I consider the Rosetta spacecraft one of the most exciting space voyagers in years. It is the first probe to orbit a comet, returning images of unprecedented richness. On November 12 it will place a lander on the comet's surface, another exploratory breakthrough. Rosetta's target, Comet 67P (its mouthy full name is Comet 67P/Churyumov-Gerasimenko) is a frozen relic from the early days of the solar system. Studying it up close will teach us a lot about how the planets formed, how Earth got its water, maybe even how life began.