Hi Space-Settlers,

the list of economic reasons to settle space is unfortunately very short.

Do you know if anyone did serious studies on the use of orbital mirrors
for weather control? Like having some large mirrors (like von Oberth
suggested) or more probably many smaller ones, that redirect sunlight to
certain spots on earth. I know that the areas lighted by such mirrors
have to be somewhat on the large side. Sun diameter is 1.4 million km,
distance earth sun is 150 mio km. So a perfect mirror at a 400 km orbit
will distribute its light over at least 400*1.4/150 = 5 km on earth. So
anything below 10 km diameter would be unrealistic. But even with this
inaccuracy I'd reckon one could create weather changing effects. (Like:
increase solar input on that area by 20%, ground warms up a few degrees,
air heats up a little and starts to rise. Air from the sides flows
towards the spot.)

Tornadoes, Cyclones etc. do a serious amount of damage every year. Being
able to dampen, dissolve, divert or prevent them before they kill any
people, destroy houses and farms might be worth an investment of some
billion dollars. Yes? If I remember the numbers correct, a single storm
can do as much (financial) damage as was done on september 11th in New York.

A country (or group of counties) able to render such a weather control
service world wide would have a tool of significant international
political influence.

Also selling good weather for special events and some daylight at night
(e.g. to light cities in the evening and in the morning) may be an idea.

Additional thermal input into earth would be small. So environmentalists
shouldn't be bothered by this more than by artificial lakes and
electromagnetic smog by mobile phones. On the contrary, this is only
another way of using clean sun-power. Think about the reduced pollution
if city lights energy consumption can be reduced this way.

I heard of some greenhouses using artificial light to supplement
daylight. Idle time of these mirrors could be used to light grain fields
etc.

Doing such kind of weather control needs a lot of mirrors, so it's a
much bigger market than communication and surveillance satellites. Maybe
it is worth enough to motivate orbital mirror maintenance and production
facilities using lunar materials?

Again my question: do you know of any serious studies on that? Or
reasons why this can't work?

Axel

Axel Walthelm wrote:

Hi Space-Settlers,

the list of economic reasons to settle space is unfortunately very
short.

Do you know if anyone did serious studies on the use of orbital mirrors
for weather control? Like having some large mirrors (like von Oberth
suggested) or more probably many smaller ones, that redirect sunlight
to
certain spots on earth. I know that the areas lighted by such mirrors
have to be somewhat on the large side. Sun diameter is 1.4 million km,
distance earth sun is 150 mio km. So a perfect mirror at a 400 km orbit
will distribute its light over at least 400*1.4/150 = 5 km on earth. So
anything below 10 km diameter would be unrealistic. But even with this
inaccuracy I'd reckon one could create weather changing effects. (Like:
increase solar input on that area by 20%, ground warms up a few
degrees,
air heats up a little and starts to rise. Air from the sides flows
towards the spot.)

Tornadoes, Cyclones etc. do a serious amount of damage every year.
Being
able to dampen, dissolve, divert or prevent them before they kill any
people, destroy houses and farms might be worth an investment of some
billion dollars. Yes? If I remember the numbers correct, a single storm
can do as much (financial) damage as was done on september 11th in New
York.

A country (or group of counties) able to render such a weather control
service world wide would have a tool of significant international
political influence.

Also selling good weather for special events and some daylight at night
(e.g. to light cities in the evening and in the morning) may be an
idea.

Additional thermal input into earth would be small. So
environmentalists
shouldn't be bothered by this more than by artificial lakes and
electromagnetic smog by mobile phones. On the contrary, this is only
another way of using clean sun-power. Think about the reduced pollution
if city lights energy consumption can be reduced this way.

I heard of some greenhouses using artificial light to supplement
daylight. Idle time of these mirrors could be used to light grain
fields
etc.

Doing such kind of weather control needs a lot of mirrors, so it's a
much bigger market than communication and surveillance satellites.
Maybe
it is worth enough to motivate orbital mirror maintenance and
production
facilities using lunar materials?

Again my question: do you know of any serious studies on that? Or
reasons why this can't work?

Axel

Rick Brooks:

Consider how much northern cities (in the northern hemisphere) spend on
snow plows in the winter. I consider it probable that orbital mirrors
could replace some if not all of the snow plows.
Not to mention the market for snow plows. And snow shovels.

I'm not sure, but Environmental Impact Statements might be a problem

As far as I'm concerned, winter sports are a waste. But many people like
them. If we warm up Buffalo New York to the point where they don't need
any other snow removal, how far outside the city will be affected? Will
winter sports be confined to a few reservations in sparsely populated areas?

Too, what would be the impact of keeping winter excluded from more of our
planet? Insect pests are worse where freezing doesn't keep their numbers down.

Longer growing seasons would improve crop yields. I was raised on a farm
just south of Michigan. Around here, you get two cuttings of
alfalfa hay a year. Would a longer year mean several more?

Weather control due to orbital mirrors would be a great help. But we could
see a lot of new problems.

