And Dave, this almost looks like it could be a GSA presentation! Very nice.

An article from Space earlier this year says that Enceladus’ oceans may be heading for a permanent freeze though…
http://www.space.com/scienceastronomy/080619-am-enceladus-ocean.html

But in all likelihood, there is some kind of ocean on Enceladus, so something must have prevented Enceladus from fully freezing.

“There has to be an ocean to allow the flexing — that’s a well-founded conclusion,” McKinnon said.

Although McKinnon thinks this new work is important, he does not think it covers all possible scenarios. For one, he believes the water in the Enceladus ocean will be full of salts and maybe ammonia. Such a mixture will freeze at a lower temperature than pure water.

McKinnon also said that the ocean itself will generate tidal heating by sloshing back and forth like the ocean tides do on our planet.

But even including these other elements, Enceladus may still not retain enough heat to allow for an ocean to exist today. This is why Roberts and Nimmo consider the possibility that the moon has migrated from a more eccentric orbit in the past.

If Enceladus’ orbit had been three times more eccentric than it is now, the tidal heating would have been enough to keep an ocean. Assuming this high eccentricity (high heating) phase ended within the last 30 million years, the moon would not yet have had enough time to freeze up. The researchers speculate that the moon’s eccentricity and tidal heating may have fluctuated up and down many times.

The orbital history of Enceladus is not known, but migration of satellites is not unheard of, McKinnon said.