The Dawn spacecraft, which entered orbit around the main-belt asteroid Vesta in July, has just spiraled in for a closer look. Earlier this month the NASA orbiter entered a low-altitude mapping orbit, swooping down to about 200 kilometers above the surface of the asteroid to capture high-resolution imagery of the odd-shaped body. Dawn had previously mapped Vesta from an altitude of 680 kilometers.
The orbiter photographed the partially shadowed, relatively fresh impact crater shown above on December 13, shortly after the start of the low-altitude observing campaign. The region surveyed in the image is 18 kilometers on a side; Vesta itself is about 560 kilometers in diameter. The crater is in the asteroid's ancient, heavily pocked northern hemisphere. In the south, where a large impact resurfaced a large swath of Vesta billions of years ago, the terrain appears to be significantly younger.
Next year Dawn will move deeper into the asteroid belt to its next target, the dwarf planet Ceres.