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What We’ll Eat, Drink and Breathe on Mars

As the new movie "The Martian" makes clear, the Red Planet is a perfectly horrible place to live. Though it doesn’t have the hurricane-like dust storms seen in the film (only weak ones), the surface is unprotected from deadly radiation. With an average temperature below -60 degrees Fahrenheit in its midlatitudes, Mars can make Antarctica seem like a good place for a picnic. And you can’t breathe the atmosphere, which is 96% carbon dioxide.


We are likely to have human settlements on Mars sooner than you think. Pictured, Matt Damon in a scene from ‘The Martian.’ PHOTO:20TH CENTURY FOX/EVERETT COLLECTION

Despite all this, we are likely to have human settlements on Mars sooner than you think. Elon Musk’s SpaceX aims to put a dozen or so humans on the planet in 2027. NASA, which recently found signs of flowing water on the planet, says that it will get astronauts there eventually, too. Once the transportation is established, settlements won’t be far behind. So how will people manage to survive in a hostile environment 250 million miles away? 

First, consider food. For the first few decades, most of it will be ferried from Earth, freeze-dried. But we won’t be without fresh vegetables. Although experiments on Earth show that Martian-like soil is a good medium for plants, settlers will likely opt for more controllable methods like hydroponics or airponics—growing plants in the water or air. Mars-grown produce would be mostly for a psychological boost. People like the crunch of fresh veggies.

As for water, if all of it on Mars melted or came to the surface, it would cover the planet 1,000 feet deep. It is underground in reservoirs, frozen in the soil, in glaciers under a layer of dust, as ice at the poles, and even—occasionally—flowing from what may be springs. Nonetheless, it isn’t easy to get at or melt. So early settlers are likely to use something like a WAVAR (Water Vapor Adsorption Reactor), a dehumidifier developed for NASA to extract water from the humid atmosphere of Mars.

On Earth, we are protected from cosmic rays and solar radiation by our dense atmosphere and magnetic fields, both missing on Mars. One way to block radiation is to shelter buildings by heaping soil (called regolith on Mars) around them. NASA has a clever brickmaking device that adds a bit of plastic to regolith and cooks it in a microwave oven, so settlers could build thick brick walls. A simpler scenario would be to find caves. Lava tubes, created by volcanic action, could be especially handy.

Humans are built to withstand 14.7 pounds per square inch of atmosphere piled above them. Mars has very little pressure, so special pressurized clothing is mandatory; without it, our bodies would swell, and our skin and organs would rupture. Studies indicate that we can survive with a minimum of 5 pounds of pressure, which means that Mars gear can be relatively light and comfortable, unlike the clunky deep-space suits that made it look as if you’re going diving in the Marianas Trench.

And, of course, we must breathe. Machines can help. NASA plans to send an experimental device called Moxie to Mars in 2020 for testing. It can process the Mars atmosphere and break oxygen out of it for both rocket fuel and respiration.

Before long, new pilgrims will be aggravated by the hardships of Mars and will insist on trying to make it more like Earth. This terraforming will mostly be about warming up the planet. A lot happens if we just change the temperature at the poles by a few degrees. One strategy is to place giant mirror-like solar sails in orbit to reflect sunlight on the poles. That would add a few degrees quickly, which could start a continuous reaction. Frozen carbon dioxide at the poles would turn to gas, thickening the atmosphere and trapping much more solar energy. Mars would enter a greenhouse-gas cycle. Within decades, liquid water could be flowing in temperate zones around the equator. Water would allow some plants to grow, adding oxygen to the atmosphere. Water vapor would block more radiation.

More radically, we could use modified viruses to alter our own genes. We could create a variant of humans who can breathe more carbon dioxide and are more resistant to radiation. We’ll probably call those people Martians, and they may need special spacesuits and helmets to visit Earth.

All this may seem like a lot, but consider that, in a billion years, our sun will begin to die and expand, consuming Earth and threatening Mars. Other planets in our solar system make Mars look like paradise. At some point, we will need to become a truly space-faring species and find an Earth-like home in a completely different solar system. Mars is practice.



—Mr. Petranek is the former editor in chief of Discover magazine and the author of “How We’ll Live on Mars.”