Pluto

Pluto is a (dwarf) planet in the Generation 1 continuity family.

Pluto is a small, icy world first discovered in 1939, and recognized as the ninth planet in Earth's Solar System until quite recently. It is now considered a dwarf planet.

Generation 1 Cartoon
The Earth Defense Command maintained a space station in orbit around Pluto, as well as a warp gate on the world's surface.