Seeing the Potential
Why develop space is the big question from most people. In a few decades it will seem curious it was ever asked. Tipping points – that is what has to be appreciated here. Many ventures have them, but none has ever had one on this scale. Getting beyond the break even point in space development doesn’t just mean a net profit in one industry, and it doesn’t lead to linear growth. It means a hundred different industries appear and take off within 20 years. The growth is then exponential, limited only by the bounds of the very solar system. It’s hard to overstate how important that will be. It will change the nature of our species.
There are no materials on the moon that aren’t also available and far more accessible on Earth. It isn’t the moon’s materials that are valuable. It’s the moons qualities.
The moon is lifeless. All material exploitation moved there from Earth relieves all life here from that exploitation from then on. For a while we’ll continue to only move intangible products off-world: communications, data processing, and energy production – three huge and quickly growing industries. Eventually it will make sense to make a host of manufactured goods in space as well and deliver them to Earth by skyhook. This will allow the Earth to heal.
The moon is bathed in strong sun for two weeks solid every month. Shadow is rare in the vastness of space in the Earth – moon system. Once it’s possible to manufacture solar cells on the moon (which can be done with materials it has in plenty), there is gigantic incentive to scale that up and ship those cells into space as much and as quickly as possible. In the near term there are better solutions for Earth’s energy needs. Beyond the next few decades, nothing can compete with space solar – not thorium fission, not fusion, not anything. Solar power generated in space will be the cleanest and cheapest source. It’ll be the obvious source for power needs in space itself. For a few more decades that won’t be a significant factor, after that this will be an increasingly important point.
Because of the two things above, once manufacturing processes on the moon have been worked out, their scale will explode soon after. There is no need for any kind of caution in how expansion is done, there is an entire world of materials just sitting there, and no practical limit to the amount of energy available to do the work. If humans workers were necessary to scale up production, that would be the limiting factor. But they mostly aren’t. The level of automation needed to have robots do many things themselves is nearly here already, and much human oversight could be done from Earth, until such time as there is a suitably comfortable place closer by from which to do it.
Chemistry in Space
But there’s more. The moon sits in a hard vacuum. Any chemical process on Earth that’s done in a vacuum, or in a non-reactive gas like argon, can be done on the moon far more easily. Any processing that has been designed to avoid problems due to contamination by water, oxygen, nitrogen, carbon dioxide, or any other common component of Earth’s atmosphere, can be redesigned to benefit from the utter absence of those things on the moon. Resulting metals, alloys, ceramics, and glasses will be produced faster, cheaper, and of superior quality. Some materials will be fundamentally different because of it.
For instance, glass of all kinds on Earth is universally contaminated with water. Molecules of water interrupt the crystal lattice, riddling it with weak points. Glass made on the moon would be naturally free of all such flaws and so would be far stronger. It’s probable that different kinds of glass will substitute for metals in many applications for this reason.
The moon has low gravity. There are many ways to pair this nicely with the hard vacuum to obtain effective novel ways to get things done. Various fundamental techniques in chemistry benefit from the moon’s environment. Distillation processes can be performed at any chosen pressure in reactors containing any chosen atmosphere, or none at all. That drops the temperature at which evaporation occurs, saving on energy. Separation in centrifuges is greatly aided by both the low gravity and the vacuum. The vacuum eliminates atmospheric drag on fast moving objects, and the low gravity makes it far easier to create low-friction bearings. In fact, because in a vacuum heat moves only by radiating as photons, it’s far easier to insulate objects to keep them very cold or very hot. That greatly lowers the barrier to practical use of superconductors, for instance so they can be used to create frictionless bearings by magnetic levitation. Precisely controlling the heat in a furnace becomes much easier in a vacuum for the same reason, and placing hot and cold areas close together while precisely manipulating the temperature of each is also far easier. Several of the best ways to produce high purity metals and crystals benefit greatly both from this, and from how the low gravity aids precise control of the movement and orientation of even very large things. The Czochralski method and the Bridgman-Stockbarger method are examples.
