A well-known Earth threatening asteroid is named Apophis. At the length of an oil supertanker, Apophis will approach Earth to within 16,000 miles on April 13, 2029. (By the way, that happens on a Friday, for superstitious type to sweat over.) Apophis will sweep below orbits of our geostationary satellites. The pesky intruder comes back again in 2036.
But Covey estimates that if it were snagged and placed into orbit around the Earth it would provide enough material - 27 million tons - to construct about 125 solar power satellites (SPS). They would each generate five gigawatts of energy beamed to Earth ground receivers.
Covey says that the material would also be used to build a cylindrical rotating space habitat for the SPS constructions workers and families, numbering a population of 100,000.
Iron from Apophis could build a radiation shied around the habitat. Oxygen freed from iron compounds would provide breathable air.
Building such a space colony by lofting materials out of Earth's deep gravity well will never happen because of the cost per payload pound. Even NASA's Space Launch System is estimated to cost at least $5,000 per pound of payload.
"I believe that humanity will view Earth-crossing, potentially hazardous asteroids as low-hanging fruit, and each future discovery of an asteroid on a possible collision path will be followed by a gold-rush style race culminating in another new moon for our planet," Covey wrote.
Even a small asteroid weighs millions of tons. But "warp drive" doesn't have to be invented or some other form of exotic physics to tow it around. It's all in the simple application of Newtonian physics.
So, where there's a political will there's a way.
Among numerous scenarios, Covey suggests modifying the asteroid's orbit such that it makes a subsequent close approach to the moon with a relatively low velocity. This can drop that asteroid into a highly eccentric Earth orbit with a nine-day orbital period.
The fuel needed to nudge Apophis via rocket motors would be less than 10 tons, depending on the efficiency of the propulsion engine, he estimates.
Private industry might undertake such a space-mining mission that would be funded by selling electricity to Earth from SPSs. The revenue could be $150 billion per year according to Covey.
But filing a, ahem, environmental impact statement might be problematic. Would countries see captured asteroids as a celestial Sword of Damocles?
Advanced extraterrestrial civilizations might routinely harvest asteroids in this manner. Extraordinarily powerful space telescopes of the far future would be capable of recording transits of numerous small bodies across the face of an exo-Earth.
The only plausible explanation might end up being that they were deliberately placed in orbit about the planet. After much debate, the observations might be accepted as indirect evidence for a technological civilization elsewhere in the galaxy.
Image credits: National Space Society, Space Studies Institute, NASA