Billed in Holst's The Planets as the "bringer of old age", Saturn is the second largest planet in the solar system. It is also the least dense, being composed mainly of hydrogen and helium.

Saturn is most famous for its rings - although Jupiter, Uranus and Neptune all have rings, Saturn's are by far the largest.

Saturn can be seen with the naked eye in the night sky. It takes almost 30 years to orbit the Sun, but each saturnian day lasts just over 10 hours.

Three craft have flown past Saturn before: Pioneer 11 in 1979, and Voyagers 1 and 2 in 1980 and 1981. But Cassini will be the first spaceship to pay an extended visit, orbiting the planet for four years.

Cassini's insertion into orbit around Saturn at 01:12 GMT on 1 July, will take it skimming just 18,000 kilometres above the cloud-tops. The spacecraft will be closer to the planet at this point than at any other time during its tour of the region.