Asteroids have been roughing up the Earth since it formed 4.6 billion years ago. Hundreds of thousands of potentially devastating asteroids are still out there, and whizzing past our planet all the time. Eventually, inevitably, one is going to score a direct hit and cause catastrophic damage. But what if we could get a better idea of where all these asteroids are or even learn to shift their orbits? Dr Edward Lu is a NASA astronaut, and a member of the B612 Foundation - an organization raising awareness about the threat of these asteroids and some potential solutions.