A few thoughts from a sometime project manager and onetime NewSpace guy (’97–’02; project never got funded; will tell you about it if we ever meet in person):
Scope
• A bit of searching establishes that M-type, that is, metallic asteroids, whose composition resembles that of Earth’s core, have concentrations of target metals just about 100x higher than the highest-grade ores in Earth’s crust.
• We may therefore, and treating this as something of a Fermi problem, forecast a price drop consisting of moving everything two decimal places to the right, so (in 2024 $) Au $880/kg, Pt $340/kg, Ag $11/kg, etc.
• I note that Cu has recently been > $11/kg, which raises the possibility of silver replacing copper as an electrical conductor (silver is ~5% more conductive than copper).
• Also, there is a power-law distribution of asteroid sizes such that there are 200x as many bodies with each reduction of the radius by 10x; 1 1-km asteroid = 200 100-meter asteroids = 40k 10-meter asteroids. And there are at least 1M of the 1-km-sized ones in the Main Belt.
• Note also that given the two-order-of-magnitude difference in ore concentration, a single 10-meter asteroid, volume ~500 m³, would be the equivalent of 50k m³ of terrestrial ores, enough to fill 2,500 “ore jenny” train cars.
• Assuming a PGM concentration of 300 g/T in the asteroidal material, the current value of 500 m³ with a density of 5 T/m³ is $~25M.
• We are within a very few years, that is, within this decade, of making recovery of PGMs from small asteroidal bodies a viable economic proposition.
• I expect that actual smart people at AstroForge, among others, have worked this out in some detail.
Time
• Retrieval times are dictated by a combination of orbital mechanics and propulsion techniques.
• A minimum-energy Hohmann transfer ellipse to and from the asteroid belt, say 2.6 AU from the Sun, to Earth orbit has a period of 4 years and 2 months.
• Futures markets should be indicative of whether a 99% price collapse in PGMs is coming, but if the disruptive shipment is several years away while the transit time of minerals from, say, South Africa to North America is on the order of a month, that signal might not appear until the asteroidal material is already on its way back to Earth.
• Exotic propulsion techniques (eg ζ-pinch fusion) may eventually allow continuous acceleration rather than merely ballistic transfer, reducing transit times to weeks rather than years.
Complications
• As you note, the most important uses of space resources may be in space itself rather than on Earth.
• In that context, more volatile materials, and carbon, will be far more important: water and ammonia ices and carbonaceous chondritic bodies rather than metallic ones.
• There is also the usual caveat regarding nanotech, in that suitably controlled manufacture of graphene and other such materials may render PGMs and sulfide minerals largely obsolete.
A few thoughts from a sometime project manager and onetime NewSpace guy (’97–’02; project never got funded; will tell you about it if we ever meet in person):
Scope
• A bit of searching establishes that M-type, that is, metallic asteroids, whose composition resembles that of Earth’s core, have concentrations of target metals just about 100x higher than the highest-grade ores in Earth’s crust.
• We may therefore, and treating this as something of a Fermi problem, forecast a price drop consisting of moving everything two decimal places to the right, so (in 2024 $) Au $880/kg, Pt $340/kg, Ag $11/kg, etc.
• I note that Cu has recently been > $11/kg, which raises the possibility of silver replacing copper as an electrical conductor (silver is ~5% more conductive than copper).
• Also, there is a power-law distribution of asteroid sizes such that there are 200x as many bodies with each reduction of the radius by 10x; 1 1-km asteroid = 200 100-meter asteroids = 40k 10-meter asteroids. And there are at least 1M of the 1-km-sized ones in the Main Belt.
• Note also that given the two-order-of-magnitude difference in ore concentration, a single 10-meter asteroid, volume ~500 m³, would be the equivalent of 50k m³ of terrestrial ores, enough to fill 2,500 “ore jenny” train cars.
Cost
• If Starship gets payload cost to LEO down to $10/kg (https://www.nextbigfuture.com/2024/01/how-will-spacex-bring-the-cost-to-space-down-to-10-per-kilogram-from-over-1000-per-kilogram.html) and a fully-fueled retrieval module for 500 m³ of M-type asteroidal material masses 1000 T, then the launch cost would be only $10M.
• Assuming a PGM concentration of 300 g/T in the asteroidal material, the current value of 500 m³ with a density of 5 T/m³ is $~25M.
• We are within a very few years, that is, within this decade, of making recovery of PGMs from small asteroidal bodies a viable economic proposition.
• I expect that actual smart people at AstroForge, among others, have worked this out in some detail.
Time
• Retrieval times are dictated by a combination of orbital mechanics and propulsion techniques.
• A minimum-energy Hohmann transfer ellipse to and from the asteroid belt, say 2.6 AU from the Sun, to Earth orbit has a period of 4 years and 2 months.
• Futures markets should be indicative of whether a 99% price collapse in PGMs is coming, but if the disruptive shipment is several years away while the transit time of minerals from, say, South Africa to North America is on the order of a month, that signal might not appear until the asteroidal material is already on its way back to Earth.
• Exotic propulsion techniques (eg ζ-pinch fusion) may eventually allow continuous acceleration rather than merely ballistic transfer, reducing transit times to weeks rather than years.
Complications
• As you note, the most important uses of space resources may be in space itself rather than on Earth.
• In that context, more volatile materials, and carbon, will be far more important: water and ammonia ices and carbonaceous chondritic bodies rather than metallic ones.
• There is also the usual caveat regarding nanotech, in that suitably controlled manufacture of graphene and other such materials may render PGMs and sulfide minerals largely obsolete.