starship-design: Tugs

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

Hello Kelly,

>>>One alternative is to have fleets of little tugs sheparding the sail into
>>>shape.  Not very eligant, but an option worth consideration.
>>
>>You've to elaborate about this, so far I don't see where this differs from a
>>parachute.
>
>With the chute, the sail is held in place by tension with and between the
>cables.  If you add tugs.  The little ships can move out to push or pull on
>spots of the sail that start to flap or wrinkle.  Also could twist the sail
>for steering.
>
>For my fuel/sail idea this is especially interesting, since the ship would
>weigh less then 0.25% of the total weight.  Being that light, it couldn't
>exercise enough damping to stablize a sail thousands of miles across.

I wonder if these tugs are heavy enough to damp the sail. I also wonder
where they get their power from (and how their outlet doesn't damage the sail).

You also write "start to flap or wrinkle", sounds like you assume they are
flapping very slowly.
Anyhow, why would they start to flap? Flapping is caused by tubulence, I
wonder where we would get that from.

That leaves wrinkling, which can only be caused by uneven beam pressures.
Uneven beam densities indeed may be really troublesome. They will not only
wrinkle the sail, but also start to turn it (since the pressure on one side
of the center of mass is bigger than on the other side).

Oh wait, wrinkling is likely not an issue, since we will make the sail so
that there is a slighly outward pressure that keeps the sail streched. Only
very big (catastrophic) uneven beampressures will then wrinkle the sail.

I wonder what the concequences of such high uneven beampressures will do.
If only we could make parts of the sail transparent at will...

Timothy