starship-design: Re: Required microwave-antenna size. 100-light-year trip.

[T.L.G.vanderLinden@student.utwente.nl (Timothy van der Linden)]

Zenon wrote:

>However, if the platform moves along the Sun-centered orbit,
>its velocity is of the order of tens of kilometers a second
>(see another table below), hence it must compensate 
>for its change of position with appropriate change of orientation,
>and the latter must be VERY accurate (as the deviation table shows).

>==================================================================
>The beaming platform must orbit the Sun, thus: 
> 
>a) It will move quite fast, depending on the distance 
>   from the Sun, e.g: 
> 
>           Distance 
>   Orbit   from Sun  Velocity  Remarks 
>   of      [mln km]    [km/s] 
>   ---------------------------------------------------------------- 
>   Mercury      60        50   good place for solar-powered lasers 
>   Earth       150        30   near home... 
>   Jupiter     800        13   lots of local resources & moons to mine 
>   Pluto      6000         5   rather too far... 

I'd rather turn things around, not let the emitter follows the ship, but let
the ship follows the emitted beam.
The beaming station makes a "focussed" (as far as interference allows) an
beams it straight forward (in the direction of Tau Ceti).
In this case not the velocity of the orbiting station is important, but it's
acceleration (to the center of gravity), which is rather low. Low enough for
the starship to compensate and change its direction.

Also a note to Kelly, the lasers/masers have to be in sync, not having
phased lasers will decrease the effectivity immensly due to diffration.
To overcome difficulties, building it on a moon would not be a bad idea
 
Timothy