The moon gets very cold at night. Pre-dawn temperatures on the surface are below -100 Celsius. It may not make sense to have huge numbers of radiators busily shedding heat, so the smart thing might be to store that cold so it can be used as coolant during the day. Lunar industry can’t simply disperse heat with fans, or make use of abundant water as coolant. On the other hand, it can expose an arbitrarily large amount of stuff to deep freeze for up to 2 weeks, and a few layers of reflective foil would be enough to preserve that cold almost completely all through the 2 weeks of day. So, for instance, if slag was disposed of in a field in such a way that it congealed into a continuous shallow layer, and that layer contained planned gaps coolant can be pumped through, and that growing field of old slag was covered with great insulation blankets at dawn, and uncovered at dusk, it could be used as a vast, vast heat sink. In more general terms, any amount of freezing of stuff can be achieved by putting things out at night for a few days. To freeze dry things perfectly, just leave them uncovered.
Moon dust makes excellent insulation. Mind you, the only reason it does is because it’s in a vacuum. If it wasn’t, it would only be okay insulation. As long as the slag field was on top of at least a foot of moon dust, then, its temperature would be virtually unaffected by the temperature of the ground in general. It’s nice that moon dust isn’t always just a menace.
Toxic byproducts? Don’t give it a second thought. They ought to be contained, but really that isn’t hard. There is no air to waft gasses away, and no water solids and liquids can leach into. Do that process in a separate hut and let the toxins collect in some suitable container. At worst, the enclosure might need to have surfaces that absorbs gasses or causes them to condense. If all of that needs to be stored for a few centuries somewhere isolated, it’s really no hassle. Very little happens on the moon, it isn’t going to go anywhere. Short of letting some contaminated robot enter a hab and tramp around, no living creature will ever come anywhere near it.
The many substances the moon lacks that are essential tools in chemistry on Earth will have to be imported and carefully recycled as much as possible. The better option will be to find alternative approaches that don’t use those substances. The many chemistry stunts quite feasible on the moon but impossible on Earth will allow alternatives to be created much of the time. In remaining cases, conducting the process at a different temperature or a lower pressure is an easy option that can reduce the need for scarce imported reagents. Something that works by using a lot of energy will be generally cheaper than something that consumes an imported reagent. Energy will be really cheap. Imported mass will get an awful lot cheaper, but will always be more expensive than energy.
Creating the First Products
What the first few products made on the moon have to be is pretty clear. The first one has to be power. That has already been done with solar panels, but they have to be set up permanently to provide power for whatever comes around needing it.
The next is fuel. There are actually two options for this, although water is the one that gets all the press these days. Water is the better choice as long as it is easy enough to access in large enough quantities, which is likely true at the bottom of polar craters. Oxygen is the other option. It’s available everywhere as it is over half of the atoms in the moon’s crust. It’s just that breaking that oxygen free and putting it in canisters presents much greater challenges than breaking water into hydrogen and oxygen and doing the same. Sooner or later it will also be a product, though, because any processing of minerals into pure metals is going to produce it as a by-product. Then it will be used as rocket fuel because that will probably be the most useful thing to do with it. It’s possible an engine could be developed that works with one of the other things that are around in great supply – like aluminum, processed into a fine pure powder. It wouldn’t be very efficient, but that hardly matters if it can be produced in bulk anywhere on the moon with entirely local materials. That isn’t the kind of fuel to use in a nuclear engine though. The choice Moonwards depicts is that of minimizing the fuel that isn’t locally produced by using hydrogen in a nuclear engine but injecting oxygen in vast quantities after that, into the bell of the engine’s nozzle, where it works like an afterburner. That gives you a high-thrust engine that is still pretty efficient and whose fuel is 95% to 98% oxygen by mass. With those kinds of ratios, if the moon itself isn’t supplying enough hydrogen to service all the rocket traffic, ships can bring their hydrogen with them and refuel only the oxygen at Moon Town. It just means they have to sacrifice some of their payload capacity, switching it from cargo to hydrogen fuel. At any rate, long before such engines are feasible, the moon will be selling fuel.
