Saturn's rings, Cassini image. The rings consist of particles of nearly pure water ice and meteoric dust and span almost 300,000 kilometres. The largest gap in the rings is the Cassini Division, which separates the A (outer) and B (inner) rings. The smaller gap within the A ring is the Encke Division. Pandora, one of Saturn's moons, is seen as a minute speck above the A ring at upper left. The Cassini-Huygens spacecraft was launched in 1997 to investigate Saturn, its rings and its moons. This image was taken by Cassini's wide-angle camera on the 13th April 2007 at a distance of 1.8 million kilometres from Saturn.