15 October

1997: On 15 October 1997, the joint NASA/ESA/ASI Cassini-Huygens mission was launched. It was the first spacecraft sent to land on a world in the outer Solar System - on the surface of Titan, Saturn’s largest moon. Indeed, the Cassini-Huygens mission was the most ambitious effort in planetary space exploration ever mounted.

On its seven-year journey to Saturn, Cassini-Huygens performed four gravity-assist swing-by manoeuvres: Venus (April 1998), Venus (June 1999), Earth (August 1999), and Jupiter (December 2000). The gravity assists gave Cassini-Huygens the cumulative boost to reach Saturn. The spacecraft arrived at Saturn in July 2004.

The Cassini-Huygens mission is named after two European astronomers from the 17th century. The Dutch astronomer Christiaan Huygens (1629-95) discovered Saturn's rings and Titan. A few years later the French-Italian Astronomer Jean-Dominique Cassini (1625-1712) discovered Saturn’s four other major moons – Iapetus, Rhea, Tethys and Dione. He also discovered that Saturn’s rings are split largely into two parts by a narrow gap, known since as the 'Cassini Division'.