text: NASA is planning on a smash hit with a comet You can learn something about a rock by looking at it. But what most geologists really want is to smack it with a hammer. That #39;s just what planetary scientists will do July 4 when NASA #39;s 
inputs: NASA is planning on a smash hit with a comet You can learn something about a rock by looking at it. But what most geologists really want is to smack it with a hammer. That #39;s just what planetary scientists will do July 4 when NASA #39;s 