An analysis of the E ring particle composition revealed that the ring particles contain sodium salts.  Detecting salty ice indicates that Saturn's moon Enceladus, which primarily replenishes the ring with material from discharging jets, harbors a reservoir of liquid water beneath its surface, which is on contact with the moon‘s rocky core. Besides the salts, we also found carbonates like soda within the grains. This finding strengthen the case of an Enceladus water reservoir because the found concen-trations matches the predicted composition of an Enceladus ocean.

Enceladus‘ plume particles grow within the water vapour ascending through the cracks within the moon‘s ice crust. The subsurface water reservoir contains sodium salts dissolved from the moon‘s rocky core. Sodium-rich grains (6% of the analysed data set) are directly frozen submicron droplets from the water reservoir. Sodium-poor grains constituting the majority of the plume particles condensate from water vapour and  may be enriched with traces of sodium salts by direct or indirect interaction with sodium-rich grains.