The roughly 20-kilometer-diameter (12-mile-diameter) crater, named Helena, in the center of this image of Vesta has an interesting bipolar morphology. The left side of Helena crater has a fresh and distinctive rim. Dark and bright material crops out of this part of the rim and slumps towards the center of the crater. But, the right side of Helena crater is much less distinct and grades into the surrounding hummocky (i.e. wavy/ undulating) terrain. Another smaller crater to the right of Helena has a similar morphology, where about one third of the crater is eroded into the surrounding terrain and is much less distinct than the other two thirds. There is a small crater surrounded by bright ejecta to the top left of the Helena crater and there are patches of dark material spread across the image.
This image is located in Vesta’s Sextilia quadrangle, in Vesta’s southern hemisphere. NASA’s Dawn spacecraft obtained this image with its framing camera on Oct. 21, 2011. This image was taken through the camera’s clear filter. The distance to the surface of Vesta is 700 kilometers (435 miles) and the image has a resolution of about 70 meters (230 feet) per pixel. This image was acquired during the HAMO (high-altitude mapping orbit) phase of the mission.
The Dawn mission to Vesta and Ceres is managed by NASA’s Jet Propulsion Laboratory, a division of the California Institute of Technology in Pasadena, for NASA’s Science Mission Directorate, Washington D.C. UCLA is responsible for overall Dawn mission science. The Dawn framing cameras have been developed and built under the leadership of the Max Planck Institute for Solar System Research, Katlenburg-Lindau, Germany, with significant contributions by DLR German Aerospace Center, Institute of Planetary Research, Berlin, and in coordination with the Institute of Computer and Communication Network Engineering, Braunschweig. The Framing Camera project is funded by the Max Planck Society, DLR, and NASA/JPL.
More information about Dawn is online at http://dawn.jpl.nasa.gov.
Image credit: NASA/JPL-Caltech/UCLA/MPS/DLR/IDA