Prospect of life on Jupiter moons 'not so crazy'

The European Space Agency (Esa) is about to launch one of its most ambitious ever missions. Its Juice satellite will leave Earth on Thursday to begin an eight-year journey to Jupiter, where it will study the gas giant's major moons. There's good evidence that these icy worlds - Callisto, Europa and Ganymede - hold oceans of liquid water at depth. The Esa mission aims to establish whether the moons might therefore also be habitable, says the agency's director of science, Prof Carole Mundell. She's been speaking with our science correspondent Jonathan Amos.