Many asteroids are literally shattered planets, the planet-forming processes leaving them rich with valuable materials such as gold, iron, nickel, platinum and tungsten. The company Planetary Resources has recently proposed an endeavour to mine the precious metals from these asteroids. The project will begin in 2014 when small telescopes will be launched with the purpose of seeking out Near-Earth asteroids in ideal orbits. The asteroids will either be mined in their existing orbit, requiring intelligent robots to work unsupervised for years until the asteroid passes close enough to earth for the ore to be transported back, or smaller asteroids will be deliberately put into orbit around the earth or moon to be mined at leisure, possibly presenting a danger of collision. Either way, the expenses will be astronomical (pun intended)—for example, bringing back one 500-tonne asteroid would cost $2.5 billion—and the mining may not even work economically, because precious metals are only precious because they’re rare. If they become abundant and cheap, profit margins will take a hit. It’s complex and expensive, but if this endeavour goes ahead, it will drive the construction of extra-terrestrial infrastructure—something dearly needed if we want to make progress on the space frontier.