Look Nick I'm not in the same league as a lot of people here when it comes to space science. I know that. I'm an enthusiast, not a scientist. I'm simply throwing out ideas. That said, I've read quite a bit about Europa and the ice layer thickness is thought to be about 12 miles but that's not certain. Further, there IS speculation, even expectation, that it is thinner in some areas. Certainly large fresh cracks, of which there are many, would be thinner. The bottom of the ocean of Europa is thought to look a lot like Io, except underwater of course. A large underwater eruption could also make the ice thinner directly above it. We don't really know how deep the ocean is or how tall the tallest underwater volcanoes are. The entire premise of the idea I put out was based on finding a very thin part of the ice during a mapping and sonar phase of exploration.

IF, and of course it's a huge IF, a thin enough part of the ice could be found bunker buster technology might be feasible. If a current bunker buster hardened shell can penetrate 150' of solid concrete at a speed of 4000 ft per second, I imagine we have the technology now to penetrate at least a mile into ice when dropped from orbit.

There was talk of a kinetic energy impactor for a Europa mission a few years ago. Granted it wasn't to penetrate the ice all the way to the ocean below but the idea still has merit.

I'm not so naive as to think this idea is a possiblity for a mission like the one described in the article. Maybe a future one. One thing's for sure, if we are ever going to explore that ocean we have to get through the ice one way or another.