From: tkoenig@netcologne.de   
      
   dsdy120@gmail.com  schrieb:   
      
   > Several assumptions for the following calculations:   
      
   > 1. Planet is airless and nonrotating   
      
   OK.   
      
   > 2. Attacker occupies circular orbits only.   
      
   Hmmm...   
      
   > 3. Defender fires projectiles straight upward - this makes sense   
   > because defenders only care about altitude - not velocity. Anything   
   > above 1 km/s generally starts becoming a bad day for either   
   > combatant   
      
   No, this does not make sense.   
      
   Asuume you're in LEO, at 7.9 km/s.  You have 3.3 km/s delta v at   
   your disposal.   
      
   Now, you can add that delta v tangential to your velocity, giving you   
   escape velocity, so you can hit everything in orbit around Earth.   
      
   Alternatively, you can add the delta v perpendicular to your   
   current velocity.  According to Phythagoras, this will give   
   you a combined velocity of 8.56 km/s, so you get only 0.66 km/s   
   additional velocity.   
      
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