Saving energy is silly; the bottom line is money (was Forklifts tip

>>
>>> You only need power generating solar cell
>>> arrays and
>>> the transmission antenna.
>>>
>>> I would try to get rid of those mirrors, using a solar cell array and a
>>> transmission antenna
>>> only. Both would be independent spacecraft but connected through power
>>> lines.
>>>
>>
>> I could not find any dimensions on the drawings so I don't know how
>> much power you are thinking about. However, the minimum is about a
>> GW. It is worth considering the size and stiffness of a GW power
>> connector.
>>
> It was just a design using a Ring Segment System
> http://solar-thruster-sailor.info/rss/rss.htm
> thought for very large space structures in the square km region,
> like solar sail spacecraft or Solar Power Satellites.
>
> Since it comes up into space in segments,
> the size of the construction and the dimensions are up to you.
> If you want a gigawatt SBPS, choose the size which fits to your
> solar cell arrays you'll need for 1 GW.
>
> How to get those segments into space look here:
> http://solar-thruster-sailor.info/lth/lth.htm
>>
>>> While the larger collector-unit with it's solar cell arrays points
>>> toward Sun,
>>> the transmission antenna unit points toward Earth. They both move and
>>> point independently.
>>>
>>> The torus-like Solar Power Station would look about like this :
>>> http://solar-thruster-sailor.info/figs/fig11.html
>>>
>>>
>>>
>>>> If you tilt the power
>>>> sat, the non radial force against orbital motion on the near side of
>>>> the earth toward the sun is opposed when it is on the far side of the
>>>> earth from the sun. And changing the tilt of something that big over
>>>> a short time is going to take an awful lot of reaction mass or some
>>>> heavy other method.
>>>>
>>>>
>>> I think you would change the tilt of the craft gradually during 24 hours,
>>> not twice a day in a few minutes.
>>>
>>
>> Fast or slow makes no difference in the amount of reaction mass it takes.
>>
> No, but if you can steer and point the craft without reaction mass at all,
> that would be a difference!
> The Roller Reefing System I link to at,
> http://solar-thruster-sailor.info/figs/fig18.html
> delivers that
> - Fuel less attitude control, Steering and Station-keeping for solar sails.
>
> In my eyes a solar power satellite is a solar sail spacecraft.
> You have to operate it like a spacecraft - constantly, since you constantly
> get thrust, at least 4.5 N per square km of solar cell arrays.
> Why not using this thrust for station keeping, steering and pointing
> instead of reaction mass?

The force is in the wrong direction?

Seriously, this is a huge problem with some of the designs companies
are currently considering putting up. They are talking extremely
large amounts of money to service the power sats with replacement
reaction mass for station keeping, mainly against solar light
pressure.

If you or any of the solar sail people know how to solve it this
problem, it would be of huge interest.

Keith