Case Study: Iceland

This is an excerpt from my book on Mars industrialization. It goes into a lot of detail on how we can think about the interaction between hostile environments and technological sustainability.

Why Iceland?

Iceland is an apt analogy for a potential Mars city, and a useful way to think about self-sufficiency. Today, Iceland enjoys a high standard of living and is a popular tourist destination famed for its natural beauty. It has a population of about 335,000 and a GDP per capita of about US$60,000. Naturally, it is highly dependent on a range of imports, exporting mainly aluminium and fish.

Further, Iceland is similar to a city on Mars in that it is relatively small, isolated, and cold. It is not a perfect analogy, as it also has breathable air, mainly basaltic geology, and abundant readily accessible geothermal and seafood resources. 

It is clear, however, that if Iceland was cut off from international trade, its standard of living would rapidly regress to that of the 19th or 18th century, as first petroleum was exhausted, then parts of the electrical infrastructure suffered failures necessitating parts that could not be made locally. 

While many of the goods upon which Iceland depends could be made locally with some forward planning, some parts are truly “magic widgets” that are very difficult to make. The smallest nation that is able to make, for instance, a sufficiently complete set of computer components is probably Japan, with a population of 127 million and a GDP per capita of US$39,000. 

In 2018, the world’s largest containership is OOCL Hong Kong, with a cargo capacity of nearly 200,000T. This behemoth can carry, on a single voyage, about as much cargo as I can imagine 50 years of BFRs bringing to Mars. 

Here is the thought experiment. Given one large containership of any desired cargo, can one devise a strategy that will forestall Iceland’s post-isolation living standard collapse indefinitely? Can one fit, into a single ship, a complete industrial stack and the tools to run it with a relatively tiny population? It seems like a tough problem, but achieving autarky in Iceland is a much easier task than doing it on Mars.

Population, technology, and environmental hostility

The Icelandic question is a good starting point for a broader discussion of the interplay between population carrying capacity, technology, and environmental hostility. 

Screenshot from 2020-07-19 23-08-42

First, consider the relationship between population and technology level in a given environment, holding hostility constant. For any given level of technology, there is both a maximum carrying capacity (Malthusian limit) and a minimum population required to sustain that technology. In this sense, technology is a disaggregated knowledge base that must be propagated through education even as individual practitioners are born or die. Technologies that increase carrying capacity include germ theory, mechanization of agriculture, and the Haber process for producing nitrate fertilizers, but in practice it is not useful to attempt to be perfectly granular about such a rich constellation of practices.

Provided that the carrying capacity at any level of technology always exceeds the maintenance population, there is a surplus of labor to invent new technology and a stable “band” in which the population can survive without losing or gaining technology. Outside this band, however, the population or technology will fall until stability is achieved. If, for example, Iceland were to suffer a repeat of the 1784 eruption of Laki, environmental fluorine poisoning would increase hostility and reduce carrying capacity, manifesting as a prolonged famine and substantial fall in population. 

The asymptotic behavior of this graph is not well defined, so it has limited utility for predicting the far future of humanity. In particular, it is possible that beyond a certain technology level, the minimum population level stabilizes as computers are doing all the work. On the other hand, it is clear that there is a finite limit on the population capacity of Iceland, the world, or the universe, set by fundamental thermodynamic and volume constraints. 

Screenshot from 2020-07-19 23-09-49

Second, consider the relationship between population and environmental hostility at a constant technology level. This graph shows a markedly different behavior to the previous figure. As the environmental hostility increases, the carrying capacity decreases, which seems obvious. What is less obvious is that because individual worker efficiency falls in hostile environments, the minimum population required to support a level of technology increases. 

On the left part of the graph, the situation is similar to the previous case, with a band of stable population. Moving to the right, the limits converge at the critical hostility level, beyond which there is no stable population size. The early North American colonies Jamestown and Roanoke straddled this point. 

As technology level changes, the critical hostility point traces out a trajectory demarcating the fully generalized limits on population and hostile environments.

