Coal is Toxic - need SPS

"Joe Strout" wrote in message
...

What problem? I've read about SPS quite a bit and haven't seen any
evidence of a problem. Please elaborate.

http://fti.neep.wisc.edu/neep602/FAL...lecture35.html From Professor
G. L. Kulcinski and probably the best reference I found after just three
pages of webcrawler search.

--
Alan Erskine
We can get people to the Moon in five years,
not the fifteen GWB proposes.
Give NASA a real challenge

In article ,
"Alan Erskine" wrote:

"Joe Strout" wrote in message
...

What problem? I've read about SPS quite a bit and haven't seen any
evidence of a problem. Please elaborate.

http://fti.neep.wisc.edu/neep602/FAL...lecture35.html From Professor
G. L. Kulcinski and probably the best reference I found after just three
pages of webcrawler search.

....which describes it as "probably not a health hazard" (but perhaps a
political one). Is it the political issue you were referring to? Or is
there some more serious problem somewhere on this page (please quote)?

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"Alan Erskine" wrote in message ...
"Joe Strout" wrote in message
...
What problem? I've read about SPS quite a bit and haven't seen any
evidence of a problem. Please elaborate.

http://fti.neep.wisc.edu/neep533/FALL2001/lecture34.pdf

good article

A couple of points not covered:

1. It certainly didn't raise any serious environmental issues for the
Earth.
2. It only looked at SSP using Earth based resources - nothing on
O'Neill's vision. I certainly don't think it's an option to do it
without lunar or NEO resources (unless space elevators can be cost
effective).
3. It didn't mention Wi-Fi. 2.45 GHz is between Channel 8 and Channel
9 of 802.11g (b as well?). Would this effect WiFi?

"Alan Erskine" wrote in message ...
"Joe Strout" wrote in message
...
In article ,
"Alan Erskine" wrote:

We need Solar Power Satellites rather urgently, built from lunar
materials.

1. don't forget the problem of microwave radiation (Electromagnetic
radiation);

What problem? I've read about SPS quite a bit and haven't seen any
evidence of a problem. Please elaborate.

Several problems, but a quick search on SPS's will elaborate. I used
webcrawler (www.webcrawler.com) and came up with the following:
http://www.wws.princeton.edu/cgi-bin...981/8124/81240
3.PDF (page 10 - Environment and Health) which states: "Too little is known
about the biological effects of long-term exposure to low-level microwave
radiation to assess the health risks associated with SPS microwave systems."

How do you assess this? Lab experiments.

There's a lot to be done to "prove" they are safe. To date, most
research strongly indicates there's no problem, but you need proof
before investing billions.

Then there's the Electromagnetic interference to be considered (comms).
Such an amount of radiation would be hazardous to long-distance metal comms
systems in the same way as a nuclear weapon is, but not to the same level.
Find me areas in the size range of New York (for the rectennas) without
copper cables anywhere near a city that would use these systems.

I'm more worried about Wi Fi. 1W/m2 of 2.45 GHz shouldn't bother
powerlines, but could upset my wi fi link.

It has been estimated by SSI that only 10% of the mass of an SPS would have
to come from Earth,

Do you have a reference for this? It seems very high - what do they
need apart from Silicon, Silicon dioxide, and aluminium? Remember, if
we're using lunar resources, suitability for construction becomes more
important than efficiency.

but that is still somewhere near 10,000 tonnes - 83
Saturn V's or similar, for each SPS and the U.S. alone would require how
many? Multiply that number by 83 and see the environmental damage.

With anywhere near these volumes we'd use a rotovator (or a full GEO
elevator). A rotovator could be built now, and would more than
quadruple the payload to GEO for each launch - especially if it were
returning sand (from the moon) to Earth.

With air filtration equipment, PV cell production is not going to do
_nearly_ as much environmental damage as an SPS. In addition, there is
Solar Thermal which is already more cost-effective than large scale PV, but
not as aesthetic (personally, I like the look of the metallic blue PV
panels - replace roof tiles quite nicely, in my opinion), but for factories
and warehouses, Solar Thermal (ST) is the preferred option. This is called
a Grid Connected system and provides electricity when it's most needed -
during daylight. Before you chuckle at this, imagine all the offices,
warehouses and factories - most energy is consumed in daylight hours - use a
(comparitively) small SRC/TDP/gassification system for night-time
electricity generation.

Before you look at this, look at solar water heating. This is already
economical and pays back now.

As for ground based PV (or ST), it has a role, especially in hot
countries where there is a lot of day time air conditioning. In colder
climates, peak consumption is evening, after sun down.

But I'd be a lot more ambitious with SSP. The first may be really
expensive but the 100th 5GW unit will be very cheap - cheap enough to
start to replace oil as a primary energy source.

And lets face it - if the world all wants to consume energy as
wastefully as the Americans do today, then we're going to need 50TW.
That's 500 power sats, each 25 by 40km. They would certainly make an
impressive constellation (The Arch?). Luckily, by then, most astronomy
would be conducted off planet.

"jeff findley" wrote in message
...
Scott Lowther writes:

Would be to do what we should have done thirty years ago: build a
****load of nuclear and breeder reactors.

Scott! Don't say the "n" word, it will get you into trouble. ;-)

Seriously, nuclear energy today isn't the same as nuclear energy back
when we had Three Mile Island. After watching a documentary on the
Three Mile Island accident, it's clear that may of the problems were
with communication. There was *one* phone line in the control room.
Luckily communications are cheap today.

TMI had a lot of problems, especially the humans.

Thing is, we can build safer reactors today.

And we should.

Hell, as an environmentalist I think nuke is one of the best ways to go.

