back to article TITANIC: Nuclear SUBMARINE cruising 'Sea of KRAKENS' may be FOUND ON icy MOON

NASA boffins have come up with a design for a submarine they reckon could one day be used to explore the liquefied hydrocarbon seas of Saturn's mysterious freezing moon, Titan - the only bodies of surface liquid confirmed to exist off Earth. The submarine – to be revealed at the 46th Lunar and Planetary Science Conference in …

  1. Woza
    Mushroom

    Have they planned for

    Deep Ones?

    1. Simon Sharwood, Reg APAC Editor (Written by Reg staff)

      Re: Have they planned for

      Let's just assume Bob Howard gets a ride on the mission to take care of that, shall we?

      1. launcap Silver badge
        Boffin

        Re: Have they planned for

        > Bob Howard gets a ride on the mission

        That would be some mission briefing. And a more-wierd-than-usual mission code..

        (Upvoted for Laundry Files reference - I tried to get my wife interested but (even though she's somewhat technical) she doesn't get most of the tecnical stuff)

  2. Flatpackhamster

    Why a sub?

    What would a submarine be able to give you that a ship equipped with lidar and sonar to map the depth of the sea wouldn't? If you really wanted to look underwater then a camera mounted on the underside of the ship would do that but I can't see that it would give us any fresh knowledge (apart from 'how to build a submarine on Titan' that sending a ship wouldn't. Are they making life too complicated for themselves?

    1. Robert Helpmann?? Silver badge
      Childcatcher

      Re: Why a sub?

      What would a submarine be able to give you that a ship equipped with lidar and sonar to map the depth of the sea wouldn't?

      I think you missed the bit about the “benthic sampler.” It's pretty much the same with any mission of this nature in that you get much more data if you can dig down into the surface than if you use a more limited set of measurements. That and because it is a lot more fun to touch than to look.

      1. notowenwilson

        Re: Why a sub?

        Even if you wanted to sample the bottom sediment, you'd still be much better off with a ship and then deploy a sampling instrument on the end of a cable. Look at the oil and gas industry. They spend an inordinate amount of time doing things underwater and the vast majority of those tasks are done with ROVs and Divers which are both surface supplied. The main issue I can see with a ship is the weather. If you've got strong winds you're going to need a powerful engine which may become problematic (or failing that, put a sail on it and then you can skip the engine altogether).

        1. LINCARD1000
          Pirate

          Re: Why a sub?

          While I agree a boat (with various bits for sampling attached to a cable) would be simpler and actually quite sensible from an engineering POV, I seem to recall that there has been a lot of talk and speculation that the lakes could be subject to some pretty serious waves. Waves which given the density of the liquid hydrocarbons along with the lower gravity (and possibly also affected by wind) would be fairly gnarly, dude :-)

          This would knock any surface vehicle around quite a bit making sample collection awkward, and would also make getting a sub into the 'water' a tricky exercise as well.

          It might seem like wasting valuable time and resources but perhaps some sort of aerial (balloon or drone?) mission first to scope conditions out first might save a lot of heart-ache. All this is still very cool though - I love space science! :-)

          PS: if it came down to funding for a submersible mission to the outer planets, I'd much rather see money/effort spent on exploring probable sub-ice seas on moons like Europa as a priority. Ideal world we'd have both, however,

    2. Anonymous Coward
      Anonymous Coward

      Re: Why a sub?

      Ship? The proposed weight budget for this vehicle is about a ton, so more like a small motor boat. Accommodating a tethered bottom-probing device able to reach 600m would be quite an engineering feat on something that size. On Earth, remote-controlled submersibles have mother-ships weighing hundreds of tons.

  3. MrDamage

    Aerodynamic Subs

    "The proposed solution is to pack the submarine into a vehicle like the X-37 autonomous space plane which would make a water landing, open its cargo bay and then sink, leaving the submarine to go about its business."

    The proposed solution is to pack the submarine into a pod, which is then incorporated into a vehicle like Thunderbird 2 which would hover over the ocean, drop its pod and then return to orbit as relay and monitoring station, leaving Thunderbird 4 to go about its business.

    FTFY

  4. A Non e-mouse Silver badge
    Happy

    The document points out that submarines aren't very aerodynamic..