How do we interpret this in the case of Iceland being artificially isolated from the rest of the world? 

Iceland’s imports of advanced technology help to insulate Icelanders from the hostility of their environment. This makes it more livable at a higher standard of living, at the cost of dependency on an extrinsic supply chain. If this technology became unavailable, then Icelandic people would be compelled to operate in a more hostile environment, with the associated labor and health overheads that implies. 

Screenshot from 2020-07-19 23-10-47

This graph shows the full relation between population, hostility, and technology. For any given level of technology there is a family of curves that together define the stable region. As Technology increases, I have suggested that maximum population carrying capacity drops off more gradually with increasing hostility. That is, increased technology lessens the sting of increased hostility. Conversely, the minimum population to support the technology increases more quickly with increased technology, because of the increased complexity of co-dependent industrial processes. In combination, the critical hostility increases with technology, as expected.

This is only a simple, qualitative diagram. A more precise calculation of the system may reveal cusps, stable points, and multiple pockets of relative stability with voids in between. It’s also imprecise to force all of technology onto a single dimension, since environment-specific technologies are more relevant for solving a given problem. Despite the imprecision of this diagram, it does deliver one key insight, which is that management and amelioration of the hostile environment is vitally important for reducing the overall cost and population needed to reach autarky.

It is clear that the vast majority of human labor on Mars should be performed in as controlled an environment as possible. That is, the city is built within a series of enormous, pressurized structures that enable comfortable, safe, efficient shirt-sleeves operations. Even mining operations would be preferentially operated within pressurized tunnels unless automated surface mining machinery reached a sufficiently high level of reliability. Yet establishing a local supply chain for essentially all the chemical elements will require hundreds of labor intensive, hostile mines, and some in remote places. For that reason, the labor requirement with primary resource extraction scales much more aggressively than for secondary manufacturing. Complexifying manufacturing, once large pressure vessels exist, is mostly a matter of direct translation from Earth analogs in a shirt-sleeves environment, and comes with a much less stringent labor requirement.

Is it even possible to build and maintain a habitat on Mars with a sufficiently benign environment for humans to get on with the job? Although the answer seems trivial, there is an overhead for building walls to keep the air in, and this overhead increases as the environment gets more hostile. For instance, it is probably possible to do this on Iceland, or Mars, or the Moon. But a comet? Or isolated city in deep space? What about on the surface of Io, or inside Jupiter, or the bottom of the ocean? While I am sure that a human terrarium on Mars is doable, I am quite sure that no amount of technology would permit humans to build an industrial city inside the sun. 

Detailed Icelandic prescription

To return to the Iceland question, what 200,000T of stuff should be obtained to survive a period of indefinite isolation with minimal reduction in standard of living?

Let’s look at trade to get some ideas about what Iceland will miss the most, and to understand what needs to be duplicated locally. Here’s a treemap of Icelandic imports in 2015, which groups by sector and ranks by total value. 

Screenshot from 2020-07-19 23-11-32

As expected, the major part of Iceland’s imports are connected to its role as one of the world’s largest smelters of aluminium, an energy intensive industrial process that exploits Iceland’s cheap electricity. Iceland exports nearly all its aluminium, so it’s not clear that retaining that industry would be a high priority in the event of total isolation.

The next most salient component is refined petroleum, cars, and other heavy machinery. This component concerns the obtaining and disposal of energy for useful work. Iceland has an abundance of electricity, but gasoline remains the universally preferred way to fuel mobile machines. These machines increase the per-capita work capacity of humans by a factor of 10-100, so it’s clear that maintaining a modern standard of living will require some way to fuel them. This is the single largest challenge for Iceland, and also for a city on Mars. In Iceland’s case, a mixture of high power electrical umbilicals at work sites and battery driven hydraulic power units are probably the best way to retrofit existing machinery and ensure the continuing availability of industrial capacity.