Rick

I've sometimes wondered if one could obtain better leverage with
microwave beams alternately busting up cloud cover and creating it by
training on lakes/oceans. Changing amounts of insolation might have
more leverage (and in both directions) than just providing somewhat
more light. Might be a good side business for SPS.

Regards,

Mike Combs

--- In spacesettlers@yahoogroups.com, Axel Walthelm
wrote:
>
> Hi Space-Settlers,
>
> the list of economic reasons to settle space is unfortunately very
short.
>
> Do you know if anyone did serious studies on the use of orbital
mirrors
> for weather control? Like having some large mirrors (like von
Oberth
> suggested) or more probably many smaller ones, that redirect
sunlight to
> certain spots on earth. I know that the areas lighted by such
mirrors
> have to be somewhat on the large side. Sun diameter is 1.4 million
km,
> distance earth sun is 150 mio km. So a perfect mirror at a 400 km
orbit
> will distribute its light over at least 400*1.4/150 = 5 km on
earth. So
> anything below 10 km diameter would be unrealistic. But even with
this
> inaccuracy I'd reckon one could create weather changing effects.
(Like:
> increase solar input on that area by 20%, ground warms up a few
degrees,
> air heats up a little and starts to rise. Air from the sides flows
> towards the spot.)
>
> Tornadoes, Cyclones etc. do a serious amount of damage every year.
Being
> able to dampen, dissolve, divert or prevent them before they kill
any
> people, destroy houses and farms might be worth an investment of
some
> billion dollars. Yes? If I remember the numbers correct, a single
storm
> can do as much (financial) damage as was done on september 11th in
New York.
>
> A country (or group of counties) able to render such a weather
control
> service world wide would have a tool of significant international
> political influence.
>
> Also selling good weather for special events and some daylight at
night
> (e.g. to light cities in the evening and in the morning) may be an
idea.
>
> Additional thermal input into earth would be small. So
environmentalists
> shouldn't be bothered by this more than by artificial lakes and
> electromagnetic smog by mobile phones. On the contrary, this is
only
> another way of using clean sun-power. Think about the reduced
pollution
> if city lights energy consumption can be reduced this way.
>
> I heard of some greenhouses using artificial light to supplement
> daylight. Idle time of these mirrors could be used to light grain
fields
> etc.
>
> Doing such kind of weather control needs a lot of mirrors, so it's
a
> much bigger market than communication and surveillance satellites.
Maybe
> it is worth enough to motivate orbital mirror maintenance and
production
> facilities using lunar materials?
>
> Again my question: do you know of any serious studies on that? Or
> reasons why this can't work?

But wouln't those merroirs, as oppoise to SPS, be used for malvolient
purposes (i.e. terrorists, corrupt gov'ts, etc.)? It bring about the
image of kids out on a sidewalk with magifying glass, burning ants
(only on a global scale, and people instead of ants).

Beside, we are still trying to understand the dynamics of global
cilmate and weather. Messing with something we don't understand fully
is not the best idea in the world.

Combs, Mike wrote:

>I've sometimes wondered if one could obtain better leverage with
>microwave beams alternately busting up cloud cover and creating it by
>training on lakes/oceans. Changing amounts of insolation might have
>more leverage (and in both directions) than just providing somewhat
>more light. Might be a good side business for SPS.
>
>Regards,
>
>Mike Combs
>
Interesting question. For one thing I do not understand completely the
nature of such a microwave beam. Doesn't it need a receiver?
Furthermore, won't those SPS microwave transmitter be tuned to send
microwaves *not* being absorbed by water vapor, oxygen or nitrogen? So
they can be transmitted to earth on cloudy days too.

Second, redirecting sunlight by mirrors is easy and something like 95%
efficient. Admittedly clouds are white, which means they scatter and
reflect visible light, but how much of it? Even absorbing 90% and
reflecting only 10% of the light could make them blindingly white
(Remember: moon dust is mostly black, but still looks white in the night
from earth). I don't know about IR-absorption, but IIRC satellites use
some IR-channels to see through clouds. Do you have any numbers
indicating that overall efficiency/cost to convert sunlight into
microwaves and then send this energy into clouds is more efficient?

Finally, with all that talk about electro-smog, many people will make
war on that idea. Giving them only more sunlight like they would get
from a vacation sounds more agreeable, I'd say.

By the way, does any one know how difficult it would be to produce
mirrors that do not reflect UV-rays (which can cause skin cancer, even
though it is a perfectly natural form of radiation, and known to be
important to produce vitamins in the skin)?

Talking about SPS, if you go for thermal power generation, those mirror
producing orbital and lunar facilities can be shared between both
projects. Even if you use solar cells, mirrors could be used to put more
light on the solar cells.
So SPS and weather control may turn out to share a lot of development
costs and make each other more economic due to the larger quantities
processed.

