent conference will open the way for real exploration of the Cosmos. I’m proud to be on the same planet as Elon Reeve Musk. His missiles will be useful to lift designs for the first biosphere from the lunar factories. This is a close and direct way to conquer the Cosmos.”
With NASA scientists and entrepreneurs like Elon Musk and Bas Landorp looking to colonize Mars in the near future, and other commercial aerospace companies developing LEO, the size and shape of humanity’s future in space is difficult to predict. Perhaps we will jointly decide on a path that takes us to the Moon, Mars, and beyond. Perhaps we will see our best efforts directed into near-Earth space.
Or perhaps we will see ourselves going off in multiple directions at once. Whereas some groups will advocate creating space habitats in LEO (and later, elsewhere in the Solar System) that rely on artificial gravity and robotic spaceships mining asteroids for materials, others will focus on establishing outposts on planetary bodies, with the goal of turning them into “new Earths”.
Between them, we can expect that humans will begin developing a degree of “space expertise” in this century, which will certainly come in handy when we start pushing the boundaries of exploration and colonization even further!
Image taken by the Viking 1 orbiter in June 1976, showing Mars thin atmosphere and dusty, red surface. Credits: NASA/Viking 1
Human exploration of Mars has been ramping up in the past few decades. In addition to the eight active missions on or around the Red Planet, seven more robotic landers, rovers and orbiters are scheduled to be deployed there by the end of the decade. And by the 2030s and after, several space agencies are planning to mount crewed missions to the surface as well.
On top of that, there are even plenty of volunteers who are prepared to make a one-way journey to Mars, and people advocating that we turn it into a second home. All of these proposals have focused attention on the peculiar hazards that come with sending human beings to Mars. Aside from its cold, dry environment, lack of air, and huge sandstorms, there’s also the matter of its radiation.
Causes:
Mars has no protective magnetosphere, as Earth does. Scientists believe that at one time, Mars also experienced convection currents in its core, creating a dynamo effect that powered a planetary magnetic field. However, roughly 4.2 billions year ago – either due to a massive impact from a large object, or rapid cooling in its core – this dynamo effect ceased.
Artist’s rendering of a solar storm hitting Mars and stripping ions from the planet’s upper atmosphere. Credits: NASA/GSFC
As a result, over the course of the next 500 million years, Mars atmosphere was slowly stripped away by solar wind. Between the loss of its magnetic field and its atmosphere, the surface of Mars is exposed to much higher levels of radiation than Earth. And in addition to regular exposure to cosmic rays and solar wind, it receives occasional lethal blasts that occur with strong solar flares.
Investigations:
NASA’s 2001 Mars Odyssey spacecraft was equipped with a special instrument called the Martian Radiation Experiment (or MARIE), which was designed to measure the radiation environment around Mars. Since Mars has such a thin atmosphere, radiation detected by Mars Odyssey would be roughly the same as on the surface.
Over the course of about 18 months, the Mars Odyssey probe detected ongoing radiation levels which are 2.5 times higher than what astronauts experience on the International Space Station – 22 millirads per day, which works out to 8000 millirads (8 rads) per year. The spacecraft also detected 2 solar proton events, where radiation levels peaked at about 2,000 millirads in a day, and a few other events that got up to about 100 millirads.
For comparison, human beings in developed nations are exposed to (on average) 0.62 rads per year. And while studies have shown that the human body can withstand a dose of up to 200 rads without permanent damage, prolonged exposure to the kinds of levels detected on Mars could lead to all kinds of health problems – like acute radiation sickness, increased risk of cancer, genetic damage, and even death.
Diagram showing the amount of cosmic radiation the surface of Mars is exposed to. Credit: NASA
And given that exposure to any amount of radiation carries with it some degree of risk, NASA and other space agencies maintain a strict policy of ALARA (As-Low-As-Reasonable-Achievable) when planning missions.
Possible Solutions:
Human explorers to Mars will definitely need to deal with the increased radiation levels on the surface. What’s more, any attempts to colonize the Red Planet will also require measures to ensure that exposure to radiation is minimized. Already, several solutions – both short term and long- have been proposed to address this problem.
For example, NASA maintains multiple satellites that study the Sun, the space environment throughout the Solar System, and monitor for galactic cosmic rays (GCRs), in the hopes of gaining a better understanding of solar and cosmic radiation. They’ve also been looking for ways to develop better shielding for astronauts and electronics.
In 2014, NASA launched the Reducing Galactic Cosmic Rays Challenge, an incentive-based competition that awarded a total of $12,000 to ideas on how to reduce astronauts’ exposure to galactic cosmic rays. After the initial challenge in April of 2014, a follow-up challenge took place in July that awarded a prize of $30,000 for ideas involving active and passive protection.
When it comes to long-term stays and colonization, several more ideas have been floated in the past. For instance, as Robert Zubrin and David Baker explained in their proposal for a low-cast “Mars Direct” mission, habitats built directly into the ground would be naturally shielded against radiation. Zubrin expanded on this in his 1996 bookThe Case for Mars: The Plan to Settle the Red Planet and Why We Must.
