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Dynamic Outer Planets Expedition Planned!

  1. Apr 14, 2008 #1

    Astronuc

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    Staff: Mentor

    Heads up!
    Really cool! :cool:

    I hope they do both the aircraft and submarine on Titan and Europa. Talk about a design challenge.
     
  2. jcsd
  3. Apr 14, 2008 #2

    Danger

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    Absolutely cool. (Well, frigid, actually).
    Thermal management for that sub must be mighty tricky; it won't be the same as just dealing with the cold of space.
    It'll also be interesting to see what kind of instruments/sensors they come up with. Will sonar work in methane?
     
  4. Apr 14, 2008 #3

    turbo

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    Very exciting! Sonar should work in liquid methane - the sound waves will have a different rate of propagation, though, so unless conditions can be simulated accurately, there may have to be a way to calibrate the sonar on-location.
     
  5. Apr 14, 2008 #4

    FredGarvin

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    Whoa. That is a design challenge and a half. I shudder when I see the term "fast paced" or "aggressive" when it comes to scheduling.

    I think the sonar aspects would be some of the easier parts of this design. Acoustic responses are pretty well known depending on physical properties of the media. I would think we can replicate liquid methane pools here on Earth.
     
  6. Apr 14, 2008 #5

    Danger

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    Yeah, I knew that sound would propagate through any liquid; my concern was as Turbo mentioned regarding calibration. Also, I was wondering about the 'stability' of methane as opposed to water, specifically whether or not it tends to bubble.
    The operational aspects would probably be more problematic. While it's possible to design a sub with no moveable surfaces, I expect that they'll probably go for something more traditional. That implies to me some serious issues with seal materials and bearing lubricants.
     
  7. Apr 14, 2008 #6

    FredGarvin

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    I wasn't referring to the fact that sound does propagate, I was just thinking that we know acoustic responses pretty well, especially in the sonar area. All we really need to do is understand the state of the methane.
     
  8. Apr 14, 2008 #7

    turbo

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    Current seal and bearing technologies are likely sufficient as long as the materials can take the very cold temps without differential shrinkage screwing up the clearances. There are some very high-tech packing materials - often graphite-based. And up in the Great White North there is a company making Thordon bearings. They are machined polymer composites that are very hard and slippery that can be lubricated by the liquids they are immersed in. These bearings are already used for ships' propeller shafts and the main shafts of hydro-turbines where oils or other lubricants can be problematic. I sold seals and bearings such as these once, but that was over 10 years ago, and I'm sure the materials and designs have been improving ever since.

    http://www.thordonbearings.com/
     
  9. Apr 14, 2008 #8

    Danger

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    I didn't realize that materials technology had progressed that far. It still won't be an easy project, but apparently not as complicated as I thought.
     
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