From: andrew.gray@dunelm.org.uk   
      
   On 2005-02-17, Peter Fairbrother  wrote:   
   > Andrew Gray wrote:   
   >   
   >> On 2005-02-15, David Summers  wrote:   
   >>>   
   >>> Another related question - is it possible to get telemetry during   
   >>> re-entry?  (Assuming a very high altitude / high L/D / high Drag to   
   >>> mass re-entry)  I know that the shuttle manages to get some data   
   >>> through its plasma sheat, so is that technology something a small   
   >>> company can use?   
   >>   
   >> The Shuttle's telemetry, as I understand it, doesn't go "through" the   
   >> plasma sheath, but rather out of the "back" of it, and is relayed   
   >> through one of the TDRS satellites in geostationary orbit.   
   >>   
   >> It may well be considered impractical to replicate this capability   
   >> yourself.   
   >   
   > Hmmm ... plasma is conductive ...  would a plasma sheath make a good   
   > antenna?   
      
   I doubt it.   
      
   Incidentally, a recent post on sci.space.history mentioned a couple of   
   Gemini research papers, which involved injecting water into the plasma   
   sheath during re-entry -   
      
      FLIGHT INVESTIGATION AND ANALYSIS OF ALLEVIATION   
            OF COMMUNICATIONS BLACKOUT BY WATER   
             INJECTION DURING GEMINI 3 REENTRY   
         By Lyle C. Schroeder and Francis P. Russo   
                 Langley Research Center   
      
   A method of overcoming reentry communications blackout by injecting   
   water into the flow field was demonstrated during the Gemini-Titan 3   
   (GT-3) mission. Significant levels of signal strength increase during   
   the early portion of the water injection sequence over an altitude range   
   from 272000 to 246000 ft (82.90 to 74.98 km) were noted by ground   
   stations on VHF telemetry (230.4 MHz) and VHF voice (296.8 MHz).   
   Enhancement of C-band beacon signal (5690 MHz) was observed during the   
   latter portion of the water injection sequence over an altitude range   
   from 200000 to 160000 ft (60.96 to 48.77 km).   
      
              [NASA TM-X-1521, March 1968]   
      
   Not sure if any more research was done on this, though.   
      
      
   --   
   -Andrew Gray   
    andrew.gray@dunelm.org.uk   
      
   --- SoupGate-Win32 v1.05   
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