NASA's Hubble Space Telescope snapped these images of the asteroid Vesta in preparation for the Dawn spacecraft's visit in 2011.
Each of the four Hubble images captures views of Vesta during its 5.34-hour rotation period. Hubble's sharp "eye" can see features as small as about 25 miles (40 kilometers) across in these images. Vesta was 131 million miles (211 kilometers) from Earth when Hubble made the observations.
The images show the difference in brightness and color on the asteroid's surface. These characteristics hint at the large-scale features that the Dawn spacecraft will see when it visits the potato-shaped asteroid.
Vesta is somewhat like our Moon, with ancient lava beds (the dark patches) and powdery debris, the pulverized remains of impacts (the orange-colored areas). The flattened area on one end of Vesta, visible in the top row of images, is a giant impact crater formed by a collision billions of years ago. The crater is 285 miles (460 kilometers) across, which is close to Vesta's roughly 330-mile (530-kilometer) diameter. Vesta is about the size of Arizona.
Astronomers used the images, taken with Hubble's Wide Field Camera 3, to better determine the orientation of Vesta's spin axis.(Video Above)
This will help scientists refine the Dawn spacecraft's orbit around the asteroid. Dawn will orbit the rocky object for a year, beginning in July 2011. The spacecraft then will travel to the dwarf planet Ceres, arriving in 2015.
Vesta is one of the largest of a reservoir of about 100,000 asteroids, the leftover material from the formation of our solar system's planets 4.6 billion years ago.
About the video above. Astronomers combined 146 exposures taken by NASA's Hubble Space Telescope to make this 73-frame movie of the asteroid Vesta's rotation.