# 16920 byrmenich@... on Sept. 27, 2002, 5:43 p.m.
Member since 2022-08-22
Maybe y'all saw this already:
"The Earth-Moon L1 Lagrange point is at a distance of some 200,000 miles
(323,110 kilometers) from the Earth, or 84 percent of the way to the Moon.
NASA's Martin said the L1 Gateway, replete with a habitat for crew
occupancy, is a good spot to support a locus of activity. "
Did O'Neill and Co. ever discuss the Earth-Moon L1 point as a prime
location for space activity? If I recall correctly, Earth-Moon L2 was
favored by O'Neill and others as the point of capture by the space tug for
buckets of material flung from the lunar surface by the mass driver. What
about Earth-Moon L1 ?
Ron
# 16921 byvictoriatangoman on Sept. 27, 2002, 5:47 p.m.
Member since 2022-08-22
I hold the opinion that L1 would be the location of a SPS to supply
energy to the mass driver, which will be on the near side of the
moon, directly in sight of L1.
can't think of a better alternative to supplying energy to the
moonbase than a SPS.
We'll just have to get there before NASA so that we can claim the
best postion within the L1 region. Well, we can dream can't we . . .
> Maybe y'all saw this already:
>
> http://www.space.com/news/beyond_iss_020926-1.html
> "The Earth-Moon L1 Lagrange point is at a distance of some 200,000
miles
> (323,110 kilometers) from the Earth, or 84 percent of the way to
the Moon.
>
> NASA's Martin said the L1 Gateway, replete with a habitat for crew
> occupancy, is a good spot to support a locus of activity. "
>
> Did O'Neill and Co. ever discuss the Earth-Moon L1 point as a
prime
> location for space activity? If I recall correctly, Earth-Moon
L2 was
> favored by O'Neill and others as the point of capture by the space
tug for
> buckets of material flung from the lunar surface by the mass
driver. What
# 16922 byHuebner, Jay on Dec. 13, 2002, 11:04 a.m.
Member since 2022-08-22
The title for this line is too long, so I shortened it for my response.
and establish a base there and begin to live off the land? No need for
nukes or SPS demonstrators, because 93% of the time the peak's in sunlight."
I agree the Lunar South Pole at is a good place for some lunar industry,
but I don't think anyone will "live off the land" on the Moon for a long
time. Compare it to Antarctica, where there is lots of ice, minerals, coal,
etc. But, "corn and potatoes" just don't grow there. Even the crusty
prospectors in the "old west," who might have come close to living off the
land, needed to find something of value to take back to civilization to
exchange for their salt and tobacco. Crewed space ventures in the short
term, in my opinion, will only work economically if they can return
something of value to pay for the supplies they will require. We have
gotten to where we are beyond geosynch by "showing off" for the world during
the cold war, and supplying scientific data since. We can keep doing the
latter, but the scale of activity will be limited and humans will likely not
go. By chance I had a conversation with a physician-radiologist who
indicated that before astronauts went to Mars they would have to have cells
taken out of their bone marrow so when they got back they could have
replacements done, or else they would not long survive the cancers which
would surely follow from their radiation exposures. Who wants to go to
Mars?
I favor colonizing the Moon, a 2 or 3 day trip to get there where one can
live under ground, as I believe solar power from there can supply a
significant fraction of the Earth's industrial electrical energy needs
without generating greenhouse gasses. A useful paper, "Advanced Technology
Paths to Global Climate Stability: Energy for a Greenhouse Planet, by M. I.
Hoffert and 17 others, including J. S. Lewis, Science Vol. 298, pages
981-987" comprehensively reviews the problems. An article by D. R.
Criswell, "Solar Power via the Moon," The Industrial Physicist, April/May
2002, pages 12-15, is also very good. I recommend both. Sorry they are not
on line, that I know of.
And in response to "Cut to the chase." I have to ask, What is the chase?
Enabling all, or at least most, humans to achieve their potential on Earth
by having access to the energy resources that those of us who play on
computers do, and also to have some humans survive the possible future
disasters and mass extinctions on Earth, are goals I have in mind for space
ventures.
Massive (by current standards) space habitats that are well shielded
could be assembled in orbit and sent decades from now, taking years in
transient, to other planets if there are reasons to want to send large
numbers of people there. But, if the O'Neill habitats work like it seems to
me they will, who would want to go to other planets and crawl back down in
gravity wells.
