Intro. [Recording date: October 18, 2023.]
Russ Roberts: Today is October 18, 2023, and my guest is Zach Weinersmith. This is Zach's third appearance on EconTalk. He was last year in March of 2023, talking about his book, Bea Wolf.
Our topic for today is his latest book, co-authored with his wife, Kelly, A City on Mars: Can We Settle Space, Should We Settle Space, and Have We Really Thought This Through? Zach, welcome back to EconTalk.
Zach Weinersmith: I'm excited to be here.
Russ Roberts: It's a crazy book. It is at times wildly funny; but I learned many things that I knew nothing about, covering a wide array of topics. I think, like most people, I just sort of assume that sooner or then[?] later, and probably sooner, we're going to populate space in some fashion; and your book brought me up short. It certainly prepared me to think about it in a much richer way.
So, why don't we start off with how you got started on the book? What was your goal? What were you and Kelly trying to do, and how did your perception of space settlement change as you did the research and the writing?
Zach Weinersmith: Yeah. For our last book--we did a book that was on emerging technologies--we had two chapters that were pertinent to space, and one was on asteroid mining and one was on cheap access to space. Asteroid mining, we were, I think, appropriately skeptical and have grown more skeptical of, but cheap access to space actually happened basically due to SpaceX and other factors, but the short version is SpaceX.
So, we thought, wouldn't it be cool to write a book about the things people seem to be ignoring when we talk to them, which is what are the rules going to be for this coming space expansion? Because we had this experience where we talked to asteroid-mining people and be like, 'What's going to happen if someone mines a bunch of iron out of an asteroid and wants to throw it at Earth?' And, to add a little flavor to that, imagine it's Vladimir Putin doing it. What are the rules going to be for flinging a giant hunk of metal at Earth?
And generally speaking, people didn't have a good answer. I have opinions on why they didn't have an answer now, but it was surprising.
So, we thought we'd write a book about how this sort of thing ought to happen. It just turned out the optimistic picture we'd been led to was basically wrong. So, about two years into the research, the book went from: Here's how we're going to do this awesome thing, to: Here's why we have to and ought to slow down.
Russ Roberts: Let's start with some of the myths, as you do in the book, that people have about this. Somehow if we travel into space, we're going to be able to start the world anew--a Garden of Eden, free of the constraints of human failure, either international conflict and so on, a sort of utopian vision, which I think is very common and very appealing. What's wrong with that?
Zach Weinersmith: Well, I mean I suppose that the obvious thing wrong with it is just that humans remain social apes, and there's no reason to suppose there will be a discontinuity with history. I remember very early on--my older brother is a Constitutional scholar--and a while back--we ended up not using it--but I said something like, 'Well, how would you write the Constitution for Mars if you were going to do that?' First question--he's a tweedy conservative--he said, 'Well, who's going?' Which, nerds tend to think, well, we just need the right people and the right set of rules and nothing bad will happen.
He was, like, 'No, they're not going to be discontinuous with the culture. They come with a culture. There's no way to undo it.' And so, you have to, like humans always have done, exist within these constraints.
I would say that the other thing that should give you pause is--so, that particular fantasy tends to be either a more libertarian, in the American sense, or a kind of conservative frontier fantasy; but I have seen it as a leftist fantasy. Like: We'll avoid capitalism when we go to space. So, it should make you pause when space allows every utopia to exist. So, at least some percentage is wrong.
Russ Roberts: Now, you outline legal issues that confront us if we think about populating space, ethical issues, and much of the book is on what we might call the physical constraints--technology and biology of human beings. But, at the beginning, you talk about the fact that the literature on these questions of how we might move forward tend to be written by people who are biased.
If you're ignorant about space settlement and want to become educated, many of the articles you'll read, many of the documentaries you'll watch, and pretty much every single book on the topic have been created by an advocate for space settlement. Now look: there's nothing wrong with advocacy. The space settlement geeks that we've met are smart, thoughtful people, most of them anyway. But, reading about space settlement today is kind of like reading about what quantity of beer is safe to drink in a world where all the relevant books are written by breweries.
That's fascinating, in and of itself. It's a great paragraph. First of all, why is that the case? Of course, some advocates are right. But, you're going to suggest, through the course of this book, that they've missed some of the challenges.
Zach Weinersmith: Yeah. So, as to why it's the case that most of the books are by advocates, it's very hard to know what people's motivations are. I will say, as a popular science writer, there is a kind of ecological aspect to this, which is: if you're writing for nerds, which is what most popular scientists do, or at least for curious people or however you want to say it, usually the book is about how you're going to get the thing.
So, if I'm writing a book about AI [artificial intelligence], usually the book is not why you're not going to get AI. I don't know if it's a bias towards optimistic takes. I actually had this experience of, partway through the process, of talking to a friend who is a fairly well-known pop science author, and he actually gasped when I told him we weren't going to say, 'You're going to get space settlement soon,' because he's, like, 'You can't do that. You can't go to the nerds and say: here's the thing you're not going to have.' So, I think there is just a basic bias.
I think it's also just space is a persistent fantasy. If you want to trace it, modern-style space fantasies at least go back to the 19th century. There are classical precursors, depending on what you want to count. But, it is this long-term adventure fantasy, and it is, like, the last remaining one that people can consider plausible if they don't know enough about it.
And then, I would say it's also--and this is what we go through a lot in the book--it is intertwined with many fantasies that defy political categorization. They're like Westward Ho!-sort of fantasies. They're all over the place, especially among Americans. But, they're also, like, 'We'll save the environment because all the bad stuff can just be in space.'
Like I said, there is a small number of people who, my impression is, they have a kind of leftist fantasy. There's also, especially in the literature from the 1970s, there's a lot of fantasies of space that are sort of tied to the counterculture. That is to say: we can start 800 new governments and try everything out and learn a better way to exist than we have now. And so, I think it's not surprising that, in that milieu, a lot of people writing are in favor of making it happen.
The last thing I would say is a lot of people--separate from the utopian part--are we would maybe now say, like, Silicon Valley types, but they used to call themselves Prometheans. Right? Like: This is the awesome thing we're going to bring to humanity, and you people don't realize how great it's going to be. So, you're going to suffer through lack of abundance. And so there's this fantasy of bringing the fire to humanity.
