First, some bad news: If you've been practicing for a job as an in-person asteroid miner-wearing an old-timey diving suit, drinking your own (recycled! purified!) urine, etc.-you can give it a rest. Asteroid mining and prospecting probably won't involve astronauts with jackhammers and pickaxes. Like most of the space exploration in the near future, we're looking at a robot workforce. The human asteroid miner will likely be more of a robot puppetmaster. The good news: That still looks pretty nice on a resume. "Robot Puppetmaster."
To follow up on my previous post, yes, it might actually make economic sense to extract metals and water from free-floating asteroids in space. But now I want to discuss a few ideas about how we could get this boulder rolling, and what some of the challenges are.
A few stressful things that potential asteroid miners must consider:
1.) Space is huge and empty.
2.) The things floating through it tend to move really fast, and it's hard to catch them.
3.) It's no trivial task to maneuver unmanned probes for remote landing or docking with tiny gray clumps in the far darkness.
4.) Most asteroids are relatively small and pretty far away, so we don't yet know for sure which ones are the most feasible to mine.
When I first looked into this, I immediately wondered: Have we ever successfully landed on an asteroid before? Actually, the answer is yes. In 2005, a probe called the Hayabusa, launched by the Japanese Aerospace Exploration Agency (JAXA), intercepted the S-type near-Earth asteroid Itokawa, landed on its surface and collected a teensy-tiny dust sample to bring back to the home office. Analysis showed that the dust contained minerals like olivine and pyroxene, both of which are abundant on Earth-a nostalgic reminder that Earth and these asteroids probably all graduated from the same protoplanetary accretion disk about 4.5 billion years ago.
This is cool, but don't get carried away. Just because we've done it once doesn't mean that asteroid sampling is free beer and pizza. Even in this successful mission, there was a lot of difficulty-for one thing, Hayabusa should have collected more dust than it did. Originally, the plan was to shoot the surface of the asteroid with a big bullet, the impact of which would cause clouds of dust to fly up and settle into the sample return container. In a moment of classic action movie misfortune, the gun jammed on the asteroid's surface (technically, it seems a built-in safety feature prevented the projectile from firing), leaving only the dust kicked up by the landing itself in the chamber. On top of that, Hayabusa's main engine failed, and the probe had to rely on supplementary ion thrusters to sputter across the finish line to its touchdown in Australia in 2010. Fortunately, researchers were able to learn something from the few invisibly small particles it did manage to gather. Even so, the close shave reminds us that missions like this are crazy hard to pull off. And that's just the surveying angle.
So, once private enterprise has its hands on the wheel, how will it be done?
The asteroid mining venture Planetary Resources offers a multistage technological outline, beginning with the deployment of a privately owned "Arkyd Series 100" low-Earth orbit telescope named Leo, which will do early scouting for the most promising asteroids within our reach. Once the field has been surveyed and candidates have been chosen, the company plans to launch its primary Interceptor vehicle to perform fly-bys of near-Earth asteroids as they scrape closest to our orbit. More distant candidates will meet with interplanetary ranger spacecraft known as Rendezvous Prospectors, which will likely work in teams to provide enhanced data, including the "shape, rotation, density, and surface and sub-surface composition" of asteroids, and also to protect against unforeseen failures in single probes (think what almost happened to Hayabusa).
Deep Space Industries, the other major asteroid mining company in operation, has announced plans to begin unleashing waves of its own small prospector robots, known as "Fireflies," by 2015. I'd be surprised if they stay on schedule, but if they do, consider that this is only two years from now.
All of this prospecting leads up to the final stage, where the greatest technological challenges lie: The mining itself. Will probes try to extract valuable metals from asteroids and then launch away with their payloads, or will we end up lassoing small asteroids and steering them into Earth orbit for easy access? (Just something to consider: If you think the concern about an oil tanker spill is something fierce, how much more would we freak out when some corporation moves a potentially planet-killing rock right into the drop zone? With this in mind, it would seem that any asteroid we bring to Earth orbit to be picked clean by robot miners would have to be a very small one-small enough to burn up in the atmosphere if we lost control.)
According to Planetary Resources' timeline, the very first outer-space mining operations will be focused on water, rather than metals, whether precious or construction grade. If this seems weird to you, remember that water is an absolutely vital resource in space, and it costs enormous amounts of money to launch even just a few gallons from Earth to orbit. The massive stores of frost that we drill from a near-Earth asteroid will enable subsequent missions to operate more easily, and may even be necessary in order to build hydraulics and other machinery necessary for refining metals in space.
Speaking of such machinery, we should pause to think about what a mining and refining operation in space actually entails. The miniscule gravity and lack of atmosphere on an asteroid present both advantages and disadvantages to potential harvesters. Microgravity means that it's way, way easier to send payloads off into the sunset. To launch from Earth, Mars or any other sizable object, you need a huge amount of thrust. This is one reason that, as I mentioned before, space launches are so heinously expensive. Comparatively, launching a payload of platinum from a small asteroid is nothing. There's no real gravity well-you could almost just hire a beefy guy to throw it. But then there are the costs: All of our industrial experience with extracting and refining metals from the Earth has taken place in an environment where flames roar to life on a healthy diet of free oxygen, and where atmospheric pressure and gravity act on everything. Just think how few of our machines would work in a place where: 1.) Things don't catch on fire, and 2.) Things with mass don't accelerate toward the ground at 9.8 meters per second per second. Not so easy.
And there's another challenge-one that might have occurred to you if your technical emphasis is less mechanical and more legal. Assuming these companies pull it together and mount some prospecting missions, who actually has the right to set down on an asteroid and plumb its rocky depths? Can the contents of space really be said to belong to anyone? Are asteroids a case of first come, first serve?
Ever since the Outer Space Treaty of 1967 was signed and ratified by the United States, the Soviet Union and other potential space-traveling powers, we've basically agreed that space doesn't belong to anyone. This treaty prevents sovereign nations from staking new territories on celestial bodies, but it doesn't explicitly mention whether persons or private companies can make a profit exploiting extraterrestrial materials. This is uncharted legal territory. It's legitimate to wonder if potential asteroid miners are getting into a situation like that of Dennis Hope, the Nevada-based entrepreneur who has made millions of dollars selling people property on the moon and other planets. Does he actually have a right to do this? I'm skeptical, but who knows? His claim is basically that the rules are ambiguous and he thought of it first. This doesn't stop him from taking people's money right now, but once moon colonization really gets going, it's hard to believe the tickets he's selling will be redeemed. How are asteroids any different?
University of Tennessee law professor Glenn Harlan Reynolds makes a useful distinction in this article for Popular Mechanics: If it's something you can't move, like a planet (or even a really huge asteroid like Ceres), it's probably considered a "celestial body," and thus it cannot be claimed according to treaty. If the asteroid is small enough for you to pull or push, however, it's more like a natural resource here on Earth, and is probably fair game. Another distinction may be brutally practical: Once you harvest a bulk payload of platinum or ice from space, who is going to tell you that it isn't yours? Is someone going to try to physically take it away from you? Now, owning a slip of paper that claims to be the deed to a tract of dusty moon land - somehow that's not quite the same thing.
Got a brain-itch about the feasibility of this project? Feel free to leave a comment.