Proposals have also been made to build habitats above-ground using inflatable modules encased in ceramics created using Martian soil. Similar to what has been proposed by both NASA and the ESA for a settlement on the Moon, this plan would rely heavily on robots using 3D printing technique known as “sintering“, where sand is turned into a molten material using x-rays.
MarsOne, the non-profit organization dedicated to colonizing Mars in the coming decades, also has proposals for how to shield Martian settlers. Addressing the issue of radiation, the organization has proposed building shielding into the mission’s spacecraft, transit vehicle, and habitation module. In the event of a solar flare, where this protection is insufficient, they advocate creating a dedicated radiation shelter (located in a hollow water tank) inside their Mars Transit Habitat.
But perhaps the most radical proposal for reducing Mars’ exposure to harmful radiation involves jump-starting the planet’s core to restore its magnetosphere. To do this, we would need to liquefy the planet’s outer core so that it can convect around the inner core once again. The planet’s own rotation would begin to create a dynamo effect, and a magnetic field would be generated.
Artist impression of a Mars settlement with cutaway view. Credit: NASA Ames Research Center
According to Sam Factor, a graduate student with the Department of Astronomy at the University of Texas, there are two ways to do this. The first would be to detonate a series of thermonuclear warheads near the planet’s core, while the second involves running an electric current through the planet, producing resistance at the core which would heat it up.
In addition, a 2008 study conducted by researchers from the National Institute for Fusion Science (NIFS) in Japan addressed the possibility of creating an artificial magnetic field around Earth. After considering continuous measurements that indicated a 10% drop in intensity in the past 150 years, they went on to advocate how a series of planet-encircling superconducting rings could compensate for future losses.
With some adjustments, such a system could be adapted for Mars, creating an artificial magnetic field that could help shield the surface from some of the harmful radiation it regularly receives. In the event that terraformers attempt to create an atmosphere for Mars, this system could also ensure that it is protected from solar wind.
Lastly, a study in 2007 by researchers from the Institute for Mineralogy and Petrology in Switzerland and the Faculty of Earth and Life Sciences at Vrije University in Amsterdam managed to replicate what Mars’ core looks like. Using a diamond chamber, the team was able to replicate pressure conditions on iron-sulfur and iron-nickel-sulfur systems that correspond to the center of Mars.
What they found was that at the temperatures expected in the Martian core (~1500 K, or 1227 °C; 2240 °F), the inner core would be liquid, but some solidification would occur in the outer core. This is quite different from Earth’s core, where the solidification of the inner core releases heat that keeps the outer core molten, thus creating the dynamo effect that powers our magnetic field.
The absence of a solid inner core on Mars would mean that the once-liquid outer core must have had a different energy source. Naturally, that heat source has since failed, causing the outer core to solidify, thus arresting any dynamo effect. However, their research also showed that planetary cooling could lead to core solidification in the future, either due to iron-rich solids sinking towards the center or iron-sulfides crystallizing in the core.
In other words, Mars’ core might become solid someday, which would heat the outer core and turn it molten. Combined with the planet’s own rotation, this would generate the dynamo effect that would once again fire up the planet’s magnetic field. If this is true, then colonizing Mars and living there safely could be a simple matter of waiting for the core to crystallize.
There’s no way around it. At present, the radiation on the surface of Mars is pretty hazardous! Therefore, any crewed missions to the planet in the future will need to take into account radiation shielding and counter-measures. And any long-term stays there – at least for the foreseeable future – are going to have to be built into the ground, or hardened against solar and cosmic rays.
Approximate true-color rendering of the central part of the “Columbia Hills”, taken by NASA’s Mars Exploration Rover Spirit panoramic camera. Credit: NASA/JPL
But you know what they say about necessity being the mother of invention, right? And with such luminaries as Stephen Hawking saying that we need to start colonizing other worlds in order to survive as a species, and people like Elon Musk and Bas Lansdrop looking to make it happen, we’re sure to see some very inventive solutions in the coming generations!
If you want, learn more about the MARIE instrument on board NASA’s Mars Odyssey spacecraft, and the radiation risks humans will face trying to go to Mars.
Surface features of the four members at different levels of zoom in each row
Continuing with our “Definitive Guide to Terraforming“, Universe Today is happy to present to our guide to terraforming Jupiter’s Moons. Much like terraforming the inner Solar System, it might be feasible someday. But should we?
Fans of Arthur C. Clarke may recall how in his novel, 2010: Odyssey Two (or the movie adaptation called 2010: The Year We Make Contact), an alien species turned Jupiter into a new star. In so doing, Jupiter’s moon Europa was permanently terraformed, as its icy surface melted, an atmosphere formed, and all the life living in the moon’s oceans began to emerge and thrive on the surface.
As we explained in a previous video (“Could Jupiter Become a Star“) turning Jupiter into a star is not exactly doable (not yet, anyway). However, there are several proposals on how we could go about transforming some of Jupiter’s moons in order to make them habitable by human beings. In short, it is possible that humans could terraform one of more of the Jovians to make it suitable for full-scale human settlement someday.
Artist's conception of a terraformed Mars. Credit: Ittiz/Wikimedia Commons
As part of our continuing “Definitive Guide To Terraforming” series, Universe Today is happy to present our guide to terraforming Mars. At present, there are several plans to put astronauts and ever settlers on the Red Planet. But if we really want to live there someday, we’re going to need to do a complete planetary renovation. What will it take?
