Industrializing the Moon

When discussing the options for colonizing the Moon as a stepping stone to the solar system we'll see that it's not just one small step for a man, but one giant industrial park for mankind. So today we will be looking at colonizing the Moon, not just small bases but real colonies, and to do that we have to discuss the reasons why we would do that. This is not our first trip to the Moon on this channel, and it won't be our last either. We have visited briefly a number of times, and even did an entire episode on Moon-based concepts. In spite of this, there's a lot of material left to cover and we won't do anything like exhaust it today. Our focus today is on the industrialization of the Moon, essentially the reason to colonize it with thousands or even millions of people, not just visit, plant the flag, and head home. The Moon has a bit of a strange position in the discussion of space travel. It remains the only place mankind has ever visited in person, but it's been nearly half a century since we've been there and only a dozen folks have ever set foot on it. It's a big place with a surface area larger than any continent but Asia, so those dozen astronauts didn't explore much of it. It's hard to picture the Moon. We tend to envision it as a grey desert pockmarked with craters, which is true enough, but people tend to forget that those craters range from the microscopic up to craters bigger than all but the very largest nations and deeper than the Marianas Trench. Craters big enough to swallow whole nations and deep enough to hide Mount Everest in aren't what we usually picture when contemplating the Moon. We also hear a lot about Lava Tubes on the Moon, corridors cutting through the stone near the surface. These can range in size a lot, and the low gravity allows them to get quite monstrous in size, looking less like a tunnel a mole or worm burrowed and more like something one of the sandworms from Dune made. There are thought to be Lava Tubes on the Moon as wide as 500 meters, and many kilometers long. We've got dozens of craters, big enough to house major metropolitan areas, or even decent sized nations. Domed over they are big enough to be their own mostly closed ecosystems. You could build domes that big too, and upside of low gravity, and as we discussed in the Life Support episode, even if a panel got shattered, air would not leak out so fast that you couldn't repair it even if you didn't have some high-tech self-sealing method. That's an important thing to remember though, all those handy craters we can dome over exist because something big landed there, and while ones that big are quite infrequent, the Moon's lack of an atmosphere means that small meteors aren't burning up before hitting and pea-sized meteors will be hitting in your vicinity reasonably often, though not so much as be a normal cause of death any more than lightning is. If you lack the ability to make sturdy or self-sealing domes, those underground lava tubes are a lot more appealing, particularly since the Moon's day-night phase is a month long and the light isn't filtered of harmful radiation by an atmosphere, so that you would tend to want artificial lighting anyway. You could get some interesting colonies in a lava tube, since they'd tend to stretch out thin and long, akin to how we tend to develop habitats along rivers or roads. The craters and geology of the Moon, while fascinating, haven't proved enough justification to send more manned missions back there yet, let alone enough to set up permanent bases, which is solidly inside our current technological abilities if expensive. What we're interested in today is to step beyond that, not purely scientific and exploratory missions, nor prestige voyages to prove to people you can land astronauts there and bring them home. That's why the Moon holds that strange position in space travel, because it needs to be the place where we settle two questions, first, whether or not space exploration will be done only by robots, or if we will once again stick boots on the ground of an alien and inhospitable world. Second, whether or not we will ever do more than explore, but genuinely get out there and settle these places. We've already talked about how one can terraform planets or even the Moon, and certainly how to make comfortable habitats on such places, or orbital habitats floating in space by themselves. We know also the ultimate goal is to spread ourselves outward to other stars, and to take dead and barren alien planets and make them homes for people, our pets and parasites, and all the other eggs we keep in this one fragile pale blue dot of a basket. But there's a middle ground folks don't spend much time on, which is what draws millions of people to the Moon to live there and work there. It's a bit like the underpants gnomes from South Park, they've got a business plan, phase one, collect underpants, phase three, profit. Almost everybody wants to go to the Moon, almost everybody wants us to set up bases and colonize the place, almost everybody wants us to send out ships to explore and settle the stars, but we've essentially got the gnomish dilemma. We know what phase one is, get people back on the Moon again and set up a base, and we know what phase three is, a profitable and growing colony on the Moon. Phase two is a bit of a question mark. This has gotten to the point that some folks want to cut the Moon out of the loop entirely and go straight to Mars, or the asteroids, or even Venus. I'm all for doing all three and more, but I believe that the Moon holds the potential to be the best foothold to truly getting into space, and I think that means it needs to benefit us in a very real and tangible