NASA's Cassini spacecraft is preparing to make its lowest pass yet over the south polar region of Saturn's moon Enceladus, where icy particles and water vapor spray out in glittering jets. The closest approach, at an altitude of about 46 miles (74 kilometers), will occur around 11:30 a.m. PDT (2:30 p.m. EDT) on March 27.

This flyby is primarily designed for Cassini's ion and neutral mass spectrometer, which will attempt to "taste" particles from the jets. Scientists using this spectrometer will utilize the data to learn more about the composition, density and variability of the plume.

The Cassini plasma spectrometer, which team members worked to return to service so it could gather high-priority measurements during this flyby, will also be analyzing Saturn's magnetic and plasma environment near Enceladus and sampling the plume material near closest approach.

In addition, the composite infrared spectrometer will also be looking for hot spots on Enceladus, and the imaging cameras will be snapping pictures.

A flyby in October 2015 will bring Cassini about 16 miles (25 kilometers) closer to the Enceladus surface near the south pole. Cassini's closest approach to any part of Enceladus occurred on Oct. 9, 2008, when it flew within about 16 miles (25 kilometers) of the surface at the equator.