Deep Impact Mission - NASA - First look inside a comet

Deep Impact is an ambitious mission aiming to accomplish the incredible: Blast a hole in comet Tempel 1 in an effort to see what it's made of. Comets like Tempel 1 are thought to have existed since the early days of our Solar System. Scientists suspect that frozen within these celestial nomads are the same chemical building blocks that lead to the formation of water -- and life -- here on Earth. Do comets and our own planet have something in common? This clever mission could answer the question once and for all.