Subsurface ocean

There are a number of places in our solar system where subsurface oceans are expected. In some cases there might be more or less cryovolcanism present which many or may not provide access channels all the way down to the subsurface oceans. where a research probe or (even a crewed submarine) may or may not fit through.

High pressures in these oceans

Despite the low gravities of these bodies the great depth of the upper end of these subsurface oceans causes a great deal of pressure which may not be easily handelable for some of the bodies.
(TODO: add some minimum depth and pressure estimations to give some perspective)
(TODO: add some temperature estimates too)Cryovlocanic channels and "magma" chambers might be easier way accessible than directly melting through through the icy crust. Also these would be more interesting for human colonization.

APM's high pressure suitability

Note that deep-sea probes built with advanced APM will be able to handle tremendously higher pressures than what is possible with today's (2020) technology. (See: High pressures). It might get to the point where one needs to think about avoiding crystal structures of the probe being crushed rather than rather than internal voids being crushed. There is much less heat in many of the bodies of interest than when going down in depth on Earth. And extreme heat is the bigger problem for advanced AP systems. Also there is massive temperature equilibration in an open body of water. At the depth of the Mariana Trench but under land it is way hotter than just 4°C due to the geothermal gradient that is not present in water.

List of bodies with potential subsurface oceans

mars

• Well, not an ocean but some "small" lakes under thick ice sheets have been confirmed.

Asteroid belt:

• Ceres -- it does not visually obviously look like it but there are wight salt spots (and a strange young mountain) proving cryovolcanism

Moons of Jupiter:

• Europa -- Probably the best bet to find one. It has by far the youngest surface. It literally looks like ice on an ocean.
• Ganymede -- visually its in-between Europa and Kallisto
• Kallisto -- It's quite heavily crated and does not visually look like it's harbouring a subsurface ocean
  (TODO: find out what's the water ice to siclicate rock ratio on Kallistos surface)

Moons of Saturn:

• Titan -- it visually doe not look like it but instruments tell otherwise Template:Wiki-todo
• Enceladus -- huge water ice plumes from cracks confirmed

Moons of Neptune:

• Triton -- gysirs confirmed.

• Pluto and Charon? -- It seems like there is some large scale some nitrogen ice convection going. There may be some cryocolcanism involved. We don't know.