It looks like Star Trek fever isn't restricted to Newt Gingrich or failed French presidential hopefuls; Google founders Larry Page and Eric Schmidt and filmmaker James Cameron are planning to get out into space and mine asteroids for rare resources within just a few years. Their plans involves building a bunch of powerful telescopes to check out nearby asteroids and eventually mine them for platinum and gold primarily. NASA is trying the same thing and will spend 1 billion to get 60 grams of material; last time I checked gold wasn't worth a 500 million dollars an ounce and that is the cost *if* it works.
What boggles my mind is that people want to mine rare resources from objects so incredibly far from home. It isn't just a matter of hoisting things into orbit because on earth if something breaks you just buy more parts and get some person to fix it while up in space if something breaks you chuck millions or billions in the bin to replace it. It isn't as ridiculous as colonizing space of course because until Antarctica and the ocean floor are completely colonized the idea of space colonization is preposterous; it is actually possible that at some point getting resources from asteroids could be economically viable as resources on earth run dry. We aren't there yet, nor anywhere near it, but it it an eventuality that humans will someday face.
It is simply a matter of the relative costs of stuff and energy. Stuff is cheap right now. Anything that can be dug up out of the earth is dirt cheap compared to something that must be gotten out of space and there just isn't anything up there that we can use that isn't available here on earth. This equation will change as energy costs do; with no new innovation the price of energy will go up and up as fossil fuels become harder to get to and things in space will become even more costly. If we develop fusion in the next decade or so or perhaps find some even more amazing energy source then we could potentially arrive at a point where the geographic availability of resources becomes the limiting factor instead of the colossal energy investment required to get into space.
Unfortunately for space adventure when energy gets cheaper it gets easier to dig deeper and refine more and get more resources from the earth itself. There is certainly a point where there is so little of a resource on earth that heading out to space makes sense but before it becomes economically sensible the price of energy needs to drop by an order of magnitude or three. Not that I object to billionaires building telescopes and thinking about big projects of course; better than buying a dozen yachts. I just think it has no chance whatsoever of actually turning a profit barring us inventing magic wands.