Google billionaires Eric Schmidt and Larry Page have decided to provide funding for an interesting space exploration start-up named Planetary Resources. The new company, which is focused on natural resources and space exploration, plans to mine natural resources from asteroids and add trillions of dollars to the global GDP.
The latest idea put forward to alleviate our looming energy problem is asteroid mining. We hate to be a somewhat lonely voice in pointing this out, but there’s a whacking great asteroid sitting about 240,000 miles away, made up of much the same ‘stuff’ as all the millions of little ones flying around our corner of the universe. If there were anything commercially viable there, commercial interests would have been shifting it back to Earth decades ago.
But before we get into space economics. Let’s discuss the more down to earth variety. I fill up my car with chemical energy and run it for a week. If I haven’t earned more in that week than I paid for the energy I put in, then I’m either running at a loss or on vacation. If I sink an oilwell, I’m faced with the same economic reality. It’s called EROEI or Energy Returned on Energy Invested.
Moon-mining is subject to exactly the same law.
One must assume that the means of reaching asteroids would be with a chemical-fuelled machine, (like my car) so the same economics apply as earth-bound vehicles. Fill it up and blast off a $20 billion dollar firecracker (or $100billion?) They’ve been powering space transport that way since Werner von Braun started it back in the 1940’s, Even the Wright brothers used explosive chemicals back in 1903. No other viable way has yet been discovered that will lift us clear of gravity.
Wish-science won’t work.
But supposing you do blow $20Bn on fuel, anything you bring back has to be worth more than that, or you’ve just been on an expensive vacation.
As we’re still using chemical propulsion, any weight carried is strictly pro-rata to the energy burned, so it follows that anything ‘mined’ on an asteroid will have a value greater than the effort expended in getting hold of it. (EROEI again I’m afraid). We already know the geological composition of asteroids, so what’s there can only be stuff we know about already. (Quantities are irrelevant). Bring back 10 tons of anything, and it will cost far more than any value it could have in Earth-economy’ terms.
Given that the prime ‘natural resource’ that has fuelled the Earth’s economy for millennia is based on hydrocarbon, of which there is none on the asteroids or our moon, exactly what kind of ‘natural resources’ do these people have in mind?
Cameron, Brin et al might want to blow billions on rocket fuel, but spending money does not create wealth unless you’ve discovered some as yet unknown energy source. Kryptonite maybe?
I can only imagine that the advantage of going to asteroids rather than the moon is that asteroids have much lower gravity, so anything you mine there can be got ‘off planet’ for much lower energy expenditure. It’s still hard to see how anything on an asteroid could possibly be valuable enough to offset all the energy and expense of collecting it though.
Your blog post is based on a number of assumptions that are erroneous. The moon is not an asteroid, and as you say it is very big indeed – so big that it exerts about 1/6 of Earth’s gravity at its surface. Any materials extracted from the moon and sent to orbit must overcome this gravity “well”, with the moon at the bottom and orbit at the top of the well. Similarly, any mass used for space missions must currently be lifted from the bottom of Earth’s gravity well.
Anytime a rocket is used, the propellant consumption and change in velocity follow a precise relationship called the Rocket Equation. A consequence of that equation is that for chemical rockets the majority of the mass is propellant. One of the more-commonly used propellant combinations is Liquid Hydrogen and Liquid Oxygen.
The more propellant a rocket has to carry from Earth to reach its destination, the bigger the rocket must be to carry up the weight of all its fuel.
It is said that once you’re in orbit you’re “halfway to anywhere”. That is, it takes about as much energy to get from Earth orbit to anywhere in the solar system (i.e. escape velocity) as it took to get into Earth orbit in the first place.
If a rocket only had enough propellant to make it to orbit, and then it refueled while it was in orbit, it could have enough fuel to get to any destination in the solar system. If it then refueled on the other end, it could come all the way back. With fuel depots both in Earth orbit and in orbits at various destinations throughout the solar system, you could have craft that never return to the earth but simply cross back and forth across the Earth-moon system to start, and then eventually all over the solar system, refueling as needed but never landing.
Propellant depots in Earth orbit and lunar orbit would definitely want to stock LH2 and LOX, and at first these would be supplied from the Earth. However, there is a class of asteroid called Carbonaceous Chondrite which consists of about 20% water. This is a rare sort of asteroid but meteors of this type have hit the Earth. Such an asteroid could be mined for its water, which would then be broken up into Hydrogen and Oxygen, cooled and compressed – at which point they become a commodity.
Such a rock need never be brought back to Earth. Instead, its orbit would be changed to ring it into Lunar orbit, where large (in orbit, so arbitrarily large) reflectors would focus sunlight to vaporize the rock for subsequent capture of vapor, refining and storage.