Best wishes, Jay Huebner
# 16923 byrmenich@... on Dec. 13, 2002, 11:51 a.m.
Member since 2022-08-22
Maybe we don't fully live off the land in Antarctica, but we do breathe
the air there and melt the snow.
ways. The first and most obvious is that we can take regolith and shield
ourselves from radiation, both from cosmic rays and from
short-term/high-intensity solar events.
" And in response to "Cut to the chase." I have to ask, What is the
chase?"
The 'chase' --- perhaps not a good choice of words on my part --- is to
BEGIN to use extraterrestrial resources rather than launching everything
up from Earth.
Ron
"Huebner, Jay" jhuebn@...
12/13/02 12:04 PM
The title for this line is too long, so I shortened it for my response.
RE: "Why not go directly to Malapert Mountain at the Moon's South Pole
and establish a base there and begin to live off the land? No need for
nukes or SPS demonstrators, because 93% of the time the peak's in
sunlight."
I agree the Lunar South Pole at is a good place for some lunar
industry,
but I don't think anyone will "live off the land" on the Moon for a long
time. Compare it to Antarctica, where there is lots of ice, minerals,
coal,
etc. But, "corn and potatoes" just don't grow there. Even the crusty
prospectors in the "old west," who might have come close to living off the
land, needed to find something of value to take back to civilization to
exchange for their salt and tobacco. Crewed space ventures in the short
term, in my opinion, will only work economically if they can return
something of value to pay for the supplies they will require. We have
gotten to where we are beyond geosynch by "showing off" for the world
during
the cold war, and supplying scientific data since. We can keep doing the
latter, but the scale of activity will be limited and humans will likely
not
go. By chance I had a conversation with a physician-radiologist who
indicated that before astronauts went to Mars they would have to have
cells
taken out of their bone marrow so when they got back they could have
replacements done, or else they would not long survive the cancers which
would surely follow from their radiation exposures. Who wants to go to
Mars?
I favor colonizing the Moon, a 2 or 3 day trip to get there where one
can
live under ground, as I believe solar power from there can supply a
significant fraction of the Earth's industrial electrical energy needs
without generating greenhouse gasses. A useful paper, "Advanced
Technology
Paths to Global Climate Stability: Energy for a Greenhouse Planet, by M.
I.
Hoffert and 17 others, including J. S. Lewis, Science Vol. 298, pages
981-987" comprehensively reviews the problems. An article by D. R.
Criswell, "Solar Power via the Moon," The Industrial Physicist, April/May
2002, pages 12-15, is also very good. I recommend both. Sorry they are
not
on line, that I know of.
And in response to "Cut to the chase." I have to ask, What is the
chase?
Enabling all, or at least most, humans to achieve their potential on Earth
by having access to the energy resources that those of us who play on
computers do, and also to have some humans survive the possible future
disasters and mass extinctions on Earth, are goals I have in mind for
space
ventures.
Massive (by current standards) space habitats that are well shielded
could be assembled in orbit and sent decades from now, taking years in
transient, to other planets if there are reasons to want to send large
numbers of people there. But, if the O'Neill habitats work like it seems
to
me they will, who would want to go to other planets and crawl back down in
gravity wells.
Best wishes, Jay Huebner
# 16924 byArthur P. Smith on Dec. 13, 2002, 1:37 p.m.
Member since 2022-08-22
> I favor colonizing the Moon, a 2 or 3 day trip to get there where one can
>live under ground, as I believe solar power from there can supply a
>significant fraction of the Earth's industrial electrical energy needs
>without generating greenhouse gasses. A useful paper, "Advanced Technology
>Paths to Global Climate Stability: Energy for a Greenhouse Planet, by M. I.
>Hoffert and 17 others, including J. S. Lewis, Science Vol. 298, pages
>981-987" comprehensively reviews the problems. An article by D. R.
>Criswell, "Solar Power via the Moon," The Industrial Physicist, April/May
>2002, pages 12-15, is also very good. I recommend both. Sorry they are not
>on line, that I know of.
>
Science magazine (many universities already have this). I led a
discussion of the Science article (over 300 comments) at k5:
http://www.kuro5hin.org/story/2002/11/11/83056/403
which also has links to Criswell's Industrial Physicist article:
http://www.aip.org/tip/0402.html
and subsequent discussion in later issues.
