Elon Musk has pledged to settle Mars. This book offers a reality check

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The promise of starting life anew on Mars may appear alluring, even feasible, as the climate crisis intensifies and space and rocket technology advances.

But the reality would be dreadful, according to one book that argues that Elon Musk’s intention to settle the red planet within the next 30 years is doomed to failure.

Written by Kelly and Zach Weinersmith, “A City on Mars: Can We Settle Space, Should We Settle Space, and Have We Really Thought This Through?” won the 2024 Royal Society Trivedi Science Book Prize and was published in November 2023.

The husband-and-wife authors investigate what life would actually be like in the unforgiving environment of the red planet and clear up any misconceptions about what it might involve.

Kelly Weinersmith, a biologist and an adjunct assistant professor at Rice University in Houston, and, Zach Weinersmith, a cartoonist, delve into all sorts of questions that humans would face if we became a multiplanetary species. How would we build space farms to feed everyone? What about giving birth to babies and raising kids? Would settling Mars unleash a new space race?

Initially enthusiastic about the prospect of humans living on Mars, the authors said their research turned them into space settlement skeptics. “Leaving a 2 (degree Celsius) warmer Earth for Mars would be like leaving a messy room so you can live in a toxic waste dump,” they wrote in the book’s introduction.

This interview has been edited for length and clarity.

CNN: Why did you want to write this book?

Kelly Weinersmith: We’re geeks. We were pretty excited about space settlement happening. We had written a book called “Soonish: Ten Emerging Technologies That Will Improve and/or Ruin Everything,” and two of the emerging technologies we talked about in that book were cheaper access to space and asteroid mining. Between those two technologies, we thought, we can either now ship up all the equipment we need to keep humans alive in space, or we can use space resources to build space settlements. So even though people have been saying for decades that this is coming soon, we thought maybe now it finally is coming.

CNN: But that’s not what you concluded after researching and writing the book?

KW: The more we got into it — by year two out of the four-year research process, we were like, OK, there’s a lot of stuff we don’t know that we still need to figure out. And if we do this soon, it could be an ethical catastrophe.

CNN: Can humans settle Mars in the near term?

KW: Musk is saying that in the next 30 years, we’re going to have a million people on Mars. No way that you could scale up to a million people on Mars without something catastrophic happening, either in terms of it turns out we can’t have babies up there, and moms and babies are dying or getting cancer.

If you want to do this, it’s got to be the slow work of generations to build up to a point where we could be self-sustaining on Mars.

It’s such a harsh environment requiring complicated equipment to keep you alive, and I just can’t see that happening on Mars in the near term.

CNN: What is achievable then in our current lifetime?

KW: Lots of research, and that’s exciting, I think. I would love to see, for example, a research station on the moon where we have rodent colonies, and we see how they do when they go through a couple generations. Maybe in our lifetime, we’ll see people land on Mars, do some exploration and come home, that could happen, but I don’t think we’re going to have babies on Mars.

CNN: You highlight reproduction as one of the major challenges. Why’s that?

KW: One of the places we started was biology and medical stuff. That was our first eye-opening moment. I think we had assumed the 50 years of research we had gotten from astronauts in the space stations orbiting Earth had told us everything we needed to know about how humans respond in gravity regimes unlike Earth’s, and how humans respond to space radiation.

But it turns out that the astronauts (there) are protected by the magnetosphere (a protective bubble surrounding Earth’s atmosphere), and we do know that being in free fall, which is essentially like experiencing zero gravity, is predictably bad for bones, for muscles. That microgravity explains why vision tends to degrade over time, and being in space could result in cognitive declines long-term.

The longest stay in space has been less than a year and a half, and astronauts predictably experience something like 1% bone loss in their hips every month. Even if that goes down to just 0.1% every month on Mars (where gravity is 38% of Earth’s surface gravity), you could imagine that being really bad, for example, when labor kicks in and you’ve got to hope that your hips are strong enough to handle it. We were just surprised by how many problems we thought we had a handle on. But it turns out that we have very little relevant data for how adults will do, let alone how having babies would work out.

Zach Weinersmith: There needs to be a lot more research in reproduction, simply because it’s a big, open question. It could be completely benign for all we know — we would be surprised by that, but there should be a lot more research on that. Prima facie, the assumption should be that (babies) are going to have a higher-than-normal rate of abnormalities that have to be dealt with without any of the kind of (medical) care we take for granted on Earth.

CNN: Why is the environment on Mars so hostile?

ZW: The fundamental thing is to understand that humans evolved on Earth, and Mars just lacks a lot of the stuff that we have on Earth. It’s about 40% gravity and we know that humans in microgravity have all sorts of major problems, and what happens at 40% we just don’t know.

The soil is laden in perchlorate, which is known to cause hormone disruption. We actually don’t have a lot of data on prolonged exposure to high levels of this stuff, because why would we? But presumably it’s not great for developing humans.

You have an extremely thin atmosphere. Essentially that means you cannot go outside without a pressure suit. The atmosphere is nevertheless powerful enough to whip up worldwide dust storms and also large, localized ones. There is also this stuff called regolith, which has jagged stone and glass, all that is hurling around, which is bad for equipment, bad for humans. Also, if you’re intending to use solar power, you better have a really good backup system, and you’re going to have to spend a huge amount of time maintaining it.

Also, if you’re anywhere near the surface, you’re exposed to high levels of radiation, because the Martian atmosphere is so thin, and because Mars is only very weakly magnetic, it doesn’t have a very powerful magnetosphere like the Earth has.

KW: Mars, on average, is 140 million miles (225 million kilometers) away, which means there is always going to be a communication delay: (at least) three minutes, and sometimes as much as 22 to 24 minutes. So if there is an emergency, you can never make a live call to physicians back on Earth.

CNN: What about space governance?

KW: There are a lot of unknowns there. In 1967, we got the Outer Space Treaty through the United Nations, and that is the main document that governs space. It’s only some 2,000 words long. It’s a very short document, and it specifically was meant to be vague, because the people who wrote it knew that you can’t really predict how the future is going to unfold. Now we’re at the point where things are starting to get cooking in space, but we don’t have clear guidelines for what’s allowed. You’re definitely not allowed to claim sovereignty.

Also, anybody who goes to space is the responsibility of some nation, so Musk would almost certainly be the responsibility of the United States.

Some questions are less clear, like what are you allowed to do with resources in space. You have this lack of clarity about who’s allowed to go where, how long they are allowed to stay there, what they are allowed to do with those resources, you could imagine the space race part two between the United States and China. This time, instead of just going and coming back, which doesn’t prohibit anybody else from doing the same thing, you land and you create a research station in the best part (of Mars or the moon), that means that somebody else can’t use that spot anymore. So we can imagine there being higher stakes this time around, which is a bit concerning, given current geopolitical circumstances between China and the US.

CNN: How would we feed ourselves on Mars?

ZW: Something else that needs a huge amount of research is closed loop ecology. That is, say, how do you have an underground, sealed bubble that is a sort of intensive agricultural area that produces oxygen and other consumables? We don’t really know how to do that.

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