Based on known terrestrial reserves and growing consumption in developing countries, there is speculation that key elements needed for modern industry, including antimony, zinc, tin, silver, lead, indium, gold, and copper, could be exhausted on Earth within 50–60 years.[2] 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,[3][4] and water processed from ice to refuel orbiting propellant depots.[5][6][7]
In fact, all the gold, cobalt, iron, manganese, molybdenum, nickel, osmium, palladium, platinum, rhenium, rhodium, ruthenium, and tungsten mined from the Earth's crust, and that are essential for economic and technological progress, came originally from the rain of asteroids that hit the Earth after the crust cooled.[8][