One day, humanity will mine the asteroids for water, platinum, and many other things besides. That’s the goal of a new startup called Planetary Resources.
Their lofty vision is no less than:
Planetary Resources is bringing the natural resources of space within humanity’s economic sphere of influence, propelling our future into the 21st century and beyond. Water from asteroids will fuel the in-space economy, and rare metals will increase Earth’s GDP.
In the long term, I think they’ve got a point. Water – electrolyzed into hydrogen and oxygen and then burned in a chemical rocket, used as reaction mass in a solar or nuclear thermal rocket, or as free mass for the extensive radiation shielding required for a realistic interplanetary mission – is a key enabler for space beyond low earth orbit. And there are virtually unlimited quantities of high-grade platinoids out there.
Platinum used to be the world’s most valuable metal. At the moment, gold is marginally more valuable, thanks to the relentless goldbuggery of Paulites and other assorted American wingnuts. But at around 50,000 USD per kilogram, it’s still pretty damn valuable, and most of that value is to due industrial demand rather than mindless hoarding. Its main use is as a chemical catalyst, including the “catalytic converter” in your car exhaust. With any luck, a decade or two from now, that use will have faded into history. But there’s another potential use relating to clean transport. While the hype surrounding fuel cells has died down a bit since the mid-2000s, various companies continue to work on them both for transport and stationary energy applications.
It’s important to remember, here, that while incremental improvements in batteries might get us workable electric cars, trucks, buses, heavy machinery, and marine applications are a different kettle of fish entirely. These days, a Commodore’s V8 has a peak power output almost as high as the engines in a B-Double. But those B-double engines are run much closer to their peak power for many hours on end. The latest Mack B-double uses about 56 litres per 100 km in highway use, and can carry 1400 litres of diesel. That’s the equivalent of 34 tonnes of next-generation lithium-ion batteries, which would cost over 2 million dollars to purchase, if you just go on heating value. However, in practice, only about 22% of the energy in diesel actually ends up spinning the wheels of the truck, so we’re probably talking something closer to 7.5 tonnes and $600,000 worth of batteries. And, I suppose, you could halve the range – but we’re still requiring nearly 4 tonnes of batteries worth around $300,000!
So…to get back to my point, battery-electric long-haul heavy trucks aren’t going to be economic for a while yet. Nor are battery-powered tractors, outboard motors, and so on. So something else will be required, and hydrogen-powered fuel cells are potentially that “something else”. And fuel cells use a certain amount of platinum to work efficiently. Research is constantly being conducted to reduce the platinum required, but it’s still an issue.
Besides, if platinum became available at the bargain price of, say, $5000 a kilogram, or $1000 a kilogram, we’d undoubtedly find ways to use it in dozens of other applications. Look what happened when we figured out how to churn out aluminium by the megatonne.
And we haven’t mentioned the other platinoids – ruthenium, osmium, and the like – which are all very rare and extremely valuable.
So that’s the dream. What about the reality?
Even they admit that mining asteroids for minerals – and any chance of a revenue stream from it – is “decades” away. There’s also the little issue of the Outer Space Treaty, which states that “Outer space, including the moon and other celestial bodies, is not subject to national appropriation by claim of sovereignty, by means of use or occupation, or by any other means.” If nation-states can’t claim them, they can’t assign property rights, and it’s hard to imagine commercial mining taking place without some kind of property rights regime.
So what about their short-term target – water?
Rather useful stuff to have in space. You can drink it. You can use it as radiation shielding – for high-energy cosmic rays, it apparently provides amongst the best shielding possible per unit mass. And, rather usefully, you can use it as propellant in just about any rocket you’d care to name. Split it into hydrogen and oxygen, and you’ve got a chemical rocket. Or use it in a solar thermal or nuclear thermal rocket. And the overwhelming majority of the mass of most rockets is actually the fuel.
To give an example, the Mars For Less mission design uses multiple launches of existing medium-lift rockets (akin to the Falcon 9), to lift four fuelled-up rockets into low earth orbit. These are then used to give the crew the push to Mars. Of the 100-odd tonnes of mass in these, 80% is fuel. So (at least in theory) instead of five Falcon 9 launches for the trans-Mars propulsion system, you’d need one.
And similar arguments would apply to, say, uncrewed planetary probes, though the advantage would probably be much more in terms of payload mass. Instead of sending a one-tonne rover to Mars, NASA could send half a dozen of them.
And that’s before you start using the water mining to leverage a platinoid mining operation.
But, in the short term, the potential customers for the water mining service are essentially limited to the national space agencies, because they’re the only ones with the budget to do interplanetary exploration missions. And they take their sweet time to do things – if they started planning now, it takes the best part of a decade to do this kind of mission. Nor are they design mission architectures around a water supply that may or may not be available – they’d want demonstrations before they consider using it for anything serious.
So even the water mining business would be over a decade from producing any revenue, and that revenue would be fairly limited if all you’re doing at the present rate of missions conducted beyond Earth orbit.
As such, it’s hard to see how these guys could have a “business plan” for generating a traditional commercial return on the eight-figure sum they will need to invest, even on their first stage of launching a private space telescope to go looking for NEO’s with water and/or platinoids.
So, we’re back to the conclusion that this is a hobby for some rich sci-fi fans. One that might produce some interesting things a few decades from now, sure, but a hobby nonetheless.