I'm definitely more optimistic about the prospects for large-scale space
development after reading these articles and their discussion of the
prospects for space-based solar power... Now if we could get NASA and
the energy department working together on such a project...?
Arthur
# 16925 byHuebner, Jay on Dec. 13, 2002, 2:01 p.m.
Member since 2022-08-22
Thanks for the link, Arthur. Interesting stuff. We seem agreed. I also
feel all of this could work well for space developments, and the next few
years may be the time when we will be heard. But so far these discussions
are about solving the greenhouse problem by not making more greenhouse gases
by generating power from combustion. Another issue, which seems to me could
cause worse greenhouse problems and maybe even mass extinctions, is the
release of a substantial amount of the methane hydrate in the tundra and
continental shelves. This could be disposed of by burning it in schemes to
generate energy, if economical ways to mine it can be found. It would make
CO2, but less per joule of energy releases, i.e. two H2O molecules for each
CO2, while hydrocarbons are more like 1 to 1 and coal releases mostly CO2.
I have been wondering why it was not discussed by Hoffert et. al. And I
couldn't find anything on methane hydrate using the search engine on k5.
Isn't all of this methane a "time-bomb?"
Jay Huebner
can
>live under ground, as I believe solar power from there can supply a
>significant fraction of the Earth's industrial electrical energy needs
>without generating greenhouse gasses. A useful paper, "Advanced Technology
>Paths to Global Climate Stability: Energy for a Greenhouse Planet, by M. I.
>Hoffert and 17 others, including J. S. Lewis, Science Vol. 298, pages
>981-987" comprehensively reviews the problems. An article by D. R.
>Criswell, "Solar Power via the Moon," The Industrial Physicist, April/May
>2002, pages 12-15, is also very good. I recommend both. Sorry they are
not
>on line, that I know of.
>
They are both online, though the first requires a subscription to
Science magazine (many universities already have this). I led a
discussion of the Science article (over 300 comments) at k5:
http://www.kuro5hin.org/story/2002/11/11/83056/403
which also has links to Criswell's Industrial Physicist article:
http://www.aip.org/tip/0402.html
and subsequent discussion in later issues.
I'm definitely more optimistic about the prospects for large-scale space
development after reading these articles and their discussion of the
prospects for space-based solar power... Now if we could get NASA and
the energy department working together on such a project...?
Arthur
# 16926 bycharles radley on Dec. 13, 2002, 3:30 p.m.
Member since 2022-08-22
First point:
valuable.
The problem with solar power is that PV conversion
efficiency is only about 20% efficient, for rather
high priced PV cells. Plus PV cells are rather heavy
to ship from Earth and soft land on luna, rather
expensive to do.
A rectenna, on the other hand, is lightweight and has
a conversion efficiency of over 90%.
Soft landing hardware on to the Moon is very
expensive.
Let us assume a PV array is 10 times heavier per watt
than a rectenna.
That means we can get 5*10 = 50 times as much power
per kilogram for a rectenna than for a PV array.
That means a rectenna will be be at least 50 times
cheaper per watt of useful power than PV array at
Malapert. I say "at least" because the manufacturing
cost of a rectenna will be much cheaper than for PV
array.
=====
Second point:
I am not particularly interested in subsistence level
"living off the land" on luna or anywhere else.
I am interested in breaking open the vast resources of
the high frontier.
That means solar power satellites beaming power to
Earth as the primary economic power house for space
development.
That means an SPS demonstrator at L-1 is top priority.
==========
SPS makes lunar development cheaper, and it opens a
vast energy market for Earth.
A win-win scenario.
# 16927 byColin Keizer on Dec. 14, 2002, 7:34 p.m.
Member since 2022-08-22
My vote is also for an SPS demonstration unit at L1.
the next five to ten years.
Cost of new, efficient photovoltaics may drop to about the cost of LEDs.
http://www.lbl.gov/Science-Articles/Archive/MSD-full-spectrum-solar-cell
.html
GOOGLE for "Full Spectrum Solar Cell" and enjoy the reading.
Very promising technology. Looks rather important to SPS.
CONJECTURE: It could be even more important to Earth-based deployment of
photovoltaics. This might attract much available investment money into
broader implementation of community and residential solar power.
