The European Space Agency's Rosetta spacecraft woke from a deep sleep today after hibernating for two and a half years of its journey to the comet 67P/Churyumo-Gerasimenko. It's been a long one; Rosetta was launched in 2004 and completed two flybys of Earth and one of Mars in order to put it on course. At it's farthest point, it was 800 million kilometers (past Jupiter!) from the Sun, and is now about 9 million km from its target. When it reaches the comet in August, it will become the first spacecraft to attempt a landing on a comet.
Rosetta has an exciting year coming up now that it's awake! It will start taking pictures of 67P/Churyumo-Gerasimenko in May, then line up for its critical August encounter with the comet. It will orbit the comet and collect data on its shape, mass, and atmosphere. This data will be used to choose a site for the Philae probe, which is presently scheduled to be released for landing in mid-November. Since the comet's gravity isn't particularly strong, Philae will have to use screws and harpoons to keep it from flying back out into space after landing. (Fun fact: Philae is named for an island in the Nile River where an obelisk that helped to decipher the Rosetta Stone was found.)
After this, Rosetta will escort the comet as it moves around to the Sun, monitoring how the comet changes as it warms. Rosetta has the potential to teach us a great deal about these "dirty snowballs", which potentially brought water (or even the building blocks of life) to Earth.