Charon

Charon is Pluto's only yet discovered moon
Charon's orbit is around 19,640 km from Pluto.
Charon has a diameter of 1172 Km, and has a mass of 1,9*1021 kg.

Charon is named for the legendary figure that shipped the dead across the River Acheron into Hades (the underworld).
Though officially named for the mythological figure, Charon's discoverer (Jim Christy) was also naming it in honor of his wife, Charlene.

Jim Christy discovered Charon in 1978. Before, it was thought that Pluto was much larger since the images of Charon and Pluto were unclear.

Charon is very odd, and unusual, when comparing its area with its primary planet Pluto. Pluto and Charon have the smallest area difference in the whole solar system, meaning that it's the only planet system in the solar system that has such a small difference in the area. That is why some scientists/astronomers prefer to call Charon and Pluto as a double planet instead of a planet and a moon.

Very little is known about Charon and its surface, however scientist believe that it is possible that it might be covered with water ice. This is quite different from Pluto, which mainly has Nitrogen ice.