...100 MW of Space Solar Power ...per single launch!

On Dec 14, 4:55*pm, Sylvia Else wrote:
I wasn't talking about on the ground. If the space side conversion of
generated power to microwaves is only 80% efficient, then there's 20% loss
in heat. That heat has to be got rid of, or the system will melt. Given
that it's in a vacuum, the heat has to be got rid of entirely by
radiation.

Sylvia.

It had to arrive entirely by radiation. Didn't you know the Sun is hot?

Yes, and if the transmitter could run at the temperature of the surface
of the sun, there'd be no problem.

Then why not make a plasma transmitter?

"Sylvia Else" wrote in message
...
Androcles wrote:
"Sylvia Else" wrote in message
...
Uncle Al wrote:
Sylvia Else wrote:
Uncle Al wrote:

80% bull**** business plan number for RF
conversion
At 80%, the remaining 20%, or 80MW, is heat that has to be got rid of,
by radiation alone.

Sylvia.
Given 0% carbon footprint, 80 MW continuous ground heating cannot add
to Global Warming. Besides, it is add over a broad area. It's not
like lighting a candle or grilling a steak - both of which are
Enviro-whiner atrocities.

I wasn't talking about on the ground. If the space side conversion of
generated power to microwaves is only 80% efficient, then there's 20%
loss in heat. That heat has to be got rid of, or the system will melt.
Given that it's in a vacuum, the heat has to be got rid of entirely by
radiation.

Sylvia.

It had to arrive entirely by radiation. Didn't you know the Sun is hot?



Yes, and if the transmitter could run at the temperature of the surface of
the sun, there'd be no problem.

Sylvia.

Oh, you mean an incandescent lamp.
It's gonna need a mighty big solar array to power it for
100 MW. Perhaps someone is planning to orbit a nuclear
reactor instead, or else they'll need a lot of coal.

Sylvia Else wrote:
Peter Fairbrother wrote:
Sylvia Else wrote:
Uncle Al wrote:
Sylvia Else wrote:
Uncle Al wrote:

80% bull**** business plan number for RF
conversion
At 80%, the remaining 20%, or 80MW, is heat that has to be got rid of,
by radiation alone.

Sylvia.

Given 0% carbon footprint, 80 MW continuous ground heating cannot add
to Global Warming. Besides, it is add over a broad area. It's not
like lighting a candle or grilling a steak - both of which are
Enviro-whiner atrocities.


I wasn't talking about on the ground. If the space side conversion of
generated power to microwaves is only 80% efficient, then there's 20%
loss in heat. That heat has to be got rid of, or the system will
melt. Given that it's in a vacuum, the heat has to be got rid of
entirely by radiation.

For physics reasons (in order to get a small enough beam spread) the
transmitter will need to be 0.5-1 km across, regardless of power; and
there is no real reason why it should not be made from heat-tolerant
materials, excepting maybe some of the electronics.

Typically, the transmitting antenna would be a mesh to minimise the mass
- the holes merely have to be small compared with the transmitted
wavelength. But a mesh doesn't have a large surface area, which would be
required to radiate away the heat.

Most designs don't use a mesh, but rather a matrix of transmitting
elements in a solid plane. The individual elements are closely spaced,
and even if a grid was used it would be fairly full. Think of a phased
array antenna rather than a loose grid of wires


Even for my proposed 100 GW systems, cooling the transmitter isn't a
big problem. No external cooling systems are needed, just sunshades.
Indeed if it can operate at a few hundred C even sunshades are not
required.

What's the blackbody radiation per square metre at a few hundred Celsius?

7348 w/m^2 at 600 K or 327 C.

A 3 km^2 area transmitter at 327C would radiate over 20GW, enough for a
100 GW transmitter at 20% efficiency.

-- Peter Fairbrother

Peter Fairbrother wrote:
Sylvia Else wrote:
Peter Fairbrother wrote:
Sylvia Else wrote:
Uncle Al wrote:
Sylvia Else wrote:
Uncle Al wrote:

80% bull**** business plan number for RF
conversion
At 80%, the remaining 20%, or 80MW, is heat that has to be got rid
of,
by radiation alone.

Sylvia.

Given 0% carbon footprint, 80 MW continuous ground heating cannot add
to Global Warming. Besides, it is add over a broad area. It's not
like lighting a candle or grilling a steak - both of which are
Enviro-whiner atrocities.


I wasn't talking about on the ground. If the space side conversion
of generated power to microwaves is only 80% efficient, then there's
20% loss in heat. That heat has to be got rid of, or the system will
melt. Given that it's in a vacuum, the heat has to be got rid of
entirely by radiation.

For physics reasons (in order to get a small enough beam spread) the
transmitter will need to be 0.5-1 km across, regardless of power; and
there is no real reason why it should not be made from heat-tolerant
materials, excepting maybe some of the electronics.

Typically, the transmitting antenna would be a mesh to minimise the
mass - the holes merely have to be small compared with the transmitted
wavelength. But a mesh doesn't have a large surface area, which would
be required to radiate away the heat.

Most designs don't use a mesh, but rather a matrix of transmitting
elements in a solid plane. The individual elements are closely spaced,
and even if a grid was used it would be fairly full. Think of a phased
array antenna rather than a loose grid of wires


Even for my proposed 100 GW systems, cooling the transmitter isn't a
big problem. No external cooling systems are needed, just sunshades.
Indeed if it can operate at a few hundred C even sunshades are not
required.

What's the blackbody radiation per square metre at a few hundred Celsius?

7348 w/m^2 at 600 K or 327 C.

A 3 km^2 area transmitter at 327C would radiate over 20GW, enough for a
100 GW transmitter at 20% efficiency.

Duh, 20% loss, not 20% efficiency. Sorry.

