Over the past 40 years, a handful of space probes has given us glimpses of Saturn. But NASA’s Cassini, which explored the gas giant’s realm for 13 years, delivered the most breathtaking new insights. NOVA takes you inside Cassini’s epic journey as it makes stunning discoveries: Saturn’s rings are younger than the dinosaurs and may be remnants of an ice moon. And geysers erupting ice and gas on the moon Enceladus show that it could have all the ingredients for life. But to protect it, the Cassini mission team makes a bittersweet decision.

• Konstantin Batygin
• David Grinspoon