From: alcore@uurth.com   
   Copy: sci-space-tech@moderators.isc.org   
      
   On Sun, 15 Aug 2004, Bill Bonde ( ``Soli Deo Gloria'' ) wrote:   
      
   >Lizerd wrote:   
   >>   
   >> Re: Brute force re-entry   
   >>   
   >I wouldn't have expected using the atmosphere to slow you down would be   
   >considered using a 'brute force' method of slowing down. I would think   
   >it would be considered elegant, and spending fuel to slow down or just   
   >running directly into the planet at full speed would be consider the   
   >brute force approaches.   
      
   I think the point that he was trying to make was that given the steep   
   angle of re-entry that NASA always uses, you might as well be "running   
   directly into the planet at full speed" instead of "skipping repeatedly   
   off the top of the atmosphere to shed speed".   
      
   I think the basic idea here is that there is a *lot* of energy being shed   
   by steep re-entry... and if there's enough energy to heat the air blasting   
   past the spacecraft into a plasma, is doesn't *seem* like so much of a   
   stretch to try and use some of that energy to alter the spacecraft   
   trajectory upwardly... in order to deliberately remain in the thinnest air   
   possible or even deflect completely outside the atmosphere briefly.   
   Which in turn, should reduce the heat loading.  (Or at least stretch out   
   the heat loading over a long enough period of time to allow some scheme to   
   manage it more efficiently.)   
      
   Conceptually you might deliberately use a series of shrinking sub-orbital   
   skips to shed speed (while within the upper atmosphere) and then heat   
   (while above the atmosphere) in alternation until the final sub-orbital   
   entry *can't* be shaped back into a trajectory that climbs above the   
   atmosphere again.   
      
   All that plasma rushing by the outer skin of the spacecraft just seems   
   like an energy resources that just begs to be harnessed and manipulated.   
   (The phrase "Magneto-Hydrodynamic Boundary Layer Control" comes to mind.)   
      
   Gene Pharr   
   Slidell, LA   
      
      
      
   --   
   Alcore Nilth - The Mad Alchemist of Gevbeck   
   alcore@uurth.com   
      
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