The next largest category are manufactured goods, including parts, electronics, appliances, chemicals, medicines, and so on. A simplified local manufacturing capability for some minimum viable combination of these must be designed. This is a tough problem!

The next largest category are raw structural materials, including metals, plastics, and textiles. This is particularly challenging as Iceland does not have commercial deposits of mineral ores or onshore oil. Limited quantities can be produced from non-standard feedstocks, but it will be labor and cost intensive. This is also a tough problem. While Mars is believed to have ores concentrating all the usual minerals, it does not have a global supply chain so settlers will be limited by what they can access in the immediate vicinity of their base.

The Iceland National Statistics Institute has 4468 categories of traded goods, including live primates, trichloropentafluoropropanes, and nine categories of cranberry juice. A detailed discussion of alternate sources for every last product is beyond the scope of this chapter, but does underscore the utility and diversity of modern trade. 

34 thoughts on “Case Study: Iceland

  1. It has been proposed that the inhabitants of Tasmania lost a lot of their technology when the sea level rose; see: “DEMOGRAPHY AND CULTURAL EVOLUTION: HOW ADAPTIVE CULTURAL PROCESSES CAN PRODUCE MALADAPTIVE LOSSES- THE TASMANIAN CASE”

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  2. Thank you for the post. Makes a permanent colony look less doable.
    Question? Has SpaceX or anyone had plans for launching supplies ahead. Is a space container style vessel possible so a sufficient amount of supplies could be in orbit waiting to be ferried down.

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    1. Starship can carry about 6 containers of stuff to the surface. This is an improvement as the best currently operating system can carry about one pallet. I think SpaceX would deliver lots of cargo before humans. But not 20,000 containers’ worth.

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      1. I really like the “shipping container” comparison. It just emphasizes how many launches it would take to send what really isn’t that much in terms of cargo. A cargo carrier is a big ship, but not “found a self-replicating society” big if you need advanced technology to do so.

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  3. I found this post very interesting. Perhaps, because you chose to illustrate the questions via a earth bound example, and particularly the review of Iceland’s imports and exports, the issues are easier to comprehend. Thanks

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  4. I would quibble with Japan being the smallest country being capable of making “a sufficiently complete set of computer components”. I would estimate that Germany with a population of 83 million is quite capable with the GlobalFoundries Dresden fab, Siemens and many other component manufacturers.

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  5. Great post! I love the breakdown of Icelandic imports. I wonder if there are pre-modern or early modern island settlements where import data are available from their establishment. the Azores come to mind but I don’t know much about them.

    I have one quibble with a minor example which doesn’t detract from your argument– I would scratch early colonial Virginia from this essay and replace with examples of isolated island settlements. Early Euro-American colonies were trying to establish trading colonies amid dense, settled agricultural communities rather than autarky in “hostile environments.”

    All Euro-American colonies relied on trade with their indigenous neighbors for agricultural and commercially-hunted foods for decades, even well after establishing export-oriented plantations. For example, in the 17th century South, cornbread would have been made from cornmeal and clarified bear fat (sold by the deer skull’s worth) sweetened with persimmon molasses, all shelf-stable indigenous trade goods predating European colonization.

    Additionally, The concept of North America as a “hostile environment” has an insidious history that is best avoided. Humans were densely settled and thriving in the Powhatan Confederacy, and dirty English swamp forts were only permitted in the hope of local political advantage through access to trade goods. Same goes for Plymouth, Louisiana, etc. To label such places “hostile environments” writes later processes of indigenous genocide back into the early colonial narrative.

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    1. I agree that with the correct (cultural) technology North America was very habitable but the early European colonialists went out of their way to make things difficult.

      The only island that has sort of attempted autarky is Cuba and they failed, but it may be interesting to track down what they imported from the Soviet Union.

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  6. Fun!

    Reactions as I go:

    “Here is the thought experiment. Given one large containership of any desired cargo, can one devise a strategy …”

    No. The dynamic, trial-and-error aspect of the process is essential. Even running it once won’t completely work, because a different city will make different errors.

