Titan sub might explore Kraken Mare.

[Robotengineer]

From NASA: Titan Submarine: Exploring the Depths of Kraken.

From Space.com: Submarine Animation.

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Looks like it has a carbon fiber body in the video. What are your thoughts on it?

[LordFerret]

Seas of ethane, methane and propane ... should be very interesting to see how this is pulled off. Talk about cold! Do they know if there's any manner of oxidizer present? "BOOM!" come to mind?

[KerikBalm]

There's no boom, because there is no oxidizer present.

"We propose to develop a conceptual design" - could it be any more in the "just an idea" phase...I think not.

And that idea is years old by now

[Robotengineer]

There's no boom, because there is no oxidizer present.

"We propose to develop a conceptual design" - could it be any more in the "just an idea" phase...I think not.

And that idea is years old by now

Most ideas are years old by the time they get implemented. However I do doubt this will fail to get off the ground, unless there is going to be another large flagship mission to Saturn-Titan.

[Bill Phil]

Seas of ethane, methane and propane ... should be very interesting to see how this is pulled off. Talk about cold! Do they know if there's any manner of oxidizer present? "BOOM!" come to mind?

Activation energy is a bit high, and Titan is very cold. Even if there is Oxodizer, it won't do much.

[andrew123]

Squad, please improve the water physics. I want to probe some moons with my maritime vessels.

Subs would also force me to tinker around with x planes for better underwater and surface control.

If Squad adds AIP/Li ion powerplants and electric drive shafts, or even nuclear reactors, it would be a boon for naval development.

Edited February 13, 2015 by andrew123

[LordFerret]

There's no boom, because there is no oxidizer present.

"We propose to develop a conceptual design" - could it be any more in the "just an idea" phase...I think not.

And that idea is years old by now

lol ... that was just a bit of a joke.

Joking aside however, what about (explosive) rapid expansion? Suggestion was made (OP) that the sub appeared to be of carbon fiber, which, what if it was?... carbon fiber is generally not heat conductive, but does even on the low end possess some such quality. Surely the internal power source and electronics will generate heat, heat that will need to be dissipated. Dropping a 'cool' or even 'cold' sub into a methane sea could provide some interesting catastrophic results - due to rapid expansion. Yes/No?

[KerikBalm]

At most, it would be like dropping a hot rock into water.... the liquid around the sub might boil if there is not enough insulation.

The atmosphere will already cool the surface of the sub, and from there it can directly conduct heat to the liquid -> raising the temperature locally... but kraken mare is a huge heat sink, and boiling shouldn't be an issue.

Sure, you could drop an RTG into direct contact with the liquid, and have a constant boil... but its easy to make a design that doesn't do that.

Nothing catastrophic.

[LordFerret]

At most, it would be like dropping a hot rock into water.... the liquid around the sub might boil if there is not enough insulation.

The atmosphere will already cool the surface of the sub, and from there it can directly conduct heat to the liquid -> raising the temperature locally... but kraken mare is a huge heat sink, and boiling shouldn't be an issue.

Sure, you could drop an RTG into direct contact with the liquid, and have a constant boil... but its easy to make a design that doesn't do that.

Nothing catastrophic.

It will be interesting to see what they come up with... same for any Europa mission.

Now, you mentioned there was no oxidizer present (on Titan). But there is. Titian is composed mainly of water-ice and rocks, and current speculation has it there is a liquid saltwater ocean beneath the crust. That tells me the potential for it exists.

http://science.nasa.gov/science-news/science-at-nasa/2014/02jul_saltyocean/

[Robotengineer]

What about using the thermal power of a RTG to melt through Europas' ice?

[peadar1987]

What about using the thermal power of a RTG to melt through Europas' ice?

There have been proposals to do this. Problem is Europa's ice is about 10-30km thick, as far as we can tell, and even if you did get through the ice, you would have big trouble communicating through it.

It takes about 333kJ to melt one kg of water. Assuming a spacecraft with a 1m by 1m cross section, you would need to melt 10,000m^3 of ice, with a mass of about 9,000,000kg to get down to the ocean. That would take about 3PJ of energy, or, alternatively, a 1kW heat source would take 95 years to melt all the way down.

[LordFerret]

There may be no need to melt/drill ice to reach Europa's oceans, as discussed in a number of research papers and book (here). There are daily fractures which appear on Europa's surface, which flush with fresh liquid water... this in essence could mean a direct pipe/path to the ocean beneath. Obviously more study and survey needs to be done here. All a probe would need do, is find such a fissure, either liquid, or with thin skim of ice covering, and it's in.

