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The Challenges of Building a Colony on Mars

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In this series, mental_floss will examine the engineering problems associated with humanity’s most extreme endeavors, from mining asteroids to colonizing the ocean, and explain how engineers plan to solve them.

“Twenty years from now you will be more disappointed by the things you didn’t do than by the ones you did. So throw off the bowlines, sail away from the safe harbor, catch the trade winds in your sails. Explore. Dream. Discover.” – Not Mark Twain (regardless of what Virgin Galactic would have you believe).

If you’re going to settle Mars, there are a couple of questions that you have to answer straightaway: 1. Where? 2. How? 3. Who? That third question is especially difficult to answer—building a colony on Mars isn’t like discovering some Polynesian island and building a hut. Mars doesn’t want you there, and will be doing everything it can think of to keep you away. And if you do plan to go there, you shouldn’t expect to come back. You should, in fact, probably expect a confined life of loneliness, misery, disease, and starvation before you eventually descend into madness and death. Jack Torrance is likely the best-case scenario. Personally, my money’s on a colony of Reavers.

But all of that assumes a Martian colony can actually be built. Let’s start with the basic problems associated with moving to Mars.

Weathering the Weather

The average temperature on Earth is 61 degrees Fahrenheit (with wide variations, obviously). The average temperature on Mars is -80 degrees. But here’s the real challenge: A warm summer day on Mars might hit 71, which is pretty nice. Maybe wear jeans and carry along a light jacket. But that same warm summer day will plunge to -100 degrees come nightfall, with 100 percent humidity going into the following morning. (I’m going with’s numbers here.) So even though we have lots of experience (relatively speaking) living at research stations in Antarctica, it’s not exactly a 1:1 comparison. (Average temperature in Antarctica: -34.4 degrees, with no 170-degree swings.) The point is, if you’re building a house on Mars, you need to build one that neither braises nor freezes the Reavers inside.

We should also talk about the weather. The Butterfly Effect aside, when there’s a sandstorm in Dubai, your average New Yorker doesn’t change her dinner plans. Mars is a little different, though, with dust storms that engulf the entire planet. So in addition to moderating temperature, your shelter needs to be pretty durable. When it’s humidity-caked in red dirt, it’s not like you can just find someone on Angie’s List to pressure wash the siding.

And those are only the trivial problems. 

The Radiation Problem

In 2001, NASA sent a particle energy spectrometer to Mars to study the red planet’s radiation. This was called the Mars Radiation Environment Experiment, or MARIE. The device found that the surface of Mars has two and half times the radiation that you’d get at the International Space Station, and that’s not even counting the solar proton events, which come without warning and really bombard the place. “Wait a minute,” you say. “Why don’t we worry about solar proton events here on Earth? I mean we share the same sun!” Good question. When the protons of an SPE hit Earth, the magnetosphere pulls them to the poles, and the ionosphere (just below the magnetosphere) handles the rest. This is called polar cap absorption, and is one of the many reasons why Earth is a wonderful place indeed. Mars, lacking a magnetosphere, offers no such protection. How much of a problem is this, human-life-wise? After a series of solar flares in 2003, MARIE was damaged and rendered inoperable. If the sun is frying the machines on Mars designed to measure such solar salvos, imagine what it will do to humans. So, cancer: CHECK.

Power Issues

Even the dust storms are more than an annoyance. See, if we’re going to live on Mars, we’re going to need a reliable source of electricity. Because of the temperatures, lack of natural resources, incompatible atmosphere, etc., life support systems are really, really important. In six words: If the power fails, you die.

There are few more reliable sources of power than the sun, right? (Well, there’s nuclear power, but present political opposition has effectively removed that from the table.) The problem with solar panels is that those planetary dust storms can reduce sunlight by 99 percent. Uh-oh. Suddenly, your greenhouses aren’t growing vegetables and your solar cells aren’t charging very well. Your water-recycling and air filtration and temperature regulation systems are in jeopardy. You’re living off of reserve power and reserve supplies. Better hope the storm ends before the batteries do.

Conquering the Atmosphere

Another thing. Human beings have evolved very nicely for long, comfortable lives on Earth. We developed to enjoy the air, the sun, the land, the microbes, the gravity. We’re biologically equipped to survive a good 70 years on terra firma, and some of us much longer.

