Bonnie J. Buratti, P. C. Thomas, E. Roussos, Carly Howett, Martin Seiss, A. R. Hendrix, Paul Helfenstein, R. H. Brown, R. N. Clark, Tilmann Denk, Gianrico Filacchione, Holger Hoffmann, Geraint H. Jones, N. Khawaja, Peter Kollmann, Norbert Krupp, Jonathan Lunine, T. W. Momary, Christopher Paranicas, Frank Postberg, Manuel Sachse, Frank Spahn, John Spencer, Ralf Srama, T. Albin, K. H. Baines, Mauro Ciarniello, Thanasis Economou, Hsiang-Wen Hsu, Sascha Kempf, Stamatios M. Krimigis, Donald Mitchell, Georg Moragas-Klostermeyer, Philip D. Nicholson, C. C. Porco, Heike Rosenberg, Jonas Simolka, Laurence A. Soderblom

• Saturn’s main ring system is associated with a set of small moons that either are embedded within it or interact with the rings to alter their shape and composition. Five close flybys of the moons Pan, Daphnis, Atlas, Pandora, and Epimetheus were performed between December 2016 and April 2017 during the ring-grazing orbits of the Cassini mission. Data on the moons’ morphology, structure, particle environment, and composition were returned, along with images in the ultraviolet and thermal infrared. We find that the optical properties of the moons’ surfaces are determined by two competing processes: contamination by a red material formed in Saturn’s main ring system and accretion of bright icy particles or water vapor from volcanic plumes originating on the moon Enceladus.