The relatively small asteroid that exploded in the skies over Siberia last February, injuring over 1,000 people, was a shocking reminder that our planet is a target in a cosmic shooting range. Larger asteroids, from the width of a football field to the size of a small city, have the potential to be killers on a massive scale: in previous collisions with Earth, they have set off deadly blast waves, raging fires, and colossal tidal waves. Fortunately, space rocks like these can be deflected––if we have enough warning. But whose responsibility is it to survey for, and protect against, these potential doomsday bringers? Leaders of governmental and private organizations discuss the defense against the next strike. Speakers: Lindley Johnson, Ed Lu and Paula Apsell