Asteroid mining gets sold as a trillion-dollar gold rush, but the economics point the other way: hauling platinum back to Earth would crash its price, so the only prize that adds up is mining water an

Every few years asteroid mining returns to the headlines as a trillion-dollar gold rush waiting to happen, usually attached to a single staggering number about how much some metal-rich rock is theoretically worth. It is a genuinely exciting idea. It ... [4530 chars]