    Anyone else read that and immediately think of the whale in H2G2?

    1. Trigonoceps occipitalis

      "aerodynamic"

      The clue is in the word. Hydrodynamic is better for subs. (Methanedynamic?)

  5. Mephistro Silver badge
    Coat

    After watching the design of this submarine...

    ... I think space boffins should get over their obsession with anal probes. Nuff said.

  6. Vladimir Plouzhnikov

    Density

    "for the heavier methane."

    Are you sure about that?

    1. Rick Brasche

      Re: Density

      if they design for neutral buoyancy in heavier fluid, and it turns out to be lighter, aren't they headed straight to the bottom?

      Wouldn't it be better to plan on the lighter medium, at least for flotation purposes, but concern with depth as the heavier one, hybridizing the two?

  7. Paul Dx
    Mushroom

    Extend the mission time

    Why not add a system to use the methane as a power source and extend the 90 day mission time ?

    Just make sure you don't end up with ---->

    1. Vladimir Plouzhnikov

      Re: Extend the mission time

      "Why not add a system to use the methane as a power source"

      No... *coughs* *chokes* ...oxygen.....

      1. Paul Dx
        Facepalm

        Re: Extend the mission time

        Good point.

        1. Swarthy Silver badge
          Flame

          Re: Extend the mission time

          But a couple of tanks of LOX to burn and possibly act as ballast control... ->

          1. Vladimir Plouzhnikov

            Re: Extend the mission time

            In that case you would want F2 or OF2, as they are more efficient oxidizers for methane than LOX.

            1. cray74

              Re: Extend the mission time

              "In that case you would want F2 or OF2, as they are more efficient oxidizers for methane than LOX"

              To an extent, but LOX has a number of advantages: lots of engineering experience; space storage experience; and available in situ from water ice (with a secondary power source). Space programs never put fluorine-based oxidizers to use since the gains weren't worth the trouble.

  8. Little Mouse

    What's long and hard and full of...

    ...seamen hi-tech sensors and a radioisotope Stirling generator power source?

  9. Bob Wheeler
    Coat

    Two questions...

    the mission design precludes an orbiter to relay data home

    All great fun, but two questions.

    If this is blue sky thinking, so has the mission design has been written?

    Would the cargo craft that drops off the submarine not be able to act an orbiting relay?

    1. Vladimir Plouzhnikov

      Re: Two questions...

      I guess they are planning for direct insertion from interplanetary without going to orbit in between... or, rather, without wasting mass on a carrier whose only job will be to deploy the sub on arrival. If they strap on a disposable retro-motor on the sub, use it to slow it down for insertion, then discard - kind of thing...

  10. Chozo
    Boffin

    Kiss Me Deadly

    That's going to be one helluva big radioisotope generator to deliver 1kw.

    The one on the cassini probe was 57kg and produced only 300watts.

    1. Vulch

      Re: Kiss Me Deadly

      That's the reason for the Stirling generator, much more efficient converting the heat to electricity but at the expense of having moving parts which might fail.

      1. Voland's right hand Silver badge

        Re: Kiss Me Deadly

        Mass will be less in either case - cooling is trivial. You have a whole ocean at sub-liquid-nitrogen temperature around you and the possibility to conventional cool it.

        IMHO the bigger design problem is keeping the amount of whatever isotope they load on the ship from overheating in-transit while it still does not have the cooling it will get at destination.

        As far as Stirling, moving and fail, there are plenty of striling engines which are past their 100 year anniversary and still run with minimal maintenance. Stirling may be big, it may be slow, it may have atrocious mass to power ratio, but in general it does not fail for many years. Frankly, the isotope will run out of energy first.

      2. cray74

        Re: Kiss Me Deadly

        "That's the reason for the Stirling generator, much more efficient converting the heat to electricity but at the expense of having moving parts which might fail."

        I believe testing for the ASRG reached several years of operation without difficulty.

  11. ukgnome

    erm

    it looks a bit penisy

    1. launcap Silver badge
      Alert

      Re: erm

      > it looks a bit penisy

      More like some form of Gallente ship. Does it come with drones and good armour?

