You may wonder what good asteroids are if you can’t deftly fly your spacecraft through a field of them to impress a girl and outrun bad guys. But it turns out that asteroids are a great source of precious metals — so great that companies like Planetary Resources have already developed plans to mine asteroids. But before that happens, we have to identify and access the giant space rocks. A team at Scotland’s University of Strathclyde in Glasgow has been doing just that, scouring the skies for asteroids classified as Easily Retrievable Objects, or EROs. A recent report indicates that they’ve found a dozen ERO asteroids that could be mined with today’s rocket technology.
Of some 9,000 objects currently in the near-Earth database (why can’t my databases be that interesting?), the 12 asteroids are of particular interest because it would be possible to change their velocity by about 500 meters per second to bring them into an accessible orbit.
The accessible orbit scientists are after is roughly 621,000 miles from Earth, around either the L1 or L2 Lagrangian points — areas where the Sun and Earth’s gravitational forces are balanced. Just as satellites that occupy Lagrangian points (also known as the Clarke belt) between the Earth and Moon remain in geostationary orbit, asteroids pulled into this orbit would stay in the same line with the Earth and Sun.
The asteroids have diameters that range from 2-20 meters, and scientists believe that the smallest of them could be sent into orbit around the L2 point with a change in velocity of roughly 58 meters per second. If everything lines up perfectly (a little celestial humor there), this asteroid could be within reach around 2026.
So, how does one move an asteroid, exactly? This helpful NASA infographic provides as much information as most of us might want, but in a nutshell, the propulsion of a rocket’s engines would push the big ol’ rock into orbit.
NASA’s current plan involves outfitting a rocket with a “capture bag” (it’s just like hunting for butterflies…in space!) to enclose an asteroid, making it easier to guide into orbit. They estimate that it would take a single low-thrust engine burn, roughly planned for February of 2021, to get the asteroid into orbit by 2026.
Just be sure not to point it straight toward Earth, please. Although if that happened, we could always save ourselves with paintballs.