Saturns moon Enceladus. Computer artwork of a view across Enceladus towards Saturn in the sky above. Enceladus is the sixthlargest moon of Saturn. It measures 500 kilometres in diameter and is a frozen world with a surface consisting mostly of water ice. Like all of Saturns major satellites, Enceladus always keeps the same side facing its host planet. This image also illustrates a recently discovered phenomenon: sunlight reflecting off Saturns rings casts a faint glow onto the cloud tops of Saturns night side.