Despite having a very cold and very dry climate – not to mention little atmosphere to speak of – Earth and Mars have a lot in common. These include similarities in size, inclination, structure, composition, and even the presence of water on their surfaces. Because of this, Mars is considered a prime candidate for human settlement; a prospect that includes transforming the environment to be suitable to human needs (aka. terraforming).
That being said, there are also a lot of key differences that would make living on Mars, a growing preoccupation among many humans (looking at you, Elon Musk and Bas Lansdorp!), a significant challenge. If we were to live on the planet, we would have to depend rather heavily on our technology. And if we were going to alter the planet through ecological engineering, it would take a lot of time, effort, and megatons of resources!
The challenges of living on Mars are quite numerous. For starters, there is the extremely thin and unbreathable atmosphere. Whereas Earth’s atmosphere is composed of 78% nitrogen, 21% oxygen, and trace amounts of other gases, Mars’ atmosphere is made up of 96% carbon dioxide, 1.93% argon and 1.89% nitrogen, along with trace amounts of oxygen and water.
Artist’s impression of the terraforming of Mars, from its current state to a livable world. Credit: Daein Ballard
Mars’ atmospheric pressure also ranges from 0.4 – 0.87 kPa, which is the equivalent of about 1% of Earth’s at sea level. The thin atmosphere and greater distance from the Sun also contributes to Mars’ cold environment, where surface temperatures average 210 K (-63 °C/-81.4 °F). Add to this the fact that Mars’ lacks a magnetosphere, and you can see why the surface is exposed to significantly more radiation than Earth’s.
On the Martian surface, the average dose of radiation is about 0.67 millisieverts (mSv) per day, which is about a fifth of what people are exposed to here on Earth in the course of a year. Hence, if humans wanted to live on Mars without the need for radiation shielding, pressurized domes, bottled oxygen, and protective suits, some serious changes would need to be made. Basically, we would have to warm the planet, thicken the atmosphere, and alter the composition of said atmosphere.
Examples In Fiction:
In 1951, Arthur C. Clarke wrote the first novel in which the terraforming of Mars was presented in fiction. Titled The Sands of Mars, the story involves Martian settlers heating up the planet by converting Mars’ moon Phobos into a second sun, and growing plants that break down the Martians sands in order to release oxygen.
In 1984, James Lovelock and Michael Allaby wrote what is considered by many to be one of the most influential books on terraforming. Titled The Greening of Mars, the novel explores the formation and evolution of planets, the origin of life, and Earth’s biosphere. The terraforming models presented in the book actually foreshadowed future debates regarding the goals of terraforming.
Kim Stanley Robinson’s Red Mars Trilogy. Credit: variety.com
In 1992, author Frederik Pohl released Mining The Oort, a science fiction story where Mars is being terraformed using comets diverted from the Oort Cloud. Throughout the 1990s, Kim Stanley Robinson released his famous Mars Trilogy – Red Mars, Green Mars, Blue Mars – which centers on the transformation of Mars over the course of many generations into a thriving human civilization.
In 2011, Yu Sasuga and Kenichi Tachibana produced the manga series Terra Formars, a series that takes place in the 21st century where scientists are attempting to slowly warm Mars. And in 2012, Kim Stanley Robinson released 2312, a story that takes place in a Solar System where multiple planets have been terraformed – which includes Mars (which has oceans).
Proposed Methods:
Over the past few decades, several proposals have been made for how Mars could be altered to suit human colonists. In 1964, Dandridge M. Cole released “Islands in Space: The Challenge of the Planetoids, the Pioneering Work“, in which he advocated triggering a greenhouse effect on Mars. This consisted of importing ammonia ices from the outer Solar System and then impacting them on the surface.
Since ammonia (NH³) is a powerful greenhouse gas, its introduction into the Martian atmosphere would have the effect of thickening the atmosphere and raising global temperatures. As ammonia is mostly nitrogen by weight, it could also provide the necessary buffer gas which, when combined with oxygen gas, would create a breathable atmosphere for humans.
Scientists were able to gauge the rate of water loss on Mars by measuring the ratio of water and HDO from today and 4.3 billion years ago. Credit: Kevin Gill
Another method has to do with albedo reduction, where the surface of Mars would be coated with dark materials in order to increase the amount of sunlight it absorbs. This could be anything from dust from Phobos and Deimos (two of the darkest bodies in the Solar System) to extremophile lichens and plants that are dark in color. One of the greatest proponents for this was famed author and scientist, Carl Sagan.
In 1973, Sagan published an article in the journal Icarus titled “Planetary Engineering on Mars“, where he proposed two scenarios for darkening the surface of Mars. These included transporting low albedo material and/or planting dark plants on the polar ice caps to ensure they absorbed more heat, melted, and converted the planet to more “Earth-like conditions”.
In 1976, NASA officially addressed the issue of planetary engineering in a study titled “On the Habitability of Mars: An Approach to Planetary Ecosynthesis“. The study concluded that photosynthetic organisms, the melting of the polar ice caps, and the introduction of greenhouse gases could all be used to create a warmer, oxygen and ozone-rich atmosphere.
