RE:

[Brian Mansur <bmansur@oc.edu>]

>From Brian

>Kevin
Ship's  Sail  Sail   Sail    Total   Accel   Maser   Refl  Excess  Stress
Mass   Radius Dens   Mass    Mass            Energy  Eff.  Energy
Kg       Km   g/m^2   Kg      Kg     M/s^2   Watts    %    KW/m^s  Pascals
5E5      10    50   1.57E+07  1.6E+07  10  2.43E+16  0.99  773.8  0.515915
5E5     100    50   1.57E+09  1.6E+09  10  2.36E+18  0.99  750.2  0.500159
5E5     500    50   3.93E+10  3.9E+10  10  5.89E+19  0.99  750.0  0.500006
5E5    1000    50   1.57E+11  1.57E+11 10  2.36E+20  0.99  750.0  0.500002
5E5    5000    50   3.93E+12  3.93E+12 10  5.89E+21  0.99  750.0  0.5
5E5   10000    50   1.57E+13  1.57E+13 10  2.36E+22  0.99  750.0  0.5
5E5  100000    50   1.57E+15  1.57E+15 10  2.36E+24  0.99  750.0  0.5
>

Brian
How are these %reflections figured.  Is it .99% efficiency, 99%, .0099%?
Also, are these stresses acounting for the stress at cable connection points 
or what?

>Kevin
>4) smaller sails may be better.  Why in the world you would need a sail
>the size of Luna, much less Jupiter, is beyond me.

>Kevin
>5) Thermal load is a big problem.  750 KW on .05 Kg is a big worry.
>I have not calculated the limiting temperature yet, but I am hopeful that
>titanium alloy will stand up to the load.  To do this model, I will use
>heat capacity and blackbody radiation equation.  I do not have time right
>now, but expect it soon.

Brian
Jupiter size was to make sure we could keep our now defunct retro mirror 
inside of a distance diverged beam.  A Luna sized sail was, I think, 
proposed to be certain that the E18W that we were putting into it wouldn't 
melt the thing.  Also, the models that I was working with hoped for a sail 
that weighed closer to 50g/km^2, not 50g/m^2.  But if you can keep the 
thermal load managable on say a 10km^2 sail, and keep enough power focused 
on that sail for 1E4 to 2E4 AU, then I think we have a way to at least 
launch ships via masers.



Kevin