    “In particular, it is possible that beyond a certain technology level, the minimum population level stabilizes as computers are doing all the work. ”

    I don’t think it takes such an extreme, for required population to stabilize. If you have better ways of modifying an aluminum smelter to run on whole basalt, instead of having to go through multiple leaching steps, you’ve simplified the process, and slightly reduced the number of people involved. If you have bacteria that secrete a selenium-binding protein, you can have one person grow them in a jar instead of needing several to run a chemical factory to get usable amounts of selenium from your slag leachate. We’ve been doing economies of scale, rather than trying to minimize required population, but having more options means you probably have options that are better for whatever you want to do, not just for what we’ve actually wanted.

    “That is, the city is built within a series of enormous, pressurized structures …”

    It’s not clear to me that the structures will be enormous. Fewer airlocks is nice, for decreased cost. But less distance to travel in the event of a pressure vessel breach is nice too, as is less volume to repressurize.

    “Yet establishing a local supply chain for essentially all the chemical elements will require hundreds of labor intensive, hostile mines, and some in remote places”

    As we’ve said on other posts, I envision the whole periodic table coming from at most a handful of sites, by “fracking for minerals”. On Earth, we have ultra-cheap ocean shipping and a wide range of ores and fossil fuels, so it’s worth bringing stuff from everywhere to where the workforce lives. On Mars, we have ice, basalt, and evaporate deposits. (Maybe some other stuff, but we can’t count on it.) And we’ll have the workforce live wherever there’s ice at the boundary between the two kinds of rock. Basalt has everything but C, N, and H. Air and ice have those. But it will be easier to get some things from meteorites or evaporites.

    “I am quite sure that no amount of technology would permit humans to build an industrial city inside the sun.”

    That tech, if it exists, would be indistinguishable from magic indeed. Maybe that’s what happened to all the ultra-advanced space aliens. They have no use for the tiny crumbs of matter that aren’t in stars.

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  7. It seems to me that autarky isn’t a plausible short-term goal. We can establish a city on Mars, but the way to do it is by having as much of the human work as possible be done on Earth. Human labor here is a lot cheaper than human labor there. Setting up a city on Mars is hard. If we make it harder by trying to achieve fast autarky, we’re likely to push it from hard to impossible.

    On the other hand, eventual autarky is one of the biggest reasons for having humans on Mars. We want (at least) a bi-planetary species, that can survive a global extinction. For this goal, we should try for autarky as soon as possible — but no sooner.

    I think the right approach, in order to get to autarky ASAP-BNS, is to maximize the growth of the capabilities of the Martian city. That means not maximizing the population, early on, because of the labor-cost difference.

    I imagine the early part of the process as being done almost entirely with semi-autonomous remotely-operated machines, and mostly with systems where the #1 design criterion is the ability to safely shut down for an hour or two, so that normally when a problem is encountered, people on Earth can look into it and send back a response. It doesn’t have to be absolutely 100%. The processes can be designed so that some rare events do require an immediate human response, as long as the volume of such events doesn’t exceed the capacity of the human population there. Some processes will be worth having a person on Mars monitor them in real time. At the very beginning, that will be most of the processes, because hardly any will have been started up yet; as more stuff gets underway, and the number of human workers on Mars remains fixed (we hope) until the next launch window.

    I imagine that the first thing to set up will be fuel production. Actually, I imagine that fuel production, or parts of it, will be set up in launch window zero, the one before the first humans go, along with test-scale versions of other systems that seem feasible to run entirely from Earth. These will be designed to do as much as possible without real-time human monitoring, plus a bit more, so that the engineers can learn from the failures.

    Fuel production will involve deploying lots of photovoltaic film made on Earth. I imagine lots of extremely energy-intensive processes, and I imagine that producing PV locally will require too many prerequisites for the Martians to do it early on, so I imagine something on the order of a whole Starship-load of nothing but PV film, initially deployed by unrolling it onto the ground, with no supporting structure.

