Exploring Saturn's Moons | Mission Saturn

This mission has been anything but straightforward. We have to adapt; we have to be agile to make sure that we don't put a $3 billion asset in harm's way. If you want to effect what's coming up, you need—these flybys are planned out many, many months and sometimes years in advance. And so, if something is discovered and we can do something about it, we'll stop at nothing; we'll work literally day and night in order to make these new observations that the scientists, you know, desperately want to make happen.

NARRATOR: Pressure is building to rethink the route map. Immediately, the scientists wanted to get much, much closer to get high-resolution imaging but also move the closest approach from the northern hemisphere to the southern hemisphere. We finally arrived at a solution and we lowered the altitude from 1,000 kilometers all the way down to 165 kilometers.

NARRATOR: This pass is seven times closer than the first flyby. The discoveries are worth the diversion. This was the flyby where we saw, for the very first time, these fissures in the south polar regions. What was later named The Tiger Stripes.

NARRATOR: The stripes are gaping wounds where pressure from below opens vents to the surface. They're marked by whiter, fresher ice solidifying along the cracks. We saw about a dozen or more jets erupting 200 or more kilometers above the surface of the south pole. We strongly suspected that these were geysers and that this was vapor and particles coming from these fractures.

NARRATOR: Nothing now is more important than Enceladus. We wanted to go back again and again to learn more and even fly through and taste what was coming out of those jets.

NARRATOR: The scientists' thirst for knowledge can butt up against the need for spacecraft safety. And the guardian of that is Julie Webster.

JULIE WEBSTER: The engineering team is the 900-pound gorilla. If we don't think it's safe, we win. But you're there to take science, so if you don't take the data because you're too scared, you're not going to get what you're there for.

BRENT BUFFINGTON: We had to learn a lot about this plume. What was it made of? How dense was it? Was it variable in time? Variable in geometry?

NARRATOR: To answer such questions, Cassini dices with real danger.

BRENT BUFFINGTON: We're talking about an object that is over a billion kilometers from Earth. We went all the way down to 25 kilometers from the surface—a very, very hard surface—going in excess of eight or ten kilometers per second. So we're moving.

NARRATOR: The terrifying maneuver reveals how active this moon is. We found over 101 geysers and material coming from the fractures. And other teams found that the vapor contains simple organic compounds. Those geysers are coming from an ocean that is salty, comparable to the salinity of the Earth's ocean, and it's shooting into space.