So, with all that in mind, it's not surprising that a lot of the writers are optimists.
Russ Roberts: And of course, in the course of writing the book, you inevitably had to talk to people who weren't advocates--scientists and others--who remind us of the challenges that are involved. And, you know--I'm not a stupid person. I'm aware there's challenges to space. But I guess, I think part of the reason that the average person might be a little overly optimistic is that, 'Well, we got to the moon. So, we'll just go and stay there, and we'll build stuff.'
So, let's start with the moon, and we'll go on to Mars. They're the two likely places we might choose. And, I encourage listeners who haven't read your book yet just to think, 'Well, which one would I choose? Well, the moon is closer. Mars is more colorful. It seems to be redder; longer trip.' It's, like: Should I go to London or Mumbai? Well, London is closer, etc. So, you might think about that. But, now, Zach, is it going to be hard to get settlements on the moon? I mean: We've done it.
Zach Weinersmith: Yeah, right, we've done it. Yeah. So, just to give a little context--
Russ Roberts: Or at least I think we've done it. There are skeptics, but--
Zach Weinersmith: Don't even start. Don't--
Russ Roberts: I'm pretty sure we've done it--
Zach Weinersmith: Yeah. So, the thing to know about the Apollo Program: So, there's this dominant narrative among, like, I think, just the general population--I don't think historians or legal people share this--but there's this view that the Moon Program, like, we took one step up the stairwell and then kind of wimped out. And Americans became wimps, and we decided not to go back.
I think the correct view is more like, due to confluence of political factors, a political choice was made to expend an extraordinary amount of money making an obviously non-repeatable mission happen on the moon--that was not even that popular among the public, if you look at surveys at the time.
And so--there was an older proposal by von Braun--and you hate to, like, cite a Nazi, an ex-Nazi--but his proposal was at least more sensible. He wanted to build a giant space station with, like, 80 people; know what we were doing there, then go to the moon in style. I think he would have wanted a dozen people to go at once with a lot of scientists.
And instead, we made this set-up where you can send a teeny tiny craft--a lander with two test pilots. Like, two he-men can just barely make it there. And so, there is no infrastructure. There is no attempt to easily drive down the cost.
So, the moon is very hard. And, a lot of the ways in which it is hard were not tested out on Apollo--because I think if you sum up all the time spent on the surface of the moon by humans, it's about 10 days total. Armstrong and Aldrin walked around for under three hours on the moon. And so, a lot of the stuff shows up over time.
And so, for example, there are two days' night--fortnightly days, fortnightly nights--meaning it's, like, 14 Earth-days of day, 14 Earth-days of night. So, it gets extraordinarily cold and extraordinarily hot.
Which is: obviously you're going to have to be protected from as a human. It's terrible on equipment. We talked to one guy who said it's hard to even come up with a lubricant that can deal with that for rovers. You're exposed completely to radiation. So, on Earth, even the International Space Station is protected by Earth's magnetosphere, which blocks or reroutes ionizing radiation. You don't have that on the moon.
The moon obviously has no atmosphere, which means you die very quickly if there's a full pressure loss.
One thing for me is really compelling. So, if you see a picture of the moon--and I think this is where a lot of misconception comes from. If you see a picture, it looks okay. But, one thing you can't see, for example, is that dust is not like dust anywhere on Earth. Right? So, there's never been water flowing on the moon. There's never been wind. Right? It's just a bare surface that's been smashed by objects from space and radiation for eons. And the result of that is that if you put it under a microscope, it looks like little tiny knives made of stone and glass. It's called regolith. There are reasons to believe it's dangerous. Humans haven't had much interaction with it.
But at least on, I think, on Apollo 17 I want to say Schmitt said he got an allergic-style reaction to it.
And, there's speculation that you could get something like what's called stone grinder's disease, which just is accumulated lung scarification over time. So, it's bad.
The one other thing I would say--because, for me, this was a big turning point in my perspective--from the perspective of a settlement as opposed to sending a couple guys to run around and plant the flag, the moon is very poor in carbon. Right?
So, for people who don't remember high school physics and chemistry, carbon is about 20% of your body. More so for most plants. And you can't just get it: it is made in stars. Right? You can't, like, spin up a carbon machine.
So, the joke--I can't remember if we put this in the book--but the joke is, like: you'll see articles that say, 'You can grow plants in moon soil.' And then, if you look at the fine print, you can grow plants in moon soil if you add nutrients and sunlight and an atmosphere. Which is true of anything that is not plant poison. In fact, the soil is just existing as a substrate; and there's even evidence that it's a bad substrate: that it stresses the plants.
So, essentially, what you need to do to survive on the moon is to create a bubble that does not interact with the moon except to take in resources and somehow convert them to useful stuff. Which is extraordinarily difficult.
And then the last thing I want to say, actually, it's nice: We really did try to take a kind of economist's perspective, because you will often hear, let's say, more physics-y types say, 'Well, we can have titanium on the moon.' Why? 'Because there's any amount of titanium on the moon.' And, we never talk about Earth this way. Ever. Right? I never say, 'I can have a house because my backyard has silicon for windows and aluminum for metal. And wood is, of course, made of carbon and hydrogen. So, I'm all good.'
And, yet, somehow this is okay to talk about the moon like this, as if no trade-off exists. All of which is to say it's extraordinarily difficult.
Russ Roberts: The trade-off being that the fact that it's, quote, "there." You have to extract it in some way that's vaguely productive, cost-effective, and worth doing.
Russ Roberts: So, yeah, that's very demoralizing. The soil is not pleasant. The radiation is not pleasant. There's no oxygen. You can't breathe. By the way, I don't remember--I'm sure you talked about it because you cover pretty much everything, at least it felt that way, in a good way, to let listeners know--how do I breathe in my, say, moon bubble? As you point out in a number of places, because the atmosphere itself is so inhospitable to humans, you have to create either a bubble or an underground thing. How do I get oxygen into it? and then into me?
