RE: starship-design: Beamed power

["L. Parker" <lparker@cacaphony.net>]

Zenon,

Just a few comments...
> 
>Not all jitter must necessarily be fast - 
>what about gravitational influences from a stray comet or asteroid
>sweeping through a few millions of kilometers from the transmitter?
>Also, we considered some time ago the design with
>the beam spiraling due to orbital motion (around the Sun) 
>of the transmitter(s). Otherwise, the orbiting transmitter(s)
>must constantly change its (theirs) aim along the orbit,
>which may cause additional jitter, too fast to compensate
>adequately at the starship distance.
>
> 
>No way. Any message to Earth signaling the trouble
>will take years to go here, and the same time for
>the correction to appear at the starship place
>(not speaking about that the starship will be in quite 
>a different place at the time...).
>If there CAN happen such thing as the beam veering to the side,
>I can see only two solutions:
>- a possibility of the ship to chase the beam
>  (which means sideways motion);
>- send back the farewell messages and declare
>  the mission to be "The First Valiant Suicide Interstellar Flight"...
>

We will have a constant course prediction and update to steer the beam 
with. Unless you are planning some pretty radical course change maneuvers 
in mid mission, the time lag won't matter any. All that is really necessary 
is that the beam is steered on the correct course continuously and that the 
sail can perform minor steering to remain ON THE SAME COURSE. Ignore beam 
jitter, it should average out to the baseline of the course. You may 
experience some fluctuation in acceleration, but it also should be 
relatively minor, unless of course something drastic happens to radically 
alter either the beam's path or the ship's course. In which case, you're 
right, forget steering, and make your peace...

Lee Parker

                                                          (o o)
------------------------------------------------------oOO--(_)--OOo---------
Chaos n. Predictable unpredictability.

Heuristic adj. Pertaining to a lucky guess.

Quantum mechanics n. The ghost in the clockwork.

Sex n.  Nature's multiplication algorithm.