Tethered momentum transfer

>> The question is, when the asteroid fragment reaches L5, how much
>
> thrust will be required in order to slow it down?
>
>> Will it require hundreds of meters per second of velocity change?
>
> or will it come in slowly at about 30m/s?

Depends on its orbit and how long you are prepared to wait for it.
Given enough time it wouldn't surprise me if you couldn't get it to
arrive arbitrarily slowly. However that would probably require centuries
or millenia.

> Tony
> There are a lot of interesting dynamics. What we need is a combination
> Finite Element Anaylsis with gravity and mass included as dynamic
> forces and orbital mechanics program. I have been gathering information.
> There is an interesting concept called manifolds that is being
> used for some of the newest interplanetary missions where they seem
> to be calculating the local gravity gradiants to determine where
> the lowest energy location is to slip from one orbit to another.
> At the moment I am skimming though, "Structual Dynamics by Finite
> Elements" to get a feel of what a Finite Element Anaylsis program
> is vs what is needed to simulate a tethered intercept.

Been there done that, bought the tea shirt. Wrote a simulator for
an electromagnetic tether. Kinda interesting actually. Makes a nice
bracket shape.

> Answering
> the above questions requires being able to simulate moving an asteroid
> and finding out what the limits are. The goal would be for it to
> slip into the desired orbit with as little energy expenditure as
> possible and maximum tricks.
>
> I have a lot of questions too.
>
> Like what would be the result of changing the distance between the
> rotating masses in synchronization with the rotation in a gravity
> gradiant?

I've studied this. You can exchange the angular momentum of the
tether on its axis with angular momentum about a planet or star.
That can change the radius of the orbit in fact.

But there are strength limits on how much momentum you can exchange
(the tether snaps if you spin it too fast). And so the amount of
radius change is typically quite tiny. Still, its quite possible to
use this for attitude control and momentum wheels.

> How about doing the same thing while crossing the boundary
> between two gravity gradiants?

You can just extend the tether across the boundary and let
gravity help you across, provided you are within half a tethers
width of the boundary anyway.

> Can rotational energy be transelated and stored in a chemical battery
> useing regenerative breaking by going up and down the tether?

Yes.

> Mitchell James
> mejames@...
> http://www.InnerTransit.net (Email distribution for multilevel organizations)
> http://www.InnerTransit.org (Homebase for collaborative engineering)

civilization?"