For a 400 MW system, as opposed to a 100 GW system, even with a wire
grid, the cooling requirements are ... piffling. You'd want to take them
into account, but that's about all.



Oh, on antenna sizes - the larger the antenna in orbit the tighter the
beam, and thus the smaller the required ground antenna, and the required
exclusion zone.

For a 100 GW system I'd use a considerably larger space antenna than the
1.4 km diameter antenna implied above so that the irradiation at the
edge of the terrestrial antenna's exclusion zone was *much* less than eg
the exposure caused by carrying a mobile phone or using a microwave oven.

Safety first, precautionary principle (you don't want to get sued), and
so on.

-- Peter Fairbrother

Jonathan wrote:
"Sylvia Else" wrote in message
...
Jonathan wrote:
"Sylvia Else" wrote in message
...
Solaren has not provided details on just how its technology
works, citing intellectual property concerns.
Meaning it wouldn't stand up to the inevitable expert scrutiny if they got a
patent.

Maybe, but keeping a secret could mean fraud or it could mean
a breakthrough, we don't know for sure.
If they have a breakthrough, they should get a patent on it, ASAP. As long as
it's merely secret, they're exposed to industrial espionage, accidental leaks,
you name it.


They claim to have a patented 'system'. But that's all I found, no details.

http://www.freepatentsonline.com/7612284.html

Usual case of patenting the bleedin' obvious, while not identifying a
solution to the technical difficulties involved.

Sylvia.

Pat Flannery wrote:
Peter Fairbrother wrote:


Most designs don't use a mesh, but rather a matrix of transmitting
elements in a solid plane. The individual elements are closely spaced,
and even if a grid was used it would be fairly full. Think of a phased
array antenna rather than a loose grid of wires

Something like a huge version of this:
http://www.bharat-rakshak.com/NAVY/Images/MR-775.jpg
Unlike a big parabolic dish, you can steer the microwave beam from a
flat array electronically without having to physically move the antenna.

Pat

Imagine a large square in orbit over the equator, oriented so that its
surface is horizontal, (w.r.t. the surface of the Earth immediately
below) and so that it has one of its four sides (the "front")
perpendicular to the direction of motion.

It seems to me that all four sides experience a force with a component
towards the centre of the square, and a component away from the centre
of the Earth. The forces on the front and rear arise because they are
travelling too fast for the orbit they are in. The forces on the left
and right arise because of that, and also because they are not actually
in an orbit about the centre of the Earth. These forces tend to make the
square crumple into a ball.

The forces on the front and rear sides can be eliminated by making the
square curved, but the forces on the left and right sides remain.

Making a very large antenna that is sufficiently rigid not to collapse,
but light enough to be launched, doesn't seem such a straigthforward
proposition.

Sylvia.

On Dec 13, 1:41*am, "Jonathan" wrote:
Controversy Flares Over Space-Based Solar Power Plans

Jeremy Hsu
space.com - Wed Dec 2, 10:15 am ET

"Solaren would then need to launch a solar panel array capable
of generating 400 megawatts. The total launch weight of all the
equipment would be the equivalent of about 400 metric tons,
or 20 shuttle-sized launches, according to Hoffert.

But Solaren says that it would just require four or five heavy-lift
rocket *launches capable of carrying 25 metric tons, or about
one fourth of Hoffert's weight estimate. The company is relying
on developing more efficient *photovoltaic technology for the
solar panels, as well as mirrors that help focus sunlight.

Solaren has not provided details on just how its technology
works, citing intellectual property concerns. But it expects that
its space solar power can convert to RF energy with greater
than 80 percent efficiency, and expects similar conversion
efficiency for converting the RF energy back to DC
electricity on the ground in California. The company also
anticipates minimal transmission losses from the space
to the ground."http://news.yahoo.com/s/space/20091202/sc_space/controversyflaresover...

The 'inevitable' is steadily becoming possible...imho.

Jonathan

s

64% all-inclusive efficiency isn't half bad,

Getting so much created, deployed and serviced is likely going to
consume most every megawatt of energy it produces, and then some.

Is this energy going to cost us $1/kw.h?

~ BG

On Dec 13, 6:37*am, gaetanomarano wrote:
.
.

Space Solar Power hoax/illusion DEBUNKED article:

http://www.ghostnasa.com/posts/038sspdebunked.html

.
.

Why the Ares-1 is already DEAD article:

http://www.ghostnasa.com/posts2/058ares1dead.html

It's called job security without having to invest a dime of your own
loot. William Mook was always good at suggesting ways of his living
large off the backs of others, as well as always protecting Big Energy
and their puppet government at the same time.

~ BG

Peter Fairbrother wrote:
I was just pointing out that the aircraft, even a composite one,
wouldn't melt or anything like that!

I was more worried about the microwaves going right through the
composite parts of the aircraft and hitting the people and electronics
inside of it.
As someone pointed out earlier, a all-metal aircraft works like a
Faraday Cage and shields its interior from the microwaves...although I'd
expect some pretty impressive electrical displays off of the static
discharge wicks at the wing and tail tips as the plane itself will act
like a rectenna for the microwaves, and that electrical energy has to go
somewhere.
It's best just to have aircraft just steer clear of the beam.

Pat

Peter Fairbrother wrote:


Most designs don't use a mesh, but rather a matrix of transmitting
elements in a solid plane. The individual elements are closely spaced,
and even if a grid was used it would be fairly full. Think of a phased
array antenna rather than a loose grid of wires

Something like a huge version of this:
http://www.bharat-rakshak.com/NAVY/Images/MR-775.jpg
Unlike a big parabolic dish, you can steer the microwave beam from a
flat array electronically without having to physically move the antenna.

Pat