A group of 21st-century private space entrepreneurs is expected to unveil an ambitious new venture to mine the surface of near-Earth asteroids in search of precious metals and rare metallic elements.
The plan may seem like it was torn from a science fiction novel, and critics say the idea may be far-fetched and difficult for a small company to accomplish. But the company, Planetary Resources Inc., has already drawn an A-list of investors and advisers.