Colin Keizer
# 16928 byrmenich@... on Dec. 18, 2002, 9:29 a.m.
Member since 2022-08-22
With respect to your "First point", let us consider two scenarios:
1.) Keeping the solar cells at Earth-Moon L1, and landing rectenna
equipment at some point on the Moon.
2.) Landing solar cells at Malapert Mountain and using them directly.
With option (1), solar cells need to be launched from Earth, the same as
in option (2). With (1), additional rectenna equipment and the means to
deploy it must be launched from Earth and landed on the Moon. With (2),
solar cells need to landed on Luna.
How many square kilometers would the rectenna in option (1) cover? What
would the mass be of that area of rectenna? What kinds of machinery
would be required to deploy it over that area, and what would the mass be
of those robots? Do you still think that combined the it would be a lot
less mass than landing solar cells directly on the Moon?
The biggest delta-V hit is in getting things from the surface of the Earth
to L1 or lunar orbit. Getting them from L1 or lunar orbit to the surface
of Luna is a much smaller amount of delta-V.
Another point.... it is possible to conceive of a plan to start
bootstrapping at Malapert Mountain. Land the minimal amount of robotic
equipment necessary to begin manufacturing solar cells from lunar
materiel.
Ron
charles radley cfrjlr@...
12/13/02 04:29 PM
First point:
Continuous solar power at Malapert is not that
valuable.
The problem with solar power is that PV conversion
efficiency is only about 20% efficient, for rather
high priced PV cells. Plus PV cells are rather heavy
to ship from Earth and soft land on luna, rather
expensive to do.
A rectenna, on the other hand, is lightweight and has
a conversion efficiency of over 90%.
Soft landing hardware on to the Moon is very
expensive.
Let us assume a PV array is 10 times heavier per watt
than a rectenna.
That means we can get 5*10 = 50 times as much power
per kilogram for a rectenna than for a PV array.
That means a rectenna will be be at least 50 times
cheaper per watt of useful power than PV array at
Malapert. I say "at least" because the manufacturing
cost of a rectenna will be much cheaper than for PV
array.
=====
Second point:
I am not particularly interested in subsistence level
"living off the land" on luna or anywhere else.
I am interested in breaking open the vast resources of
the high frontier.
That means solar power satellites beaming power to
Earth as the primary economic power house for space
development.
That means an SPS demonstrator at L-1 is top priority.
==========
SPS makes lunar development cheaper, and it opens a
vast energy market for Earth.
A win-win scenario.
# 16929 bycharles radley on Dec. 18, 2002, 10:05 a.m.
Member since 2022-08-22
> With respect to your "First point", let us consider
> two scenarios:
> 1.) Keeping the solar cells at Earth-Moon L1, and
> landing rectenna
> equipment at some point on the Moon.
> 2.) Landing solar cells at Malapert Mountain and
> using them directly.
>
> I think your claim is that (1) has a big advantage
> over (2). I wonder.
when measured in watts per kilogram = watts per
dollar, delivered at the surface of the Moon.
> With option (1), solar cells need to be launched
> from Earth, the same as
> in option (2). With (1), additional rectenna
No. The starting point is irrelevant since it is the
same for both. The cost difference is governed by
where the cells end up.
In option 1 PV solar cells are delivered to L-1.
In option 2 PV solar cells are delivered to the
surface of the Moon.
Option-1 is at least an order of magnitude cheaper.
Watt for watt, the additional cost and weight of the
rectenna is very small compared to the cost/weight of
the associated solar cells.
> equipment and the means to
> deploy it must be launched from Earth and landed on
> the Moon. With (2),
> solar cells need to landed on Luna.
>
Five times more equipment is needed for deploying a PV
array than for a rectenna of comparable power, see
below.
> How many square kilometers would the rectenna in
> option (1) cover? What
> would the mass be of that area of rectenna? What
The rectenna will cover about five times less area
than an equivalent array of PV cells, assuming
rectenna efficiency of ~95% and PV efficiency of ~20%
> kinds of machinery
> would be required to deploy it over that area, and
> what would the mass be
> of those robots? Do you still think that combined
> the it would be a lot
> less mass than landing solar cells directly on the
> Moon?
>
The equipment needed for deploying PV array and
rectenna are about the same. Deployment of the
rectenna can be done five times faster or with five
times less equipment for the same time, because teh
area it needs is five times less.
