Celestial objects are made entirely of valuable materials. Space mining is the process of mining objects in space in order to harvest these various materials.
The Monetary Potential for Near-Earth Objects
In the early phases of the Earth's formation, all of the siderophilic, or "iron loving", metals were stripped from the surface due to gravity and the intensity of the heat. The Earth is mined for various precious metals and minerals, including iron, gold, cobalt, nickel and platinum. However, these materials are mined from the crust, not the core. Where did these materials come from then?
These materials, in fact, came from various asteroid, comet, and meteoroid impacts after the crust of the Earth cooled and solidified. Since these materials came from asteroids and other near-Earth objects, obviously these materials can be found in the objects. While mining objects from non-terrestrial sources might sound like something strictly from science fiction, this idea is being given serious consideration, especially since an average sized asteroid would yield billions of dollars of materials.
The Process of Space Mining
While there are several proposed methods for space mining, the most economical method would probably be to capture a near-Earth object and tow it to a closer, safer orbit to Earth. There would also be the question of where to actually process the material. Should the raw material be processed on site? Or should it be brought back to Earth to be refined?
There would also be the question of how the material would actually by mined. The processes which would be considered would be similar to mining techniques on Earth. A method similar to strip mining whereby the material would be scraped off of the surface could be used. Digging shafts below the surface and extracting materials could also be utilized.
There would also be the question of how to move the asteroid. Rockets could be placed on the asteroid which would fire and change the orbit. There would be a question of how much fuel would be needed and whether or not the gravity of a larger object could be used to sling-shot the asteroid as well. The materials from the asteroid itself could be used in order to create fuel on the asteroid, which would lessen the amount of fuel that the space miners would have to bring with them in the first place.
The Problems of Space Mining
The largest amount of actual work involved with space mining would probably be done with robotics. Experiments using automated systems and dealing with the time delay for communications posed by such distances have been tested on Mars and have shown successful results. However, these were not large-scale systems actively involved in a complicated process such as mining. With the proper funding, though, it would not be difficult to advance the technologies needed sufficiently in order to successfully run a space mining operation.
One of the biggest problems of space mining is not the logistics or the technology involved; it is the financial implications. While the pay-off for space mining is huge, the amount of money needed to finance such a venture would be incredibly steep. It could take decades before the investment would begin to yield profits. It is interesting to consider how the concept of space mining, which most people might consider to be strictly science fiction, could possibly be caught up on such an ordinary problem such as finance.