Not so much on Mars, though. The Martian atmosphere is thin. Really thin. A guy named George Armstrong did some research and determined that there exists an altitude at which the boiling point of water is 98.6 degrees. You might recognize that temperature as the happy result on a thermometer—unless you’re at the Armstrong Limit. Then it’s a really sad result because your bodily liquids will begin to boil. Tears, saliva, the lining of your lungs, etc. (Your blood is OK, as is your interior water, so to speak. Skin is an excellent protectant.) The atmospheric pressure of Mars is well over the Armstrong Limit. That means you’re confined to the colony. If you want to take a stroll, you’re confined to a space suit. “Well fine,” you say, “I’ll just wear a space suit.”

Getting Around

That’s a smart thing to do. But that suit is also pretty limiting. When you land on Mars, you won’t be climbing mountains and planting very many flags. You’ll have a small radius of travel, and that’s it for the foreseeable future. Are you familiar with the color brown? Because that’s all you’re going to see on Mars. “Well I’ll just saddle up one of those rovers,” you say, “and zip around to see the sights.”

This might not be the most effective means of travel. It’s taken the NASA rover Opportunity a full decade to travel a total of 23.94 miles. In six years, rover Spirit traveled 4.8 miles. Rover Curiosity is expected to travel a minimum of 12 miles. Rover Sojourner traveled 330 feet. None of this is to diminish the extraordinary engineering that was required to build, deploy, and operate the rovers. Those things are nearly indistinguishable from magic and have advanced human knowledge immeasurably. But they also offer a little perspective on what the best of our efforts can do. None of these rovers would have been able to finish a marathon in less than 10 years, if they could finish one at all. So it’s not as though we’ve established a proof of concept for a Martian freeway.

Getting There At All

One more point concerning our frail bodies: Consider that the ride from Earth to Mars takes about six months when the planets are close. At a compounding loss of 1 percent bone density per month, which is what you’re going to get in zero gravity, you’re looking at brittle bones before you even touch the Martian surface. Likewise muscle atrophy. A recent study by NASA found that even our steely-eyed astronauts, disciplined and no strangers to physical fitness on Earth and in space, lost significant calf muscle volume, peak power, and force-velocity characteristics over six-month stays on the International Space Station. We’re talking significant decreases in the 30% range, all around, even while engaging in a pretty serious exercise regimen. Try moving into a new house while you have pneumonia. That’s about what it’s going to feel like when you get to Mars.

Taken together, all of this probably makes temporary human settlement on Mars—let alone permanent colonies—sound impossible. But it’s not. In the next entry we’ll take a look at what engineers have up their sleeves to counter the problems of Martian settlement, and why it really can become a reality.

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A One Way Mission to Mars
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Wikimedia Commons

In this series, Mental Floss will examine the engineering problems associated with humanity’s most extreme endeavors, from mining asteroids to colonizing the ocean, and explain how engineers plan to solve them.

“The founders of a new colony, whatever Utopia of human virtue and happiness they might originally project, have invariably recognized it among their earliest practical necessities to allot a portion of the virgin soil as a cemetery, and another portion as the site of a prison.” —Nathaniel Hawthorne, The Scarlet Letter

As we’ve seen in this series, there are countless nontrivial engineering problems associated with building a Martian colony, and there are as many solutions as there are engineers. What everyone seems to agree on, however, is that when we finally decide to pull the trigger on this thing, we’re playing for keeps. A colonization mission is one-way.

Mars to Stay

You might have heard of Buzz Aldrin. He was a Korean War fighter pilot who earned the Distinguished Flying Cross. Later, he was an Air Force aerial gunnery instructor and a flight commander for the 22nd Fighter Squadron. He enrolled at MIT and earned a doctorate of science in Astronautics. But he’s also a known street brawler, and when the on/off switch for the lunar module broke, he stabbed it with a felt tip pen, teaching it a little thing about respect, and saving the mission from certain doom (he also went to the moon).

So when Buzz Aldrin says the people we send to Mars need to just quit whining and stay there, maybe it’s not his genteel nature. But he makes a compelling argument. As he explained to Vanity Fair: "Did the Pilgrims on the Mayflower sit around Plymouth Rock waiting for a return trip? They came here to settle. And that’s what we should be doing on Mars. When you go to Mars, you need to have made the decision that you’re there permanently. The more people we have there, the more it can become a sustaining environment. Except for very rare exceptions, the people who go to Mars shouldn’t be coming back. Once you get on the surface, you’re there."

