PUBLIC INFORMATION OFFICE
JET PROPULSION LABORATORY
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PHOTO CAPTION                           P-48292
                              February 10, 1997
                                        Callisto Crater Chain 
                                        Mosaic

This mosaic of three images shows an area within the Valhalla 
region on Jupiter's moon, Callisto. North is to the top of the 
mosaic and the Sun illuminates the surface from the left. The 
smallest details that can be discerned in this picture are knobs 
and small impact craters about 160 meters (175 yards) across.  
The mosaic covers an area approximately 45 kilometers (28 miles) 
across. It shows part of a prominent crater chain located on the 
northern part of the Valhalla ring structure. Crater chains can 
form from the impact of material ejected from large impacts 
(forming secondary chains) or by the impact of a fragmented 
projectile, perhaps similar to the Shoemaker-Levy 9 cometary 
impacts into Jupiter in July 1994.  It is believed this crater 
chain was formed by the impact of a fragmented projectile.  The 
images which form this mosaic were obtained by the solid state 
imaging system aboard NASA's Galileo spacecraft on Nov. 4, 1996 
(Universal Time).

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.

This image and other images and data received from Galileo are 
posted on the World Wide Web Galileo mission home page at 
http://www.jpl.nasa.gov/galileo. Background information and 
educational context for the images can be found at 
http://www.jpl.nasa.gov/galileo/sepo.

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