- - - Updated - - -

...and as for communications, just as we've fly-by-wire missle control (TOW missle), a probe about to plunge the depths of a crack could eject and drop an anchored antenna at the rim of the crack, and unfurl its Comm wire behind it on the way down.

[KerikBalm]

Now, you mentioned there was no oxidizer present (on Titan). But there is. Titian is composed mainly of water-ice and rocks, and current speculation has it there is a liquid saltwater ocean beneath the crust. That tells me the potential for it exists.

What the? what are you talking about? what does a saltwater ocean have to do with the presence of an oxidizer?

What does an oxidizer have to do with the potential for life to exist?

[meve12]

What the? what are you talking about? what does a saltwater ocean have to do with the presence of an oxidizer?

What does an oxidizer have to do with the potential for life to exist?

Water ice has oxygen in it, is what he's saying.

He's not referring to whether life exists, by the way; he's expressing a concern that there might be free oxygen on Titan, which if mixed with methane and given a high enough temperature...

[CptRichardson]

Water ice has oxygen in it, is what he's saying.

He's not referring to whether life exists, by the way; he's expressing a concern that there might be free oxygen on Titan, which if mixed with methane and given a high enough temperature...

"Well, there's our problem!" [/Adam Savaging as Titan turns into Hell]

[KerikBalm]

Oxidizer != oxygen

Water is not oxidizer, its what you get after you've used up your oxidizer combusting it with hydrogen.

You might as well call sugar and Rust oxidizer if you're going to call anything containing an oxygen atom "oxidizer"

[Northstar1989]

Oxidizer != oxygen

Water is not oxidizer, its what you get after you've used up your oxidizer combusting it with hydrogen.

You might as well call sugar and Rust oxidizer if you're going to call anything containing an oxygen atom "oxidizer"

Precisely. If there's a surplus of Hydrogen on the planet/moon, you can have LOADS of Water without there being any O₂ to be found *anywhere*.

Titan can't have free oxygen- it would interact with the Methane seas. Just because the activation energy is high enough that you don't get explosive combustion doesn't mean you don't get a very *gradual* reaction over the course of thousands or millions of years...

Regards,

Northstar

[-Velocity-]

Oxidizer != oxygen

Water is not oxidizer, its what you get after you've used up your oxidizer combusting it with hydrogen.

You might as well call sugar and Rust oxidizer if you're going to call anything containing an oxygen atom "oxidizer"

Yea, water is not oxidizer. Generally, it's a product that you frequently get from oxidation. Water and CO2 is what you get from burning methane, in fact. So it's silly to talk about as an oxidizer in this case.

Though to be technically precise, while rust is a product of oxidation, it can be in fact be an oxidizer in certain situations. It is the oxidizer in thermite (a high temperature incendiary explosive), for example. The key is that the oxygen in the iron oxide has an even lower chemical energy state it can go to by bonding with the aluminum "fuel". At least I think that's how it works. I only had a single college level chemistry class; they don't require much chemistry for electrical engineers.

Another example, water can in fact be an oxidizer too under the right conditions. If I want to grow a thick layer of silicon dioxide on a silicon wafer, then I flow a mixture of about 3 parts oxygen and 5.9 parts hydrogen into our oxidation oven at 1000C; I run it oxygen rich so that we don't run the risk of a hydrogen buildup on the ceiling of the lab (yea, that could be bad). Anyway, it makes water vapor inside the furnace, which for some reason I don't understand, actually grows an oxide layer on the silicon faster than if I just flow pure oxygen. Go figure.

[zekes]

darn you NASA stealing my ideas... I put a sub on eve in 0.16

[moronwrocket]

One problem with melting a hole to a deep ocean is dealing with all the debris that would collect at the bottom of that hole. The ice isn't pure, think of slush on the side of the road. It's full of dust/pebbles and other gunk that will probably settle at the bottom of the hole you're trying to melt, and eventually prevent the heat from melting through. Maybe the sub could gently turn diagonally every few hundred meters to dump the debris, and back up and start a new hole. Will require decades of development and testing here on Earth though before hitting Europa or Enceladus.

[Kruleworld]

Seas of ethane, methane and propane ...

prototype?

[KerikBalm]

Yea, water is not oxidizer. Generally, it's a product that you frequently get from oxidation. Water and CO2 is what you get from burning methane, in fact. So it's silly to talk about as an oxidizer in this case.

