In 1948, a German scientist named Wernher von Braun wrote a book called Das Marsprojekt—The Mars Project—that explained exactly how to build and fuel 10 spaceships that would carry the first humans to Mars.
Von Braun’s fellow scientists mostly dismissed the work, but by the late 1960s he was widely recognized as a genius who had masterminded the rocket that got Apollo astronauts to the moon. Science journalist Stephen Petranek’s new book, How We’ll Live on Mars, reports on the latest efforts to realize the outlandish dream that von Braun first articulated.
Petranek thinks that four astronauts will make the 243-day voyage to Mars and touch down on the red planet in the year 2027. By 2050, he sees a permanent self-sustaining colony flourishing on Mars. We spoke about the perils and promises of becoming an interplanetary species.
I couldn’t help noticing how many times words like “projected” and “planned” appear in the book. What would you say to someone who is skeptical that all these projections actually have a scientific basis?
Two things: Until recently NASA did not even want to talk about Mars. Then a few months ago they hired someone to run their Mars mission and said the Orion spacecraft is a Mars rocket. When the federal government shifts its focus that much you know something real is happening. Second, the mission of SpaceX, Elon Musk’s company, says this: The only reason we exist is to send humans to Mars. Musk got laughed at 10 years ago when he said he would build and execute the perfect electric car. People said it wouldn’t happen for 50 years. But Tesla has literally revolutionized the automobile industry in the past decade. SpaceX has already had 18 successful flights. So I think you can take this guy seriously when he says my life is about one thing: getting people to Mars.
What are the most serious challenges to establishing a permanent self-sustaining colony on Mars, and how will they be solved?
Food, water, clothing, and even oxygen are not very significant challenges. We have brilliant, relatively low-tech machines that can reliably make all the oxygen and water we need. The space station has shown that you can put astronauts in space for a long period of time. Ten years ago people thought nobody could survive a year in space in a weightless environment. Now a Russian and an American are going to spend a year at the International Space Station.
The only really significant problem is solar radiation. Earth’s magnetosphere and thick atmosphere deflect solar radiation, but there is nothing comparable on Mars, which has an incredibly thin atmosphere. So there’s much more exposure to radiation. You can defend against solar radiation with water or metal, but cosmic radiation is trickier. Mars has lots of caves and probably lots of lava tubes near the equator. And Martian soil, regolith, is very good for making bricks. Ten feet of Martian soil will probably prevent significant risks from radiation. In the long term, we’ll have to start thinking about terraforming the planet.
How could we terraform Mars to make it habitable?
The most direct way is to erect solar mirrors that are 150 miles long and reflect the sun’s rays on the South and North poles where there’s a lot of frozen carbon dioxide. When that is released the atmosphere becomes thicker and you get a greenhouse effect that will make Mars a much warmer place. Right now summer temperatures at the equator reach 70°F during the day, and drop to -100° at night. If you warm the planet, you’ll get flowing water. Flowing water allows for plants, which produce an incredible amount of oxygen, which makes the atmosphere more breathable.
What about the unintended consequences of terraforming. Couldn’t a lot go wrong?
There’s no question that we will be not always be successful. One frightening scenario is a single plant species that thrives in a high CO2 atmosphere takes over so that there is only one plant growing on Mars. But we often underestimate the rate at which we’re accumulating knowledge. The amount of knowledge gained on Earth since World War II is far more than was created in all the time before World War II. What we know is basically doubling every year or two now. In 50 years, people doing the terraforming experiments on Mars will be far wiser than we are.
Engineering Mars is one approach, but you also discuss genetically engineering ourselves so we can thrive on the red planet. Is that a viable option?
To convert the atmosphere of Mars into something breathable by humans could easily take 1,000 years. But we are getting very good at controlling our own genes. We’re on the cusp of being able to attach a gene to a virus and inject it in all the women in the world to prevent breast cancer. Every woman who has a mutated gene that causes breast cancer would suddenly get a replacement gene. Right now if you breathe more than 5 percent carbon dioxide you pass out. We could change humans so that they can breathe 40 percent carbon dioxide.
During the first 50 years of settlement, what would daily life on Mars be like?
