I was now able to concentrate a burst of shrapnel on the other missile and take it out. I looked back to the one missile left, the one that my buster had caught up with, and realized I had a problem. The busters depended on kinetic energy to destroy their targets—high speed ramming, basically. This buster had instead run down a missile that was just as fast as itself. Now the buster and missile were flying together, with the buster repeatedly and ineffectually bumping the missile. It was interfering with the missile’s trajectory, but not causing any damage.