🚀 go-pugleaf

I know this has been hashed around before, but there was no mention in
the FAQL, so...

  A light sail works by light pressure (I calculate F = Power/C,= 
4.66 E -6 /m^2 at 1 AU)  My question comes from what happens if you tilt
the sail.  It will red or blue shift the light just as much as a nontilted
sail, so the force on it should be the same, but is it applied in the same
direction as the light, or perpendicular to the sail?
   force            force
     | /               \  /
     |/         or      \/________>  light path
     /_____>            /|
    /|                 / |
   / | <light         /  |
  ^mirror            ^mirror

  If possible could somebody explain why it happens whichever way.  Its not
clear to me why the energy lost or gained in red or blue shifting the light
has to go into kinetic energy  (couldn't it just heat up the sail?)

  Dave Patterson,
 
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