One of the real driving forces in any human exploration has been intense need. In the initial human migrations around the globe, people explored out of a need for food, and a need to be safe from other potentially hostile bands–there is safety in distance. During the European colonization period the nations and kingdoms of Europe felt an intense need for hard currency (gold) and other physical wealth (spices, gems, etc.) to support their mercantilist economic systems. In today’s world, many hope for human exploration of space in a noble adventure to make our mark in the galaxy, but what will really pull us off the planet will be our needs.
Asteroids inhabit the space near to Earth and contain high percentages of metals and other minerals that are more rare on Earth. Mineral- and metal-rich asteroids require less energy to visit than the surfaces of moons or other planets, while the amounts of the resources they hold are readily determinable from telescope observation from Earth.
This image of the Gaspra asteroid from JPL.
As this article makes clear, the value of these minerals for different purposes are high, but not yet high enough to offset the costs to utilize them. What this interesting study makes clear, however, is that we have the means to predict economically when real space exploration, in terms of a more permanent human presence in space will begin.
Just looking at our world’s consumption of important metals, we can see from the graphs below that steel and gold are all increasing at a fairly rapid rate over time, not to mention the many other valuable metals like nickel, magnesium, platinum, etc. Increases in consumption drives increases in price as the easy to reach supplies on Earth are depleted. Unless we were to completely or drastically reduce our need for metals in buildings, vehicles, and consumer goods, it is inevitable that these commodities will reach the point that these asteroids become profitable ventures for courageous individuals.
The other side of this equation is reduction in cost of access to space. Launch vehicle prices have been decreasing over time, as more competition between national government space programs and commercial corporations has developed. This data shows that as of 2000, the real price of access to Low Earth Orbit (LEO) had fallen to $22,000 per kilogram, while access to Geosychronous Orbit (GSO) has fallen to about $25,000 per kilogram. These values demonstrate a reduction of around 40% from the prior decade for GSO, and a reduction of around 15% for LEO. These costs would be directly applied to the capital costs of developing a mine in space.
While launch costs are surely one of the most significant at the moment, return costs not to mention engineering costs required to develop the necessary equipment will also be substantial at least at first.
So, the balance between the value of the minerals and the costs to retrieving them will determine when this equation becomes positive in favor of pulling or pushing us off the planet. Until then, as the world economy develops over time, demand will be increasing pushing the prices of these commodities up as more of the world approaches the lifestyle of the rich countries.