Discovery invites you on a mission to the most intriguing body in the solar system – Saturn’s moon Enceladus. It’s a small icy world with gigantic geysers, blasting water into space at supersonic speeds. It’s also become the most promising place among the planets to search for extra-terrestrial life. These astonishing discoveries come from Nasa’s Cassini mission to Saturn launched 18 years ago and still underway. The BBC’s Jonathan Amos talks to scientists who have been at the centre of the unfolding story of Enceladus and those who want to return to answer the great question which it poses.

(Photo: Enceladus. Credit: NASA/JPL/SSI)