Zach Weinersmith: Yeah, yeah. So, there are a couple of ways. Right now, the way the ISS [International Space Station] works is essentially you have these oxygen tablets--
Russ Roberts: That's the International Space Station--
Zach Weinersmith: The International Space Station, yeah, yeah, yeah. And this is the way all space stations have worked: You have a scrubber for carbon dioxide, because if carbon dioxide gets above something like 1%, you start getting these really bad headaches, and you can get carbon narcosis. It's bad. So, you have a scrubber.
And then, you have a tablet that just releases oxygen, which at least in one case was a source of a fire. So, it can be a little dangerous.
Ideally, if you want something that can be a little more permanent--you want to live off the land to the extent you can. So, the question is: Can you get oxygen on the moon? And, the answer is yes, but not easily. The best source of oxygen on the moon are what are called the Craters of Eternal Darkness, which are these craters near the poles, which have such an angle to the sun that there are parts in the rim that never see sunlight. Right?
Remember, the moon has no atmosphere. So, if you spat on the moon, the spit would just bubble off and be lost forever. All that water would be gone. But, if you--in these craters, it's locked in the form of ice, so it can't get away.
And so the idea is: Well, could you go get that? And the answer is: With extraordinary difficulty, you could. Right? So, it's incredibly cold. It's a lot more like melting a rock than melting ice. I mean you can do it. You can heat it up and melt it. But it's in these extremely cold areas.
It's also got a lot of nasty volatiles with it. We list some of them: but, like, ammonia, stuff you would have to clean out.
The big point, though, and this is the thing I really want to emphasize: There is not that much water. You will regularly see articles in reputable publications that talk about water as if it's like an on-off switch: They have water or they don't on the moon.
There is water. It's about as much as a small lake, and it will never replenish. Right? If you use it up to launch rockets by making propellant out of it, if you lose some to the atmosphere--as you will if you put it into a gas form to breathe it--it's going to be gone. And there's not that much.
So, these ideas that we're going to have a permanent gas station on the moon with rocket propellant, forget about it. It will not work.
But, yeah, so that's how you're going to get yourself oxygen.
I think, you know, so the nice thing about Mars--which we'll get to--is there just is oxygen.
You could on the moon, by the way, also bake it out of stone. Like, there's lots of stone with oxygen in it. But, the amount of stone you would have to cook, it's on the order of tons just to get your supply per day. So, water is extremely scarce.
Russ Roberts: Before we go on, I want to ask a general question that I wonder if it crossed your mind. I suspect it did. That last remark of yours is--there are many passages in the book like that: 'You might think this is going to work, but it's not because--,' and you have many reasons. It's not just, like, it's expensive. It's more like: It's a tiny amount; it'll never replenish; and so on. Did you worry--and do you worry--that many, many technological breakthroughs were said to be impossible throughout history? Human beings will never fly. Human beings will never do this. Human beings will never do that. And of course, many of those things we've done that skeptics and scientists of the day thought were impossible. How much time did you spend wondering if there were technological breakthroughs that might make some of these things phenomenally easier?
Zach Weinersmith: Yeah. It's something I think about a lot. And so, when you talk to space people, the classic example they'll bring up is aviation. I actually find in older books, they often bring up steam. You get books from the 1940s or 1950s talking about the future of space: people thought you'd never get beyond the age of sail, and then here's the steamboat. Right? So there are, of course, lots of examples.
Aviation is a great example because it's so fast, possibly because of warfare. I don't know the historiography, but if you've ever seen the Wright Flyer, it's amazing that it flew at all. And then, a generation later, you have stuff that's recognizably somewhat modern. And then, a generation after that, you have basically today's stuff. So, you have the time from the Wright Flyer to a supersonic jet is less than a single lifetime, which is insane. I'm sorry, it's much lower than that.
Anyway, so that's brought up a lot. Of course, you don't want to fall afoul of it, but you have to be a little careful with this kind of reasoning because, for me, it's very indicative that the aviation comparison in space books about the incoming imminent future of awesome space stuff, that comparison was being made in the 1950s. So, in that case, you would have been right if you said it's certainly not coming soon. Right?
I would say--if you wanted, I could list technologies that, to my mind, would really change a lot of what I'm saying. I have friends working at Commonwealth Fusion Systems in Massachusetts. They're trying to make a fusion reactor. Absolutely, if you could just fire up a fusion reactor, it would change a lot. It would not change the equation for water on the moon, but it might change the math for delivering water from Earth to the moon.
But to me, you can--of course, you can never predict the future. I would actually say a really good example of that is AI now. I mean none of us know the future but--I don't know if we'll get to this--but one question very briefly that we tried to analyze was what do people think is the minimum number of humans for self-sustaining, a settlement that could survive the loss of Earth? The lowest number we found, which I think was pretty fanciful, was 100,000 people.
And that was based on the idea that there will be extraordinary advances in robotics, so that you would actually have the equivalent of something like 10 million people or more. I sort of laughed at that when I first saw it in 2018, and I think now maybe that kind of idea is more serious. Robots can now use a little bit of common sense, and who knows?
But, I guess what I want to say is: One, of course I can never predict that, and the people who said we'll never have an anti-gravity drive, they were right. So, there have been plenty of people who just said stuff and they were right.
But also, the extent to which a particular scenario requires extraordinary developments tells you something about its nature in that if it requires 100 butlers per person to go to Mars, then it is not a, like, hind-line[?] libertarian frontier fantasy. It's a Star Trek fantasy. It's a future, ultra-advanced humans making an aesthetic choice to do something really cool like going to Mars.
Russ Roberts: To be clear, you don't say in the book that humans will never or should never populate places outside the Earth. You just say many of the semi-optimistic claims that in the next 10, 20 years we'll do x are not likely--
Zach Weinersmith: Unlikely--
Russ Roberts: and, more than that, maybe not even a good idea.
Russ Roberts: Let's go to Mars, the Red Planet. We've been there--not with human beings, but with robots, with various pieces of technology. Any better there?
Zach Weinersmith: Much better, I would say. We argue Mars, if you are going to try to create a permanent settlement, it's basically Mars or nothing, or Mars or something extraordinarily harder.
