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11:49 am
Wed November 20, 2013

Deflecting An Asteroid, With Paintballs

When you think about ways to deflect an asteroid, your mind probably immediately jumps to heavy artillery. Things like lasers. Or Bruce Willis-style nuclear bombs. But Sung Wook Paek is working on a much lower-key approach to preventing Armageddon: paintballs.  

Paek, a graduate student at MIT, one day found himself riding a bike and thinking about how we could deflect an asteroid hurtling toward earth. He said cherry blossoms were in bloom on MIT's campus, and he was navigating across a path littered with little balls of fruit.

"Whenever I rode my bicycle on [the fruit], it popped up and made my bicycle tire dirty," Peak said. Then the idea hit him: exploding balls of color -- probably not the first thing that pops into your mind when you think about diverting a planet-destroying asteroid, but Paek's idea is brilliant in its simplicity.

Here's how it works: a delivery system hovers near an asteroid, peppering its surface with a shower of tiny objects with what Paek called "micro impacts." Each hit transfers a tiny bit of kinetic energy, progressively diverting an asteroid thousands of miles off its current course. And here's the genius part: each impact also explodes a blast of white paint powder on the asteroid's surface.

"The pressure of light is very small, and cannot be measured on earth, but in space there are no other forces," Paek said. "So in space you can use the pressure of light to slowly push away this asteroid from its original path."

That's right: photon impacts. It doesn't get much more micro than that. And Paek said that if an asteroid is detected early enough, say, a couple of decades before it hits earth, these photon impacts could divert an asteroid away from earth. The white paint also gives trackers on the ground an advantage, making the asteroid appear brighter in the sky. Brighter objects are easier to follow.

In 2012, Paek's idea won the "Move an Asteroid Technical Paper Competition," which was sponsored by the United Nation's Space Generation Advisory Council. He said he's talking with NASA officials about refining the idea, gauging how his white powder would interact with different asteroid materials, or with ice. There's also the pesky problem of dust. When you throw stuff at an asteroid, it kicks up sediment that could settle back onto the asteroid's surface, mixing with the white paint. 

"If you hit it, then you will make a crater and there's dust that's flying off," Paek said, "and coming back onto the surface of the asteroid. The paint and the dust might be mixed, and the color might not be changed as I wanted." 

So there's a few kinks to work out. But Paek said he'll continue modeling scenarios, and in the meantime, I'll hope his theories never come into play.