way. To demonstrate that though, we have to begin by asking what benefits the Moon has. What has the Moon got that Earth lacks? What is on the Moon that the rest of the solar system lacks? To answer this question we have to get a bit geocentric, because the first thing the Moon has, that the rest of the solar system lacks, is its proximity to Earth. The Moon is just over a light second away, meaning we can talk to people there real time. There's a pause of 2.6 seconds for a message to get there and back, but that amounts to an annoying real-time lag, nothing more. Every other object is at least light minutes away, and constantly varies in distance. Venus is the closest after that and can be as close as 38 million kilometers, or 2 light minutes away, to 261 million kilometers, 15 light minutes away. Mars is even further off and those two, along with Mercury, are our nearest neighbors. A ship with a power plant strong enough to provide 1-gee of acceleration constantly, so that you could walk around over the engines like you were in normal Earth gravity, could reach the Moon in less than 4 hours, shorter than many routine flights on Earth. Such a flight is very energy wasteful and would involve flipping over halfway through to slow down, usually called turnover, and reaching a speed of 63 kilometers per second. That's fast but not truly huge compared to modern spacecraft, and something within the realms of possibility for the fission-powered or metallic hydrogen-fueled ships we discussed in the Upward Bound series. That same speed would make a trip to Mars take more like 40 days, not 4 hours, and even a power plant able to provide a constant 1-gee burn would take about a week and would need to be fusion-powered. What else does the Moon have that the solar system lacks? Well it lacks a significant atmosphere, but so does every other body in the solar system except the 4 gas giants, Earth, Venus, and Saturn's moon Titan. Of course, obviously excluding Earth, none of those atmospheres are breathable so they offer little benefit. The lack of one is quite handy for getting away from those places. Not so handy for landing on them though, since you can't aerobrake and have to burn fuel to slow down. However this is the same with virtually every one of the millions of large objects in the solar system. It also lacks much of a gravity well, making shipping stuff off it a lot easier. In fact it is so easy, especially with a lot of the methods we discussed and will discuss in the Upward Bound series, that it is actually easier to ship material from the Moon to Earth's low orbit, a distance of 400,000 kilometers, than from the Earth's surface to our low orbit, a distance of less than a thousandth of that. Truth be told, one can ship mass in from various asteroids without spending much more fuel, but only if you don't mind waiting years for your shipments to arrive. The Apollo missions used that lower energy approach, so they took a lot more than the 4 hours a continuous 1-gee burn would take, and still only needed 3 days. That's comparable to a lot of normal freight times here on Earth, faster than low-priority bulk freight in fact. Shipping in from other planets or asteroids in the belt could take many months or even years, especially if you're conserving fuel. Now folks often discuss the riches to be found in asteroids, we even did an episode on it, hypothetical dragon hordes of gold or platinum. The Moon on the other hand has a composition pretty similar to Earth's crust, that's much of the reason why we think the Moon was made when some smaller planet slammed into the Earth during the early days of the solar system. That means it is quite rich in materials we like to build out of, plenty of silicon and oxygen, plenty of aluminum and iron, and surprisingly rich in titanium. Indeed there are good odds a lot of those craters, especially the polar ones, have ice in them, and water is quite precious in the inner solar system outside of Earth. Yet it's worth remembering that ice isn't the only thing at the bottom of those craters, they were after all made from the impacts of the same meteors and asteroids folks are talking about mining. The Moon also has its dark side, which of course is not always dark, it gets as much light as the other side, but what it is dark to, and doesn't get light from, is the Earth, making it a handy place for observatories, blocked from all glare and radio noise. The Moon is also a good place to do dangerous or controversial biological experiments, far from life and surrounded by lifeless, inhospitable places. Ditto possibly dangerous nanotechnology experiments. We discussed setting up habitats for living space in the craters and lava tubes a few minutes ago, but it is also a great place for experimenting with terraforming techniques for small, low-gravity places, which is most of them. We talk a lot about terraforming Mars or Venus, but there are thousands of small rocky bodies in our solar system we would want to mine and make livable, and they will be far away from Earth. The Moon is close enough we can fly in emergency supplies in enough time for it to matter or supplies for projects we can't make on the spot, in-situ. All those asteroids and moons around other planets are not close enough, even if you are pulling constant acceleration. So the Moon gives us a place to experiment with those techniques before we head out into deep space, where resupply can take months or years, and even advice from the experts can take hours to arrive by radio. And if you do plan to have spaceships that can carry out near-perpetual 1-gee thrust around the solar system, it helps to have access to fuel. Hydrogen isn't terribly common in the