>
> Another point.... it is possible to conceive of a
> plan to start
> bootstrapping at Malapert Mountain. Land the
> minimal amount of robotic
> equipment necessary to begin manufacturing solar
> cells from lunar
> materiel.
>
Sure. But a machine to build a rectenna will be
cheaper, simpler and lighter.
Cheers,
Charles R.
# 16930 byrmenich@... on Dec. 19, 2002, 8:06 a.m.
Member since 2022-08-22
Charles:
Earth-Moon L1. Roughly what size of rectenna would you require on the
surface of the Moon with which to capture the microwave energy beamed
there from L1 ?
Ron
charles radley cfrjlr@...
12/18/02 10:57 AM
> With respect to your "First point", let us consider
> two scenarios:
> 1.) Keeping the solar cells at Earth-Moon L1, and
> landing rectenna
> equipment at some point on the Moon.
> 2.) Landing solar cells at Malapert Mountain and
> using them directly.
>
> I think your claim is that (1) has a big advantage
> over (2). I wonder.
Correct. It is at least an order of magnitude cheaper
when measured in watts per kilogram = watts per
dollar, delivered at the surface of the Moon.
> With option (1), solar cells need to be launched
> from Earth, the same as
> in option (2). With (1), additional rectenna
No. The starting point is irrelevant since it is the
same for both. The cost difference is governed by
where the cells end up.
In option 1 PV solar cells are delivered to L-1.
In option 2 PV solar cells are delivered to the
surface of the Moon.
Option-1 is at least an order of magnitude cheaper.
Watt for watt, the additional cost and weight of the
rectenna is very small compared to the cost/weight of
the associated solar cells.
> equipment and the means to
> deploy it must be launched from Earth and landed on
> the Moon. With (2),
> solar cells need to landed on Luna.
>
Five times more equipment is needed for deploying a PV
array than for a rectenna of comparable power, see
below.
> How many square kilometers would the rectenna in
> option (1) cover? What
> would the mass be of that area of rectenna? What
The rectenna will cover about five times less area
than an equivalent array of PV cells, assuming
rectenna efficiency of ~95% and PV efficiency of ~20%
> kinds of machinery
> would be required to deploy it over that area, and
> what would the mass be
> of those robots? Do you still think that combined
> the it would be a lot
> less mass than landing solar cells directly on the
> Moon?
>
The equipment needed for deploying PV array and
rectenna are about the same. Deployment of the
rectenna can be done five times faster or with five
times less equipment for the same time, because teh
area it needs is five times less.
>
> Another point.... it is possible to conceive of a
> plan to start
> bootstrapping at Malapert Mountain. Land the
> minimal amount of robotic
> equipment necessary to begin manufacturing solar
> cells from lunar
> materiel.
>
Sure. But a machine to build a rectenna will be
cheaper, simpler and lighter.
Cheers,
Charles R.
# 16931 bycharles radley on Dec. 19, 2002, 9:12 a.m.
Member since 2022-08-22
>
useful size.
The minimum rectenna size is about a few kilometres diameter, otherwise the transmitter antennas must become
incredibly
large, and the microwave beam power intesity way high. The bigger the rectenna, the smaller the transmitter antenna
size.
The optimmum sizing is where the rectenna and the transmitter antenna are each a few km diameter.
So it is true that for small scale bootstrapping, a rectenna will not work and we are stuck with less efficient PV
arrays.
Once we get to the breakthrough size it would go like this:
A 10 km^2 rectenna generates as much as a 50 km^2 PV array. This is about the smallest useful size for a rectenna.
But we cannot bootstrap our way from small scale operations to a rectenna. They are simply not dependent on each
other, i.e. the one does not need the other, nor even benefit from the other.
I do not see the value of boostrapping from small beginnings, we can and should jump straight do a L1 SPS demo. It
is easier to sell than the bootstrapping approach because of its economic payback.
# 16932 byrmenich@... on Dec. 19, 2002, 10:14 a.m.
Member since 2022-08-22
Charles:
of the Moon? What area of solar PV cells at Earth-Moon L1 are you
suggesting for this L1 SPS demo? Would all of this equipment be
launched from Earth?
Ron
charles radley c.radley@...
12/19/02 09:34 AM
>
There is a minimum size for a rectenna based on microwave antenna geometry
which means that 100 m^2 would not be a
useful size.