Combine that with an even more effecient use of railroads, and you can start
to solve your oil/coal power plant pollution AND reduce car-induced smog in
many urban areas/



That and monitoring equipment is better today than it was back then.
With modern equipment, you can do *far* better today than when nuclear
power was actually popular (i.e. pre-Three Mile Island).

Jeff
--
Remove "no" and "spam" from email address to reply.
If it says "This is not spam!", it's surely a lie.

Joe Strout wrote:
In article ,
"Alan Erskine" wrote:

"Joe Strout" wrote in message
...

What problem? I've read about SPS quite a bit and haven't seen any
evidence of a problem. Please elaborate.

http://fti.neep.wisc.edu/neep602/FAL...lecture35.html From Professor
G. L. Kulcinski and probably the best reference I found after just three
pages of webcrawler search.

...which describes it as "probably not a health hazard" (but perhaps a
political one). Is it the political issue you were referring to? Or is
there some more serious problem somewhere on this page (please quote)?

Hmm.. look at all the wrangling about whetever mobile phone towers are a
health hazzard or no. Now imagine the sma ething except with much higher
power density.



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--
Sander

+++ Out of cheese error +++

"Sander Vesik" wrote in message ...

Hmm.. look at all the wrangling about whetever mobile phone towers are a
health hazzard or no. Now imagine the sma ething except with much higher
power density.


So it's better to choke from real smog than getting our chi misaligned
by the evil powers of electro-smog?

It's also not as if I'd be holding the SPS to my ear or live only a
few hundred meters from the nearest rectenna...



--
__ “A good leader knows when it’s best to ignore the __
('__` screams for help and focus on the bigger picture.� '__`)
//6(6; ©OOL mmiv :^)^\\
`\_-/ http://home.t-online.de/home/ulrich....lmann/redbaron \-_/'

"Alan Erskine" wrote


Then there's the Electromagnetic interference to be considered (comms).
Such an amount of radiation would be hazardous to long-distance metal comms
systems in the same way as a nuclear weapon is, but not to the same level.

Are you basing this on a study, or your intuition? Given the
relatively low energy density at the receiving point, this seems very
doubtful. This isn't going to be like the inside of a microwave oven.
I've discussed this with several knowledgeable people, and there are
techniques to shape the beam so stray energy is very low outside the
receiving area, so that shouldn't be an issue. Inside the beam 80-90%
of the energy is supposed to be captured by the "rectenna" (assuming
the standard microwave power beaming scenario), so what would actually
be hitting the ground to bother bits of metal would be less than 100
Watts/sq meter.

A 1 kW microwave oven, since it acts as a resonance chamber with a
high Q factor (10,000 or so when empty) has electromagnetic field
intensities over 1 million Watts/sq meter. No real comparison here.

It has been estimated by SSI that only 10% of the mass of an SPS would have
to come from Earth, but that is still somewhere near 10,000 tonnes - 83
Saturn V's or similar, for each SPS and the U.S. alone would require how
many? Multiply that number by 83 and see the environmental damage.

Has there been much environmental damage from the 100 shuttle
launches? The shuttle stack launches as much as the Saturn V did (it's
just most of that mass is in the orbiter).

Anyway, compare this to aircraft activity - every year in the US about
a billion tons of jet aircraft take off for regularly scheduled
service. The entire shuttle stack is about 2500 tons at liftoff
(Saturn V was about 3000 tons); a billion tons worth of shuttle-class
(or Saturn-V if you prefer) launches would mean 400,000 (300,000)
launches per year, to have comparable environmental impact to what we
do with jet aircraft already.

There is WAAAAY too much innumeracy in these discussions - "oh look,
wow, that's a huge number, that's impossible, we can never do that".
Look at what we're doing now, and compare; people just don't seem to
have much perspective for some reason.

And the SSI mass estimates are probably gross overestimates now for
SPS mass, with modern thin-film PV technology. I just wish some R&D
money were being spent in this area - O'Keefe's NASA killed it all
after 9-11.

"Alex Terrell" wrote in message
om...

It has been estimated by SSI that only 10% of the mass of an SPS would
have
to come from Earth,

Do you have a reference for this? It seems very high - what do they
need apart from Silicon, Silicon dioxide, and aluminium? Remember, if
we're using lunar resources, suitability for construction becomes more
important than efficiency.

I've got a report at home which I got from SSI that said 99% of the mass of
a SPS could be derived from lunar materials, assuming a design optimized for
this.

--


Regards,
Mike Combs
----------------------------------------------------------------------
We should ask, critically and with appeal to the numbers, whether the
best site for a growing advancing industrial society is Earth, the
Moon, Mars, some other planet, or somewhere else entirely.
Surprisingly, the answer will be inescapable - the best site is
"somewhere else entirely."

Gerard O'Neill - "The High Frontier"

In article ,
Sander Vesik wrote:

...which describes it as "probably not a health hazard" (but perhaps a
political one). Is it the political issue you were referring to? Or is
there some more serious problem somewhere on this page (please quote)?

Hmm.. look at all the wrangling about whetever mobile phone towers are a
health hazzard or no. Now imagine the sma ething except with much higher
power density.

Higher for people standing in the beam, yes. Much lower for people not
standing in the beam (and nobody's going to be standing in it except for
the occasional maintenance crew). Cell phones have to broadcast their
microwaves widely, since the whole point is for them to reach your phone
wherever they happen to be (and of course, your phone is also a
microwave transmitter). Power beams aren't like that; they're focussed
on a rectenna and the power proceeds using normal electrical cables from
there.

In fact, the relatively little ruckus over cell phones should clearly
indicate that beaming microwaves is not a problem for SPS.

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