> This remarkable transformation in our understanding is the result of just three missions: Voyager, Galileo, and Cassini—along with some computer modeling and hard staring by the Hubble and Webb space telescopes.
Seems odd to neglect to mention New Horizons immediately after mentioning the probable existence of liquid oceans under Pluto's surface, a finding made possible thanks primarily to New Horizons.
True for all the Galilean Moons more or less. Their orbits all lie within the Jovian equivalent of the Van Allen belts. And Jupiter's magnetic field is much stronger than earth's.
Not Callisto. Being within Jupiter's magnetosphere but out of reach of Io's shenanigans makes it one of the mildest radiation environments in the solar system.
> What about rocks in the surface of the water?. Some volcanic rocks can float.
This is... not something you lay plans on. Even on Earth, these rocks are formed at surface pressure, just barely float, and don't float for long (I've tried). If they form in the deep ocean, I'm guessing the pressure isn't going to let the bubbles be big enough to create bouyancy at all. Either way they would be super rare.
Europa Clipper, launched 2024, starts Europa flybys on March 2031
Dragonfly, hopefully launching July 2028, arriving on Titan 2034
https://en.wikipedia.org/wiki/Europa_Clipper
https://en.wikipedia.org/wiki/Dragonfly_(Titan_space_probe)
Seems odd to neglect to mention New Horizons immediately after mentioning the probable existence of liquid oceans under Pluto's surface, a finding made possible thanks primarily to New Horizons.
> The radiation environment around Europa is punishing; an astronaut standing on the surface would get a fatal dose in about a day
Io, meanwhile, is 35 Sv/day. Location really matters among the four Galilean moons.
> We want rocks in contact with water,
But there is ice compressed between the water column and the xenoceanic bottom, ok. I see the problem.
What about rocks in the surface of the water?. Some volcanic rocks can float.
This is... not something you lay plans on. Even on Earth, these rocks are formed at surface pressure, just barely float, and don't float for long (I've tried). If they form in the deep ocean, I'm guessing the pressure isn't going to let the bubbles be big enough to create bouyancy at all. Either way they would be super rare.