    Fuel production also involves extracting lots of ice, which involves either moving or heating lots of regolith. Even if the resource was originally a glacier, the surface ice has sublimed away over the millions of years, leaving rocks behind, and wind-blown dust has filled in the spaces between.

    Once they have fuel production going, the Martians are making hydrocarbons from local resources. Making some hydrocarbons means they’ve done most of the work to make at least some other organic chemicals. Compressing air to make fuel means they’re also collecting a little N2, which opens up another category of organic chemicals. So I think one of the next things they make will be one or two kinds of plastic. Those will be used to make simple components of machinery that was designed to have its high-mass low-complexity components made locally, and shipped mostly-assembled but without those parts. The plastics will also be used to make supporting structure for the PV film, so that it can be angled at the best slope for the latitude, and so that it accumulates less dust.

    Also involved in making these components will be basalt fiber. The machinery to make basalt fiber should be relatively simple, at least compared to the complexity of the overall industrial stack. They’ll need to quarry rock, transport it, melt it, extrude the melt, cool it at a controlled rate in a non-reactive atmosphere, and coil it up.

    And so on, through aluminum, steel, and a small but expanding range of specialty chemicals, along with a small but expanding set of fabrication processes to make use of them.

    None of this looks like autarky.

    Everything will still be mostly done with tele-robotics, with everything designed to tolerate minutes of light-speed lag so that as much of the human labor as possible can be done on Earth. Mars will need a virtual population of engineers and remote operators, many times larger than its actual population of real-time machine operators.

    Notice that phrase, “many times larger.” It provides another way of looking at autarky.

    Initially, more equipment will be set up and combined with its locally-sourced components. More process will start, as their feedstock becomes available, and their output provides the input for yet more. So the virtual population will expand rapidly as the human population stays constant. On a longer time scale, though, the number of Martians will expand, launch window after launch window, and eventually through local births. As the human population expands, the constraints of having to design everything for a light-speed lag will begin to be lifted. The ratio of virtual population to actual population will begin to fall. Eventually that ratio will be close to one, and that’s when autarky is possible.

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      1. This finally got me to order a Kindle book. I like having physical copies of books, which will still be physical copies after the purveyors of electronic content have changed format enough times that the current ones are unreadable.

        At the moment, I’m thinking that full autarky on Mars is impossible, same as it is anywhere on Earth, and for the same reason: the transportation costs just aren’t high enough to get an entire society to abandon the advantages of trade, except by the kind of fanaticism that winds up with zealots running your economy into the ground. What we need is a city that has a glide path to autarky, so that if humans on Earth suffer global catastrophe, Mars will be able to have the results there only be a disaster, not extinction.

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  8. Here’s a specific question as I’m reading: why are metals shown on the diagram as being an order of magnitude harder (as measured by the human population needed for self-sufficiency) than cement/masonry?

    On Earth, cement is made from limestone, clay minerals, and gypsum. It seems unlikely that Mars has all three in the same place with adequate amounts of ice.

    I imagine that the Martians will use plastic in applications where we use cement, and that Martian concrete will use waste from basalt-processing as aggregate. Or just regolith, which they might run past a magnet to get any iron meteorites, or past imported equipment that can distinguish all kinds of meteorites from ordinary low-value material.

    Using imported metals to build a railroad, or a long-haul truck fleet and regular roads, seems like a non-starter. Potentially, they could live far from the ice, and transport water with a pipeline, or methane plus O2 with a two-pipe pipeline, if insulation is harder than I think it is. Either way, a pipeline doesn’t sound like a winning option unless the mineral resources are really valuable. Or if there’s enough water for the first several years in one location, and then they switch to another glacier after the first one is depleted.

