[ExI] EP and Peak oil.
hkhenson at rogers.com
Mon Apr 7 18:27:16 UTC 2008
At 09:29 AM 4/7/2008, John K Clark wrote:
>"hkhenson" <hkhenson at rogers.com>
> > It [the magnetic force between wires] would
> > be .2 N/m for 1000 amps
>Perhaps I'm missing something but I don't understand your point.
You did. This was for a highly optimistic voltage and *one* GW. The
force I noted goes up as the square of the current. Plug in 1000 GW
which is the production of about 3 years of power sats and try
again. You can also reduce the voltage to a more reasonable number.
There is an additional problem. If a space elevator/tether is cut it
falls along the equator. Not a hazard on the ground since the
terminal velocity of the cables is no higher than rope of a similar
low density. But it's a major problem in space because it whacks at
high speed into other elevators/tethers if there are any. Bringing
down hundreds of power leads from GEO is just inviting a catastrophe.
Still another problem, high vacuum and air good insulators, but low
pressure gas is not, and these wires transit a lot of low pressure
gas. Any ideas for really lightweight solution? If you *really*
have something against microwaves, bringing power down
mechanically like the elevator sends it up might be the best solution.
>One Newton is the force of earth's gravity on an object with a mass
>of 102 g, so we're talking about a force of 20 grams per meter.
>A meter long toothpick wade of WOOD inserted ever meter to act as
>a spacer to keep the wires the proper distance apart would be far
>stronger than necessary.
You also missed that the force is in tension. Shut off the power and
the wires are going to move toward each other. Unless you do have
close spacers that also work in compression to keep them apart, the
conductors are going to hit and stick in the vacuum. Be an
interesting task to bring them back into service.
> > about 7.14 million N going to GEO.
It's 1/5 the lift off thrust of a Saturn 5, and it's applied in a way
which is massively multiplied into tension on the conductors.
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