Asteroid mining has been, quite literally, the object of Sci Fi movies and literature for many decades. But more recently, several people are trying to bring it out of the imaginary world and into the real one.
Granted, for the most part, their plans sound more fantastic than the premises of most Sci Fi movies, but the sheer amount of interest is a hint that there is something there.
A few months ago, Planetary Resources made a splash, with its big plans and its big-name investors, including Google billionaires Eric Schmidt and Larry Page. Avatar director and deep-sea explorer James Cameron is an advisor.
Now, a new company, Deep Space Industries, is launching with somewhat the same goal. It's probably even more ambitious, as it plans to have a fleet of spacecraft flying as early as 2015 and ready to harvest resources off of near-Earth asteroids within a decade.
These plans may seem ambitious, or worse, today, but a decade ago Elon Musk was setting up SpaceX with the goal of becoming the first or one of the first private companies to put a rocket and then people in orbit. Now, SpaceX is very close to that goal and is already making money.
Asteroid mining could prove to be a profitable business. Even a small asteroid may be worth billions of dollars, in precious and rare metals, but, more importantly, in water.
The soft asteroids that these companies are targeting, since they're easier to exploit, are mostly made up of ice. Water may not be worth much here, but it's a lot more valuable than gold in space.
The water could be used by astronauts and, more likely to create fuel used by rockets. The ability to refuel once in orbit means that rockets can lift off with a much smaller fuel payload, meaning they can carry more useful cargo for less.
A space refueling station is seen as a major stepping stone in deep space exploration, i.e. going beyond the moon. That said, the complexities of building a craft that is capable of arriving at an asteroid, mine it and then retrieve whatever resources it can, are daunting to say the least.