Charon

Centuries later, there were "lighthouse" outposts as far as Pluto and its moon Charon.

Pluto is not alone. It has a friend named Charon.

Charon is considered to be a satellite of the (dwarf) planet Pluto. However, because its diameter is more than half as large as that of Pluto itself, it can be considered an equal partner; and Pluto and Charon can be considered a double planet.

Pluto and Charon are tipped on their sides.

One of Pluto's moons is Charon.

Charon is Pluto's largest moon.

Charon, Pluto's largest moon, is very different from its parent planet.

Pluto is tightly locked to its largest moon, Charon.

Charon took Tom to the other side of the lake.