The biggest advantage of Mars, in general, is that Mars has all the stuff you need in a chemical sense. So, whereas the moon is carbon-poor, Mars not only has carbon, its atmosphere is carbon dioxide. It's a very, very thin atmosphere. You can't run around naked outside. You will die. But, carbon dioxide, if people remember, is CO2. That carbon is quite valuable because you can react it with hydrogen to make methane, which is a good flammable gas for propellants, and oxygen is a popular chemical with humans.
Mars also has much more access to water. There's plentiful water at the poles. Most places on the surface, we now think you can dig down far enough and find water.
So, I would say on the moon, again, outside of very exotic technology, there is no hope of a permanent settlement that could last through the loss of contact with Earth. Whereas on Mars, it's at least possible.
That said, Mars has most of the problems of the moon, but to a lesser degree. Mars has Earth-like days in terms of--it's a little over 24 hours so that you get a nice regular light/dark cycle.
There is regolith that is jagged. And actually, it's also a little worse because it has perchlorates, which are a hormone disruptor--which will come up again if we talk about the risks to human development in space, in the sense of adolescents being exposed to these chemicals.
There's also massive dust storms. There's this great story that--I forget, maybe it was Mariner 8 or 9, one of the first Mars probes sent by the United States to go see Mars. At some point in the journey, Mars, which has a surface, suddenly looks like a flat disc. And it turns out what happened is there was a global dust storm, which is not an irregular occurrence. So, you try to imagine what that looks like from the surface, especially if you're using solar panels as your energy source--kind of terrifying.
The other big problem is, and again without major new technology, it's six months inbound and six months outbound; and there's a period where it's not just that it's six months home: it's that you can't go back because Earth is racing ahead of Mars around the sun. A Mars year is over 600 days. So, at some point, Earth is literally on the other side of the sun. So, even if you have your fusion drive and whatever Star Trekky technology, you cannot go home.
So, it's much more challenging. It's the better place ultimately, but it's going to be far more challenging given the distance and all the problems.
Russ Roberts: You mentioned regolith, which is these jagged, knife-like dust particles--very pleasant. I'm just going to take a walk with the dog. I don't think so.
And, that Mars has hormone-disrupting or -altering things in its dust, aren't I going to not interact with that at all? Don't I have to be either in a suit or inside a bubble that insulates me from the surface of the planet because I can't breathe?
Zach Weinersmith: I would say basically, yes. I mean, so yeah, yeah. So, the classic picture of a space base involves a giant Buckminster Fuller style geodesic dome, which is almost certainly a bad idea. I mean the obvious upside would be that you get that sunlight for your plants. But you try to think about--so, on Biosphere 2--I don't know if we're going to talk about it--but it was this experiment where they built a huge enclosed greenhouse and actually pressure differences inside and outside the glass were a serious problem, and that was on Earth. Right? So, you imagine, like, a greenhouse. The inside heats up, so the pressure increases. And there's a concern that you're going to break the glass.
On Mars, the internal pressure should be at least something like what we have on Earth--Earth pressure. Outside is basically zero or almost zero. So, that greenhouse glass is going to have to be really strongly protected. Right?
So they have windows on the International Space Station, but they're really thick and they have these really strong, I guess you'd say window panes. I don't know what the technical term is, but the thing that holds them in place.
So you're not going to have that. You're probably going to live underground because there you're shielded from radiation and temperature swings and other stuff.
But, so, ideally, if you want to be permanent, you do need to interact with the environment in the sense that what you would like to do is incorporate materials from it. So, if you want to be permanent--be able to survive the death of Earth or the loss of contact with Earth--you've got to turn that bad soil into soil you could actually use like part of a little ecology.
Unfortunately, we just don't know a lot about this. Because--again, regularly you will see an article that's, like, 'We can grow plants in Mars soil.' They will say the plant was grown in Mars-simulant soil. What they don't tell you is Mars-simulant soil is a product that physically simulates Mars soil, but it's not actually chemically much like Mars soil.
So, it's still an open question what you need to do and can do on Mars. I worry it won't be answered until there's very advanced robots or actual humans there.
Russ Roberts: You spend an entertainingly large amount of time chronicling some of the high jinks of people living in close quarters in various space vehicles--space stations, space capsules from the early days. Although it appears no one has actually killed another person, you do talk about some of the psychological challenges of space travel, which I'll let you elaborate on it as much as you'd like.
But, my first thought when you mention living underground in Mars is that: So, what's the appeal of this? Am I going to get Netflix and have decent Internet so I'll be able to watch YouTube in my basement? I mean, really, it's not--when I think about the moon, there is something lovely about the little blue marble that we'd watch from a distance. Actually, it would be quite depressing to see Earth at that distance over more than two or three days. It would be horrifying. Worse, probably, from Mars. The nighttime sky might be lovely. But, being underground, I don't get it.
Why would anyone want to romanticize the idea that you could go live in the basement of a house in a toxic area where you're not allowed to go outside ever? Where's the romance? Where's the frontier? Where's the Westward Ho!, the mesas, the canyons, the Rockies? It's awful.
Zach Weinersmith: So, with the caveat that I totally agree and I would not be signing up, you have to recognize that there is a subset of humanity that has trouble even understanding your question.
So, I think of the explorer, Byrd--I'm blanking on his first name [Richard--Econlib Ed.]. He wrote a book that was famous in the early 20th century called Alone, which was about going close to, I think it was close to the South Pole. He basically lived down a hole, and got carbon narcosis, almost died.
But, that was his plan. It was to live down a hole. He was a married man who was going to live down a hole to get these barometric readings that, saddest of all, I think 10 years later could have just been done with a radio thing. But for him, that was like, 'Of course, I want to live down that hole. I'm doing this great thing for humanity.'
I think of, like, Fridtjof Nansen, the great northern polar explorer--spent two and a half years on a boat on the ice. I guess he could hunt and had friends and stuff. But, there is a subset of humanity that would be up for this.
But, I do think the general point there that people have--I think, for example, there's this--it's a stupid example, but I think it's enlightening--which is there's this animated GIF [Graphic Interchange Format] file that gets passed around of a guy walking in a suit on the moon and looking at the Earth on the horizon. That's true that you could do that, but later you're going to have to do the dishes and clean up the toilet and scrub the mold. This is a lot of what happens on the International Space Station.
