With Europa's 0.135 Earth gravity, and assuming the same 1.022 SG seawater
density, excluding all other small variables, real pressure at 12 miles
depth on Europa is equivalent to an Earth ocean depth of about 8550 feet, or
3790 Earth PSI, or around 23.8 Earth mPa.
Jack
We discussed this issue some time ago. I'm no scientist, but with 0.135 Gravity, I don't see how the water pressure could be the same, unless it is under great pressure from the ice above it.
This raises the problem that if the water is under pressure, a boring submersible would cause a rupture... unless the submersible allowed the ice to refreeze behind it. At a depth of 12 miles, however, the ice would likely have a flow similar to Earthside glaciers, wherein ice at depth has a plasticity that allows them to flow down mountainsides, and across terrain.
The question I'm more interested in was the one regarding the density of the ice itself. If the gravity of the planetary mass is so low, then presumeably, the ice would form under very low conditions, the exact reverse of pressure-frozen water.
If this condition is so, then the 'ice' of Europa might have a crystalline structure which no Earthside computer models can emulate, and the 12 mile ice sheet might be surprisingly 'soft', thereby greatly increasing the efficiency of an ice-borer.
-- JH Byrne
