I’m studying some ideas for a future hard sci-fi adventure using Mongoose Traveller 2ed and Orbital 2100, with player characters landing in Europa (Jupiter’s moon) to study the chance of life in the ocean under the moon’s icy shell.
I’m thinking about giving them some kind of submarine vessels, like a bathyscaphe or armoured diving suits, and probably a mobile base. Have any of you thought about how to design a vehicle that can be at the same time a dropship and a terrestrial base/vehicle to travel over the surface of Europa and transport the bathyscaphe to a chosen site?
Surface gravity on Europa isn't very high. So having the thing being extremely heavy would not be much of an issue if it's not supposed to take off and land on Earth. Once the sub is in the water it will be bouyant, that helps with dealing with weight too. But even with low gravity, the extreme depth of the ocean will lead to incredible pressures near the bottom, where the cool stuff is likely to be found. So the sub will have to be extremely strongly build.
Yes, the sub will need to be very strong and prepared to deal with depths of 100 km Europa - Subsurface ocean.
That's 10 times as much water overhead as in the Mariana's Trench (since water doesn't compress like air, this scales about linear), while having a ninth of the gravity. So water pressure at the bottom shouldn't be that much higher. And it's already doable to get down to such pressures with current technology.
Though having something the size of a medium ship instead of a car would probably require some sci-fi tech. But nothing too fantastic.