In 1982, Planetologist Christopher McKay wrote “Terraforming Mars”, a paper for the Journal of the British Interplanetary Society. In it, McKay discussed the prospects of a self-regulating Martian biosphere, which included both the required methods for doing so and ethics of it. This was the first time that the word terraforming was used in the title of a published article, and would henceforth become the preferred term.
This was followed in 1984 by James Lovelock and Michael Allaby’s book, The Greening of Mars. In it, Lovelock and Allaby described how Mars could be warmed by importing chlorofluorocarbons (CFCs) to trigger global warming.
Artist’s concept of a possible Mars terraforming plant, warming the planet through the introduction of hydrocarbons. Credit: nationalgeographic.com
In 1993, Mars Society founder Dr. Robert M. Zubrin and Christopher P. McKay of the NASA Ames Research Center co-wrote “Technological Requirements for Terraforming Mars“. In it, they proposed using orbital mirrors to warm the Martian surface directly. Positioned near the poles, these mirrors would be able to sublimate the CO2 ice sheet and contribute to global warming.
In the same paper, they argued the possibility of using asteroids harvested from the Solar System, which would be redirected to impact the surface, kicking up dust and warming the atmosphere. In both scenarios, they advocate for the use of nuclear-electrical or nuclear-thermal rockets to haul all the necessary materials/asteroids into orbit.
The use of fluorine compounds – “super-greenhouse gases” that produce a greenhouse effect thousands of times stronger than CO² – has also been recommended as a long term climate stabilizer. In 2001, a team of scientists from the Division of Geological and Planetary Sciences at Caltech made these recommendations in the “Keeping Mars warm with new super greenhouse gases“.
Where this study indicated that the initial payloads of fluorine would have to come from Earth (and be replenished regularly), it claimed that fluorine-containing minerals could also be mined on Mars. This is based on the assumption that such minerals are just as common on Mars (being a terrestrial planet) which would allow for a self-sustaining process once colonies were established.
NASA’s Curiosity Mars rover has detected fluctuations in methane concentration in the atmosphere, implying that it is added and removed all the time. (Image Credit: NASA/JPL-Caltech/SAM-GSFC/Univ. of Michigan)
Importing methane and other hydrocarbons from the outer Solar System – which are plentiful on Saturn’s moon Titan – has also been suggested. There is also the possibility of in-situ resource utilization (ISRU), thanks to the Curiosity rover’s discovery of a “tenfold spike” of methane that pointed to a subterranean source. If these sources could be mined, methane might not even need to be imported.
More recent proposals include the creation of sealed biodomes that would employ colonies of oxygen-producing cyanobacteria and algae on Martian soil. In 2014, the NASA Institute for Advanced Concepts (NAIC) program and Techshot Inc. began work on this concept, which was named the “Mars Ecopoiesis Test Bed“. In the future, the project intends to send small canisters of extremophile photosynthetic algae and cyanobacteria aboard a rover mission to test the process in a Martian environment.
If this proves successful, NASA and Techshot intend to build several large biodomes to produce and harvest oxygen for future human missions to Mars – which would cut costs and extend missions by reducing the amount of oxygen that has to be transported. While these plans do not constitute ecological or planetary engineering, Eugene Boland (chief scientist of Techshot Inc.) has stated that it is a step in that direction:
“Ecopoiesis is the concept of initiating life in a new place; more precisely, the creation of an ecosystem capable of supporting life. It is the concept of initiating “terraforming” using physical, chemical and biological means including the introduction of ecosystem-building pioneer organisms… This will be the first major leap from laboratory studies into the implementation of experimental (as opposed to analytical) planetary in situ research of greatest interest to planetary biology, ecopoiesis and terraforming.”
The “greening of Mars” would be a multi-tiered process, involving the importation of gases and terrestrial organisms to convert the planet over the course of many generations. Credit: nationalgeographic.com
Potential Benefits:
Beyond the prospect for adventure and the idea of humanity once again embarking on an era of bold space exploration, there are several reasons why terraforming Mars is being proposed. For starters, there is concern that humanity’s impact on planet Earth is unsustainable, and that we will need to expand and create a “backup location” if we intend to survive in the long run.
Other reasons emphasize how Mars lies within our Sun’s “Goldilocks Zone” (aka. “habitable zone), and was once a habitable planet. Over the past few decades, surface missions like NASA’s Mars Science Laboratory (MSL) and its Curiosityrover have uncovered a wealth of evidence that points to flowing water existing on Mars in the deep past (as well as the existence of organic molecules).
Project Nomad, a concept for the 2013 Skyscraper Competition that involved mobile factory-skyscrapers terraforming Mars. Credit: evolo.com/A.A. Sainz/J.R. Nuñez/K.T. Rial
Ergo, if Mars was once habitable and “Earth-like”, it is possible that it could be again one day. And if indeed humanity is looking for a new world to settle on, it only makes sense that it be on one that has as much in common with Earth as possible. In addition, it has also been argued that our experience with altering the climate of our own planet could be put to good use on Mars.
For centuries, our reliance on industrial machinery, coal and fossil fuels has had a measurable effect Earth’s environment. And whereas this has been an unintended consequence of modernization and development here on Earth; on Mars, the burning of fossil fuels and the regular release of pollution into the air would have a positive effect.
