Due to extensive exploitation of resources, most of the key elements that can be obtained in the Earth’s core will be exhausted by the year 2070. While some people think the Moon or Mars were likely candidates for pilfering minerals and metals after that, some think it would be easier to target asteroids. The original theory is that most minerals and metals, including precious metals came to the earth, when asteroids fall to earth after the crust has cooled off. Now it is only logical to go and get more where all this stuff originally came from.
Initially only near-Earth asteroids will be considered for mining, because of the costly round trip. The plan is to build an aircraft that will bring the mining astronauts to a C-type asteroid, where water is found in abundance. Such asteroids used to be comets, but are now stationary and can be used as a base for mining missions of other type asteroids. There are S-type and M-type asteroids, which have been identified as rich in ore of all kind, predominantly metals, whereby the S-type are believed to contain some water. The M-type asteroids do not contain any water, but seem to harbour much more metals.
With current technologies, only easily recoverable objects would be viable for targeting, whereby these would not be mined on site, but transported by velocity manipulation towards the Earth’s orbit, where already existing facilities could be used for prolonged mining. Currently most of known asteroids are being catalogued and researched by radar, in order to find out how much and what minerals and metals are available there. Around 9000 have been already checked, with many more already discovered and waiting in line. Other ideas include having an asteroid mining Moon base, or bringing the whole raw asteroid down to Earth, where further processing will then take place.
The most viable option would be to manufacture a mining ship, which will bring back to earth only already processed materials and thereby reduce the load that is being transported back, significantly saving costs. Options are also considered, where these ships would harvest fuel from asteroids for the return trip as well. Further technologies are currently being developed, which will allow the crew to research other nearby objects and send prospecting unmanned spacecraft to more distant objects, for future prospecting purposes.
The main barrier right now is the extreme cost of space exploration and travel. It costs a lot to only send a one way spacecraft out, unmanned at that, around a billion, just to bring back material that is weighted in ounces. Making such an endeavour, where a whole mining spacecraft would venture out and do mining on site, with all the supporting crew, equipment and material is currently not even technically possible. Plans are being developed, but the costs outweigh any possible profits for now. Nevertheless, some already existing companies optimistically foresee the start of the first mining adventure by 2023.