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PHOTO CAPTION
P-48124
December 12, 1996

A portion of a chain of impact craters on Jupiter's moon Callisto is seen in
this image taken by the Galileo spacecraft on November 4, 1996. This crater
chain on Callisto is believed to result from the impact of a split object,
similar to the fragments of Comet Shoemaker- Levy 9 which smashed into
Jupiter's atmosphere in July of 1994. This high- resolution view, taken by
Galileo's solid state imaging television camera during its third orbit
around Jupiter, is of Callisto's northern hemisphere at 35 degrees north, 46
degrees west, and covers an area of about eight miles (13 kilometers)
across. The smallest visible crater is about 140 yards (130 meters) across.
The image was taken at a range of 974 miles (1,567 kilometers).

On a global scale, Callisto is heavily cratered, indicating the great age of
its surface. At the scale of this image, it was anticipated that the surface
would be heavily cratered as well; however, there is a surprising lack of
small craters, suggesting that one or more processes have obliterated these
and other small-scale features. For example, downslope movement of ice-rich
debris could bury small craters. The bright slopes visible in this picture
represent places where downslope movement has taken place, exposing fresh
ice surfaces.

Launched in October 1989, Galileo entered orbit around Jupiter on December
7, 1995. The spacecraft's mission is to conduct detailed studies of the
giant planet, its largest moons and the Jovian magnetic environment. The Jet
Propulsion Laboratory, Pasadena, CA manages the mission for NASA's Office of
Space Science, Washington, DC.