So people, I think, tend to put the locus of their fantasies on that beautiful moment of Earth-rise and forget that they're in a real settlement. You're there for 60 years. Right? And most of what you do is quotidian. And that's true on the ISS [International Space Station], too. People on the space station get bored.
So, I do think that there is a certain appeal for the exploration phase. But eventually--you should, like: If you succeed, it should be exactly like Earth except you're somewhere else. Which is kind of boring. So, yeah, I don't get it.
Russ Roberts: I have to say, though, one of the things that I got from your book was what recent EconTalk guest, Adam Mastroianni, might call a vibe, which was a deep appreciation for the world we live in. That was not the purpose of the book. You mention it a couple times, I think in passing. But, the stark nature of life on Mars or the moon, which is captured in many movies, of course, for the people who sometimes return to Earth in those films--that return is so delicious not just because you're alive, but because it's so colorful and vivid. It does make you appreciate Earth more.
One other movie I'll mention--I'm not going to name it because I mercifully have forgotten the name of it. It's Chris Pratt and Jennifer Lawrence. It's one of the worst movies ever made. But in one scene--have you seen that movie?
Zach Weinersmith: No, I haven't seen it.
Russ Roberts: You've been spared. There's a plot twist in it that's so unattractive that you can't help but despise the main character, despite attempts by the script writers to redeem him. But, at the end of that movie, without giving away too many aspects of the plot, there's a world that has been created either--I think, within the spaceship--and it's marvelous. It's extraordinary. It's like Earth imagined by a AI image generator. It's a cross between Tolkien, Escher, and I don't know, van Gogh. It's really magnificent.
And, the other challenge, of course, is that doing anything productive besides breathing--creating that underground world that you're talking about--is not a straightforward thing. And you talk quite a bit and quite thoughtfully about how making things very far from Earth is not easy.
Zach Weinersmith: No. I mean, we could jump--so, that ecology question is a very deep one. I would say, just as a nerd, it's, like, disappointing there's not more work on it, because the idea of creating a sealed ecology that works is just absolutely fascinating as a problem.
So, I'll give you a really good example. If you go back to the 1970s, there was a kind of vogue in the space community for these giant rotating space stations. So, the image you're describing, there were a lot. People have probably seen these, a painting of what looks kind of like a perfect, slightly 1970s-bent, suburban dinner party next to a beautiful river, except it was down the rim of a toroid. If you've seen an image like that, it's almost certainly from the 1970s. It was probably commissioned by a guy named Gerard K. O'Neill, who, by the way, knew it was bogus. It couldn't possibly be like that. But, set that aside.
One of the promises he and other people would make is: Look, you can completely select your ecology in here. Right? So, if we don't like something, we just leave it out.
And, in Biosphere 2, they tried to do that; and they failed because it's really hard. They had cockroaches that ate a bunch of stuff. They had, I think, some kind of mildew that killed a lot of crops, killed all their beans, except the ones that were meant for animals that they ended up having to eat.
Our favorite was they brought in what are called bark scorpions, which are the only lethal scorpion in the United States. So, so much freedom.
So, there is a kind of hubris aspect to this sort of stuff. There are these ideas that are like: Well, if we could do it, wouldn't it be great? The problem is it's just really hard to control ecology. I give lots of examples from that story.
One of my favorite stories, just an example of how silly this can go--I can't remember if we put this in the book. But, they were actually poisoning themselves for a while because they were eating raw taro. And they had to actually call a guy who knew a guy in Puerto Rico--because this is pre-Internet. In Puerto Rico, they actually eat this stuff, so they were able to get recipes. That's how basic it can be.
Russ Roberts: Let's talk about some of the other problems, because they're really interesting, even if they're discouraging. I found this part fascinating, and it's just absurd. This is a quote from the book:
The environment of space also reportedly makes food taste less flavorful. This may be a result of the fluid shift creating sinus pressure similar to a cold, or it may be that in zero gravity, smells don't waft up into your nose, or it may be something about the artificial atmosphere. Whatever the reason, astronauts often lust for piquant condiments such as salt, pepper, Tabasco, and mayonnaise and, of course, taco sauce.
Salty, zesty taco sauce is so beloved by astronauts that for about a week in 1991, it became the first form of currency specific to outer space. On shuttle flights, STS-40, taco sauce went on everything. Pilot Sid Gutierrez recalled, 'Although I didn't do it myself, I observed crew mates putting taco sauce on Rice Krispies in the morning.' Around Day Eight, STS-40's commander, Brian O'Connor, realized the crew's rate of taco sauce consumption would soon outstrip the taco sauce supply.
According to Gutierrez, the commander secured all the remaining taco sauce, divided it equally among the crew members. Thereafter, taco sauce became the medium of exchange. For example, if it was your turn to clean the latrine, you could pay someone a taco sauce or two to do it for you.
End of quote.
Brought a little economics into the conversation. The currency of exchange was taco sauce. This is insane.
Zach Weinersmith: I love that story. Something we tried really hard to do--there are a lot of space stories that have been told many times, and we didn't want to tell them--we wanted to find new stuff. So, a lot of it was reading oral history. I remember that book is in an oral history of the space shuttle where they just interviewed tons of astronauts and they binned the interviews, helpfully, into 'This is stuff that was said about food'; 'This is stuff that was said about wonder.'
And, I just love that story because it captures the quotidianness of space so thoroughly. But also it tells you about, like, it is true that apparently space food doesn't taste as good. Something happens, and we don't understand it super well. But, yeah. I've told that story to many economists and they're always just delighted by it, by the idea that humans just spontaneously created currency.
By the way, I don't know how long it was, but it would have been under two weeks, that trip. Humans very quickly created economies.
Russ Roberts: Well, not just very quickly created a currency, taco sauce became--that is what is actually almost as interesting to me is that taco sauce became the currency the way tobacco or cigarettes were in prisoner-of-war camps that we've talked about on this program. We don't get to reference that classic Mike Munger episode often enough. So, we'll put a link to that in the archives.
