Saturn from the approaching Cassini spacecraft. This image was taken on 16th May 2004, when Cassini was 24.3 million kilometres and 46 days from Saturn. Enceladus, one of Saturn's 31 known moons, is below Saturn at bottom right. The Cassini spacecraft will begin its four-year mission when it arrives at Saturn on 30th June 2004. It was launched in October 1997. As well as studying the planet from orbit, it will drop the Huygens probe onto Saturn's largest moon, Titan. Saturn is the second largest planet in the Solar System. It orbits the Sun around ten times further out than Earth, some 1.5 billion kilometres. The yellow colour here is due to the filters used.