    But I imagine long-distance transport, on a planet with no oceans and a population under ten million, to be extremely expensive. Geological samples can be transported by Starship from one side of the planet to another, perhaps, if the information they contain is valuable enough. Rovers left at each sample site will travel hundreds of miles to collect surface data and place seismometers. If there’s no better source of energy, perhaps a railway could go down one of the impressively long impressively steep slopes that Mars has, with regenerative braking all the way, hauling material down and having empty cars come back up. Perhaps. But I have trouble imagining pretty much anything else going more than a few miles until long after the (first) Martian city is self-sufficient. The reason for “a web of towns” may appear in a chapter or two, but at the moment it just sounds like an analogy to a place with plate tectonics and navigable rivers.

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    1. My perception is that it’s easier and cheaper to produce rock-based products (gravel, concrete, aggregate, masonry) than metals, as the inputs are less sensitive to ore concentrations and the chemistry and thermal requirements are less stringent.

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  9. Ok, time to recalibrate my reading:

    “Brick, and masonry more generally, can be used to build large vaults, domes, towers …”

    Domes. I guess the version I’m reading is a wee bit behind your current thinking.

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  10. It makes sense not to. But “How To Industrialize” is only a couple years old, so I was thinking of it as being basically current. A couple years is longer in some contexts than others.

    Today I’m still thinking, as I was during our first “fracking for minerals” discussion, that smashing and hauling rock is something to minimize pretty stringently. It’s gritty. There’s lots of friction. Stuff will wear out, including stuff that’s hard to make on Mars. It’s probably better (usually, and as much as possible) to crush and haul once, and then use everything but the moo.

    But instead of one system, now I’m thinking two. There’s the fracking-for-minerals operation, and then there’s one that’s based on adapting aluminum manufacture to work on whole rock. They’ll dissolve the rock in some kind of molten salt, as in aluminum production, and then they’ll do both fluid-phase separations and electrolysis steps. I’m guessing that, for some mixtures, electrolysis will be a no-go because it would reduce one of the ions of the molten-salt solvent before it would reduce the stuff from the rock. Supercritical CO2 and water are miscible (with each other), and they’re immiscible with silicate melt: that’s how we get a lot of ores, in a planet where hydrated rock and carbonate sediment are constantly being subducted and then decomposing in the upper mantle. Some salts melt at a low enough temperature for organic solvents to be stable. But I don’t know what materials are soluble in what molten salt mixtures, so maybe this whole approach is a non-starter. Still, if they can have two systems of minimum-grit rock processing, it would provide appreciably more flexibility.

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  11. To elaborate on everything but the moo —

    I currently see two ways of using all of a rock: aggregate and glass.

    If you take anything vaguely rock-like, crush it to a suitable size, and mix it with something cohesive like plastic, asphalt, or cement, you’ve got a composite material that cracks can’t propagate through as easily as they could through either component alone.

    Something asphalt-like well may be a byproduct of organic chemical production. Make anything, and you’ve also made some impurities. The larger ones are likely to be more diverse, simply because a larger number of atoms have an exponentially larger number of possible arrangements. So the smaller byproducts can probably be reprocessed into a specific product, whereas the larger ones are likely to be gunk. High-molecular-weight mixed gunk is basically asphalt. They won’t be making a lot of it, unless it’s good enough to be an intended product, but they probably will make some. Most of the aggregate will probably be used with plastic, unless cement turns out to be easier than I’m guessing.

    Then there’s glass. Like obsidian, not like window panes. Take almost anything vaguely rock-like, melt it, and let it re-solidify in a non-geological amount of time, and you’ve got some kind of glass. Extrude it as it cools, and you’ve got some kind of glass fiber. Don’t extrude, but do control the rate of cooling, and you’ve got some kind of tempered glass. Melting has the advantage that it lets you reclaim volatile elements used in extracting the elements you wanted.

    My impression of glass is that it’s awesome stuff, halfway to being unobtanium. High tensile strength, high compressive strength, decent heat tolerance, ok range of chemical tolerance, ok abrasion resistance, … too bad about the brittleness, but that’s why we have fiberglass composite materials. I currently imagine two types of mass glass: one optimized, and one that gets made of the leftovers.