The early colonists are going to have a diet of approximately 80 percent freeze-dried food brought from Earth. We’ll grow lettuce and mushrooms and other fruits and vegetables in a greenhouse environment on Mars, mostly for psychological reasons. People like eating crunchy food and they want things to taste like real food. The sun will never be as intense or warming on Mars as on Earth. It will be like the winter sunlight in Chicago. Mars has 12 hours of daylight and 12 hours of night, but the seasons are twice as long, so each year is a 24-month cycle. People will live underground or in protected environments. Most of us already live indoors. More than half the world lives in cities, and cities are indoor living environments. Look at what passes for a park in New York.
People spend most of their time in an office, or sleeping inside, or eating inside restaurants or visiting with friends in their houses. It won’t be that different on Mars. And people will be able to drive around in vehicles shielded from radiation with an oxygen supply. The spacesuits have already been shrunk down to something that’s like a lightweight exercise suit, a spandex kind of thing. And we have nonintrusive devices for breathing a contained air supply, and light, clear bubble helmets.
Many scientists compare the colonization of Mars to the great migration of Europeans to the Americans. What’s the strength of this analogy?
One hundred and two people came over to America on the Mayflower. Only 20 years later there were 30,000 Europeans in the Americas. It went from a few ships to 700 ships a month within 20 years. The size of colonies on Mars will also grow very quickly.
What about the darker aspects of the analogy, like the settlers who resorted to cannibalism during the cold winters in Jamestown, or the high rates of death from violence and disease?
People died in Jamestown and Plymouth because they lacked food, health care, and protection from the natural environment. We would bring all those things with us to Mars. We’re constantly condensing the size of X-ray machines and other medical equipment. It’s also very hard to say what challenges will encounter up there. The history of migration is one of extraordinary hardship.
How many people will be living on Mars in 10, 20, and 50 years?
Elon Musk is probably the best person to estimate that. In 2025 or 2027, he envisions two rocket ships carrying the first humans to land on Mars. There will be four to ten people on each rocket ship. By 2030, the Mars colonizer rockets are slated for completion. These are huge spaceships designed to carry 80 to 100 people, which is possible if he’s building reusable rockets as planned. So as a conservative estimate, if you have 50 ships, each carrying 80 people, then by 2032 you have around 4,000 people on Mars. The ships will make the trip every two years, and he wants close to 1,000 of these ships by 2050. That’s 80,000 people per trip from 2050 on. By 2060, you could easily have a population of 1 million.
Musk calculated that a one-way ticket to Mars might cost around half a million dollars. When do you expect we’ll hit that price point?
He’s very specific about this and has clearly worked out the economics. He imagines that by 2033 or 2034 a one-way ticket would be about $400,000. A typical immigrant might be someone in their mid-40s who’s disgusted with their job and wants a different life. So they sell their middle-class house and buy a ticket to Mars. There will be lots of jobs on Mars, and they will likely pay much higher wages than jobs on Earth. Lots of companies and businesses will spring up to serve the population on Mars, but there will also be markets back on Earth. Think of the demand for documentary movie business or reality TV shows filmed on Mars. One big danger here is indentured servitude, where a company picks up the cost of your ticket in exchange for 20 years of work to pay it off.
Do you worry that ambitious plans to colonize Mars will simply allow humans to rationalize destroying the Earth?
About a year ago, Ban Ki-moon, the director of the UN, said we have to fix the Earth’s environmental problems because there is no Plan B. There is a Plan B, and it’s Mars. It’s going to happen whether we like it or not. Now if the existence of a Plan B causes people to be less diligent about saving this planet that would be a terrible tragedy. But is it is a far greater tragedy if humanity disappears altogether. You could wake up tomorrow morning and learn that an asteroid with a 10-mile diameter is going to collide with Earth. There would be absolutely nothing we could do about that. Everyone would die. We have no plans, no rockets ready. And that’s just one scenario; there are so many serious threats to the long-term survival of humans that we need to become an interplanetary species. I’m very worried about people saying we can always go to Mars if we corrupt the Earth, but I’m more worried that humans could disappear from Earth altogether.