This is straight out of science fiction. A team of researchers at the University of Strathclyde has identified a group of asteroids whose orbits could be altered relatively easily to bring them to a spot where they would be accessible from Earth. They call these bodies “Easily Retrievable Objects” (EROs). They have found 12 from about 9,000 near-Earth objects that could be shifted into convenient orbits with a velocity change of less than 500 metres per second. This is within the capabilities of current rocket technology.
The team points out that one object, 2006 RH120, between 2 and 7 metres across, could be shifted with a single burn and take 5 years to reach its programmed destination to orbit one of the Lagrange points, L2. They calculate that 1,500 tons could be similarly shifted with a low-thrust engine of 3000s specific impulse. From these Lagrange points where the gravity of the Sun and the Earth are in balance, the asteroids could be visited and even mined for their resources. A business group called “Planetary Resources” was established last year to prepare for the future mining of asteroids. Its investors include Sir Richard Branson and Eric Schmidt, executive chairman of Google. This takes us straight into the stories of space miners that SF authors like Robert Heinlein wrote of.
Filed under: Updates |
Madsen Pirie 
I’m not convinced that ‘ mining ‘ asteroids will ever be worthwhile. There are no more than the original 92 elements which seem to exist in the Universe. Man has created additional elements by splitting atoms but this is apparently a process which does not appear to occur naturally in the Universe. Perhaps Diamonds, Platinum and Gold would attract the entrepreneurs but vast amounts of money would be expended to recover any element and bring it back to Earth.
While I have that Dan Dare spirit, there is still the problem of how to get them into Earths atmosphere for mining.
It would be more efficient to mine them in their new positions and use small rockets to send cargo automatically to Earth orbit, from where it could be retrieved.