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|    rec.arts.sf.science    |    Real and speculative aspects of SF scien    |    45,986 messages    |
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|    Message 45,539 of 45,986    |
|    Alain Fournier to JF Mezei    |
|    Re: Towards routine, reusable space laun    |
|    23 Jun 18 09:58:58    |
      XPost: sci.space.policy, sci.physics       From: alain245@videotron.ca              On Jun/23/2018 at 3:39 AM, JF Mezei wrote :       > On 2018-06-22 19:58, Alain Fournier wrote:       >       >> In both cases, when the fishing line or the elevator cable snaps the       >> elasticity pulls back with more force than the gravity or centrifugal       >> force.       >       > Centrifugal force is equal to gravity at genostationary orbit for this       > setup. below that, gravity is bigger so it pulls cable down.       >       > But what your argument does not consider is that the cable at       > geostationary is travelling at roughly 9370 km/h. But throughout the       > cable, all portions have the same radial speed (15° per hour, 360° per       > 24 hours).       >       > As the topmost portion of the cable is pulled down, its speed increases       > and it now has a radial speed greater than 15° per hour.       >       >       > The lower end will pull cable down (gravity) and resist beiong pulled       > forward (either because still anchored or being dragged on ground       > (resistance).       >       > The higher end will respond to being pulled down by increasing forward       > velocity, thus tugging on cable to move horizontally. Those two forces       > should keep cable fully extended and straight. It won't be snaking around.       >       > Any elasticity in the cable means that when the initial break at       > geostationaly happens, the elasticity will pull cable down more than       > just gravity. But that extra force will also result in the top most       > portion accelerating horizontally. So it isn't clear that as the       > tension is released, the cable would "snake".              You are just missing the end of you last sentence. It isn't clear that       as the tension is released the cable would snake until you do       simulations to see what happens.                     Alain Fournier              --- SoupGate-Win32 v1.05        * Origin: you cannot sedate... all the things you hate (1:229/2)    |
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