DE-STAR is designed to vaporize or divert asteroids that threaten Earth. This isn't science fiction—I build things that have to work in practice. DE-STAR stands for Directed Energy Solar Targeting of Asteroids and exploRation. It looks like an open matchbook with lasers on one flap and a photovoltaic panel for power from sunlight on the other. By synchronizing the laser beams, we can create a phased array, which produces a steerable 70-gigawatt beam. An onboard system receives orders on what to target. Our laser beam would then produce a spot about 100 feet in diameter on an asteroid that's as far away from the satellite as we are from the sun. The laser would raise an asteroid's surface temperature to thousands of degrees Celsius—hot enough that all known substances evaporate. In less than an hour, DE-STAR could have completely vaporized the asteroid that broke up over Russia this winter, if we had seen it coming. Plus, as the material evaporates, it creates a thrust in the opposite direction, comparable to the space shuttle's rocket booster. That means you could divert the asteroid by changing its orbit with a shorter laser blast.