Last night’s double episode of “Salvation,” which introduced science fiction concepts such as gravity tractors, the EM drive, asteroid impacts, and Mars colonies, presented a new idea. The series revealed that at least in the universe in which Salvation resides, the United States worked on a top secret project called “Atlas” that was hinted at in previous episodes but is now revealed to be a method of weaponizing asteroids.

How did the idea work in the series?

It turns out that on Salvation, the Chelyabinsk meteor that exploded over an area in the Ural Mountains on February 15, 2013, was a test of an American weapon that went wrong.

The meteor was supposed to strike in an uninhabited region but instead exploded at the height of 18 and a half miles over the Chelyabinsk Oblast. The explosion injured 1,500 people sufficiently to require medical attention. 7,200 buildings were damaged by the shock wave, much of it blown windows. The 20-meter meteor exploded with the force of a 400 to 500 kiloton nuclear bomb. The Russians are understandably annoyed.

Why would anyone want to weaponize an asteroid?

The one advantage of an asteroid as a weapon is that it would be hard to distinguish an attack from a natural event. Scientists have been warning for decades that Earth approaching asteroids could prove to be a threat to the Earth. 65 million years ago, a massive asteroid struck in the vicinity of the Yucatan and created a shock wave and fire storm that wiped out the dinosaurs.

A similar event could perform the same service for the human species. A smaller asteroid, say the size of the Chelyabinsk meteor, could take out a city or a hardened site such a rogue state’s nuclear weapon’s facility. The attack would not elicit retaliation because it would look like a natural event.

The disadvantage of a weaponized asteroid is that it would be tough to hide the preparations to make it change course and send it toward a precise target.

Presumably, some kind of spacecraft would have to be dispatched to an asteroid to divert it. In “Salvation” part of that spacecraft survived the explosion, revealing a navigation system. Taking out a particular target may be fraught with difficulty in any case, as depicted on the show.

The main disadvantage is a long Lead Time for launching an asteroid attack.

Unlike an ICBM, an asteroid strike would take months if not years to execute. The movement of the asteroid might well be detected, and its probable strike zone would be ascertained. The long lead time would give the nation being attacked to prepare, if not by warding off the asteroid, at least evacuating the target area.