    The last component of EBTM rock processing is ceramics. Glass is made by melting *almost* anything vaguely rock-like. But there are oxides that aren’t all that interested in melting, and aren’t the oxides of metals you want to smelt. Or at least you don’t want to smelt enough of them to use all that’s in the rock. There are high-tech ceramics that perform impressively in a decent range of applications. I imagine that the Martians will make as much of those as the rock-processing gives them the right elements for, along with a leftovers material.

    Who needs ore?

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  12. “How to Industrialize” mentions Zubrin’s “Case for Mars” for the presumed availability of ores, so I got it from the library. Not encouraging. Slightly more than in my last few comments, I’m back to guessing that there’s basically no ore.

    My guess for how the Martians will get moderately rare elements, that are needed in amounts beyond what they get by collecting meteorites, is to import them. But if the people supporting the city through its period of economic dependence are serious about autarky, I think they can set up rock processing in a way that will let the Martians get enough of everything. That’s more fun to imagine and it’s a better idea if the Martian city is to be a valid hedge against global catastrophe on Earth.

    My favorite approach is biochemistry. We can absorb any element our bodies can use, in some cases from food that only has micrograms of it.

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      1. Indeed. I imagine that the necessary molecules will be made in microbes, and used in industrial processes, such as having counter-flow separators with proteins that are mostly water soluble by themselves, when they bind to a specific element they become mostly oil soluble.

        Without biomolecules, leaching with the right sequence of solvents under the right conditions may be able to concentrate a scarce element by an order of magnitude per cycle, but biochemistry can do a lot better. Once people figure out how to do it efficiently, it will be worth it on Earth too.

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  13. I was thinking that the Martians will have two kinds of rock to work with (plus meteorites). I’ve raised my guess to three (plus meteorites).

    I was thinking that the site of the city would be chosen by identifying the two most useful kinds of rock, and looking along the boundary between them until they find a site with adequate water. But the stuff I just read sounds as though water by the km3 is available in more places than I was imagining.

    There should be four kinds of rock: basalt, aeolian sediment, evaporites, and whatever makes the southern highlands high.

    To have highlands, you need something with lower density. On Earth, it’s continental crust: granite, andesite, diorite, and so on. Oxygen contaminated with aluminum and silicon is less dense than oxygen contaminated with iron and silicon. On Mars, granite never happened.

    But something did, or we wouldn’t have highlands. My guess, based on almost nothing, is magmatic differentiation in a primordial magma ocean. As a magma chamber cools, the minerals with the highest melting points solidify first. These tend to be the more mafic ones, i.e. with lots of magnesium and iron. That makes them denser, but even at the same composition, crystals are denser than melt. By the same token, high pressure tends to squeeze material into the denser form, so it favors crystals and lower pressure favors melt. That’s part of why the mantle is solid, even though it’s hotter than magma in the crust. In Mars, the lower gravity means that pressure increases more slowly with depth, so I find it plausible to imagine that Mars had a global magma ocean long enough for the slow processes of differentiation and convection to work, leaving highland rock that’s a bit more felsic (more feldspar and silica) and has a different profile of trace elements.

    In two dimensions, the boundary between two areas is a curve, and three intersect only at a point. But there can be very many such points, if one of the areas is very convoluted or disconnected, forming a dotted line along the boundary between the other two. If adequately icy locations are common, then some of the dots will be icy enough too.

    Another potential source of minerals is the ice itself. As a body of water partially freezes, the ice is nearly salt-free and the remaining liquid is saltier than the starting composition of the water. The last ice should precipitate minerals between the ice crystals, analogous to an evaporite deposit. Adsorption of ions onto the surface of ice crystals, combined with flow of the brine and many cycles of partial melting, might result in useful separation of some elements.

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    1. I think there is granite, but mostly buried.

      The crustal dichotomy is controversial but some people think the northern plain is an impact crater. Much of the highlands is a kms think layer of ejecta.

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      1. Why do you think there’s granite? As best I understand it, you get granite by partial melting of rock that was already more felsic than anything that’s abundant on Mars. And partial melting doesn’t count unless the melt moves up out of the source rock, which is more difficult in lower gravity.

