Earth Impacts V 
It sounds like something straight out of Hollywood. Astronomers discover an asteroid that’s on a collision course with Earth. But there’s no reason to duck and cover — a giant laser in orbit takes aim, and in a few months it vaporizes the space rock. And when it’s done, it wheels around to propel a robotic probe to another star.
This system is still in the realm of fantasy, but the scientists who designed it say it could be built with today’s technology. It wouldn’t be easy — or cheap — but it could defend our planet while performing other tasks.
It’s called DE-STAR — Directed Energy System for Targeting of Asteroids and Exploration. It was designed by Philip Lubin and Gary Hughes, who are with universities in California.
There’s no doubt that asteroids present a danger to Earth. A collision with one just a few hundred feet across could cause widespread devastation.
DE-STAR would use large solar panels to power an array of lasers. A full system would span miles, and the designers say it could obliterate a good-sized asteroid or deflect a really big one. And with enough lead time, even a small version of the system — the size of a couple of football fields — could provide enough energy to push most asteroids off course.
As a bonus, DE-STAR could accelerate a small interstellar probe to a few percent of the speed of light or provide communications across interstellar distances — all while protecting Earth from deadly space rocks.
Script by Damond Benningfield, Copyright 2013