What is it, and why should we do it?
We live in the 21st century. That means we have things like computers and phones, technology that would have been impossible 100 years ago. But, these devices use a LOT of precious metals, like terbium, neodymium, and tantalum. The average computer has about 0.015 grams of gold, about a dollars worth of gold. These metals aren’t created, they’re mined out of the ground, and the way people mine these metals out of the ground is… ugly. The mining industry is mostly responsible for air and water pollution, and destroying entire landscapes. Dangerous chemicals are used to mine these metals, such as cyanide, sulphuric acid, and chlorine.
But what if we could replace the mining on Earth with a cheaper and cleaner alternative? Well, this isn’t some far-fetched idea, it’s completely possible to do! And all we have to do is look up to the stars.
Asteroids are billions of tons of rock, metal, and ice, leftover from the formation of the Solar System 4.6 billion years ago. Some are the size of a space dog (about a meter), while others are the size of entire countries. Most asteroids are in two distinct regions: the Asteroid Belt (between Mars and Jupiter) and the Kuiper Belt (located beyond the orbit of Neptune), while others are doing their own thing, like the Trojan asteroids (that trail the planets in front and behind) and still others that are scattered randomly across the Solar System.
As space travel was becoming easier and cheaper, scientists started looking at the composition of these asteroids. Even a relatively small asteroid could be very rich in minerals like palladium, platinum, gold, and even more precious metals. And bigger asteroids like 16 Psyche would be able to cover the materials needed on Earth for a few million years. At current market prices, 16 Psyche would be worth up to $700 quintillion dollars, according to mymodernmet.com. Well, kind of. There are alternate sources of money too, for instance, the oceans. The oceans have over 20 million tons of gold, just waiting to be collected! One ton of gold is worth approximately $64 million, so in total, there are about $1.28 quadrillion in the ocean! The problem is that even though $1.28 quadrillion is a LOT of money, it would cost EVEN MORE to extract all that gold from the oceans.
Right now, asteroid mining has exactly this problem. It’s too expensive to replace mining on Earth. Why is mining asteroids so hard? don’t you just send a rocket to an asteroid, collect some material, and rocket it back home?
The basic principles of asteroid mining are simple.
- Pick an asteroid
- Move the asteroid near Earth
- Take it apart into precious metals
- Be rich
Unfortunately, all of this has problems that humans have yet to solve. Going to space is expensive. It costs thousands of dollars in rocket fuel for each kilogram, just to send something into low Earth orbit. Going farther out into space costs even more money. We need cheaper space travel to make asteroid mining possible.
One option is to switch from classic rockets to electric rockets. Electric rockets propel space vehicles by applying electric or electromagnetic fields to clouds of charged particles (called plasmas) to accelerate them. Electric rockets are REALLY bad at getting into space, but once in space, they allow spacecraft to reach higher speeds than their chemical cousins.
Now that we have a spacecraft that can mine an asteroid, let’s go mine an asteroid! The first step is to pick an asteroid.Our first targets, to make the mission easier and cheaper, will probable be NEOs, or Near-Earth Objects, asteroids that are, well, near Earth.
After a few months of travel, our spaceship finally arrives at an asteroid. The first thing to do is to secure the asteroid and stop it from spinning. There are many ways to do this, from rocket boosters to vaporizing material with a laser!
Once we have a stable asteroid, we need to wait. Orbital mechanics are complicated, but if you push something in the right direction at exactly the right moment, you can move very big things with very little force. So, we wait for exactly the right moment.
The ship fires it’s thrusters and nudges the asteroid into a trajectory that takes it near our moon. The moon is useful, because we can use its gravitational pull to put the asteroid into a stable orbit around Earth. Again, the trip takes months. But all the time since the spaceship was launched will not be wasted.
While the spaceship was going to the asteroid and back, the machines that are required to mine an asteroid are put together. Mining an asteroid is VERY different from mining on Earth. You can’t just hit the asteroids with pickaxes, as all the material (because of the asteroid’s very low gravity) will go everywhere. Instead, the spacecraft puts a shield (sort of like a bubble) around the part that it’s going to mine. Then, the spacecraft uses big mirrors to heat up asteroid rock and boil out the gases. Grinders break up the dried rocks into gravel and dust, and centrifuges separate dense from light elements. Even if we only extract 0.01% of the asteroid in precious metals, that’s still much more than what we would have gotten on Earth. But what now? How do we get our precious metals back down to Earth?
There are a few ways, like loading it all into reusable rockets that launch back to Earth. Or, if the processor that separates the light elements from the metals contains a 3-D printer, we can print a faster delivery system. Heat shielded capsules filled with gas bubbles. these can just be dropped into the ocean where ships can tow them away.
If we start now, we could keep mining more and more asteroids to effectively not have to mine on earth. Even the idea of toxic mining down here might become weird, like having an open fire in your living room. Landscapes affected by pollution will heal, while the technological wonders we are so used to get cheaper and less toxic to make.
None of this is science fiction. We don’t need any fancy materials or new theories to make asteroid mining a thing. We could start pursuing this idea today. All we need is a little… push!