Though to be technically precise, while rust is a product of oxidation, it can be in fact be an oxidizer in certain situations. It is the oxidizer in thermite (a high temperature incendiary explosive), for example. The key is that the oxygen in the iron oxide has an even lower chemical energy state it can go to by bonding with the aluminum "fuel". At least I think that's how it works. I only had a single college level chemistry class; they don't require much chemistry for electrical engineers.

Another example, water can in fact be an oxidizer too under the right conditions. If I want to grow a thick layer of silicon dioxide on a silicon wafer, then I flow a mixture of about 3 parts oxygen and 5.9 parts hydrogen into our oxidation oven at 1000C; I run it oxygen rich so that we don't run the risk of a hydrogen buildup on the ceiling of the lab (yea, that could be bad). Anyway, it makes water vapor inside the furnace, which for some reason I don't understand, actually grows an oxide layer on the silicon faster than if I just flow pure oxygen. Go figure.

Umm.... I don't think water is acting as the oxidizer in that case.

And Yes, Rust can be an oxidizer if there is a lower energy state.

Throw sodium in water, and the sodium will be oxidized and Hydrogen will be released, because sodium is less electronegative than Hydrogen.

Of course, water can also be a reducing agent. Fluorine is more electronegative than oxygen, and should be able to react with water to form H-F and free O2...

But molecular oxygen would actually not be an oxidizer in a Fluorine atmosphere.

But for the chemical composition of Titan... No, water is not an oxidizing agent, and there seems to be no oxidizer present.

[-Velocity-]

Umm.... I don't think water is acting as the oxidizer in that case.

Actually, the chemical reaction is Si + 2X H2O -> SiO2 + 2X H2. That would make the H2O an oxidizer, unless there's more to the definition of "oxidizer" than I'm assuming. I don't know if this is an endothermic or exothermic reaction though. I, again, need to study my chemistry better, it's one of my weaknesses. I was actually considering breaking out my chemistry textbook sometime. The problem is, I find chemistry to be kinda boring... which is strange for me because I like most other technical fields/sciences.

But again, yes, I agree, talking of water being an oxidizer for hydrocarbons is silly.

- - - Updated - - -

One problem with melting a hole to a deep ocean is dealing with all the debris that would collect at the bottom of that hole. The ice isn't pure, think of slush on the side of the road. It's full of dust/pebbles and other gunk that will probably settle at the bottom of the hole you're trying to melt, and eventually prevent the heat from melting through. Maybe the sub could gently turn diagonally every few hundred meters to dump the debris, and back up and start a new hole. Will require decades of development and testing here on Earth though before hitting Europa or Enceladus.

That's a very interesting problem I hadn't heard about. Do they really think there will enough heavy debris in the ice to cause problems? Or do we simply not know? After all, in sea ice, there isn't any debris- but sea ice on Earth is usually between a hundred to a few million times younger than ice on Europa. I doubt there would be enough meteoric debris in the ice to cause a problem. BUT we don't really know for sure what might be in the ice, do we? It would probably be safest to just assume that this problem you speak of could arise, and plan for it.

[AngelLestat]

3 pages and the only thing that was mentioned is whether the atmosphere can "kaboom" and how to drill europa ice?

Serious questions:

Why choose that large fin that works as an omnidirectional antenna? It has a second purpose? Why not a directional dish?

Power source, 1 kw radiothermal energy.. this can be very efficient given that the extreme temperature difference with the ambient, but one problem may be the methane boiling at contact with the submarine, which may interfere with the sensors.

Maybe the second purpose of the antenna fin is to act as radiator, so the thermal difference over the area is not big enoght.

Submarine size?

From all previous concept ideas to explore titan, this might be the most interesting due its biome.

But there are all very efficient from the energy perspective.

[magnemoe]

That's a very interesting problem I hadn't heard about. Do they really think there will enough heavy debris in the ice to cause problems? Or do we simply not know? After all, in sea ice, there isn't any debris- but sea ice on Earth is usually between a hundred to a few million times younger than ice on Europa. I doubt there would be enough meteoric debris in the ice to cause a problem. BUT we don't really know for sure what might be in the ice, do we? It would probably be safest to just assume that this problem you speak of could arise, and plan for it.

The problem here is that junk in the bottom will isolate it and make most of the melting happen on the sides, this will increase the junk issue.

However the penetrator will be pretty heavy, this will make it more relevant to make it more dense as in avoiding unnecessary voids. If its heavier than most rocks and pointed it will push them asides. metallic derbies are less common and conduct heat better so I doubt it will be an issue.

We will also drill close to an fracture, ice here will be younger, note that its no wind, so any dust is from meteorites. Yes you will get some stuff who is lighter than water too but that will float up.