Callisto
Callisto is the most heavily cratered object in our solar system.
Callisto Facts
Callisto is Jupiter’s second largest moon and the third largest moon in our solar system.
Data from NASA’s Galileo spacecraft in the 1990s revealed Callisto may have a secret: a salty ocean beneath its surface. That finding put the once seemingly dead moon on the list of worlds that could possibly harbor life.
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Exploring Callisto
Callisto and Jupiter’s three other largest moons were discovered in 1610 by Italian scientist Galileo Galilei.
Almost 400 years later, a spacecraft bearing his name—the Galileo orbiter—began the first in depth study of the Jovian system, including Callisto and its sister moons. Galileo orbited Jupiter until the mission ended in 2003. Since then, several NASA spacecraft, including Cassini and New Horizons, have studied the moon.
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