This is part of what has been termed the Mars to Stay initiative, and there are two very big advantages to such a plan. First, it’s cheaper. If a ship to Mars has to carry enough fuel for a round trip, it thus needs even more fuel on top of that to compensate for the additional mass of the ship. Those dollars start to add up quickly. Secondly, it’s a commitment. Look, let’s be honest here: Every time a president makes some big speech in front of our now-mothballed space shuttle, we listen with the full knowledge that it’s probably not going to happen—that the next president or Congress will hose things up and cut funding or find something newer and shinier to chase. (These days it’s capturing an asteroid. The last guy wanted to build a moon colony. The last guy’s dad ordered a ten-year plan culminating in a manned mission to Mars, which would make this year the 15th anniversary of the first human on the Red Planet.) But, see, you put a colony of people on Mars—people who will, if we get cheap, starve to death or asphyxiate or get irradiated into a puddle of goo—and suddenly there’s no shifting priorities around.

Last week, we discussed how to actually get humans to Mars. Here’s a question: What do they do when they get there? What are they going to breathe and eat?

Terraforming the Red Planet

Let’s talk Martian cuisine. Elon Musk, the Zip2-PayPal-SpaceX-Tesla-founder/real life Tony Stark conceived of a plan called the Mars Oasis, in which he would send a robotic greenhouse to Mars, which would then gather and treat Martian soil with nutrients and begin growing food. Said Musk, “You’d wind up with this great photograph of green plants and red background—the first life on Mars, as far as we know, and the farthest that life’s ever traveled. It would be a great money shot, plus you’d get a lot of engineering data about what it takes to maintain a little greenhouse and keep plants alive on Mars.”

(While developing the project, Musk realized that the real barrier to entry for Martian settlement is in rocketry, and resolved to first solve the rocket problem, which he actually seems to be doing.)

It’s easy to say, well, gardening is boring—tell me more about the fusion rockets!—but gardening is a significant problem. By and large, humans have a hard time growing crops on Earth. Now try to do the same thing with half the sunlight, less gravity, and way more radiation. That’s Mars, and it doesn’t want your plant life. But still, where there’s an engineer, there’s a good chance of success. NASA has been experimenting with certain types of LED lighting designed to hit that wavelength sweet spot in which plants love to blossom. Meanwhile, Martian greenhouses will be able to operate at one-tenth of an atmosphere, which is great news in terms of energy efficiency and required square footage. (The downside is that gardeners will be required to hoe their rows in atmospheric suits.) According to, NASA even has ten candidate crops in mind, each chosen for its resilience and edibility. This list: “lettuce, spinach, carrots, tomatoes, green onions, radishes, bell peppers, strawberries, fresh herbs, and cabbages.”

Here’s where it gets even more interesting. The food we grow will also contribute to the air we breathe. In a self-contained bioregenerative life support system—kind of a miniature ecosystem—plants generate food, oxygen, and clean water for humans, who in turn generate waste and gray water for bioreactors, which then break down said waste and generate nutrients and carbon dioxide for plants, and so on. Hakuna matata—it’s the circle of life, minus the lions. While all this is going on, in-situ resource utilization will provide things like air, water, and power.

Water, Water, Water

In-situwha? you ask. Good question. See, Mars is a giant, inhospitable wasteland, but it’s a giant, inhospitable wasteland with potential. There’s water at its poles in the form of ice caps, water vapor in the air, and ice patches strewn across the planet. But perhaps more useful is the chemically bound water in the Martian soil, which can be extracted. According to one NASA researcher, "If you think about a cubic foot of this dirt and you just heat it a little bit—a few hundred degrees—you'll actually get off about two pints of water—like two water bottles you'd take to the gym.”

NASA is investigating the use of microwave beams to heat the soil. Microwaves have the advantage of being able to penetrate the soil without the need for digging. Extractors would use a process called sublimation, in which ice is converted directly to a gas, which would then be captured and further converted to water. Once our Martian colonists have reliable access to water, they’re really in business because that’s also where their breathable air will come from. A process called electrolysis can extract oxygen from said water. At the same time, nitrogen and argon can be extracted from the Martian atmosphere to be used as buffer gasses for our breathable air. (Man cannot live by oxygen alone.) And the sun, by way of solar panels, as we discussed previously, could power all of this.

Here, I admit, we’re going to apply a little handwavium. See, for three columns now we’ve discussed the engineering required for colonizing Mars. The sheer scope of the challenges associated with building a colony on another planet should be pretty clear at this point. Yes, each of the technologies covered have solid foundations and laboratory successes, but they’re going to have to actually work, and work well, and not break, to be useful on Mars. And they’re all going to have to work at the same time. Any one break in the chain would pretty much spell certain death for literally everyone on the planet.