Russ Roberts: The loss of tasty food is the least of it. Let's talk about issues related to radiation and bone mass and muscles, which I think most people, it doesn't cross their minds.
Zach Weinersmith: Yeah, so--
Russ Roberts: Never crossed mine--
Zach Weinersmith: The first thing I would like to note is that I will shortly rattle off a bunch of bad stuff space does to you. The longest an individual has ever been consecutively in space is 437 days--about a year and a third. Right? So, all this bad stuff is in the context of a very short period of time.
So, space reliably degrades muscle density, especially in areas of your body you just don't use in space, like your hips don't really come up in space. In one paper, they found 1.5% density loss per month. Per month. Insane. You can get renal stones because so much calcium is coming out of your system. This is what your body does: when you don't use stuff, it goes away. It's very similar to people who are stuck in bed for a long period of time. And that is with a huge amount of exercise, strength training, that sort of stuff.
Similar effects happen to muscles. People lose a lot of strength. There's a story that Jerry Linenger, who was an astronaut who went aboard Mir, the big Soviet space station--later Russian space station--he was very proud that after, I think something like four and a half months aboard, he was able to walk when he came out. Just walk by himself. Right? So, most people don't. The Soviet tradition was actually people would be carried out like the bride over the vestibule out of the capsule. Space degrades muscles, degrades bones.
There's more subtle effects. When you go to space, there's a fluid shift upward, right? Your body's plumbing is used to fighting gravity. When you go up into space, fluid just shifts up. People get what's called puffy face. If you see astronauts shortly after they've gone into space, they often kind of look baby-faced. And it's because this fluid has shifted up.
And they often have to urinate a lot because of that because it throws off what their body thinks is going on with their fluids. And so typically, when astronauts are about to land, they drink something like consommé or, like, thick Gatorade to restore this fluid balance.
That fluid shift, we think, also degrades vision. So, astronauts, especially if they're my age or older, like in their 40s, they send them up with what is--the acronym is SAG, S-A-G. It's something like Space Adjustment Goggles or something. But, basically, reliably your vision gets worse. We think that's because something with the fluid shift is changing how the nerves to your eyes get fed or something.
But, it's a little ominous because there is equivocal evidence possibly of cognitive effects. And so, it could be that that vision effect is just more obvious than cognitive effects. We don't know, but it's a little creepy.
And then, of course, there's radiation. Basically, the deal on radiation is we don't understand well what it does, but the assumption is that it's bad; and in particular, that it's bad for an increased cancer risk. But, the connection is very poorly understood because it's very hard to study radiation in humans. And, even if you have data on radiation on humans, it doesn't necessarily apply in space because it's a different type of radiation.
Russ Roberts: Now, the book is about space settlement, not space travel per se. We could almost certainly put a human being on Mars sooner than later if we worked at it. But, the question is, could Mars be an escape hatch or alternative place for human beings if either a nuclear war of unimaginable size happened here, climate change got to the point where it was no longer friendly to human life? And, could we survive by going to, say, Mars?
You earlier mentioned we'd need 100,000 people. Part of the reason is that you want to reduce inbreeding; and you want to be able to have subsequent generations. And, in my mind, okay, maybe you send among your astronauts who head to Mars, there would be a mix of men and women. They would procreate either before, during, or after. And your population would start to grow. Forgetting the 100,000 minimum, if that actually is accurate--you actually think it's larger--what's the challenge of pregnancy and growing up outside the friendly Earth that we grew up on?
Zach Weinersmith: Yeah. The short version is we know almost nothing, and what we do know is scary. And so, the deal is, so one thing we talk about, which I don't think we're going to get into here, but is that human space faring is expensive. It is usually done for political reasons. Nations do it to kind of demonstrate prestige. The scientific rewards are kind of questionable. And so, the result of that is there's not a systemic program aboard these space stations to learn how animal reproduction works.
So, you can imagine a world where NASA [National Aeronautics and Space Administration] was, like, the Space Settlement Agency; and someone would say, 'We need a space station just to study reproduction.' That has not happened. It's very grab-baggy.
So, when we tried to collect every experiment involving, like, gametes or reproduction or anything even vaguely related to reproduction, it's just a bunch of random stuff. It's like one group in the 1980s sent up quail eggs; and a group in the 1990s sent up a rat to see how it felt and measured some hormones.
So, it's extremely unsystematic. And so, the result of that is you basically can't conclude anything for sure.
And, just to be clear: no one has ever tried to conceive in space that we know of. Certainly, if they did, there's no science done on it.
So, that's the level of not knowing we have. Then, why it's scary: Well, of course, there's the radiation. As I said, microgravity reliably reduces bone density.
Russ Roberts: Microgravity being whatever level of gravity there is, say, on the trip.
Zach Weinersmith: Yeah, I'm sorry. Effectively, no gravity. The term is 'microgravity,' but you can just say zero gravity. Right? On the trip, there would be zero gravity. In the International Space Station, there is zero gravity.
Logically, we're going to be on the moon or Mars, so there will be some gravity. We have no idea what the long-term effect on bones. So, there's some [?] in which 40% gravity on Mars is enough to fix everything, or maybe 40% gravity and you wear, like, a weighted vest or something. Maybe it'll be fine, right? I do like the point--yeah[?]--so we're worried.
It's worth noting that, like, in the 1950s, it was an open question whether humans could eat in space. There was a concern that you might--frankly, I still find it surprising people can eat with no gravity. And so it's possible that bone density stuff on the moon or Mars will be fine. But, you try to imagine having an infant without the normal pull of gravity--it's just zany.
And the other thing is, usually when we talk about this question, usually people will say something like, 'Can you have babies in space?' There's an anthropologist named Cameron Smith who wrote a book called Space Anthropology. We don't agree with everything he says, but he made a really good point, which is it won't do to just talk about babies because the babies have to grow up to have babies.
So, if you successfully have a kid--which I'm willing to buy you could do in space with all the constraints--they have to develop normally. Right? So, you imagine there are gametes exposed to radiation and whatever mysterious effects of microgravity there are beyond that one-and-a-third-year threshold that we don't know about, or whatever else. You try to imagine that telescoping generations. There's no way to know.
