Kerberos is a small natural satellite of Pluto, about 12 km (7.5 mi) in its longest dimension. It was the fourth moon of Pluto to be discovered and its existence was announced on 20 July 2011.
Shiro, Matthew Holt and his father were on Kerberos, drilling into the icy surface, when the Galra appeared and captured them. Because of a lack of evidence surrounding their disappearance, Galaxy Garrison pronounced them dead.
- Unlike the tidy sphere we see in the show, the real Kerberos is shaped more like a potato, and at 7.5 by 4.5 miles, would be far too small to have the kind of gravity needed for Shiro and the Holts to have run away from the Galra.