  12. Anonymous Custard Silver badge
    Coat

    NASA's design for a submarine to operate on Titan

    Looking at the pic, I have to wonder if they've had that design around for ages and have been secretly testing it in a certain Scottish loch for a few decades?

    My coat's the extra warm one - it's chilly up there this time of year...

  13. 0laf Silver badge

    I wonder if they'd ever consider long life orbiters for planets? Some big relay sats that could last for 50yr or more so they don't need to put powerful transmitters on little probes all the time. Seems to work well on Mars.

    1. Nick Ryan Silver badge

      I thought that at one time but it's the weight that is the problem. Getting relatively light payloads as far as Titan is expensive on fuel as even with a large chunk of the journey being coasting which is likely why no orbital stages are discussed for this one. There are usually substantial course corrections (navigational changes) as they are inevitably sling shotted into place and we don't have any powerful enough engine systems which wouldn't require enormous amounts of fuel for a direct flight, even to Mars, let alone further. Lifting huge and heavy payloads into near Earth orbit is pretty much trivial in comparison to interplanetary missions.

  14. another_vulture

    Buoyancy

    A sub (or a dirigible) needs neutral buoyancy. It needs enough of its volume to be less dense than the surrounding medium to counterbalance its heavier parts. For example, the Trieste bathyscaphe used a tank of oil that was lighter than water. For liquid methane, a fabric "tank" filled with hydrogen gas would probably be the best choice. We would need a way to use electricity from the power plant to generate hydrogen (and dispose of carbon) from the methane. Alternatively, With a much larger (insulated) envelope we can use heat to keep methane in a gaseous state. In either case the result looks more like a dirigible than a submarine.

    The problem with gaseous buoyancy in liquid is compression. Positive feedback: more depth, more pressure, less gas volume, less buoyancy, more sinking. counteracting this requires active systems. For instance, with a variable-volume envelope, keep some gas at high pressure to release into the envelope to counter sinking.

  15. Lapun Mankimasta

    space plane

    I got to thinking, why the (censored) don't they design the apace plane that lands the sub, to float on the water, put on some (relatively) minor sensors, build in a humungous aerial, and use it as the sub-to-Earth relay station? That way you get to collect more info, get an extra sensor set, and get an aerial that's got the range to pass serious detail back to Earth.

    1. Pascal Monett Silver badge

      Re: space plane

      Probably because they are actual scientists and are also taking into account mission mass and total cost issues as well as point-of-failure problems.

      Adding a space plane will add mass that will increase the payload to chuck out of Earth orbit thus increasing cost. Additionally, it will increase the amount of mass to move to Titan, thus increasing the amount of fuel needed to push it, thus increasing payload even more, which increases cost. Finally, adding another element with another set of possible failure options that are extremely difficult to mitigate from a billion miles away and can totally render the entire mission useless is a risk that most true scientists, fully aware of how little money they are being allotted to work their magic, will most likely prefer to avoid.

  16. Bleu

    Heat control

    would entail a lot more weight than this result of 'brainstorming' suggests.

    How is any kind of craft to operate if it is boiling away the medium around or under it?

    As with the radiation problem with manned interplanetary spaceflight, thermal problems on super-cold worlds tend to be ignored in favour of fantasy.

    Did this 'study' suggest a solution?

  17. dsuden

    Boffins again

    For heavens sake, learn a new word, Register! Readers, try a search for "boffins" on this site and be amazed.

  18. FrankH99
    WTF?

    Water landing?

    " The proposed solution is to pack the submarine into a vehicle like the X-37 autonomous space plane which would make a water landing, open its cargo bay and then sink, leaving the submarine to go about its business."

    Water landing? Are you sure?

  19. skerns0301

    stan0301

    Uh, why not leave the transmission antenna on land and then the sub would only need a small one to up link to it?

    Stan

  20. apophis23

    All these worlds are yours except for Europa....attempt no landing there...Titan is obviously close enough...

  21. jake Silver badge

    Baby steps, NASA, baby steps.

    Instead of wasting money on "designing" this kind of complicated thing (which will never happen as envisioned, because we have absolutely zero clue as to the actual conditions involved on the ground), how about figuring out how to finance getting small boxen there for a reccy?

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