Re: starship-design: Preliminary Design for a Solar Laser Power Station

[TLG.van.der.Linden@tip.nl (Timothy van der Linden)]

Hello Lee,

About your "Preliminary design for a Solar Laser Power Station"

>OPERATIONAL DESCRIPTION
>	Sail Operation
>This is NOT an orbital design. It is designed to kill its orbital velocity 
>by tacking a solar sail until it is oriented to accelerate directly away 
>from the sun with a thrust that is equal to the gravitational pull plus a 
>reserve component of thrust to offset the pressure of the laser. Sunlight 
>is collected by the sail in the normal manner but the geometry of the sail 
>is such as to concentrate the reflected sunlight at a solar laser suspended 
>where the ship would normally be.    

You probably don't need gravity to make it float. If you collect the light
at one side and shine out to the other side, your momentum sum will be zero.
Likely you'll move towards the direction you are shining the laser to, since
the conversion efficiency will be much less than 100%.

>The laser is basically an optical concentrator whose geometry produces an 
>extremely concentrated, nearly coherent beam of SUNLIGHT. Because the beam 
>is not completely coherent and consists of multiple spectra, it cannot be 
>truly considered a laser, but in most respects (and for our purposes) it 
>behaves like one.

Having multiple spectra may be something we can't use. The mirror will
likely be optimized to absorb is little possible (to prevent melting).
Having a single frequency to reflect makes that much easier.
Making solar lasers of a single frequency is possible, but reduces its
output power per collector area.

>ADVANTAGES

>3)	Greatest conversion efficiency

Solar panels combined with the right electrical lasers do quite well too.
And if you're talking about single frequencies, their efficiency is probably
10 times higher.

Timothy