Saturn’s F ring is shepherded by the moons Pandora and Prometheus.
The F ring is a narrow, braided-looking ring located outside Saturn’s main A ring. Its structure is strongly affected by the gravitational influence of two small moons: Prometheus orbits just inside the ring, while Pandora orbits just outside it. Their repeated gravitational tugs help confine and shape the ring’s material.
Voyager images revealed the ring’s complex appearance, including kinks, strands, and changing features. Later observations by the Cassini spacecraft studied how the two moons disturb the ring and produce waves and channels in its dusty particles.
The F ring is not the same as Saturn’s brighter A, B, or C rings. It is much narrower and more dynamically active. Although Pandora and Prometheus are often called shepherd moons, their interaction is not perfectly simple: their orbital relationship can also generate instability and intricate patterns.