From: g_d_pusch_remove_underscores@xnet.com   
      
   "Chung Leong"  writes (after correcting the sin of   
   top-posting):   
      
   > Uzytkownik "Henry Spencer"  napisal w wiadomosci   
   > news:HsoDHt.6Bs@spsystems.net...   
   >> In article ,   
   >> aSkeptic  wrote:   
   >>>Would preheating the H2, to break it down to H, before it enters the   
   >>>combustion chamber improve a chemical rocket's "gas milage"/exhast   
   >>>velocity?   
   >>   
   >> If you could do that... yes, very considerably.  You could forget the   
   >> oxidizer, and just let the H recombine to H2 -- an *IMMENSELY* energetic   
   >> reaction, which would not only make most other chemical rockets obsolete,   
   >> but would eliminate all interest in solid-core nuclear-thermal rockets.   
   >> Nothing short of gas-core nuclear could compete.   
   >>   
   >> Trouble is, all that energy has to *come* from somewhere.  As you might   
   >> guess from the above, you need extremely high temperatures to break down   
   >> H2 to H.  This isn't some little add-on to the propulsion system; it   
   >> *becomes* the propulsion system.   
   >>   
   >> Practical interest in such approaches centers on finding a way to   
   >> stabilize H, so you can invest all that energy on the ground, and release   
   >> it in flight without having to carry the powerplant along.  Unfortunately,   
   >> nobody has yet found any workable stabilizing technique.   
   >   
   > Magnetic confinment? Then again, the energy density of a plasma is probably   
   > pretty low.   
      
   You appear to have confused monatomic hydrogen, which still has an electron,   
   with a plasma, which is a dissociated mess of protons and electrons.   
   Notwithstanding the ridiculaously low density issue, unless you are   
   constantly heating the plasma, its electrons and protons will recombine ---   
   and if you had that kind of heat-source available, you could just heat the   
   propellant directly!   
      
   BTW, it _is_ possible to store "triplet state" monatomic hydrogen in a   
   "magnetic bottle," but again, the maximum practical densities are absurdly low,   
   because the collision rate goes up as the square of the density, and each   
   collision has some probability of flipping the monotomic hydrogens back into   
   the "singlet state," upon which they are no longer confined, and will   
   shortly thereafter hit the walls of the confinement chamber and find   
   something to react with --- such as another singlet monatomic hydrogen   
   that has recently hit the walls...   
      
      
   -- Gordon D. Pusch   
      
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