In this artist's concept of the Nov. 2, 2009 flyby, Cassini is flying through the mysterious plumes of Enceladus.
At its closest point, the Cassini spacecraft flew about 100 kilometers (60 miles) above the surface of this moon.
Since the discovery of the plume in 2005, scientists have been captivated by the enigmatic jets. Previous flybys detected water vapor, sodium and organic molecules, but scientists need to know more about the plume’s composition and density to characterize the source, possibly a liquid ocean under the moon’s icy surface. It would also help them determine whether Enceladus has the conditions necessary for life.