The important thing to us is it's not just that we don't know. It's, like, it's obviously unethical to just send 1,000 humans and assume they're going to reproduce on Mars. I am enough of a libertarian to think if a human adult signs a waiver, they can throw their life away however they like. But, if they're going to introduce children into it who did not volunteer to grow up in this incredibly hostile, dangerous environment, that seems to me pretty clearly like experimenting on children for no good reason.
Yeah. So, sorry. It ended up kind of dark. But, yeah, we don't know much and what we know is frightening.
Russ Roberts: Well, I think the most exciting thing I think we've heard so far is that rucking--that is the use of a backpack or weighted vest to help musculature and bones stay strong--will be very popular on Mars. That will please, I think, some recent EconTalk guests and many of our listeners.
Russ Roberts: Let's turn to the question of where you started in this book, which we've yet to mention. You make a list of reasons that people might want to go to outer space and populate faraway places. The two you mentioned are the Cathedral and the Hot Tub. So, tell us what those are, and tell us how you think your expanded knowledge of the realities affects those motivations.
Zach Weinersmith: Yeah. So in the beginning of the book, we basically just try to say a bunch of this stuff you've heard is wrong. Like, space is probably not going to make us rich or save the environment--very soon anyway--or any of this stuff.
So, we say: What arguments seem plausible to us? And one we call the Cathedral of Survival, the idea being like: Okay, maybe going to settle space won't do anything for us, like sparing us from climate change or whatever. But, it would be a good thing to do, say, in the next few centuries because it would help preserve the species. Which, there are philosophical arguments about this: but basically, most people agree that having humans continue as a species would be objectively, ethically good. So, the idea is that then: Well, regardless of return on investment, or whatever people like these Weinersmiths think we should be worried about, we should start putting in pieces now so that our descendants can have this better chance to survive. So, that's one argument that at least is superficially plausible.
The other argument we call the Hot Tub Argument, which is just--I think this came up when we talked to space geeks. They would often start with these kind of highfalutin' philosophical things about, like, 'Well, we need to revitalize society and save the environment and end poverty.' And then, eventually, if you kept talking, they would say something like, 'Well, whatever. Elon Musk has the money and the rockets. And we're going to go. And you have no standing to stop us.' So: 'Even if there's no good reason to do it, we want to do it.'
The reason we say Hot Tub is kind of a joke. It's like, 'Well, if you go to buy a hot tub, all that matters is that you want it and someone is willing to sell it and you can make that transaction. Generally speaking, some third party can wag their finger, but it's none of their business. And, the way we like to talk about that is: That's true of most transactions, I would think. If you go to the grocery store, there's not a third party saying, 'Do you really need those Oreos?' Maybe, like, your spouse; but nobody else.
Whereas, there are some categories of purchase we don't say that about.
A classic example is nuclear weapons. So, I actually looked it up. Even, like, the--Mises.org--doesn't think private citizens should be allowed to have nuclear weapons. Right? I was wondering: Is there someone who is okay with private citizens building hydrogen bombs? Even they are like, 'No, because that's effectively waving a gun at everybody in the state, which violates nonaggression.' Right? And so, there's essentially no one who is okay with that. There's probably somebody, but basically nobody.
And then you can imagine the spectrum from going to buy a hot tub, which basically has no third party with any right to say No, and buying a nuclear weapon where essentially everybody should be able to say No. And then the question becomes: Where does space settlement fall on that axis?
And you might think: Why is it not a pure aesthetic choice? Well, try to imagine, as some people have proposed, putting a million tons of metal about 70 miles high in orbit. I think most of us feel like we should have a say whether anyone is allowed to just do that because it creates this huge hazard not dissimilar from the hazard of detonating nuclear weapons.
And then, so a lot of the book is kind of sussing out how valid are these seemingly valid arguments? And, our ultimate conclusion is that the Hot Tub Argument clearly won't do. It's not a simple personal choice because basically even if you imagine fusion drives and whatever else, having a world where private actors can put enormous amounts of high-speed metal in space is a world where humanity is endangered.
So, it seems like there just has to be some kind of regulatory framework. You can argue about what that should look like, but there has to be some kind of control on it for the same reason there has to be on nuclear weapons.
As for the multi-planetary aspects, that we're a bit more sanguine about. Though we do want to note, there's a scholar named Daniel Deudney who I think fairly convincingly argued--we're not quite as pessimistic--but said, 'Look, going multi-planetary carries these risks: One, of causing a war on Earth just over turf scrambles.' And there's an argument that that could happen; is even already a little bit happening on the moon.
But also, war between planets could be extraordinarily bad. Without getting into it, the point is if you have an equation that says existential risk, there's the tendency to say an extra planet is definitely a net positive, period. Because it's just--the common metaphor is: Don't put all your eggs in one basket. But, there's some world in which doing all this increases existential risk possibly more than is offset by being multi-planetary. So, it's quite complicated.
Russ Roberts: I think you're quite fair to the Hot Tub Argument, not because of the economics, but I think it's the economics meaning of externalities and whether it should reduce your right to do what you want. There is something I think about the human aspiration to do what can be done even if it shouldn't be done. AI is a perfect example. I think we're going to have a really hard time holding it back. Most things that people think of, happen.
Russ Roberts: Elon Musk, if he lives, will probably go to Mars, maybe not himself personally, but I could imagine he would. To me, there's something powerful and poignant about our desire, on our little tiny planet in the middle of an enormously large galaxy, to take a very, very small step--not for human beings meaning to be on the moon, but to actually start to go farther. Mars would be next. And then, whether we could ever go beyond that in any reliable way is a technological question, at a minimum. Even though I'm not sure how compelling the argument is, there is something moving about it even if I'm not convinced by it.
Zach Weinersmith: Yeah. So, two things on that. One, I agree. I can't remember who first said it--maybe it was Sagan, but I have a feeling it was earlier said--essentially, like, 'The difference between going to space and not is the difference between zero and infinity.' Right? If we start expanding, eventually, at some distant date, some descendant of human intellect is throughout the galaxy. Right? That's a very distant--very, very distant--day. But, the alternative is we just stay home and that's it. And eventually, the sun engulfs us, and it is no more.
