Some of the "Faces" of 4-Vesta, from Hubble Space Telescope

NASA's Hubble Space Telescope snapped these images of the Asteroid 4-Vesta in preparation for the Dawn Spacecraft's visit in 2011. Each of the 4 Hubble images captures views of Vesta during its 5,34-hour rotation period. Hubble's sharp "eye" can see features as small as about 40 Km (24,84 miles) across in these images. Vesta was 211 MKM (approx. 131 MMs) 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.

Astronomers used the images, taken with Hubble's Wide Field Camera 3, to better determine 4-Vesta's Spin Axis. Based on the HST observations, astronomers calculated a slightly different, and more precise, Rotation Axis for Vesta. The new calculation will change the pattern of sunlight expected to illuminate the Asteroid when Dawn arrives.

Determining a more accurate Spin Axis for 4-Vesta will also 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 will then travel to the "Dwarf Planet" 1-Ceres, arriving in 2015.

Hubble has kept its "eye" on 4-Vesta for more than 15 years, beginning in 1994. Hubble images of 4-Vesta in 1997 helped astronomers discover the Asteroid's very large Impact crater. Astronomers combined views of 4-Vesta in Near-UltraViolet and blue light to construct these images and the images were taken on Feb. 25, 2010.