The Human Problem

So if you plan to move to Mars, you’d better be an optimist. Which leads me to one final point: the limitations of human psychology cannot be fixed with a soldering iron and a fabrication plant. (Yet.) In June 2010, the European Space Agency and the Russian Institute for Biomedical Problems launched a study called Mars 500 in which six men were sealed in a mockup habitat for 520 days to see what would happen, exactly, on a Mars mission. How would humans handle it? Their accommodations were windowless, and “contact” with Earth was realistically delayed by 14 minutes (the same delay by which the rover Curiosity transmits). The men of Mars 500 were chosen from a pool of greater than 1000 candidates. Who would you want on such an unpleasant non-mission, sealed in a can away from the world for well over a year? Probably someone with nerves of steel or a keen understanding of how the mind can play tricks on you. Someone like, say, a navy diver or a surgeon or a psychologist—which are exactly who the Mars 500 habitat had, among others.

How did it go? First the good news: They didn’t resort to cannibalism. But it wasn’t exactly hugs and rainbows “up” there. The big problems uncovered involved sleeping disorders and depression. One test subject somehow unintentionally found himself on a 25-hour/day cycle, which meant every 12 days he was nocturnal to the other crewmembers’ diurnal. One man developed chronic sleep deprivation and began fumbling basic performance examinations.

The instance of depression, though, gets at the heart of the real challenge of a one-way Martian mission. Only a fool would suggest that there’s a colonization problem that our engineers cannot overcome. But overcoming the basic limitations of human biology and cognitive ability? That’s going to take some doing. Already, scientists are working on ways to combat this. A lot of it can be handled by certain types of lighting to manipulate alertness and better simulate life on Earth.

Here’s the thing. Our Martian colonists will be confined mostly indoors, will live with the possibility of sudden extinction at any given moment, and—garden tending and science projects aside—will be faced with jaw-clenching boredom. On Mars, there are no trips to the mall, no walks in the park, no Redbox runs, no rainy afternoons at the coffee shop, no nights on the town. There is only your habitat and what you brought with you. The Mars 500 crew tried passing the time by playing Guitar Hero and watching DVDs, but they quickly grew sedentary and lethargic. Ultimately, only two out of the six crewmembers adjusted to the mission. On an actual Martian colony, the risk of a crewmember or colonist snapping is all too real, and the result could be devastating beyond imagination.

When Hawthorne wrote that the first two things colonists built upon arrival in the New World were cemeteries and prisons, he might as well have been describing our inevitable colonies on Mars. Such an endeavor will not be for the faint of heart, and it’s possible we won’t know the faint of heart until we get there. Our best hope might be Buzz Aldrin leading the mission.

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How to Land on Mars
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In this series, Mental Floss will examine the engineering problems associated with humanity’s most extreme endeavors, from mining asteroids to colonizing the ocean, and explain how engineers plan to solve them.

“Now would I give a thousand furlongs of sea for an / acre of barren ground, long heath, brown furze, any / thing. The wills above be done! but I would fain / die a dry death.” —William Shakespeare, The Tempest, Act I Scene I.

If we’re going to colonize Mars, we’re going to have to deal with the Ghoul. See, we idle dreamers love to talk about how humanity could build that colony on the fourth rock, and how we’d handle the water situation and electricity and so on, but we’re glossing over the hardest part of the whole operation—an operation, it should be noted, that’s nothing but hard parts.

Getting something to Mars and landing it there is basically impossible. You might think it’s just a matter of building a rocket and pointing it in the right direction, and you’d be right, technically, but the men and women who have to actually carry the one and do the hard math know that there’s a dark power at work that often trumps our greatest engineering achievements. There’s no sense in dancing around the issue. There is a giant space monster that doesn’t want us on Mars.

Beating the Mars Curse

Well, not literally. But humans have been sending things to (or near) Mars since 1960, and in that time there have been an inordinate number of accidents. Sometimes we’ve lost contact with our probes. Sometimes they just crash into the planet. Sometimes they never even make it out of Earth’s orbit. Scientists sometimes attribute our weird misfortune to the Great Galactic Ghoul—also called the Mars Curse. The Red Planet, it seems, is located in the stellar equivalent of the Bermuda Triangle.

Monster or no, the challenge here is that colonizing Mars isn’t a one-and-done kind of mission. Multiple ships will need to be sent to Mars, each carrying initial colonization supplies and equipment. Then you’ve got ships carrying people. And once we’re on the ground and building New Schiaparelli (or whatever they call it), it’s not like our space invaders can just slash a few Martian forests for timber, or hunt zitidars for food. Everything they eat (but for what is grown in colonial greenhouses) will need to be shipped Planet Express; likewise, every atom of needed gear. As of today, 23 out of 41 Mars missions have ended in failure. It’s not overstating things to say that a Martian colony will need a success rate at least greater than 50 percent. (After that second rocket transporting food or soap crashes in a row, you can imagine that nerves will be thin on the ground.)

