Metals from asteroids
Asteroid mining may provide a valuable source of key metals for use on Earth
Asteroids are often portrayed as interstellar treasure troves of precious metals. Asteroid mining may provide a valuable source of key metals for use on Earth, while resource extraction on other planetary bodies could enable the production of fuel and infrastructure during space missions, which may facilitate missions further afield. Many studied meteorites are fragments of asteroids, so a breadth of available meteoritic data can be used to understand whether extraterrestrial mineral exploration – for use on Earth or in space – is viable.
Using various statistical techniques, Kevin Cannon at the Colorado School of Mines, USA, and colleagues investigate the concentration of metals in meteorites by comparing the concentrations of 83 different elements in meteorites with terrestrial ores, using data from previously published studies.
The results highlight two groups of elements with asteroidal concentrations that significantly exceed terrestrial concentrations: platinum group metals (PGMs, such as platinum, palladium, and iridium) and base metals (such as iron, magnesium, and aluminium). Based on their economic value and declining ore grades on Earth, the results indicate that PGMs should be strongly considered for return-to-Earth missions.
Although base metals are also present in high concentrations in the meteorites, due to their terrestrial abundance it would not be economically viable to mine them from asteroids and return them to Earth. However, the team suggest that base metals could be used to build infrastructure in space, such as solar photovoltaic panels.
While the results make a strong case in favour of mining asteroids, the team emphasise that for this to become a reality, further research is needed to ensure that the processing of elements on asteroids is as efficient as mining processes on Earth.
Planet. Space Sci. 225, 105608; doi.org/10.1016/j.pss.2022.105608