When the most active close-up of an asteroid most people have ever seen is an overdramatic and – sorry to say – bad Bruce Willis death scene plus build-up, there are bound to be questions about what productively moving about on an asteroid will look like. Throw in the recent James Cameron/Larry Page/Eric Schmidt/Ross Perot, Jr. suspense, and those questions might be just be a little more important come tomorrow.
Namely: What would mining on an asteroid be like?
The composition of the asteroids themselves can vary from pure metal to a crumbly mixture of silicate dirt and nickel/iron granules, with billions and billions of said asteroids belonging anywhere on that spectrum – and potentially off of that spectrum, since we really only know the asteroids studied in our solar system. Both gravity and escape velocity will be really, really low, so massive amounts of otherwise ridiculously heavy metals will be moved with low energy output. So we have potentially easy-to-move metals just floating around in space, waiting for us to get at them. How do we go about doing this?
Wikipedia, at least, gives four basic ideas for the actual process, the first two of which are commonly used on Earth: strip mining shaft mining, magnetic rakes, and heating.
1. Strip Mining:
Strip mining, at its most basic, is scraping at the surface of a mass’s body and collecting whatever valuable resources emerge. But because we’re talking about a virtually gravity-free environment, we can’t just land and start scraping away like we do on Earth.
(Not that we should do it that much on Earth, either, but that’s a different subject, one best explained by people both indignant and informed about ridiculously unsafe uranium strip-mining in Navajo lands.)
We would have to somehow tie or harpoon the mining equipment to the surface of the asteroid. The now more crumbly asteroid pieces would released into some sort of cloud due to the low escape velocity – escape velocity being the minimum velocity an object needs to escape the gravitational field. This cloud of both debris and valuable metal pieces we want to collect is both a problem, since it’s blocking the whole mining operation from view, and a good thing, since it allows for easy, low-energy collection: the mining companies will just have to sweep it all up into a net and bring it to a different location for processing, refining, et cetera.
That second part is also easy, because the same kinds of forces that dragged the majority of Earth’s valuable metals into the planet’s core will let the denser metals separate from the less useful dust.
So, asteroid strip mining. Theoretically easy, no environmental hazards to really watch for, and even the by-products can potentially be made easily useful.
2. Shaft Mining:
This idea is a bit messier and more complex, but is potentially more efficient for large asteroid that have veins of specifically sought-after metals. In a nutshell, for this method of asteroid mining, we tunnel. Again, the machines have to be harpooned or tied to the asteroid, and the drills follow the valuable bits of the asteroid until the majority of the ore has been extracted. This method seems much more useful for very compacted asteroids that are more rock than valuable metal.
While bound to be more complex than shaft mining, as this probably won’t involve the conveniently produced cloud but instead will require active collection and transport to the surface, this method of mining doesn’t seem too bad, either.
3. Magnetic Rakes:
Remember that very rough spectrum at the beginning of this post? If strip mining might be the primary mining method on loose to somewhat compact asteroids and shaft mining would be for very compact asteroids, magnetic rakes would be for the most crumbly asteroid. The best example of this sort of asteroid is Kleopatra, which is essentially a dumbbell-shaped collection of metal grains. It’s very metal rich, very loose, and potentially very, very easy to mine. Really, all you need is a magnet and a bag.
Asteroids aren’t always just metal and rock. They have quite a bit of ice, too. Aside from water being a pretty valuable commodity in the space-industrial and space-colonial world where asteroid mining is prominent, its base elements make for a pretty awesome fuel. Rocket fuel can by produced through electrolysis of liquid water for separate hydrogen and oxygen gases, and methane fuel can be made by bonding hydrogen with carbon.
Is asteroid mining as simple as just that? Not by a long shot. This just gets it from an unusable form in an asteroid to a potentially useful form out of an asteroid. There are still manufacturing costs, shipping costs, getting it from low Earth orbit to Earth’s surface (if that’s what we end up doing with all the metal that really should going towards perpetuating space travel and colonies…). But it’s a start.
So – asteroid mining: is it worth it? Yes? No? Potentially in the future replete with actual space travel, but not right now? Be sure to leave your opinion below!
Rachel is the co-founder of How To Survive Alien Invasion Novels, and spends her time writing, studying, and reading what would probably considered far too many books. Connect with her and Rusty on Twitter and Facebook, and click here to read more of her articles about alien theories and how to survive alien invasion novels.
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