inner solar system, away from large gravity wells, so the ice on the Moon offers one supply, but it also has Helium-3, which while harder to fuse than deuterium and tritium isotopes of hydrogen, isn't too much harder and also offers us aneutronic fusion. A fusion that produces very few neutrons, which is good, particularly for spaceships, since it lets you get away with smaller engines that need less shielding. But even without fusion power plants or ones using Helium-3, the Moon is a great source of fuel. It's got hydrogen, which is also a good propellant even without fusion, and it has also got plenty of Phosphorus, Sulfur, Aluminum, and Magnesium, which all burn well with oxygen, which is even more plentiful there. In addition the Moon has a lot of CREEP, which is short for Potassium, K, Rare Earth Elements, and Phosphorus, and tends to be heavy in Uranium and Thorium. I also can't stress enough the advantages of low-gravity manufacturing. Zero-G has its own advantages, but the nice thing about low-gravity is that stuff still works like we are used to. In a big smelter, denser materials still sink to the bottom of the vat, for instance. All sorts of very expensive manufacturing equipment that has to be built very sturdy here on Earth can be done a lot lighter and cheaper too. When you're building there you have no wind or snow getting in the way and requiring sturdier buildings either, so you can build huge on the Moon quite cheaply. And while actual space-based construction can be very handy too, you can build giant spaceships or even space stations on the Moon and tow them into orbit fairly easily. Here we start to see the basis for a lunar economy. Yes, tourism and science would provide a nice subsidy, yes it probably has its own stockpiles of precious metals in those craters, but the wealth there is in all those things which we actually have here on Earth but which are far easier to move from the surface of the Moon to anywhere near the Earth than up from the Earth itself. Raw mass for construction and fuel are what the Moon offers to run its economy. In a way it's like a giant orbiting warehouse, already conveniently pre-positioned to fuel our expansion out from Earth. Still a bit of a catch-22 though. To make the Moon profitable that way, you have to be expanding out into space. One has to ask, what space has to make it profitable? Yes, the Moon, if industrialized, gives us all the materials we need to expand into the solar system. Yes, it gives us a lot of practice living in space on airless rocks, but how are we to get to Phase 3, profit, when that relies on supplying all the materials for space expansion? We do need profit elsewhere in the solar system to drive that on the Moon. That though we can gloss over for today, because I still want to discuss Phase 4, what comes after that solar expansion, and how it can profit us closer to home. The Moon often gets treated as the gateway to space but tends to get ignored afterwards. When we're discussing terraforming other planets in our system and elsewhere, the Moon is always someplace vaguely referenced as having a colony on it. It becomes a footnote, historically important but no longer useful. We've talked a lot about how to get folks and material off Earth cheaper, so we didn't need to import stuff from the Moon to orbit, but almost all those same tricks work on the Moon just as well or better. It's very easy to build a mass driver or skyhook or even space elevator on the Moon. A rotating skyhook, a rotovator, could spin right down from orbit and snatch cargo right off the ground and toss it into orbit, or even right back to Earth. Because the Moon rotates on its axis far slower than Earth, once a month not once a day, space elevators there need to be longer, but don't require any super-materials to build, we could manufacture one today. The low gravity and lack of wind make tall structures quite easy to build, that same low gravity makes excavating and mining much easier too, but you don't need a super-tall building for a mass driver because there is no atmosphere to rise above. Indeed with no oceans to cross and no existing structures or borders, one can wrap a mass driver all the way around the Moon, you don't need a vacuum tunnel around it either. This makes it far cheaper, just a railroad essentially, letting you build up some very impressive speeds before letting go of the track to fly off into space. All of which lets you ship material back to Earth much cheaper than up from Earth. Now why do I keep emphasizing back to Earth? Isn't the point to use the Moon to get things away from the Earth? Well yes and no, we often give a motivation for space travel being to find new places to put people, so we can support more of them without either a loss in standard of living or further depleting our ecosystem. I generally consider any scenario that allows you to support more people without hurting the planet or reducing the standard of living for those people to be by definition a good thing, and tend to find folks who think otherwise a bit puzzling, which is putting it politely. And we've talked a lot about ways to support more people on Earth in the Arcologies and Ecumenopolis episodes. I mentioned at the time that there was a point between those and full-blown Kardashev-2 Dyson Swarms, that I generally call a Planet Cloud or the Terran Cloud for lack of a better term. In this you are constructing rotating habitats around Earth to make more space for people to live. These differ from a Dyson Swarm in that they're smaller overall in terms of living space but also far smaller and denser too. Rotating Habitats are something we've discussed a lot on this channel. They benefit from being