Asteroid Mining - Purpose

Purpose

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. 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.

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. This is because, while asteroids and the Earth congealed from the same starting materials, Earth's massive gravity pulled all such heavy siderophilic (iron-loving) elements into the planet's core during its molten youth more than four billion years ago. This left the crust depleted of such valuable elements until asteroid impacts re-infused the depleted crust with metals. Some flow from core to surface seems to occur, e.g. at the Bushveld Igneous Complex, a famously rich source of Platinum group metals.

In 2006, the Keck Observatory announced that the binary Trojan asteroid 617 Patroclus, and possibly large numbers of other Jupiter Trojan asteroids, are likely extinct comets and consist largely of water ice. Similarly, Jupiter-family comets, and possibly near-Earth asteroids that are defunct comets, might also economically provide water. The process of in-site resource utilization—using materials native to space for propellant, tankage, radiation shielding, and other high-mass components of space infrastructure—could lead to radical reductions in its cost.

Ice would satisfy one of two necessary conditions to enable "human expansion into the Solar System" (the ultimate goal for human space flight proposed by the 2009 "Augustine Commission" Review of United States Human Space Flight Plans Committee): physical sustainability and economic sustainability.

However, physical human presence is not needed beyond the near-Earth processing facilities as it would exceed current experience and physiological endurances. One practical solution would be to deploy many autonomous hunter-seeker units, similar to "celphone robots" being developed for attachment to candidate "earth crosser" asteroids and use these to assay and survey companion sources as well as track exact orbits and cycles. It would not be necessary or useful to return large quantities of the materials to Earth, since many metals are useful in themselves, such as ferronickel and injection-moulded silicates for structural components, platinum for catalysing water and methane into component elements, and gold for microprocessor production in a zero gravity environment. Values would be sharply reduced if vast quantities of intrinsically valuable metals were introduced into Earth's, instead of being used onsite as core components of microprocessor fabrication that would provide the largest benefit with minimal economic disruption.

From the astrobiological perspective, asteroid prospecting could provide scientific data for the search of extraterrestrial intelligence (SETI). Some astrophysicists have suggested that if advanced extraterrestrial civilizations employed asteroid mining long ago, the hallmarks of these activities might be detectable.