The next task is building materials. Simple dirt piled on top of imported prefabricated habitats as radiation and thermal shielding will certainly be the first use of lunar material for building. The next thing will be some form of paving so that everything can be protected from pernicious lunar dust. The great need, though, is for structural components. Lunar concrete that uses sulfur to bind an aggregate may play a role in the very early days. Melting the dirt into stone shapes will soon after become easier and better. Once large solar furnaces are available, and dirt can be sorted and processed to enrich it in desired substances, approaches that melt it will provide a range of stone, glass, and ceramics. Obtaining the needed heat using electricity will allow a wider range of products and finer quality.
The turning point will come when materials strong under tension are created. The possibilities there are glasses, and metals. Whichever is first successfully made in bulk, both are critical to real industry on the moon, and the other will soon follow. Only beyond that point can large and complex habitats be created. With habitats capable of accommodating dozens of people, the pace of innovation in manufacturing will shoot up. Scientists and engineers on-site will be able to quickly iterate through methods and prototypes, free of signal delay and able to have products brought into the hab where they can handle and test them directly. Manufacture of complex equipment also relies on available metal and glass in powder form that can be 3d printed. This is already a quickly maturing area, and perhaps it too can take advantage of low gravity and vacuum for improved quality and options. As soon as suitable materials are available in bulk, manufacture of essential machinery such as motors, actuators, reactors, and pumps will immediately be possible. That will allow local fabrication of complex machinery whose mass is only a few percent imported materials .
That’s when a true space economy will emerge, centered on the moon. One shipment of fine parts only available on Earth can then be turned into hundreds of satellites that can be launched from the moon. Those satellites can have elements far larger and heavier than practical to launch from Earth – heavy shielding, giant clear or mirror lenses, huge radio dishes, expansive solar panels and radiators. Solar cells and microwave beaming equipment will certainly be the key satellite tech whose production will be pushed up as fast as possible. It will take a while before they are being produced and launched on a scale sufficient for the moon to be running a power utility capable of supplying grid power to Earth, but that is the logical outcome. There is plenty of room in the Earth – moon system for arrays of solar cells capable of supplying all of Earth’s power many times over.
The Path that Led to Moon Town
So this is the order in which development of profitable industry is depicted in Moonwards:
First, export of satellites of all kinds, and over time the satellite business becoming composed primarily of launches of solar power array packages to be added to the various growing arrays.
Second, expanding habitat construction to a point that allows a population of thousands of people, and the establishment of true towns. Moon Town is actually the second of these, the first being a polar town on a much smaller scale.
Third, construction of ships that travel far and wide, and space stations for within the Earth – moon system. Developing skyhooks and mass drivers as mature technologies is central to this, and that work happens on the moon. Thanks to these two technologies, things can be transported from A to B anywhere in the Earth – moon system for only a few dollars a kilogram, as long as they stay above Earth’s atmosphere. Getting between the ground on Earth and above its atmosphere remains the difficult part. Once lunar industry is able to build Earth’s first skyhook transport hub, space planes able to dock with it, refuel, and return to the ground then become the main vehicles shuttling people and goods between Earth and space. A decade or so later, the price to get beyond Earth drops to the $100/kg range. Cargo coming in from space can do so for even less, by dropping off the arm of the skyhook at 5 km/s relative to the ground in reentry vehicles that are rather cheap but also entirely reusable. It will take mastery of bulk manufacture of graphene and/or carbon nanutubes to create skyhooks in Earth orbit with cables strong enough to go even further than that. It is possible that the lunar chemical industry will be key to that too. When our story opens in Moon Town, it remains out of reach. When it does happen, it ushers in an age on Earth of highways to and from space. After that it’s only a matter of time before the capital investment needed for that is looked after. This is why it’s mentioned here. There is a clear path from where we are today to an age of solar system wide shipping on a scale and economy not unlike modern container-ships on the oceans. It’s a path we know will work, we just need to figure out a few huge but well understood technical challenges.
Fourth – pretty much any product shipped around the world today. If you have enough transport, you can place any such industry on Earth in space. Some industries that are quite clean and cheap will stay here at home, but most such industries are inherently dirty or use up resources we’d rather stay in nature. The path from here to there is long but clear. It saves our planet and gives humanity wings of awesome span.