NASA's Dawn has entered the asteroid belt, and will stay there

Yay! This technically doesn't mean anything on a daily basis since the asteroid belt is still mostly just empty space as well, but it's a symbolic entry into the area where Dawn will spend the rest of its life. It's also the first spacecraft to take up residence there; all others have simply passed through en route to some other destination.

Number of days left to wait until Dawn arrives at the first destination (Vesta): 602.

Another related article from last month may be interesting: the asteroid 2 Pallas is actually a protoplanet rather than just an asteroid. Some are hoping that Dawn will be able to visit 2 Pallas as well after Ceres if it turns out to have the required fuel and health after its mission is over.