Josh Gigantino wrote:   
   >   
   > Someplace on the Tethers Unlimited website, Mr Hoyt mentions that the   
   > MXER tether system cannot be used to make plane changes for tossed   
   > payloads. Is this a function of that specific design, or a property of   
   > all proposed tethers? He only mentioned it in passing, could anyone   
   > explain the orbital mechanics reasons it would not work?   
   >   
   > The reason I questioned this is that it seems like a tether designed   
   > for catapult use could spin up and fire the payload off-axis from it's   
   > direction of travel. This should provide a change in the payload's   
   > final orbital plane.   
   >   
   > - Josh   
      
      
      
   Vertically oriented rotating tethers have extreme difficulty   
   accommodating payload orbital inclination changes, the exception being a   
   tether that can reel in and out fully. This is a property similar to   
   someone trying to rotate a toy gyro in an axis not matching the gyro   
   rotation axis. It fights you, a lot if the gyro is spinning fast. This   
   same kind of force is aggravated by the fact that the tether is not a   
   rigid object.   
      
   The reason for the exception is that such a tether could grapple a   
   payload, reel it and the counterweight in tight, then try to turn to the   
   payload destination plane, before reeling out again to release. The   
   problem being, when you reel in, you start spinning really fast   
   (conservation of angular momentum), which makes it hard to turn the   
   tether. The reason why this is the exception case is that it is much   
   easier to turn a compact rotating object than a very wide rotating   
   object more or less (imagine the tether sweeping out a disk/rotor   
   shape). The energy to turn the tether is non trivial. The tether would   
   also suffer from the combination of a drop in center of mass (CM)   
   altitude and orbital velocity (which is normal for a vertically oriented   
   tether) and a plane change of it's own when it releases the payload.   
   This is just a bad problem getting worse.   
      
   Try this for a start in an alternative.   
      
   http://space.electrosphere.org/explanations   
      
   Something like the Southern Cross configuration meets the plane change   
   need directly, but could be enhanced by use of a CatSling configuration   
   on the momentum exchange portion of Southern Cross.   
      
   --- SoupGate-Win32 v1.05   
    * Origin: you cannot sedate... all the things you hate (1:229/2)