Infographic showing a cost-estimate and time frame for the terraforming of Mars. Credit: NASA/National Geographic Channel/Discovery Channel
Other reasons include expanding our resources base and becoming a “post-scarcity” society. A colony on Mars could allow for mining operations on the Red Planet, where both minerals and water ice are abundant and could be harvested. A base on Mars could also act as a gateway to the Asteroid Belt, which would provide us with access to enough minerals to last us indefinitely.
Challenges:
Without a doubt, the prospect of terraforming Mars comes with its share of problems, all of which are particularly daunting. For starters, there is the sheer amount of resources it would take to convert Mars’ environment into something sustainable for humans. Second, there is the concern that any measure undertaken could have unintended consequences. And third, there is the amount of time it would take.
For example, when it comes to concepts that call for the introduction of greenhouse gases to trigger warming, the quantities required are quite staggering. The 2001 Caltech study, which called for the introduction of fluorine compounds, indicated that sublimating the south polar CO² glaciers would require the introduction of approximately 39 million metric tons of CFCs into Mars’ atmosphere – which is three times the amounts produced on Earth between 1972 and 1992.
Artist’s conception of a terraformed Mars. Credit: Ittiz/Wikimedia Commons
Photolysis would also begin to break down the CFCs the moment they were introduced, which would necessitate the addition of 170 kilotons every year to replenish the losses. And last, the introduction of CFCs would also destroy any ozone that was produced, which would undermine efforts to shield to surface from radiation.
Also, the 1976 NASA feasibility study indicated that while terraforming Mars would be possible using terrestrial organisms, it also recognized that the time-frames called for would be considerable. As it states in the study:
“No fundamental, insuperable limitation of the ability of Mars to support a terrestrial ecology is identified. The lack of an oxygen-containing atmosphere would prevent the unaided habitation of Mars by man. The present strong ultraviolet surface irradiation is an additional major barrier. The creation of an adequate oxygen and ozone-containing atmosphere on Mars may be feasible through the use of photosynthetic organisms. The time needed to generate such an atmosphere, however, might be several millions of years.”
The study goes on to state that this could be drastically reduced by creating extremophile organisms specifically adapted for the harsh Martian environment, creating a greenhouse effect and melting the polar ice caps. However, the amount of time it would take to transform Mars would still likely be on the order of centuries or millennia.
Artist’s concept for a NASA manned-mission to Mars (Human Exploration of Mars Design Reference Architecture 5.0, Feb 2009). Credit: NASA
And of course, there is the problem of infrastructure. Harvesting resources from other planets or moons in the Solar System would require a large fleet of space haulers, and they would need to be equipped with advanced drive systems to make the trip in a reasonable amount of time. Currently, no such drive systems exist, and conventional methods – ranging from ion engines to chemical propellants – are neither fast or economical enough.
To illustrate, NASA’s New Horizons mission took more than 11 years to get make its historic rendezvous with Pluto in the Kuiper Belt, using conventional rockets and the gravity-assist method. Meanwhile, the Dawn mission, which relied relied on ionic propulsion, took almost four years to reach Vesta in the Asteroid Belt. Neither method is practical for making repeated trips to the Kuiper Belt and hauling back icy comets and asteroids, and humanity has nowhere near the number of ships we would need to do this.
On the other hand, going the in-situ route – which would involve factories or mining operations on the surface to release CO², methane or CFC-containing minerals into the air – would require several heavy-payload rockets to get all the machinery to the Red Planet. The cost of this would dwarf all space programs to date. And once they were assembled on the surface (either by robotic or human workers), these operations would have to be run continuously for centuries.
There is also several questions about the ethics of terraforming. Basically, altering other planets in order to make them more suitable to human needs raises the natural question of what would happen to any lifeforms already living there. If in fact Mars does have indigenous microbial life (or more complex lifeforms), which many scientists suspect, then altering the ecology could impact or even wipe out these lifeforms. In short, future colonists and terrestrial engineers would effectively be committing genocide.
NASA’s Journey to Mars. NASA is developing the capabilities needed to send humans to an asteroid by 2025 and Mars in the 2030s. Credit: NASA/JPL
Given all of these arguments, one has to wonder what the benefits of terraforming Mars would be. While the idea of utilizing the resources of the Solar System makes sense in the long-run, the short-term gains are far less tangible. Basically, harvested resources from other worlds is not economically viable when you can extract them here at home for much less. And given the danger, who would want to go?
But as ventures like MarsOne have shown, there are plenty of human beings who are willing to make a one-way trip to Mars and act as Earth’s “first-wave” of intrepid explorers. In addition, NASA and other space agencies have been very vocal about their desire to explore the Red Planet, which includes manned missions by the 2030s. And as various polls show, public support is behind these endeavors, even if it means drastically increased budgets.
So why do it? Why terraform Mars for human use? Because it is there? Sure. But more importantly, because we might need to. And the drive and the desire to colonize it is also there. And despite the difficulty inherent in each, there is no shortage of proposed methods that have been weighed and determined feasible.In the end, all that’s needed is a lot of time, a lot of commitment, a lot of resources, and a lot of care to make sure we are not irrevocably harming life forms that are already there.