The minimum rectenna size is about a few kilometres diameter, otherwise
the transmitter antennas must become
incredibly
large, and the microwave beam power intesity way high. The bigger the
rectenna, the smaller the transmitter antenna
size.
The optimmum sizing is where the rectenna and the transmitter antenna are
each a few km diameter.
So it is true that for small scale bootstrapping, a rectenna will not work
and we are stuck with less efficient PV
arrays.
Once we get to the breakthrough size it would go like this:
A 10 km^2 rectenna generates as much as a 50 km^2 PV array. This is
about the smallest useful size for a rectenna.
But we cannot bootstrap our way from small scale operations to a
rectenna. They are simply not dependent on each
other, i.e. the one does not need the other, nor even benefit from the
other.
I do not see the value of boostrapping from small beginnings, we can and
should jump straight do a L1 SPS demo. It
is easier to sell than the bootstrapping approach because of its economic
payback.
# 16933 bycharles radley on Dec. 19, 2002, 10:38 a.m.
Member since 2022-08-22
> Charles:
>
> Are you saying that for an "L1 SPS demo" we must
> construct a rectenna at least "a few km diameter" on
> the surface
> of the Moon? What area of solar PV cells at
> Earth-Moon L1 are you
> suggesting for this L1 SPS demo? Would all of
About 5 times the area of the rectenna.
> this equipment be
> launched from Earth?
>
For the first one, yes.
This SPS will turn an energy starved Moon base into an
energy rich moonbase. This gives us lots of power for
mass drivers, lunar material processing, oxygen
generation, etc.
It take many decades, maybe centuries to achieve the
same level of development by bootstrapping from small
beginnings.
With an SPS at L-1 we can get to a highly developed
Moon in a few years.
# 16934 byrmenich@... on Dec. 19, 2002, 11:13 a.m.
Member since 2022-08-22
Well, that's quite a demo. If funds were available for it, then yes, it
could really open the lunar frontier in a major way.
there were a small but growing research base at Malapert Mountain that
"lived off the land" in the sense of providing its own radiation
shielding, its own oxygen for refueling of descent/ascent craft, and
providing for a few other mass-intensive needs with local resources, then
I'd be a happy camper. If small robotic factories for producing
low-grade solar cells arrived at Malapert Mountain 5 years before the
first human, that'd be o'k with me too.
Dream big or dream small. I guess I'm dreaming small.
Ron
charles radley cfrjlr@...
12/19/02 11:38 AM
> Charles:
>
> Are you saying that for an "L1 SPS demo" we must
> construct a rectenna at least "a few km diameter" on
> the surface
Yes.
> of the Moon? What area of solar PV cells at
> Earth-Moon L1 are you
> suggesting for this L1 SPS demo? Would all of
About 5 times the area of the rectenna.
> this equipment be
> launched from Earth?
>
For the first one, yes.
This SPS will turn an energy starved Moon base into an
energy rich moonbase. This gives us lots of power for
mass drivers, lunar material processing, oxygen
generation, etc.
It take many decades, maybe centuries to achieve the
same level of development by bootstrapping from small
beginnings.
With an SPS at L-1 we can get to a highly developed
Moon in a few years.
# 16935 byArthur P. Smith on Dec. 19, 2002, 11:44 a.m.
Member since 2022-08-22
Smaller transmitter and receiver sizes are practical with higher
microwave transmission frequencies, although that requires higher
quality antennas also. The typical frequency Charles is probably
assuming is 2.5 GHz, but there's nothing particularly special about that
number, other than FCC regulations and atmospheric considerations,
neither of which apply to the Moon. At 250 GHz, the two would need to be
only 1/10 the diameter (see
http://www.spacefuture.com/archive/a_few_things_you_occasionally_wanted_to_know_about_wireless_power_transmission.shtml
for example).
object of several hundred meters or kilometers across - rather several
transmitting antennas can work together in "phased array mode" to
produce a single main beam lobe at the receiving location.
In other words, I believe the demo could be quite a bit smaller than
Charles suggests.
Arthur
# 16936 byColin Keizer on Dec. 21, 2002, 2:24 p.m.
Member since 2022-08-22
If your rectanna is just a PV array optimized for a particular range of
frequencies, you might do better to use a large number of inflated
steerable mirrors rather than PV arrays in the L1 component. Reflect
LOTS of sunlight onto high efficiency (MORE than 50%), full spectrum PV
cells anywhere on the Moon.
