Life & Temperatures on Titan

[Anthony]

Originally Posted by DataPacRat

Anyone have a clue on how deep a borehole could be dug with non-^ TL10?

If you're digging through ice, you can probably drill through the crust to the underlying ocean by just melting your way through and relying on water pressure to prevent your hole from collapsing. That doesn't work on Earth because our instruments don't like liquid rock and other substances we can fill the hole with have much lower density than rock, but it shouldn't be much of a problem on Titan (you'll need continual energy to prevent it from freezing up again, but not very much, ice isn't a terribly good thermal conductor).

[DataPacRat]

Originally Posted by Anthony

just melting your way through

That'd do it. :)

Next up - coming up with a Ghost-computer-running submarine that can handle around 3,400 atmospheres of pressure (sphere, extra-heavy frame, and for a SM+2 ship, call it 1,000 DR)... and figuring out what all is there to be found, aside from mind-bogglingly massive amounts of salty water-ammonia. (Close to 20 times the volume of all of Earth's oceans, and the typical depth is 35 times the Mariana Trench's maximum.) I'm not really sure if Titan's geology leans towards the existence of hydrothermal vents, or any of the CHON compounds up on the surface would be found deeper below.

Still, even if organic life is infeasible, it could be a place for AIs and Ghosts who just want to get lost. After all, even the most expensive sonar systems in THS's Under Pressure only have a range of 30 miles, which isn't much compared to the 400-mile depth of Titan's subsurface ocean.

[Fred Brackin]

Originally Posted by DataPacRat

That'd do it. :)

Next up - coming up with a Ghost-computer-running submarine that can handle around 3,400 atmospheres of pressure (sphere, extra-heavy frame, and for a SM+2 ship, call it 1,000 DR)... n.

Unless you have computer components that breathe air this might not be neccessary. Even if some of your mechanical stuff is not an imcompressible solid many voids can be filled with oil rather than air. They did this on 20th century stuff.

[DataPacRat]

Originally Posted by Fred Brackin

Unless you have computer components that breathe air this might not be neccessary. Even if some of your mechanical stuff is not an imcompressible solid many voids can be filled with oil rather than air. They did this on 20th century stuff.

I remember that one of 3e's Vehicles Expansion books mentioned an ultra-heavy frame-strength, described as something like 'solid blocks of armor embedded with components', which seems a reasonable enough description of what to aim for.

[Anthony]

It's not 3,400 atmospheres. Assuming the crust is primarily water ice at around 1000 kg/m^3, at a gravity of 1.35N/kg, 75 km depth is a pressure of about 100 MPa or 1,000 atmospheres, it's about the same as Challenger Deep on Earth.

[DataPacRat]

Originally Posted by Anthony

It's not 3,400 atmospheres. Assuming the crust is primarily water ice at around 1000 kg/m^3, at a gravity of 1.35N/kg, 75 km depth is a pressure of about 100 MPa or 1,000 atmospheres, it's about the same as Challenger Deep on Earth.

The 3,400 atmospheres figure is for the deepest parts of Titan's ocean; I jotted a note of "up to 1,333 atm?" for its top. I get the larger number because the layer beneath the ocean is made of Ice-VI, which only exists between roughly 500 MPa to 2 GPa - that is, 3,333 to 13,333 atmospheres. As far as I understand matters, the bottom of Titan's ocean should have a pressure close to the top of the solid layer beneath it.


(Ice-VI actually has a minimum of about 620 MPa, or 4,133 atmospheres, but that's for fairly pure water-ice; mixing in the ammonia and salts and such muddies the numbers enough that I'm willing to posit 500 MPa.)

[Fred Brackin]

Originally Posted by DataPacRat

I remember that one of 3e's Vehicles Expansion books mentioned an ultra-heavy frame-strength, described as something like 'solid blocks of armor embedded with components', which seems a reasonable enough description of what to aim for.

Why do you need to maintain 1 atm. for something that has no organics? Those 3e pressure rules were for manned vehicles. I remember the playtests painfully.

[DataPacRat]

Originally Posted by Fred Brackin

Why do you need to maintain 1 atm. for something that has no organics? Those 3e pressure rules were for manned vehicles. I remember the playtests painfully.

... My understanding is that every vehicle has a crush-depth, whether it's manned or not. Going by the formula in Under Pressure p153, then the internal pressure (if any) is a fairly small component of what's involved, when dealing with external pressures of thousands of atmospheres.

[Fred Brackin]

Originally Posted by DataPacRat

... My understanding is that every vehicle has a crush-depth, whether it's manned or not. s.

This is wrong.

A vehicle that it made up of incompressible solids or has hollow spaces filled with an incompressible fluid will not be crushed by any amount of water pressure.

Those pressure rules are for vehicles trying to maintain an air-filled chamber at 1 atm. such as the bathyscathe Trieste or the research submarine Alvin. I got to know both of these well while helping with those rules. I still ember that Alvin's sherical pressure hull was an inch of titanium.

Nobody needs to worry about robot subs such as the ones used to find the Titanic. They no more need crush depths than the ship's anchor does.

[DataPacRat]

Originally Posted by Fred Brackin

This is wrong.

A vehicle that it made up of incompressible solids or has hollow spaces filled with an incompressible fluid will not be crushed by any amount of water pressure.

Those pressure rules are for vehicles trying to maintain an air-filled chamber at 1 atm. such as the bathyscathe Trieste or the research submarine Alvin. I got to know both of these well while helping with those rules. I still ember that Alvin's sherical pressure hull was an inch of titanium.

Nobody needs to worry about robot subs such as the ones used to find the Titanic. They no more need crush depths than the ship's anchor does.

Hunh. Learn something new everyday. I suppose that's what I get for having focused so much of my attention only on vehicles designed for pressures from 0 to 1 atmosphere. :)

Welp, that certainly opens up the range of design-space to draw from. I might even be able to get away with just snagging and barely-tweaking an existing robot-sub design (if I can find any). I'd just have to design the surface ice-melting-driller to make a hole wide enough for it.