So, I think that's true. I do think you have to reckon with the idea that it might be better to wait, for the simple reason that we might be more likely now to cause species destruction than we might be in a hundred years. There's no way to know. Some people make what's called a short-window argument, like, 'Actually, we're right this second in a kind of golden age, so we have to go now before we lose the juice.' Robert Zubrin makes an argument that's essentially, like, 'Americans are still a little tough from the frontier days, so we should go now while we're still tough,' which I don't buy. But, I think a lot of people buy some version of it.
The other thing I would say, I'm not sure it's the case that humans always eventually get what they want. I mean the obvious example would be nuclear power. We have kind of--
Russ Roberts: True--
Zach Weinersmith: I was going to say made a collective decision, but it's more like made a collective stumble towards basically saying we're not going to do it en masse like people would imagined in the 1950s, right?
Russ Roberts: True.
Zach Weinersmith: For space, there's an even better example, and I promise I won't get into the weeds on this. But very quickly, in Antarctica, there was an attempt in the late 1980s to say: We want to make a framework. So, Antarctica is regulated as a commons by a consortium of nations. Nobody owns it. It belongs to a bunch of nations. Right? There was a move to make it exploitable, and there was evidence, I understand, from survey data that maybe there were actually economically viable resources to get in Antarctica.
And a very standard space-geek argument is: Well, you guys can talk about regulation and danger all you want, but the moment there's money to be made in space, people are going to just go get it, and whatever. All the international law is going to go away because there's money to be made.
Well, in Antarctica, there probably was money to be made. And when it came time to make rules saying you could go get stuff, there was such an outcry that in, I think, 1998, a protocol was put into place saying not only can you not exploit Antarctic resources, you can't even look.
It's, like, an open question. Like, it gets dicey: Are geologists technically looking for resources? And there's a moratorium that lasts till 2048; and it cannot be lifted outside of unanimous consent by--I forget how many nations now, but it's something like 30.
And so, humans have at least some capacity to say, 'No, I don't want the thing. It scares me too much.' So, I don't completely buy the idea that we'll just eventually do something because it's awesome or lucrative enough. Obviously, this is an interesting question now with AI. None of us know how that's going to shake out.
Russ Roberts: Where does that leave us? You've convinced me that we're not going to have an NFL [National Football League] Exhibition Game on Mars in the next 10 or 20 years; or, even better, a franchise. That underground stadium is going to be really awesome, though, I'm sure.
Zach Weinersmith: That's cool.
Russ Roberts: So, you convinced me of that. But: What is your recommended attitude that human beings should have toward these constraints? Should we gather information, say, about radiation damage, muscle loss, bone loss, hormone imbalance, adjustments in space travel of the time it takes to get to Mars and so on? Or should we just wait until technology makes a lot of this more plausible? Where do you come down on that?
Zach Weinersmith: Right. I don't want to get to parsing your question, but when you say, 'Humanity should,' it gets a little dicey. Right? Because, so people when they talk about space tend to talk about Earth as if it's in any way unified about questions like this.
Russ Roberts: Fair enough.
Zach Weinersmith: And so I don't want to--to try to answer the sort of spirit of your question: You know, obviously, it's this deep fantasy.
So, one of the things we did as research for this book is just got every book we could put our hands on which was someone from the past saying, 'We need to go to space.' And, the kind of modern version of that, probably you'd say starts in the 1890s with a guy named Konstantin Tsiolkovsky, sort of the founder of rocketry.
Pretty much every decade you can find more of this fantasy. So, there's obviously something it's doing for us. Whereas, Antarctic fantasies, maybe a kid in 1910 was still thinking about it, but it's kind of old news now.
So, there is something deep about it. I mean, my view is essentially: If you want there to someday be creatures that look like you--human beings on these other worlds--and if what you really want is Star Trek--meaning we go out to the stars and we explore things and it's awesome--I don't know about what humanity should do.
I would say there's a lot of really interesting stuff for a human to do.
So, for example, like, as we said, we know very little about reproduction and nobody seems willing to spend on it, including the people with the billions of dollars it would take. And that would be such an extraordinarily amazing question to try to answer. It would require probably building a moon base and populating it.
These ecosystems that we need to develop, these closed-loop ecologies: that just seems to me objectively fascinating. Like, what is the minimum size of container you need to build a little tiny sort of Eden that can feed people? That's just a delightful question. They probably would have utility, too, for just regular people on Earth trying to grow food.
One thing that surprises me now--I'm surprised there aren't more young people wanting to go into international law. It's considered kind of stuffy. But, it's, like, one of these few areas where you can be scribbling ideas on a piece of paper and, 20 years later, it shapes the way, like, an entire world has its property regime. I mean it's kind of amazing.
And, again, without getting into the weeds, we have this framework for international law called the Common Heritage of Mankind, and it ultimately goes back to a speech by a single person, given at the UN [United Nations]. You can really shape the world by being a scholar--which is very unusual.
So, in terms of what needs to be done, we obviously need much better science. We do need the kind of cool engineering stuff, the scaling of our ability to do rocketry, which SpaceX and other companies are now working on.
We also, I think--and this is obviously a tall order, and I understand that we need a more harmonious Earth, in the same way that war in Western Europe is, I think, unthinkable now. It would be nice if the whole world was more like that. And that it would be safer to allow people to put these large objects in space.
I think it is still debatable, but all these things.
And then, I think, at that point, ultimately it is an aesthetic choice. Right? The people in Star Trek are going to space not to get rich because that doesn't make any sense. Space is the same everywhere. Right? You are not going to get rich by getting stuff from Mars because it's made of the same stuff you have back home. Right? You have to go there as an adventure. And, so, you need to get to a world where the technology is there, and it is possible to not increase human existential risk by going to have that adventure.
Russ Roberts: My guest today has been Zach Weinersmith. His book written with his wife, Kelly Weinersmith, is A City on Mars. Zach, thanks for being part of EconTalk.
Zach Weinersmith: This is a delight. Thank you.