The Space Shuttle Discovery launched today on its final mission into outer space. Discovery was the fourth orbiter built after Enterprise, Columbia and Challenger. It has also flown the most mission - today's launch kicks off the shuttle's 39th. In addition to stocking the International Space Station, Robonaut 2 is being brought aboard. It will be the first humanoid robot in space. The goal is to eventually have similar models work side-by-side with astronauts and perform more dangerous tasks alone.