What is the solar intensity at lunar poles?

--- In spacesettlers@y..., Lucio de Souza Coelho wrote:
> From: "victoriatangoman"
> To:
> Sent: Monday, February 04, 2002 10:21 PM
> Subject: [spacesettlers] Re: What is the solar intensity at lunar
poles?
>
> [snikt]
> > I'm sure the engineers have already figured out, from different
> > scenarios of course, how to prevent the cables that are coming
from
> > the back of the solar arrays from winding up as the solar array
> > continues its motion around the track, month after month. I could
> > imagine a solution being not having cables, and transmitting the
> > energy to a receiver, which in turn could transmit it through
> > cables. But this entails conversion loss.
> >
> I think that you could the track itself to conduct the energy,
thus avoiding
> the problem of cables winding up. I think that there are electric
trains
> that get their energy that way, and I am sure that there are
trains with
> power supply coming from "antennas" touching a cable suspended
above the
> track (the metro train in my city operates that way).

I think that is an excellent solution! My thinking was too
constrained by the requirement for wires. Your solution is so
elegant. Have the PV cells conduct down to the fixed track, and the
track feeds into the transmission infrastructure. You'd have to
insulate the infrastructure, so that maintenance could take place
without electrocuting the worker, but I think that's workable.
Thanks for your insight.

>
> [snikt]
> > Anyways, to transmit the energy to the equatorial launch base,
would
> > require transmitting it over a distance of 2600 miles. Over that
> > distance an AC system, even with massive transformers along the
way,
> > would entail significant losses, so it seems that a High Voltage
> > Direct Current transmission system is the most feasable. These
> > systems are becoming more prevalent these days, in fact, there is
> > quite a large one operating from a BIG dam in Brazil that
transmits
> > power to Argentina and Paraguay. Now, these systems are usually
more
> > expensive because they require a converter to change the AC to
DC at
> > the generating source, and then again at the destination.
> [snikt]
>
> It is Itaipu, THE largest dam in the world (www.itaipu.gov.br). By
the way,
> Paraguay and Argentina are relatively small countries and are very
close to
> Itaipu (the dam is located at the Brazil-Paraguay border), and so
> transmission lines for those locations are not that impressive. On
the other
> hand, Brazil is about the size of the United States and the power-
hungry
> spots are far way from most of the major power plants (almost all
of them
> hydro), and so there are indeed extremely long power lines
*inside* the
> Brazilian territory. For instance, as far as I know there is a 800
Km-long
> line connecting Itaipu to So Paulo state (the one more densely
populated
> and more heavily industrialized). And, in the year 2000 alone,
three new
> lines adding up 3,600 Km were built - data from the site of the
(Brazilian)
> National Agency of Electrical Energy (www.aneel.gov.br). So, based
on
> experience gathered with power lines on Earth, building a
transmission line
> 2,600 Km (not miles...) connecting the lunar equator to one of the
poles
> does not seems to be a task beyond our current electrical
engineering.
> Actually, maybe it would even be trivial with not by the exotic
> environmental conditions of the Moon.

You're right. That's exactly the information I came across and I
found it very impressive technology. I just forgot the details
because I'm kind of swamped with all sorts of details that I'm
sifting through to work through my exercise. Most often the
information becomes useful weeks or months after I first come across
it, but by then i can't remember where I came across it. :)

Actually, I thnk a 2,600 mile line is technically feasible. It just
hasn't been done on Earth because you can usually locate an energy
source closer to the users and do it more economically than laying a
2,600 mile transmission line. Economics not engineering is the
limiting factor.