Los Alamos National Laboratory

Los Alamos National Laboratory

Delivering science and technology to protect our nation and promote world stability

How to Save the World

An asteroid impact is the one natural disaster we can actually prevent.
January 1, 2020

A spacecraft currently orbiting the 800-meter-diameter asteroid Bennu, shown here, will touchdown, collect a sample, and return it to Earth for study. Understanding the composition of asteroids like Bennu will help scientists determine how best to deflect them off of a collision course.

When it comes to diverting killer asteroids, the nuclear option isn’t metaphorical.

There are a handful of people in the world making preparations to defend the world against killer asteroids. Among them, Cathy Plesko and her collaborators at Los Alamos—colleagues, postdocs, and students—are working out the plans necessary to intercept an incoming asteroid and nudge it off course with as little advance notice as possible. As things stand today, Plesko thinks we could develop and implement a plan to deflect a large asteroid if we had five or ten years of lead time—time to develop and launch a mission, time for the spacecraft to reach the asteroid, and time for the redirected asteroid to edge far enough off course to skirt around our planet.

“That far out, we couldn’t gauge its orbital path with enough accuracy to know for certain that it will hit,” says Plesko. “There might only be a one-in-four chance. But if we wait long enough to become fairly certain, there won’t be enough time to act. It’s a difficult problem.”


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