The Myth of Space Mining
We hear it all the time whenever the arguments are made for space travel and interplanetary commerce: ‘We can mine the asteroids and comets and sell the ores for millions of dollars!’ In reality, these pronouncements tend to underestimate both the astronomical realities and what actual ore extraction costs.
The meme of space mining has been with us since 1898 when Garritt Serviss penned the story
C-types are rich in carbon compounds, S-types are rich in silicates and M-types are rich in metals like iron and nickel.
Figure from F. E. DeMeo and B. Carry (Harvard University).
Fact 2: Most asteroids and recovered meteorites are relatively homogeneous.
Desirable elements are present at several grams per ton (1 part per million), but distributed throughout the rock. That means that extraction is a complex process requiring grinding the rock to dust and adding the appropriate chemical reaction or other process to extract the desired element. For example on Earth, gold is extracted using a variety of chemical methods depending on the impurities present. At some point, engineers will have to demonstrate how they can take a sample of asteroidal material in the laboratory and extract a useful element or compound from it at the lowest cost. This has not been done yet.
A typical stony meteorite (Credit: PlanetFacts.org)
Fact 3: The primary resource in the outer solar system is ice!
The vast majority of the satellites of the outer planets are either completely composed of ice, or for the larger ones, have a denser silicate core buried under hundreds of kilometers of ice and liquid water. It is cheaper to mine a kilogram of ice in the outer asteroid belt or in comets, than it is to journey into the outer solar system to mine the —> Read More