        As for the northern hemisphere being a crater, my guess is sort-of. The dichotomy sounds as though it’s too high to be superficial topography, that can ignore hydrostatic equilibrium, even with the lower gravity. I don’t know how to turn the stresses into anything simple enough to do back-of-an-envelope calculations about, but it seems like a diminished continental-vs-oceanic amount of height difference, rather than an increased hill-vs-valley amount. Anyway, in my guess that there was a magma ocean with global-scale convection, it would help to have some initial difference to get the convection going, and the heat from a major impact could do it.

        If there is granite, I agree about the mostly buried part. As I try to imagine granite on Mars, the best shot I’m coming up with is under the big volcanoes. I’ll have to look at the topography again, and try to imagine Olympus and its neighbors as not just volcanoes but a quasi-continent whose magma chamber partially re-melted some crust, and then re-melted the resulting batholith, over and over until there was a mass of quasi-continental rock there to help hold the mountains up. If that works, it could give us some ores, but they would probably still be too deeply buried to be of use.

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  14. This is very encouraging, for the existence of ores. I’m still at a level of ignorance where I keep changing my guesses all the time. I usually like to assume whatever’s worst for the Martians, and then try to figure out how they can deal with it, which leads us to scenarios like one or two quarries and fracking for minerals.

    Part of the process that gets us economically useful ore is erosion and uplift. Continents collide, and we get mountains. They wear away, and a billion years later the stuff that was ten km deep underground is only one km deep or less.

    The Martians may have reason to do very deep mining. Low gravity should help some with that. There’s also the possibility that useful mineral deposits may have been exposed by the rifting of Valles Marineris, or by the impacts that formed some of the deeper craters.

    Another part of what gives us ore on Earth is the flow of fluid (supercritical, rather than liquid or gas) through rock. A lot of the fluid gets deep underground when carbonate rock and water trapped in the sea floor get subducted. But some is primordial. Hawaii is a hot spot, based deep in the mantle, not dependent on subduction. It erupts with pretty fountains of lava that are propelled by the release of gas. There’s no ore in Hawaii, but there would be if it would just sit still for three billion years instead of rushing off to the nearest subduction zone all the time.

    One implication for the Martians is that it’s worth doing a lot more prospecting than I thought. Launch window negative one should install a global network of seismometers so we can learn about the inside of the planet. A global network means propellant production to fuel many suborbital flights. I had imagined propellant being at pilot scale following launch window zero, and ramping up to full after the first launch that brings people. Now I imagine fully autonomous fuel production four years before the first person arrives.

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    1. A seismometer can be quite small. Entry and landing gets easier as things get smaller. It might be worth dropping off a bunch of seismometer/shield/parachute packages while Starship is still a ways from the planet, rather than making tons of methane to place each one. Or, send a small hopper (as cargo) that carries a few seismometers rather than lifting 100 tons of Starship to each destination.

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  15. Interesting blog and comments. I was hoping for some rough order-of-magnitude numbers for the minimum population size for the various industries. I’m thinking the electronics part alone would require thousands of people, if you look at existing semiconductor foundries. It wouldn’t need the latest sub-micron techniques, but you would need to be able to make solar panels and reasonably smart processors, like maybe Cortex M microcontroller. In theory you could probably even start with an old 8-bit microprocessor, as long as you could eventually update it.

    I was approaching this from the idea of writing a story about an apocalyptic event where we have a few months to get one or two hundred people into a space craft, along with the necessary machinery, so they could go to an asteroid (or Mars) and start rebuilding society. I quickly realized a few months and two hundred people wouldn’t cut it, even with people picking up new skills as needed and cycling thru tasks.

    But what would you need? Two thousand? Ten thousand? Even more?
    Is it better to go old-school and bring goats, chickens, cotton, and bamboo, or go high-tech with manufactured meat and GMO algae to produce oils that can make plastics?

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