There are some people who think that mining asteroids is a good idea. And not just for building things to use in space, but to ship metals to earth to sell. They say things like, “The metals in the near-earth iron asteroid Amun are worth 20 trillion dollars
But is the current market value of metals the proper way to value an asteroid? Wouldn’t it make just as much sense to say that since I can buy meteorites for 25 cents a gram on e-bay, the market value of the asteroid is 25 cents per gram? And since it weighs 30 billion tons, therefore the asteroid is actually worth 7,500 trillion dollars? I mean that’s using the market price, isn’t it? And while these asteroid mining enthusiasts like to tell you how much money Amun is supposed to be worth, they never tell you how much a similar amount of earth dirt is worth. Well according to my calculations 30 billion tons of earth dirt is worth over $1,700,000,000,000,000. Which makes a ton of dirt worth about $57,000. Not bad, hey? Might be a good idea to run outside with a shovel.
But wait a minute, you say! How can plain earth dirt be worth that much? Well it’s quite simple. You see 99.9999% pure silicon sells for about $200 per kilogram
and the earth’s crust is 27.7% silicon
. Of course it’s only worth that much after you have removed and purified the silicon. Before that the dirt is only worth as much as dirt. But counting an asteroid as being worth what it would be if all it’s substances were refined, purified and sold at today’s prices is pretty much just as stupid.
To really test how much the asteroid is worth, let’s assume that there is a hole in the space-time continuum in your bedroom cupboard that not only allows instantaneous transportation of material from this asteroid, but it delivers it in conveniently sized chunks. Ignoring its novelty value, how much could you sell this asteroid material for on earth? Well the answer to that is simple. You could sell it for about $300 U.S. per ton because that’s what scrap metal sells for
these days and an iron asteroid is basically a big chunk of stainless steel. The good news is there are plenty of scrap metal dealers around so you won’t have to lug it too far to trade it for cash. This means that even with zero transportation costs and assuming that thirty billion tons will in no way push down today's current high prices, then at best the asteroid Amun is worth about nine trillion dollars, not 20 trillion.
But wait a minute! Some people say asteroids are supposed to be chock full of valuable metals such as platinum which currently sells for about $33 a gram
! Couldn’t we just extract the platinum and forget about the steel? Well there are some problems with this. You see on earth there’s all sorts of geological activity, mostly involving water, that can concentrate ores and metals. But iron asteroids don’t have this activity. They’re just chunks of a busted planetoid’s core. As a result, precious metals aren’t going to be concentrated but are going to be evenly spread throughout the damn thing.
But some iron asteroids, perhaps one in fifty, contain 30 grams of platinum per ton or more! On earth 30 grams of platinum per ton would be equal to moderate to high grade platinum ore, so if your chunks of asteroid had this much in them, surely you could sell them to someone who owns a platinum refinery for a good price? Well, probably not, because I don’t think they’d be very impressed by the fact that the platinum is inside a block of nickel alloy stainless steel. That could increase the cost of extracting the platinum considerably. Most things become harder to extract once they’ve been placed inside a solid hunk of steel. A platinum refinery wouldn't pay as much for it as a scrap metal dealer.
Some people say that weightlessness in space will make refining stuff like platinum easier. Well I challenge everyone in the whole wide world to name one thing that is easier in weightlessness, and you’re not allowed to say, “Floating in the air.” I can’t think of anything at all that becomes easier in zero gee. There is a reason why the space shuttle toilet
cost twenty-three million dollars, you know. But what if I’m wrong? What if it is easier to refine metals in weightlessness? If only there were some way to mimic weightlessness on earth. If only there were some sort of substance in which things could float. Just for the sake of the argument, I would call this imaginary substance a liquid. If only we could convert say platinum ore into some sort of magical liquid solution when we refine it. Wait a minute! That’s what they actually do in platinum refineries
! Several times in fact! Freaky, hey? But even so, extracting platinum from ore is a very expensive and difficult business, despite the weightlessness offered by this incredible stuff called liquid.
Then there’s the argument that we have to go into space and mine asteroids now because the earth is running out of metals. Well this just isn’t true. A couple of hours drive
from my house there is enough copper in the ground to supply the earth for maybe a couple of hundred years. But nobody is extracting it because the ore is so low grade it would take a hellacious amount of energy and effort to refine it. The more energy it costs to extract, the more the copper is going to cost. The earth might be running out of cheap and convenient high quality deposits of some metals, but it’s certainly not running out of metal. In the future we may have to pay extra for the energy to extract metals from low grade deposits, but it’s still going to be easier to extract copper from ore that only has a few kilos of copper per ton than it’s going to be to extract copper from asteroids that have only grams of copper per ton.
Now some people say that the costs of mining asteroids don’t matter because once we start it will all pay for itself. All we need to do is send a few robots to an asteroid and they will then build more robots and solar energy collectors and mining equipment and rocket ships and so on. Well, tell you what, you give me access to the same technology, you send your robots to an asteroid and I’ll send mine to say the middle of Western Australia. Then we’ll see who makes the most profit. Now you might say that my robots will have a disadvantage because it’s harder to use solar energy on earth than in space on account of things like clouds and night and bird poop, but my robots will have the advantage of being able to use wind power, or burn coal, or use geothermal energy, or dial up the local power company and get connected to the grid. All of these options are a bit tricky in the depths of space. I’ll also have the advantage of being able to drive out there with my spanner set and fix ‘em if something goes wrong. Also, you would have to waste a lot of time building and powering your rocket ships while I could spend my time building things people actually need, like robo prostitutes. Then there’s the fact that I can respond to changes in demand as they happen where as your stuff might spend years just being transported to earth.
Anyway, in conclusion I would like to say that asteroid mining is a pretty sucky idea. Now it’s probably just dandy for getting resources for use in space itself, but there just doesn’t seem to be any point in lugging stuff all the way from asteroids to earth.