What is Pandora’s main astronomical role at Saturn’s F ring?

Pandora is the outer shepherd moon of Saturn’s F ring.

A shepherd moon is a satellite whose gravity helps confine, shape, or maintain a planetary ring. Pandora travels outside Saturn’s narrow F ring, while Prometheus travels inside it. Their combined gravitational effects help keep the ring narrow and produce changing structures within it.

Pandora is small and irregular, with a mean radius of roughly 40 kilometres. Its low mass means that its influence is subtle compared with the gravity of Saturn, but it is still significant in the dynamics of the F ring. The moon’s role is one reason planetary scientists study it alongside Prometheus.

The phrase “outer shepherd” identifies Pandora’s position relative to the ring, not its distance from Saturn among all of Saturn’s moons. Several other satellites interact with rings, but Pandora and Prometheus are the classic paired shepherds of the F ring.