The prospects of a robotic manufacturing base operating off Earth is not as far-fetched as it used to be according to a study published by a team of NASA researchers. Because asteroids are loaded with minerals that are rare on Earth, near-Earth asteroids and the asteroid belt could become the mining centers for remotely operated excavators and processing machinery. In 20 years, an industry barely imagined now could be sending refined materials, rare metals and even free, clean energy to Earth from asteroids and other bodies.