The Need for Faster Spacecraft

About those missions. Right now it takes an average of six months to send something to Mars. As we discussed in the last entry, human beings—weak sacks of bones and goo that we are—don’t really thrive in zero gravity, where we suffer a 1 percent loss of bone density per month. If we want colonists capable of strutting around on their wild new real estate venture (as opposed to wobbling on JPL-emblazoned canes), scientists and engineers have to do one of two things: 1. Breed a race of superhumans to colonize Mars (this didn’t work in that most excellent early-'90s cartoon Exosquad, which totally needs to be remade stat, or at least released on Netflix, my God), or 2. Build a faster spacecraft.

Scientists seem to have chosen the latter of the two choices. Using fusion rockets, a round trip could be cut to 30 days. (By way of comparison, the voyage of the Jamestown colonists in 1607 lasted four and a half months.) We’re probably 20 years away from making them happen, but we’re really close—and not in a flying cars kind of way, but in an honest-to-goodness Oculus Rift/Lawnmower Man way.

NASA's Innovative Advanced Concepts Program has been partially funding a joint MSNW-University of Washington project that would use a magnetic field to compress a certain type of plasma into a fusion state. (Remedial physics: Fission = splitting atoms. Fusion = merging atoms.) In short, magnetic fields would crush metal rings around deuterium-tritium plasma, initiating a fusion reaction. The heated, ionized shell would in turn be shot out of rockets, generating thrust and accelerating a craft to somewhere around 200,000 miles per hour.

All that’s left is to actually do it. The UW scientists have tested each of the various stages of their fusion rocket. The next step is to combine them. Impossible? Nah, these days kids are building fusion reactors in their parents’ garages.

Nailing the Landing

For sake of moving along the discussion, let’s say the ghoul hasn’t managed to swat down our ships on the way to Mars. How do you then land something there, anyway? Let’s use the most recent and audacious example. When NASA landed the rover Curiosity on Mars, they released a video called "7 Minutes of Terror" outlining the difficulties. (The video itself was named for the harrowing length of time it takes to set something on red soil.) The Martian atmosphere is extremely thin—100 times less than that of Earth. There’s enough atmosphere to muddy up the physics of a landing, but not enough that it can sustain the landing of something with parachutes alone.

When the Curiosity craft meteored into the Martian atmosphere, it was traveling at 13,000 miles per hour. (The goal: 0 mph and a soft landing.) Once the craft passed through the atmosphere it was still moving at a speedy 1000 mph, at which point a supersonic parachute deployed with 65,000 lbs. of force. But wait—there’s more.

Temperatures on entry reached 1600 degrees, which is like New Orleans in July. A heat shield protected the craft, but, no longer needed, had to be ejected in order for the radar to see the ground. (“So the computer was flying blind at 13,000 miles per hour?” you ask. Yes!) By now—and remember all of this is happening in seven minutes on another planet—the parachute had slowed the craft to 200 mph. Here’s where things get crazy.

Next, the payload was ejected and sent into a freefall until the rockets could activate. Why? To get the rover away from the vestigial parachute. The rockets then brought everything into a slow vertical descent. The interesting problem here is that the 2000-pound Curiosity is a delicate piece of machinery, and the rockets couldn’t just land the thing, as the boosters would kick up dust and debris, damaging sensors. The solution? A sky crane, which is exactly what it sounds like. Twenty meters from the ground, Curiosity was lowered on a 21-foot tether and then gently set on the surface of another planet tens of millions of miles away.

Final problem: What do you do with those rockets? The landing system cut the tether, and the rockets blasted away from the landing site to keep them from destroying the rover. Adam Steltzner, an Entry/Descent/Landing engineer at JPL, said of the successful plan: “It looks crazy… it is the result of reasoned engineering, but it still looks crazy.”

Sky cranes aren’t expected to be part of the normal rotation because of the high chance of failure, and because a lot of the things we send to Mars aren’t as fragile as a rolling science lab, or as heavy. The svelte rovers Spirit and Opportunity used parachutes, retrorockets, and airbags to land, for example. (The Mars 2020 rover will use a sky crane.) But the Curiosity landing is a good example of how crazy brilliant our engineers are, and how fearless you have to be to put something on a planet that is (averaged) 140 million miles away.

In short, it can be done, but man it’s not easy. Now that we’ve traveled to Mars and have boots on the ground, in the next entry we’ll look at how engineers plan to build sustainable colonies—and why it has to be a one-way mission.

See Part I of this series. 


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