Soon Now.
See: http://scienceblog.com/community/article392.html or GOOGLE for
"Full Spectrum Solar Cell"
Does anybody have any guesses how long it might take for this to go from
laboratory to production PV cells? I'm guessing less than five years,
unless they hit some completely unexpected stumbling block.
Colin Keizer
# 16937 byHuebner, Jay on Jan. 4, 2003, 11:47 a.m.
Member since 2022-08-22
Have any of you built a rectenna demo? I wonder if one could put together a
couple of wires, an RF diode (what kind? Does anyone know?) and be able to
make an LED light at the Super Market Microwave door opener? If we could
get a million voters to play with such devices, beaming microwave power from
the Moon might seem more real to the electorate. Maybe SSI could market
kits. Or are they on the market now? Jay Huebner
# 16938 bycharles radley on Jan. 5, 2003, 10:55 a.m.
Member since 2022-08-22
Jay,
sure where it is right now.
http://www.tsgc.utexas.edu/tadp/1996/general/wpt.html
I agree that more public demonstrations would be a good idea, however,
there are legal liability and safety issues about doing RF demos in
public, and letting the public get their hands on such items.
It really needs to be confined to controlled conditions with qualified
people in charge. Places like planetariums, museums, classrooms and
laboratories should be OK. But selling a kit to the public would be
very risky. It would probably be OK to sell a kit to people like
Radio Hams, or licensed radio engineers.
Your average voter, unfortunately, does not possess the expertise to
safely use such equipment. For example, if you hold it up to your eye
or eardrum for long periods of time, there might be a risk of tissue
damage. The attorneys would have a field day, let the class actions
roll.
For such a program to work there really needs to be a new class of radio
operator license for operating power transmission equipment. The
licensee applicant would need to demonstrate theoretical and practical
understanding of the technology.
Best regards,
Charles R.
# 16939 byHuebner, Jay on Jan. 5, 2003, 1:36 p.m.
Member since 2022-08-22
Charles R.
Thanks for the link. I was not proposing kits with microwave generators,
but only detectors, which could be used with all of those generators which
we walk through in grocery stores, etc.
Jay Huebner
RE: "Here is a web link to a portable demonstration unit from 1996, I am not
sure where it is right now.
http://www.tsgc.utexas.edu/tadp/1996/general/wpt.html
... The attorneys would have a field day, let the class actions
roll."
# 16940 bycharles radley on Jan. 5, 2003, 3:11 p.m.
Member since 2022-08-22
> Charles R.
> Thanks for the link. I was not proposing kits
> with microwave generators,
> but only detectors, which could be used with all of
> those generators which
> we walk through in grocery stores, etc.
> Jay Huebner
of such things. Can you be more specific ?
Most microwave sources are for telecommunications, or
radar. The received intensity from those is not
enough to power an LED.
If there were a system powerful enough to light an LED
I think that would actually scare people, and have the
opposite result of what you would like !
There are some big microwave transmitters in the
Portland West Hills which expose the local population
to intensities above the national average, and a lot
of environmentalists do not like them. This system
is being studied by experts for long term biological
effects.
# 16941 byHuebner, Jay on Jan. 6, 2003, 7:40 a.m.
Member since 2022-08-22
When you walk up to usually a sliding glass door on many if not most large
stores, and before you get to the actual door, it opens, and there is a
black box above the door "looking" out and down, then you are in a x band
microwave beam, which detects you and opens the door. If you use a "fuzz
buster" radar detector, that is why they go off when you pass such large
stores.
Jay Huebner
> Thanks for the link. I was not proposing kits
> with microwave generators,
> but only detectors, which could be used with all of
> those generators which
> we walk through in grocery stores, etc.
> Jay Huebner
Microwave sources in grocery stores ? I am not aware
of such things. Can you be more specific ?
Most microwave sources are for telecommunications, or
radar. The received intensity from those is not
enough to power an LED.
If there were a system powerful enough to light an LED
I think that would actually scare people, and have the
opposite result of what you would like !
There are some big microwave transmitters in the
Portland West Hills which expose the local population
to intensities above the national average, and a lot
of environmentalists do not like them. This system
is being studied by experts for long term biological
effects.