Empress Josh asks
This wacky Lets Mine All the Asteroids scheme. Viable y/n.
Ah, a question where my answer isn’t immediately “That’s stupid” or “We couldn’t ever do that.” Mining asteroids isn’t stupid, and we probably will be able to do it at some point. The real question here is, can we do it today or (as I suspect Sergey Brin et al. damn well know) even fifty years in the future? And is it going to be worthwhile?
First, the why: why bother mining asteroids in the first place? Yes, the juicier ones will contain a vast, vast quantity of valuable resources, but asteroids are all the way up there and there’s still plenty of unexploited resources down here. Making a trip to an asteroid is currently a hugely expensive undertaking, and returning material from an asteroid to Earth is even more so (the Great Oracle tells me that it’s going to cost NASA $1 billion to get sixty grams of asteroid). While getting at Earth-based resources is going to become more difficult and more expensive over time as easily-accessible supplies run out, it should still be far cheaper to mine them from a source that’s already at the bottom of Earth’s gravity well instead of expending the huge amount of energy required to transport raw resources to and from a nearby asteroid.
That’s going to be the case for the short- to mid-term future. However, fairly soon now – and we’re talking within a period of time not more than one century – we’re going to start running out of the rarer resources our decadent Western civilisation requires for its technology and industry. Crucial elements used in electronics like gold, iridium and copper are going to become extremely thin on the ground, and consequently far more expensive. At that point we’re going to be faced with two alternatives: we either learn to live without our smart phones and our Google glasses and go back to a basic agricultural existence (which incidentally would require the die-off of about four-fifths of the human race) or we start getting our resources from further afield. Nobody is suggesting we start mining asteroids tomorrow, or even in the next couple of decades. In a hundred years, though, we’re pretty much going to have to, and so it’s good that somebody is starting to seriously think about it now.
As for the how, that’s a bit more complex. I’ve expounded before on this blog about what a bastard it is to get enough delta-V to get out of Earth’s gravity well, and at the moment this requirement makes any potential asteroid mining endeavour ridiculously expensive to the point where it would consume far more resources than it ever produced. You’ve got the following considerations to deal with:
- Lifting the equipment required to extract useful resources from an asteroid out of Earth’s gravity well and shooting it off to a nearby asteroid. This will not be a small amount of equipment; using today’s technology it would likely exceed the lifting capacity of all the major space players for the next dozen years.
- Developing technology which will autonomously harvest asteroid resources without human intervention. This is going to be absolutely necessary if we ever want to do it properly; we have a hard enough time getting minerals out of the ground on Earth where humans can do it, and sending humans to an asteroid would be a complete waste of time and effort since there would be little they could effectively do that robots couldn’t.
- Getting the mined resources back to Earth. This is somewhat less acute than the gravity well problem, but you still have to build transport vehicles in situ on the asteroid and then fuel them somehow.
In order to overcome these problems we are going to have to make some very significant advances in robotics and/or nanotech-scale devices, but the good news is that if we manage it its going to be kind of a catch-all solution. If we can somehow build functioning self-replicating machines then most of the problems facing the concept of asteroid mining are greatly alleviated. It would still be a pain to get the initial payload out of Earth’s gravity well, but you’d only need one self-replicating machine to start the ball rolling making that initial payload comparatively small. Any machine with the ability to autonomously build a perfect copy of itself would have absolutely no problem strip mining an asteroid. Ditto for returning the raw/processed materials to Earth; assuming sufficient volatiles could be found within the asteroid to fuel a transport spacecraft (for “volatiles” read “hydrogen and oxygen” or “water”) then the machines could build that as well. That’s the nice thing about asteroids: they’re so big that all the raw material to do this stuff is already on-site waiting for us to do something with it.
The bad news is that this is the only realistic way I can see of making asteroid mining work on any kind of practical level. Any other solution runs smack-bang into one or more of the three problems outlined above which spell doom for any putative asteroid mining effort: you have to either take the equipment required to mine the asteroid out to the asteroid (nigh-impossible) or else physically move the asteroid to Earth orbit where you have an easier job of getting at it (actually impossible*). What can I say? Physics is a bit of a sod when it comes to space travel.
Still, Planetary Resources Inc. is one of those things that sounds completely ludicrous but which makes perfect sense if you think about it for a bit. Half the trouble with national spaceflight programs is that they’re projects requiring planning horizons of several decades or more which are completely at the mercy of ADD-riddled governments who are only concerned with the outcome of the next election cycle. Asteroid mining is a necessary technology that could easily take 50-100 years to come to fruition and so it’s probably a good idea for this company to begin working on it now, because I guarantee you nobody else will until it’s far too late.
*On any kind of useful timescale, anyway. I said in the nukes post that you could deflect an asteroid with long-burn rocket motors, but parking an asteroid in a stable Earth orbit is a different kettle of fish entirely.