# Re: starship-design: following the beam

```> From: T.L.G.vanderLinden@student.utwente.nl (Timothy van der Linden)
>
> I'd rather turn things around, not let the emitter follows the ship,
> but let the ship follows the emitted beam.
>
That is a nice solution, if it shows to be possible...

> The beaming station makes a "focussed" (as far as interference allows)
> and 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.
>
That is, the ship must go along the helical curve with the
(assuming the plane of the orbit is perpendicular
to the direction to Tau Ceti), or along a sinusoid
with amplitude equal to the diameter of the orbit
(assuming the direction to Tau Ceti lies within the plane
of the orbit).
Can somebody calculate what lateral thrust (and acceleration,
amounting to a centrifugal force for the crew)
will be needed for such a trajectory ?

However, I wonder if the jiggle of the direction of the beam
due to "directional noise" can be compensated in this way
(may I recall: a tilt of the 100km diameter beaming antenna
by 1/25th of an inch at the edge (i.e., a 1/100 000 000 directional error)
gives a sweep of 100 000 km at 1 ly distance).

-- Zenon

```