Richard Brooks wrote:

>Consider how much northern cities (in the northern hemisphere) spend on
>snow plows in the winter. I consider it probable that orbital mirrors
>could replace some if not all of the snow plows.
>Not to mention the market for snow plows. And snow shovels.
>

Du to the low orbit the mirrors have to be in, time of lighting/warming
will probably be limited
to morning and evening. Melting the snow and then letting it freeze over
could turn out to
be worse than just plowing it.

>I'm not sure, but Environmental Impact Statements might be a problem
>
>As far as I'm concerned, winter sports are a waste. But many people like
>them. If we warm up Buffalo New York to the point where they don't need
>any other snow removal, how far outside the city will be affected? Will
>winter sports be confined to a few reservations in sparsely populated areas?
>
>Too, what would be the impact of keeping winter excluded from more of our
>planet? Insect pests are worse where freezing doesn't keep their numbers down.
>
>Longer growing seasons would improve crop yields. I was raised on a farm
>just south of Michigan. Around here, you get two cuttings of
>alfalfa hay a year. Would a longer year mean several more?
>
>Weather control due to orbital mirrors would be a great help. But we could
>see a lot of new problems.
>
No doubt the overall sun energy to earth must not be increased too much.
As a first guess I would say less than one per cent should be ok. That
means any weather control would be more surgical than powerful. That's
why I emphasis the question of tornado control. There might be a way to
influence chaotic weather events by applying not too much energy at the
right place and moment.

To heat up northern countries or Antarctica, higher orbits would do too.
But the environmental changes would be drastic. Maybe when one of the
worst case scenarios (polar ice melted away or new ice age setting in)
happens, this might be something to consider. But not for now.

Note also that to increase solar input to earth by one percent, you need
about one million square kilometers of orbital mirrors.
So let's start small and refrain from re-modeling overall world climate.

babbler36 wrote:

>But wouln't those merroirs, as oppoise to SPS, be used for malvolient
>purposes (i.e. terrorists, corrupt gov'ts, etc.)? It bring about the
>image of kids out on a sidewalk with magifying glass, burning ants
>(only on a global scale, and people instead of ants).
>

Rather improbable, I'd say. As I wrote, the focus of your magnifying
glass is very wide, at least some kilometers. So you can't destroy
tanks or buildings. It might be possible to burn large areas of land,
but much less violent than nukes would do. Surely control of those
satellites will be secured well. If terrorists could turn off
satellites (e.g. GPS-satellites), they would have done so by now.

Physical access to those mirrors is limited to space-faring countries.
There are much easier terrorist targets around on earth, if you think
about it. (But I won't make any suggestions about that here!)

In the undesirable case of two space-faring countries making war on
each other, nuclear missiles or other space weapons yet to be designed
will be able to disable those mirrors pretty easy. Think about the EMP
effect on satellites. Those mirrors must be coordinated very precise
and careful to create and maintain a dangerous hot spot.

>Beside, we are still trying to understand the dynamics of global
>cilmate and weather. Messing with something we don't understand fully
>is not the best idea in the world.
>
Like burning rain forests, burning petrol instead of using horses,
using mobile phones, low carb diets, artificial sweeteners, etc.?
Basically you're right, we are not 100% sure if those things are good
or bad in the long run. But we can make some educated guesses and act
upon them.

As long as you keep additional solar input small, harmful effects look
less likely than those possibly created by - say - using artificial
fertilizer.

From: Axel Walthelm [mailto:Axel.Walthelm@...]

> Combs, Mike wrote:
>
> >I've sometimes wondered if one could obtain better leverage with
> >microwave beams alternately busting up cloud cover and creating it by

> >training on lakes/oceans. Changing amounts of insolation might have
> >more leverage (and in both directions) than just providing somewhat
> >more light. Might be a good side business for SPS.
>
> Interesting question. For one thing I do not understand completely the

> nature of such a microwave beam. Doesn't it need a receiver?
> Furthermore, won't those SPS microwave transmitter be tuned to send
> microwaves *not* being absorbed by water vapor, oxygen or nitrogen? So

> they can be transmitted to earth on cloudy days too.

Absolutely correct on both points. Both of which means that it could
never be a simple as just redirecting the beam from a SPS. One would
have to work out some kind of highly mobile pilot beam emitter (maybe a
microwave-powered airplane like what those Japanese researchers came up
with?), and one would also have to re-tune the beam to a frequency
largely absorbed by H2O, one which might be quite a bit different from
its normal operating frequency.

> Do you have any numbers
> indicating that overall efficiency/cost to convert sunlight into
> microwaves and then send this energy into clouds is more efficient?

No, I certainly don't. You raise another good point in that the
leveraging effect from controlling insolation by controlling cloud cover
would have to be greater than the efficiency losses from the conversion
of solar power to electricity, and electricity to microwaves. I don't
know that it would. On the other hand, one might also be able to
contribute to cooling of the land by creating cloud cover by day, and
then breaking it up at nightfall.

> Finally, with all that talk about electro-smog, many people will make
> war on that idea. Giving them only more sunlight like they would get
> from a vacation sounds more agreeable, I'd say.

Could be right here, too.

Regards,

Mike Combs