But of course, should our worst predictions come to pass, we may find in the end that we have little choice but to make a home somewhere else in the Solar System. As this century progresses, it may very well be Mars or bust!
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Artist's illustration of a SpaceX Starship lands on Mars. Credit: SpaceX
Welcome back to our series on Settling the Solar System! Today, we take a look at that cold and dry world known as “Earth’s Twin”. I’m talking about Mars. Enjoy!
Mars. It’s a pretty unforgiving place. On this dry, desiccated world, the average surface temperature is -55 °C (-67 °F). And at the poles, temperatures can reach as low as -153 °C (243 °F). Much of that has to do with its thin atmosphere, which is too thin to retain heat (not to mention breathe). So why then is the idea of colonizing Mars so intriguing to us?
Well, there are a number of reasons, which include the similarities between our two planets, the availability of water, the prospects for generating food, oxygen, and building materials on-site. And there are even long-term benefits to using Mars as a source of raw materials and terraforming it into a liveable environment. Let’s go over them one by one…
Examples in Fiction:
The idea of exploring and settling Mars has been explored in fiction for over a century. Most of the earliest depiction of Mars in fiction involved a planet with canals, vegetation, and indigenous life – owing to the observations of the astronomers like Giovanni Schiaparelli and Percival Lowell.
However, by the latter half of the 20th century (thanks in large part to the Mariner 4 missions and scientists learning of the true conditions on Mars) fictional accounts moved away from the idea of a Martian civilization and began to deal with humans eventually colonizing and transforming the environment to suit their needs.
Artist impression of a Mars settlement with cutaway view. Credit: NASA Ames Research Center
This shift is perhaps best illustrated by Ray Bradbury’s The Martian Chronicles(published in 1950). A series of short stories that take place predominantly on Mars, the collection begins with stories about a Martian civilization that begins to encounter human explorers. The stories then transition to ones that deal with human settlements on the planet, the genocide of the Martians, and Earth eventually experiencing nuclear war.
During the 1950s, many classic science fiction authors wrote about colonizing Mars. These included Arthur C. Clarke and his 1951 story The Sands of Mars, which is told from the point of view of a human reporter who travels to Mars to write about human colonists. While attempting to make a life for themselves on a desert planet, they discover that Mars has native life forms.
In 1952, Isaac Asimov released The Martian Way, a story that deals with the conflict between Earth and Mars colonists. The latter manage to survive by salvaging space junk and are forced to travel to Saturn to harvest ice when Earth enforces an embargo on their planet.
Robert A. Heinlein’s seminal novel Stranger in a Strange Land (1961) tells the story of a human who was raised on Mars by the native Martians and then travels to Earth as a young adult. His contact with humans proves to have a profound effect on Earth’s culture, and calls into questions many of the social mores and accepted norms of Heinlein’s time.
Artist’s concept of possible exploration of the surface of Mars. Credit: NASA Ames Research Center
Philip K. Dick’s fiction also features Mars often, in every case being a dry, empty land with no native inhabitants. In his works Martian Time Slip (1964), and The Three Stigmata of Palmer Eldritch (1965), life on Mars is presented as difficult, consisting of isolated communities who do not want to live there.
In Do Androids Dream of Electric Sheep? (1968), most of humanity has left Earth after a nuclear war and now live in “the colonies” on Mars. Androids (Replicants) escaping illegally to come back to Earth claim that they have left because “nobody should have to live there. It wasn’t conceived for habitation, at least not within the last billion years. It’s so old. You feel it in the stones, the terrible old age”.
Kim Stanley Robinson’s Mars trilogy (published between 1992–1996), Mars is colonized and then terraformed over the course of many centuries. Ben Bova’s Grand Tour series – which deals with the colonization of the Solar System – also includes a novel titled Mars(1992). In this novel, explorers travel to Mars – locations including Mt. Olympus and Valles Marineris – to determine is Mars is worth colonizing.
Alastair Reynolds’ short story “The Great Wall of Mars” (2000) takes place in a future where the most technologically advanced humans are based on Mars and embroiled in an interplanetary war with a faction that takes issue with their experiments in human neurology.
Artist’s impression of the terraforming of Mars, from its current state to a livable world. Credit: Daein Ballard
In Hannu Rajaniemi’s The Quantum Thief (2010), we get a glimpse of Mars in the far future. The story centers on the city of Oubliette, which moves across the face of the planet. Andry Weir’s The Martian (2011) takes place in the near future, where an astronaut is stranded on Mars and forced to survive until a rescue party arrives.
Kim Stanley Robinson’s 2312(2012) takes place in a future where humanity has colonized much of the Solar System. Mars is mentioned in the course of the story as a world that has been settled and terraformed (which involved lasers cutting canals similar to what Schiaparelli described) and now has oceans covering much of its surface.
Proposed Methods:
NASA’s proposed manned mission to Mars – which is slated to take place during the 2030s using the Orion Multi-Purpose Crew Vehicle (MPCV) and the Space Launch System (SLS) – is not the only proposal to send humans to the Red Planet. In addition to other federal space agencies, there are also plans by private corporations and non-profits, some of which are far more ambitious than mere exploration.
