Callisto Valhalla Impact Structure

A portion of the central zone of the large impact structure Valhalla on Jupiter's moon Callisto was imaged by the Galileo spacecraft on November 4, 1996. The area shown here is centered at 16 degrees north, 55 degrees west and is about seven miles (11 kilometers) across. This is the highest resolution picture ever taken of Callisto and shows features as small as 200 feet (60 meters) across. The formation of Valhalla occurred early in Callisto's history; however, the central zone shown here is probably younger than Valhalla's surrounding structure. This newly [sic] acquired picture shows some small craters, although they have been softened or modified by downslope movement of debris, revealing bright ice-rich surfaces. In contrast to other areas on Callisto, most of the very smallest craters appear to have been completely obliterated. This image was taken by the solid state imaging television camera onboard the Galileo spacecraft during its third orbit around Jupiter, at a distance of 757 miles (1,219 kilometers). http://photojournal.jpl.nasa.gov/catalog/PIA00516