Planetary Resources plan is to find these Carbonaceous Chondrite asteroids. To do this, it will launch 5 small satellites (each about the size of my microwave oven. Yes, I realize you can’t see my tiny microwave, but you get an idea of the scale) each containing a small telescope. These satellites will orbit the earth scanning the skies for Near Earth Approaching asteroids, cataloging all they find. The images received will allow spectral characterization of the NEAs, which will allow them to find the CC asteroids among the millions of asteroids which orbit close to Earth.
The amount being spent to build and launch these small satellites is $30 million – a far cry from $20 billion or $100 billion. Once suitable candidate asteroids are identified, a swarm of small satellites similar to the first batch will be outfitted with ion propulsion and sent to get a close up look at target asteroids, gathering data. The total cost of building, launching, and operating these small satellites is less than even one NASA mission to an asteroid such as the NEAR mission to Eros – and the data retrieved would be worth something. Even if Planetary Resources chooses not to do anything with an asteroid but observe it up close, the scientific value of the data translates easily into monetary value. It is cheap to transport bits back to Earth.
The company then proceeds step by step in these small, inexpensive satellite swarm missions, continually building up the technology necessary to move the asteroid into lunar orbit and mine it for rocket fuel, which would then be sold to anyone looking to refuel their spacecraft in orbit. Being first has its risks, but if it pans out for Planetary Resources, they could become the biggest fuel company in the solar system.
Your line of thinking is helpful, but while I grant the relative gravity difference between moon and an asteroid, there seems little else to dispel the futility of asteroid mining.
There are 7 billion people on earth, all of whom have to be fed. That requires resources, all of which are in depletion and presenting a crisis in the immediate future.
the ultimate purpose of any kind of mining is to produce resources that humanity can use to (ultimately) feed itself. If nothing is brought back to Earth, then the purpose of the whole exercise is acquisition of knowledge. As you say ‘Data’ might be ‘worth something’, but you can’t eat it. If nothing is brought back except a few small rock souvenirs, then the trip has been a vacation. If the only ‘commodity’ created is fuel, then it is pointless if its only purpose is to burn still more fuel as a scientific exercise.
To give you an analogy: Imagine if the internal combustion engine had only been used to take people on pleasure trips in cars. Instead, it was put into agricultural machinery and used to produce vast quantities of food. Criss-crossing the solar system with no resource acquisition is rather like using a tractor to plough a field year after year but planting and harvesting nothing
One shot into space
People often argue that space mining is ridiculous and impossible given the sheer cost in energy to launch ships into space. It’s so expensive that way that even if a ship were being launched to mine a pure platinum asteroid, the costs to blast the ship up there and back are so prohibitive there’s no economic point in doing it.
But what if the trip were only one way and then grew in exponential returns? What if, one day, instead of climbing up out of the gravity well and back for every single shipment of ore, we just fire one ship up the gravity well and it STAYS OUT THERE! Imagine a future ship with whizz-bang new future AI’s and robotics. It’s not necessarily even manned. It’s not just a ship, but an automated factory. It’s designed to fly out there and replicate itself. This ship is injected into orbit with the asteroids where it replicates by mining ores and energy (uranium dust or the electromagentic energy between Jupiter and it’s moons or whatever!) and water for hydrogen and anything else this ship needs.
Viewed through tomorrow’s exponential growth in AI’s and robotics, our ship becomes a self-replicating viral robot, spreading through the asteroid belt until it reaches a critical mass. Fleets of ships would collect and manufacture what ever we required, while other ships gathered water for splitting into hydrogen to shoot their payloads back to Earth. Then, eventually, they would return their cargo, with carbon-fibre parachutes built in.
Shooting one self-replicating super-AI manufacturing ship out there would return an exponential yield of goods that would eventually return free of the gravity well so many ‘space mining critics’ are worried about. We’d literally have gifts raining down from the skies, aerobraking and parachuting down to safe locations. Maybe some of it will be parked in orbit as space-based solar power. Maybe one particularly huge gift will be a space-elevator. Who knows?
The point is that with higher technology AI + robotics, it only takes one rocket. Then instead of us trying to climb out of the gravity well all by ourselves we will one day find a hand reaching down to help.
While your comment has much merit, you have left out one essential part of the cost equation.
Suppose there was an asteroid composed entirely of platinum, or even gold say.
Several million tons of gold, which we could shoot back to Earth at very low cost.
All well and good.
Except that there’s about 130,000 tons of gold sitting around on the Earth right now, and it has been estimated that that’s pretty much all that’s ever been mined. Gold is about $1600 an ounce because of its scarcity, bring back a million tons of the stuff and the $1600 price of gold when you set out would be zero when you got back. Same for diamond and so on.
Space mining has to produce resources we can live on