The European Space Agency (ESA) has long-term plans to send humans, though they have yet to build a manned spacecraft. Roscosmos, the Russian Federal Space Agency, is also planning a manned Mars mission, with simulations (called Mars-500) having been completed in Russia back in 2011. The ESA is currently participating in these simulations as well.
In 2012, a group of Dutch entrepreneurs revealed plans for a crowdfunded campaign to establish a human Mars base, beginning in 2023. Known as Mars One, the plan calls for a series of one-way missions to establish a permanent and expanding colony on Mars, which would be financed with the help of media participation.
Mars-manned-mission vehicle (NASA Human Exploration of Mars Design Reference Architecture 5.0) Feb 2009. Credit: NASA
Other details of the MarsOne plan include sending a telecom orbiter by 2018, a rover in 2020, and the base components and its settlers by 2023. The base would be powered by 3,000 square meters of solar panels, and the SpaceX Falcon 9 Heavy rocket would be used to launch the hardware. The first crew of 4 astronauts would land on Mars in 2025; then, every two years, a new crew of 4 astronauts would arrive.
On December 2nd, 2014, NASA’s Advanced Human Exploration Systems and Operations Mission Director Jason Crusan and Deputy Associate Administrator for Programs James Reuther announced tentative support for the Boeing “Affordable Mars Mission Design.” Currently planned for the 2030s, the mission profile includes plans for radiation shielding, centrifugal artificial gravity, in-transit consumable resupply, and a return-lander.
SpaceX and Tesla CEO Elon Musk also announced plans to establish a colony on Mars with a population of 80,000 people. Intrinsic to this plan is the development of the Mars Colonial Transporter (MCT), a spaceflight system that would rely on reusable rocket engines, launch vehicles, and space capsules to transport humans to Mars and return to Earth.
As of 2014, SpaceX has begun developing the large Raptor rocket engine for the Mars Colonial Transporter, and a successful test was announced in September of 2016. In January 2015, Musk said that he hoped to release details of the “completely new architecture” for the Mars transport system in late 2015.
In June 2016, Musk stated in the first unmanned flight of the Mars transport spacecraft would take place in 2022, followed by the first manned MCT Mars flight departing in 2024. In September 2016, during the 2016 International Astronautical Congress, Musk revealed further details of his plan, which included the design for an Interplanetary Transport System (ITS) and estimated costs.
There may come a day when, after generations of terraforming and numerous waves of colonists, that Mars will begin to have a viable economy as well. This could take the form of mineral deposits being discovered and then sent back to Earth for sale. Launching precious metals, like platinum, off the surface of Mars would be relatively inexpensive thanks to its lower gravity.
But according to Musk, the most likely scenario (at least for the foreseeable future) would involve an economy based on real estate. With human populations exploding all over Earth, a new destination that offers plenty of room to expand is going to look like a good investment.
And once transportation issues are worked out, savvy investors are likely to start buying up land. Plus, there is likely to be a market for scientific research on Mars for centuries to come. Who knows what we might find once planetary surveys really start to open up!
Over time, many or all of the difficulties in living on Mars could be overcome through the application of geoengineering (aka. terraforming). Using organisms like cyanobacteria and phytoplankton, colonists could gradually convert much of the CO² in the atmosphere into breathable oxygen.
In addition, it is estimated that there is a significant amount of carbon dioxide (CO²) in the form of dry ice at the Martian south pole, not to mention absorbed by in the planet’s regolith (soil). If the temperature of the planet were raised, this ice would sublimate into gas and increase atmospheric pressure. Although it would still not be breathable by humans, it would be sufficient enough to eliminate the need for pressure suits.
A possible way of doing this is by deliberately triggering a greenhouse effect on the planet. This could be done by importing ammonia ice from the atmospheres of other planets in our Solar System. Because ammonia (NH³) is mostly nitrogen by weight, it could also supply the buffer gas needed for a breathable atmosphere – much as it does here on Earth.
Similarly, it would be possible to trigger a greenhouse effect by importing hydrocarbons like methane – which is common in Titan’s atmosphere and on its surface. This methane could be vented into the atmosphere where it would act to compound the greenhouse effect.
Zubrin and Chris McKay, an astrobiologist with NASA’s Ames Research center, have also suggested creating facilities on the surface that could pump greenhouse gases into the atmosphere, thus triggering global warming (much as they do here on Earth).
Other possibilities exist as well, ranging from orbital mirrors that would heat the surface to deliberately impacting the surface with comets. But regardless of the method, possibilities exist for transforming Mars’ environment that could make it more suitable for humans in the long run – many of which we are currently doing right here on Earth (with less positive results).
Another proposed solution is building habitats underground. By building a series of tunnels that connect between subterranean habitats, settlers could forgo the need for oxygen tanks and pressure suits when they are away from home.
Additionally, it would provide protection against radiation exposure. Based on data obtained by the Mars Reconnaissance Orbiter, it is also speculated that habitable environments exist underground, making it an even more attractive option.
Potential Benefits:
As already mentioned, there are many interesting similarities between Earth and Mars that make it a viable option for colonization. For starters, Mars and Earth have very similar lengths of days. A Martian day is 24 hours and 39 minutes, which means that plants and animals – not to mention human colonists – would find that familiar.
