Saturn’s moon Prometheus shepherds the F ring alongside Pandora.
Prometheus is an irregular, potato-shaped satellite orbiting just inside Saturn’s narrow F ring, while Pandora travels just outside it. Their combined gravity helps confine the ring’s material and produces changing structures such as channels, kinks, and streamer-like features.
Voyager images revealed the moons’ importance, and later observations from the Cassini mission provided much more detailed information about their interactions with the ring. Prometheus is considerably more active in perturbing the F ring because it is larger and has a stronger gravitational influence than Pandora.
The pairing is also mythological. Prometheus and Pandora belong to the same Greek mythic cycle, although their roles differ: Prometheus is associated with giving fire to humanity, while Pandora is associated with the vessel that released troubles. Epimetheus, another Saturnian moon, is a separate satellite and is not the F ring’s principal partner.