... "Hopes of easy access to the subsurface ocean were called into question at December's meeting of the American Geophysical Union. [Engineering professor] Colin Meyer (Dartmouth), an expert on sea ice and glaciers on Earth, presented an alternative view. By applying computer models developed for terrestrial sea ice, Meyer and his colleagues found that pockets of slushy brine produced by the localized heating of tidal stress and shear should be present within Enceladus's icy shell.

"Dissolving salts in water lowers its freezing point, and the resulting brine can percolate to the surface through porous ices, where it erupts into the vacuum. The concentration of non-volatile salts in this meltwater should increase as the water vaporizes and escapes into space. While Meyer does not doubt that a global subsurface ocean is present, he cautions that the plume’s measured saltiness 'may not be representative of the ocean chemistry or the chemistry of the shell but is actually concentrated interstitial liquid.'

"If sampling Enceladus's hidden ocean proves to be more difficult than many have imagined, the designs of several proposed missions to assess its habitability may have to be revised. However, Meyer notes that pockets of slushy brine in the icy crust may be habitable zones in their own right."