Two other known regular satellites orbit within gaps in Saturn's rings.

Ferdinand is the most distant known satellite of Uranus.

There are also 84 known natural satellites of trans-Neptunian objects.

None of the known inner satellites possesses an atmosphere.

Notable for its two known satellites and unusually short rotation period (3.9 h).

There are fifteen known satellites, and their total area is about half that of Earth.

All the known large satellites but one, however, circle gas giants.

In the mid-1950s, when the novel was written, Jupiter had twelve known satellites.

As of 2003, there are 58 known natural satellites orbiting the planet Jupiter.

Two more small moons were discovered, bringing the planet's number of known satellites to eight.