After a years-long voyage since 2007, the Dawn spacecraft is now finally getting closer to the giant asteroid Vesta, which has never been seen up close until now. The newest images taken are now starting to surpass the previous best ones from the Hubble Space Telescope. Dawn will arrive at and orbit Vesta on July 16.
Vesta is the second largest asteroid, with an average diameter of about 520 km (320 miles). Dawn is then scheduled to leave Vesta in July 2012 and arrive at the largest asteroid, Ceres, in February 2015. Ceres and Vesta are also considered to be minor planets due to their much larger size than most other asteroids. Ceres may even have a very thin atmosphere and seasonal polar caps of water frost.
The images of Vesta will keep getting better as Dawn approaches and I will post more as they become available.