What value do we get from doing things in space? What is the potential for the commercialization of space? And what does that have to do with asteroids?
Every non-biological resource that we use here on Earth can be found in asteroids. Once we begin to extract and use these resources, we will have everything we need to expand our economy and civilization into the solar system.
Basis of an Economy
An economy is essentially the production, distribution, and consumption of goods and services. Currently, the global space industry, worth over $300 billion, is very much centered around services for consumption here on earth. This includes examples like satellite communications (TV, phone, and internet), GPS services, weather observation, and military intelligence. Every other sector in the space industry supports these services…from building rockets and providing launch services to manufacturing satellite hardware and writing software for analyzing satellite imagery.
This economy can expand in the same way that any other economy expands...new products, more affordable products, or a growing consumer base. As an example, a rocket company building cheaper rockets would allow more satellite companies to pay for putting more satellites in orbit, which would increase the amount potential customers that might buy their satellite TV service.
The Problem of the Rocket Equation
Right now, everything must be built here on Earth in order to launch it into space. This includes everything from electronics and fuel to spacesuits and drinking water for astronauts. Sending things into space on a rocket is the biggest bottleneck in the supply chain of getting things to space. Basically this is all because Earth's gravity is a huge jerk. It takes a LOT of energy and a complex rocket with a specific size and shape to get something into orbit, BUT once you're in orbit, you're basically halfway to nearly anywhere in the solar system. Rockets are greatly limited by their cost, mass, shape, and volume. Each of these factors contributes to this bottleneck, but getting resources from another source, like asteroids or the moon, can alleviate many of these issues.
Cost and Mass
The cost of launching something from Earth can be considered a baseline for any potential markets for resources from asteroids (or the moon or any other body). It actually takes much less energy to get from low-earth orbit to some near-Earth objects like the moon or asteroids AND BACK than it does to launch from Earth in the first place. A company taking advantage of this approach could provide any given mass at a cheaper cost than launching it from Earth. This is especially useful for raw resources like water or fuel as opposed to "smart" payloads, like electronics equipment, which need to be made on Earth (for now) due to their complexity.
As a current example, United Launch Alliance has already put out offers to buy propellant in low Earth orbit for $3000/kg or $1000/kg at Earth-Moon L1 Lagrangian point.
Shape and Volume
One advantage of building things in space is that "space" isn't an issue. If you have the raw materials available, things can be built without many mass, volume, or other dimensional constraints in space. For example, manufacturing a steel beam 100 meters long, which would be very impractical to make on Earth, is completely within the realm of possibilities if made directly in space using a metallic asteroid as feedstock. Building a complex structure like the International Space Station (ISS) took dozens of heavy launches, and every part had to fit inside a rocket in order to be launched and assembled in orbit.
Disclaimer: Nobody has yet mined an asteroid and turned it into anything useful. The only comet and asteroid samples returned to Earth for analysis have been dust from NASA's Stardust mission and JAXA's Hayabusa mission. Resource characterization is based largely upon remote sensing, and resource extraction examples are based upon present-day technology that has not been field tested in a space environment. Building this infrastructure will take a large investment of time and capital, but the implications for the future economy of space cannot be understated.
That said, companies like Planetary Resources and Deep Space Industries are beginning to test these capabilities with the aim to process asteroid materials and build amazing things.
That's great, but what materials of real use can be refined from asteroid material?
Asteroids are typically characterized by their spectra (the wavelength of light that is emitted), which can tell us their composition. Most asteroids fall into 3 main groups:
- C-type (carbonaceous)
- S-type (silicaceous or stony)
- M-type (metallic)
Some materials that are very rare and valuable on the surface of Earth (like platinum-group metals) can be found in much higher concentrations in certain asteroids than here on Earth. Every one of these types is useful. Carbonaceous asteroids contain lots of water, which can be used to make food, rocket fuel, and radiation shielding. Metallic asteroids can be used to build all kinds of storage containers, mechanical parts, or large structure components. Stony asteroids can be used to manufacture solar panels, heat-resistant ceramics, and radiation shielding.