Asteroid mining

Asteroid mining is the exploitation of raw materials from asteroids and other minor planets, including near-Earth objects. Minerals and volatiles could be mined from an asteroid or spent comet then used in space for in-situ utilization (e.g. construction materials and rocket propellant) or taken back to Earth. These include gold, iridium, silver, osmium, palladium, platinum, rhenium, rhodium, ruthenium and tungsten for transport back to Earth; iron, cobalt, manganese, molybdenum, nickel, aluminium, and titanium for construction; water and oxygen to sustain astronauts; as well as hydrogen, ammonia, and oxygen for use as rocket propellant.

Due to the high costs of current space transportation, extraction techniques still being developed and lingering uncertainties about target selection, terrestrial mining is currently the only means of raw mineral acquisition today. This situation is likely to change in the future as resources on Earth are becoming increasingly scarce and the full potentials of asteroid mining and space exploration are researched in greater detail.

Based on known terrestrial reserves, and growing consumption in both developed and developing countries, key elements needed for modern industry and food production could be exhausted on Earth within 50–60 years. These include phosphorus, antimony, zinc, tin, lead, indium, silver, gold and copper. In response, it has been suggested that platinum, cobalt and other valuable elements from asteroids may be mined and sent to Earth for profit, used to build solar-power satellites and space habitats, and water processed from ice to refuel orbiting propellant depots.

...
Wikipedia