NASA announced on April 3, 2014 that thanks to gravity measurements taken by the space probe Cassini, that Saturn’s moon Enceladus indeed has a vast subsurface ocean that may contain life. Scientists have suspected this ever since a plume of water was detected shooting out of that moon’s south pole.
As with Jupiter’s moon Europa, which also has a subsurface ocean, tidal heating, in this case from Saturn, is likely providing warmth to Enceladus’ under-ice ocean. Water plus warmth could well equal life, which has just put that 500 kilometer diameter moon on a prime list of targets for a follow up planetary mission, along with Europa and another moon of Saturn, Titan.
Any expedition to a moon of Jupiter or Saturn is likely to cost several billion dollars, whether the probe is an orbiter, a lander or, like the Viking expedition to Mars, both. The heavy lift Space Launch System would certainly have enough power to get a large probe to Enceladus or another destination in the outer planets. The question remains, is there the money and the will to do any of that?