字幕表 動画を再生する 英語字幕をプリント Some say humanity's future as a space-faring species is just around the corner. But realistically, how are we going to get there? The answer is asteroids. These seemingly unimpressive lumps of rock could actually be the intergalactic pit stops for exploring the universe. They have the potential to become cosmic gas stations and the building blocks for habitats on Mars; to change how we navigate through space, and even to revolutionize Earthly engineering and economies. But their potential remains untapped. - We call the asteroids the stepping stones to the solar system. And we live in the age where humanity will make the leap into space. So how close are we to mining in space? Scientists and entrepreneurs want to mine asteroids because they can contain metals, water, rare minerals, and even elements that are impossible to form on Earth. They're huge, they're everywhere, and while they all sort of look like your average space rock, there are some key differences between each type that determine which one to mine first. From the outside, the one with the most gold-rush potential would seem to be “metallic asteroids,” made of nickel-iron, that may also contain valuable metals like palladium, platinum, and of course, gold. But don't be fooled. The real jackpot here is the Carbonaceous asteroids, which might just contain the most valuable resource of all... water. - Before we go after the minerals for mining purposes, the first thing we need to do is learn how to extract water from asteroids. Water is going to be like the oil of the Space Age. A water source in our planetary neighborhood would be like a space oasis: a source of hydrogen and oxygen for rocket fuel and life support systems, a tool to shield us from radiation, and even a source of drinking water for astronauts. The problem is, finding these C-type asteroids is... tricky. - The carbonaceous asteroids are extremely dark, darker than a blackboard, darker than freshly laid tar. How do you find those? All that sunlight they don't reflect gets absorbed, warms them up, and they glow in the infrared. That's why scientists at NASA's Jet Propulsion Laboratory are developing the Near-Earth Object Camera, or NEOCam, which, in addition to identifying potentially hazardous Near-Earth Objects, will be able to comb the infrared for evidence of C-type asteroids. Okay, so we can identify which rock to target. Now we just have to figure out how to get a piece of it. While a number of space probes, like Hayabusa 2, are working on this right now, they're still just at the sample collection phase. What we need is to know how to successfully mine an asteroid. Nets, harpoons, augers, and even a giant magnetic “rake” have all been proposed. The problem is traditional mining methods rely on the application of force – which is a challenge in low-gravity. - If you saw the movie where Bruce Willis saved the Earth by landing on an asteroid and dropping atom bombs… that's really problematic. - A lot of these asteroids are just piles of rubble, and they're held together by microgravity, a million times weaker than gravity on Earth. If you hold onto a rock, you say, "Ah, I've landed on the asteroid," you pull on the rock because you're trying to drill in, it'll come away, right? And then the next one will come away, and then the next one. What are you actually going to hold onto? One Zen answer: nothing. At least, that's the idea behind the approach that Dr. Sercel and his team at TransAstra are developing, dubbed 'Optical Mining.' - What we do is we take large, very lightweight, thin film solar reflectors, concentrate large quantities of sunlight into small areas. When the sunlight hits the surface of the asteroid, it causes a thermal shock that breaks the surface and drives the water and other valuable volatile chemicals out. That process of driving the volatiles out actually cleans the surface so that more sunlight can drill holes in the surface. We don't even have to touch the surface of an asteroid to dig holes in it. This ant-and-magnifying glass technology sounds like some kind of sci-fi-laser-ray-gun, but it's real. And Joel's team is about to start the next phase of testing it using the world's biggest lightbulb and synthetic asteroids at the Colorado School of Mines. And with continued support from NASA, their experiments are generating some buzz. But what then? What do you do with a bag of vaporized space rock? - A clever idea that TransAstra is developing is that they will go to an asteroid and use some of the water that they mine as propellant to come back. - If we can turn near-Earth asteroids into gas stations to refuel spacecraft, that has a tremendous effect in reducing the cost of human exploration. And the propellant thruster that TransAstra is developing channels one of the most industrious creatures of the animal kingdom. - Just as honeybees harvest nectar and they use then the energy of the nectar to power their civilization, the APIS architecture harvests water and other valuable materials from the asteroids, and then uses those materials with sunlight to power space industrialization and settlement. First, TransAstra will launch Mini Bee, a small demonstrator vehicle, to test their method on a simulated asteroid in low-Earth orbit. If that can prove that Optical Mining works in space, a larger craft called the Honey Bee will follow, and with the help of tug vehicles they call Worker Bees – they'll pave the way for the Queen. - The Queen Bee is the ultimate asteroid mining system. It's designed to fly out to an asteroid that might be a hundred feet across, capture that asteroid in a giant enclosure, and then mine thousands of tons of water and other valuable volatile materials from it. - A small fleet of Queen Bees will create a large ecosystem of water and other valuable materials in Earth space that'll make it so that private venture can afford to build hotels on the moon and ordinary citizens will be able to fly into space, aggregate their resources, and build space settlements out of asteroid resources. But hold your horses... or, bees, I guess. This sounds like we're getting back into that gold rush territory. And what we don't want is to completely deplete the resources on Earth and then do the same thing in the Solar System. That's why Dr. Elvis is fighting to preserve the majority of our solar system as wilderness. - We are very bad at looking ahead and seeing the consequences. We need a warning bell, a trip wire saying, "If you got to this point, you may not think it, but you're very close to finishing the entire resources of the asteroid belt." So let's say we did preserve most of the solar system's untrammeled wilderness... like 7/8ths of it. Then what would that leave us with? - One-eighth is only three steps away from complete exhaustion of the solar system's resources. And if we stopped at that point, we could keep that going for thousands of years. So once we find the right asteroids, all we have to do is capture them, blast them with highly concentrated sunlight, catch their debris and use it to propel insect-inspired spacecraft onto their next stop, providing the ultimate 'cosmic gas stations' for humanity's highway through the solar system - all while preserving the wilderness around that highway so that our intergalactic future doesn't burn out before it even starts. Wow... sounds like a lot of work. So… how close are we to mining in space? - In 10 years, we'll be launching our first asteroid mining vehicles to go out to asteroids and bring back substantive quantities of resources. - In 100 years, it's quite plausible that there will be people living on the moon in giant structures made of iron and solum, which will come from the asteroids most likely. - What we know about life is that as life evolves, it fills whatever ecological niche or system it has. Then it finds a way to jump to the next level. Just at the time when we have the technology to make the leap into space, this is as significant a moment as when fish came up on the land. If you think the future is going to rock, check out more episodes of How Close Are We? on this playlist. And for more epic science stories, be sure to subscribe to Seeker. Thanks for watching!