From: itsd1@teleport.com   
      
   In article ,   
    alexterrell@yahoo.com (Alex Terrell) wrote:   
      
   > What is the maximum flux levels that can be beamed to space craft by   
   > lasr or microwave?   
   >   
   > The specific application would be to beam power from a SSPS (power   
   > available: 5GW) to a space vehicle using an electric drive (e.g.   
   > VASIMR). The spacecraft would be descending from High Earth Orbit to   
   > swing by Earth, and the aim would be to give it the maximum boost   
   > whilst it passes Earth (for Gravity assist).   
   >   
   > My thinking is that microwaves are the way to go because:   
   >   
   > - They are more eficient than solar panels (even single wavelength   
   > panels) and therefore there is less waste heat to dump.   
   > - The wire mesh collector can be lighter than a solar array.   
   >   
   > Trying some numbers, if the collecting area were 1km2, or 10km2, what   
   > power could it collect?   
   >   
   > Could such a system approach chemical engines in terms of thrust?   
   >   
   > A later application would be to boost electric powered vehicles as   
   > they swing by the sun at some 600km/s. This would obviously involve   
   > transmitting power over much longer distances.   
      
   You might want to ask these questions at Dr. Benford's website.   
      
   http://home.earthlink.net/~jbenford/Activities.html   
      
   He has done beamed power work for many years.   
      
   Regards,   
      
   Tom Billings   
      
   --   
   Oregon L-5 Society   
      
   http://www.oregonl5.org/   
      
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