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Re: RE: starship-design: Tugs
L. Parker wrote:
>Kelly,
>> That could be a very good idea! But would that up the power or weight
>> requirements of the sail system to much?
>Well, yes and no. The dielectrics had much lower reflectivity, on the
>order of 87 percent which means they were much less efficient to start
>with than what we had wanted.
What happens to the light which doesn't get reflected? If it's
transmitted, then 87% reflectivity is just fine. If it's absorbed,
then we've got a problem. A limiting factor to laser sails is
how much power per square meter they can handle without melting.
>But dielectrics only use milliwatts to
>control the reflectivity, negligible amounts of power as far as we are
>concerened.
A laser sail has plenty of power to spare. Small pholtovoltaic cells
can generate a very useful amount of power just about anywhere you
want it.
--
_____ Isaac Kuo kuo@bit.csc.lsu.edu http://www.csc.lsu.edu/~kuo
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