Enceladus' ice plumes in action are best seen from its night side.
The purpose of the flyby was to learn more about the nature of the plumes and measure their level of activity. Cassini used not only its cameras but also its ion and neutral-mass spectrometer to effectively "taste" the plumes.
First spotted by the Cassini spacecraft in 2005, the plumes are composed of water ice vapor with various salts and organic compounds mixed in, strongly indicating the presence of a subsurface ocean or reservoir of some sort. This puts Enceladus on the short list of places in the solar system where life may possibly be found.
Craters, cracks and wrinkles...some of the many types of terrain found on Enceladus.
Cassini was traveling approximately 17,000 mph (7.4 km/s) when it flew by Enceladus. Its next pass of the moon will be on Oct. 19, when the spacecraft will fly by at an altitude of approximately 765 miles (1231 kilometers).