able to be tailored to any climate and day length and gravity you want, unlike other planets where it requires huge efforts to, for instance, shorten the day or increase the gravity, and they also require way, way less material per square kilometer of living area than a planet does. Just as an example, if we disassembled the Moon into a bunch of 100 meter wide sheets to form Cylinder Habitats, the Moon would give us about 220 billion square kilometers of those sheets, about 500 times the total surface area of Earth, and a few thousand times what we have in terms of reasonably habitable land area. That would be about a quarter of a billion classic O'Neill Cylinder Habitats, incidentally, but there is actually more than enough room for that many in Earth's vicinity, places within a few light seconds where real-time communication is possible and where those would still be spaced out enough to not bump into each other or block light from each other or Earth below. Sounds like an ambitious task, especially if you've joined this channel only since the Upward Bound series began, which is about half the audience, but since we routinely discuss disassembling stars for fuel or moving them in whole solar systems or even whole galaxies, the construction of a planet cloud is probably about a 3 out of 10 on the logarithmic scale of hard tasks we discuss here, with a 10 being to collapse all the galaxies within about a billion light years of here into one gravitationally bound region that won't be ripped apart by the expanding Universe, and doing that only with known physics and no faster than light travel. We like to think big on this channel. In that respect, constructing a bunch of upsized soda cans in orbit for folks to live on is not terribly difficult, particularly since you can build them one at a time as needed to house folks who want to have more living space while staying near Earth. They do require a lot of mass though, even just one fairly small version of them would require far more material than everything we've ever launched into orbit combined. Even with the systems we've discussed for getting folks off Earth cheaper, none of them are really suited to moving that much mass, let alone cheaply, not from Earth anyway, not even the Orbital Ring, which we still haven't covered in the Upward Bound series, but is basically the granddaddy of cheap transport of material into space. So there's your profit source to fuel colonizing and industrializing the Moon for purposes beyond far distant space colonies and various scientific efforts. You are using the Moon to mine and manufacture all that infrastructure and living space around Earth so you can house tens or hundreds of trillions of people in relative comfort and proximity to Earth, without needing to turn Earth into some concrete covered megacity, and you can do it in stages, one station at a time. With better automation and different work environments, it's hard to put anything approaching a solid figure out for the kind of workforce needed to build an O'Neill Cylinder, but I've calculated it a few different ways off current market costs for materials like steel, aluminum, and titanium, and the ballpark figure is about a million folks working for a year to provide the construction material for one of them. We'll assume a lot more automation involved so that all the support industries and services needed on the Moon to build one per year would be a million people including their kids and other dependents. If you wanted to produce a planet cloud in less than geological times, you'd need to be working on many of them at the same time, maybe taking a decade each to assemble the structure and have thousands at a time that you were working on once things ramped up to full production. But under these kinds of values we can easily have multi-million if not multi-billion person populations on the Moon. Indeed I could easily envision a trillion person Ecumenopolis Earth commissioning about a thousand a year to house about a billion new people a year total, or more, and needing a roughly comparable workforce of about a billion to build the things. Scale always gets a bit disorienting when we start talking about even Kardashev 1 civilizations, let alone 2's or 3's. What we've discussed here would be at least a couple centuries down the road. Early on those colonies on the Moon might be thousand person installations where they are working on a way more modest space station to house a few thousand folks commissioned by, say, Brazil to support their asteroid mining fleet which is mostly delving for gold and platinum. Everything else is done incrementally. We bring up this massive case of a multi-billion population on the Moon to show that there is a potential large and long-term industry there not just for getting folks out to other planets and stars but directly tied to Earth's own normal economy. We see that industrializing the Moon can go a lot further than a few bases helping supply fuel and raw material for principally scientific endeavors in the next century or two. Of course to get all those colonists to the Moon, or to all those orbital habitats, we need much cheaper ways of getting folks into space which can also be upscaled to allow transport of thousands if not millions of people a day. We'll discuss one such system, Launch Loops, this month. After that we will be discussing Predicting the Future, and the idea of Psychohistory from Isaac Asimov's classic Foundation series. To get alerts when that and other episodes come out, make sure to subscribe to the channel, and if you enjoyed this episode, hit the like button and share it with others. Until next time, thanks for watching, and have a great week!