From: chosp@cox.net   
      
   "Mike Lepore"  wrote in message   
   news:11e8hbtfj7d96e0@corp.supernews.com...   
      
   > Someone please tell me why spacecraft are designed to reenter the earth's   
   > atmosphere at high speed.   
      
   The only reason any spacecraft remain in orbit to begin with is because of   
   their high speed.   
   Imagine, if you will, that you could build a 200 mile high ladder and could   
   climb up to a platform at the top with a scale on it. If you were to weigh   
   yourself on that scale you would only weigh about 5% less than you would   
   on the ground. A space shuttle might just zip on by you at 17,000+ mph with   
   all the astronauts on board in freefall and feeling mighty weightless - but   
   if you   
   were to step off the platform you would would drop like a rock.   
   In order for an orbiting spacecraft to return to earth it has to do   
   something   
   with that excess 17,000+ mph. It has to lose it somewhere. Using the   
   atmosphere as a brake is the least expensive way to go.   
      
    > Isn't there some way to come down slowly,   
   > so the heat shields wouldn't be needed?   
      
   The amount of fuel needed to slow it down enough in space   
   would be more than it could carry up there in the first place.   
      
   > Has anyone modeled the idea of   
   > unfolding some large wings to add a lot of surface area, or using   
   > propellers to resist falling, or parachutes?   
      
   You betcha.   
   As the saying goes:   
   Google is your friend.   
      
   Be fearless, look it up.   
      
   --- SoupGate-Win32 v1.05   
    * Origin: you cannot sedate... all the things you hate (1:229/2)