Re: EUREKA!!!!!!!!!! (ha ha ha ha ha ha) >:-)

[KellySt@aol.com]

VERY NICE KEVIN!!!  You delt with the structural and thrust problems at once!

I'll call you later, but wanted to send a couple of ideas right away.


I still have questions about momentum transfer vs power absorbsion. This
neat conversion of absorbed power and momentum bothers me.  I would think
that converting the power would use up the energy that would generate the
thrust.  Maybe I'm confused?



If the back side of the sail/collector was mirrored, and the frount side of
the inner sail elements had the rectennas.  Then durring the accel phase
all sail elements can be trimed to reflect almost all the power straight
back at Sol for max thrust.  (Note you'll need a slight outward thrust to
hold the sails out to the sides.)

Durring the decel phase.  The outer sails are trimed to reflect their
energy inward toward frount of the inner sails.  The inner sails are trimed
to reflect the energy hiting their back inward toward other sails or
dumping it.  But this foward and outward thrust, serves to support them
against  backward and inward thrurst from the energy pouring inward and
back from the outer sails onto the frount of the inner sails.  The frount
of the inner sails have the rectenna arrays.  Which absorb and convert the
microwaves.

Good news.
The sails have max reflectivity durring accel phase.

Only the inner sail array needs the more complecated rectenna and power
conversion/transmition/cooling equipment.  (The outer segments are just
wire mesh.)  So servicing and costs can be minimized.

Bad news
The expensive power converters are going to be face first into the inter
stellar medium, and they are going to be operating at much higher power
densities.  Cooling is going to be much harder.


Weird thought.  Am I right that microwaves can impart thier momentum on
ions directly?  Could you channel the power via waveguides, and feed the
reaction mass into the power stream and get it to accelerate the plasma
directly?  I can't remenber it clearly, but I think their is some such
mechanism.  If so, you could avoid the heating problems of the power
conversion step.

Kelly