Cassini mission reveals the secrets of Saturn’s walnut-shaped ring moonsNew study in in the high-ranking journal Science No 73/2019 from Mar 29, 2019 A new study of Saturn's small inner moons was published in the high-ranking journal Science . Images of Pan, Daphnis, Atlas, Pandora and Epimetheus, obtained by the Cassini spacecraft in winter 2016/17, show that several of these so-called "shepherd moons" exhibit huge ridges around their equators, giving them a very peculiar and impressing walnut-like shape (Fig.