A crater chain is a line of craters along the surface of an astronomical body. These chains are thought to be made by the impact of a body that was broken up by tidal forces into a string of smaller objects following roughly the same orbit or by volcanic rift activity. An example of the impact model was seen actually happening with the impact of Comet Shoemaker-Levy 9 on Jupiter. During the Voyager missions to the planet, planetary scientists identified 13 crater chains on Callisto and three on Ganymede. Crater chains seen on the Moon often radiate from larger craters, and are thought to be either caused by secondary impacts of the larger crater's ejecta or by volcanic venting activity along a rift.
