Want to mine an asteroid? Rather than travel to it with all their mining equipment, three Chinese scientists have proposed a better way. In a paper published today on the Los Alamos astro-ph preprint website, they have calculated the energy required to shift the orbits of the six thousand near-Earth asteroids and place them in Earth orbit for later mining. Of these, they found 46 asteroids that had the potential for such an operation, and two likely candidates for a space mission. One 30-foot-wide asteroid, 2008EA9, will actually be in the right place for this technique in 2049. As they write,
It can be seen that the velocity increment of the 2008EA9 is relatively small (-1.00km/s) and it will very close approach [approximately 645,000 miles] to the Earth in [February] 2049. Moreover the size of the NEO 2008EA9 is very small so that the capturing of it is relatively easy.
The real problem, of course, is adding that small “velocity increment” to the asteroid.
You can give the asteroid a quick push, using “conventional explosive, kinetic impactor, or nuclear explosive.” The problem with these techniques is that you have to have a very precise understanding of the composition, density, and make-up of the asteroid. For example, an impactor hitting a rubble pile will have far less success in moving it than if that asteroid was a dense solid body. Worse, an explosion might rip a rubble pile apart, sending the wreckage on a collision course with Earth. To put it mildly, such an event would have serious liability concerns for any private company.
A better method might be to give the asteroid a slow and steady push over a long time, using a space tug, a nearby heavy mass, or a beam of light — either from focused solar light or a pulsed laser — all of which slowly drag the asteroid into its new orbital path. Even here, however, it is necessary to have a better understanding of the asteroid before launching such a the tractor mission.
While at first glance all of this appears to be science fiction fantasy, the mining of asteroids has gigantic economic potential. As the scientists note, “a two kilometer-size metallic [near Earth object], for example, may contain rich metals and materials worth more than 25 trillion dollars.”
In other words, forget about science and political considerations. There is a real commercial need to mount a scouting mission to these near-Earth asteroids. And it appears the Chinese are thinking about this seriously, considering this is the second paper on the subject of accessing and adjusting the orbits of near-Earth asteroids to appear from them in less then two weeks.