How to Deflect a Killer Asteroid

Researchers come up with contingency plans that could help our planet dodge a cosmic bullet.


To defeat the enemy, you have to think like the enemy, according to the old military cliché. If so, then Rusty Schweickart is exactly the guy you want on your side when the enemy is a giant space rock. 

As the co-founder of the nonprofit B612 Foundation, he is a leader in the effort to find and ward off threatening space rocks. And as the lunar module pilot on Apollo 9, he once sailed through space at 5 miles per second. “I’ve been out there. I’ve been a human asteroid,” he says with a chuckle.

Despite the obstacles I discussed in this column last month, astronomers are rapidly developing better tools to find and track near-Earth asteroids. Inevitably, the day will come when they find one on a collision course. That incoming object will almost certainly not be the world-ender of Hollywood epics; it will likely be something the size of the Trump Taj Mahal, large enough to flatten a city or a neighborhood. 

The object also will not have a nice, clean projected point of impact. “Any asteroid impact will actually have a line of risk across the planet,” Schweickart says. “And you’re not going to know where it’s going to hit along that line until just before impact.”

That risk line will be analogous to the hurricane storm-track projections that Gulf Coast residents warily eye every summer, with one crucial difference. Nobody has the faintest idea how to stop a hurricane, but lots of people have detailed concepts of how to deflect an asteroid — and there are two ways the scenario could play out.