Diagram showing the habitable zones of the Solar System (upper row) and the Gliese 581 system (lower row). Based on a diagram by Franck Selsis, Univ. of Bordeaux. Credit: ESO
Mars also has an axial tilt that is very similar to Earth’s, which means it has the same basic seasonal patterns as our planet (albeit for longer periods of time). Basically, when one hemisphere is pointed towards the Sun, it experiences summer while the other experiences winter – complete with warmer temperatures and longer days.
This too would work well when it comes to growing seasons and would provide colonists with a comforting sense of familiarity and a way of measuring out the year. Much like farmers here on Earth, native Martians would experience a “growing season”, a “harvest”, and would be able to hold annual festivities to mark the changing of the seasons.
Also, much like Earth, Mars exists within our Sun’s habitable zone (aka. “Goldilocks zone“), though it is slightly towards its outer edge. Venus is similarly located within this zone, but its location on the inner edge (combined with its thick atmosphere) has led to it becoming the hottest planet in the Solar System. That, combined with its sulfuric acid rains makes Mars a much more attractive option.
Additionally, Mars is closer to Earth than the other Solar planets – except for Venus, but we already covered why it’s not a very good option! This would make the process of colonizing it easier. In fact, every few years when the Earth and Mars are at opposition – i.e. when they are closest to each other – the distance varies, making certain “launch windows” ideal for sending colonists.
For example, on April 8th, 2014, Earth and Mars were 92.4 million km (57.4 million miles) apart at opposition. On May 22nd, 2016, they will be 75.3 million km (46.8 million miles) apart, and by July 27th of 2018, a meager 57.6 million km (35.8 million miles) will separate our two worlds. During these windows, getting to Mars would be a matter of months rather than years.
Also, Mars has vast reserves of water in the form of ice. Most of this water ice is located in the polar regions, but surveys of Martian meteorites have suggested that much of it may also be locked away beneath the surface. This water could be extracted and purified for human consumption easily enough.
In his book, The Case for Mars, Robert Zubrin also explains how future human colonists might be able to live off the land when traveling to Mars, and eventually colonize it. Instead of bringing all their supplies from Earth – like the inhabitants of the International Space Station – future colonists would be able to make their own air, water, and even fuel by splitting Martian water into oxygen and hydrogen.
New estimates of water ice on Mars suggest there may be large reservoirs of underground ice at non-polar latitudes. Credit: Feldman et al., 2011
Preliminary experiments have shown that Mars soil could be baked into bricks to create protective structures, which would reduce the amount of material that needs to be shipped to the surface. Earth plants could eventually be grown in Martian soil too, assuming they get enough sunlight and carbon dioxide. Over time, planting on the native soil could also help to create a breathable atmosphere.
Challenges:
Despite the aforementioned benefits, there are also some rather monumental challenges to colonizing the Red Planet. For starters, there is the matter of the average surface temperature, which is anything but hospitable. While temperatures around the equator at midday can reach a balmy 20 °C, at the Curiosity site – the Gale Crater, which is close to the equator – typical nighttime temperatures are as low as -70 °C.
The gravity on Mars is also only about 40% of what we experience on Earth’s, which would make adjusting to it quite difficult. According to a NASA report, the effects of zero-gravity on the human body are quite profound, with a loss of up to 5% muscle mass a week and 1% of bone density a month.
Naturally, these losses would be lower on the surface of Mars, where there is at least some gravity. But permanent settlers would still have to contend with the problems of muscle degeneration and osteoporosis in the long run.
The Biosphere 2 project is an attempt to simulate Mars-like conditions on Earth. Credit: Science Photo Library
And then there’s the atmosphere, which is unbreathable. About 95% of the planet’s atmosphere is carbon dioxide, which means that in addition to producing breathable air for their habitats, settlers would also not be able to go outside without a pressure suit and bottled oxygen.
Mars also has no global magnetic field comparable to Earth’s geomagnetic field. Combined with a thin atmosphere, this means that a significant amount of ionizing radiation is able to reach the Martian surface.
Thanks to measurements taken by the Mars Odyssey spacecraft’s Mars Radiation Environment Experiment (MARIE), scientists learned that radiation levels in orbit above Mars are 2.5 times higher than at the International Space Station. Levels on the surface would be lower, but would still be higher than human beings are accustomed to.
In fact, a recent paper submitted by a group of MIT researchers – which analyzed the Mars One plan to colonize the planet beginning in 2020 – concluded that the first astronaut would suffocate after 68 days, while the others would die from a combination of starvation, dehydration, or incineration in an oxygen-rich atmosphere.
Artist’s concept of a Martian astronaut standing outside the Mars One habitat. Credit: Bryan Versteeg/Mars One
In short, the challenges to creating a permanent settlement on Mars are numerous, but not necessarily insurmountable. And if we do decide, as individuals and as a species, that Mars is to become a second home for humanity, we will no doubt find creative ways to address them all.
Who knows? Someday, perhaps even within our own lifetimes, there could be real Martians. And they would be us!
Universe Today has many interesting articles about the possibility of humans living on Mars. Here’s a great article by Nancy Atkinson about the possibility of a one-way, one-person trip to Mars
