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LETTERS
White Elephant in Space?
Many view the International Space Station
(“Solar-powered space station,” Photonics
Spectra, July, p. 36), as a $150 billion
“white elephant” in space that has sucked
resources from many other more worth-
while programs – construction that was
said to have been created in part to pro-
vide jobs for out-of-work ex-Soviet nu-
clear scientists so they would not run off
and give atom bombs to rogue states.
That it needs 32,800 solar cells is no
brag. The same job could have been done
with a plutonium energy cell the size of a
home computer box, and it would not be
relying on the sun to function.
Richard Anderson
Toronto
A solar fraud?
In the July issue of Photonics Spectra I
read “Solar from space” (page 35). This
concept is a complete fraud to get money
for nonsense.
First, why is it so necessary to send
power to Earth from space? Do we not
have enough from fossils or other sources?
One reason given is that it is often cloudy,
so solar power plants cannot generate
enough power.
If you look at pictures of the globe sent
from a Meteo geostationary satellite, you
can easily see that only about one-eighth
of the half-globe is covered by clouds.
This means that the remaining seven-
eighths has unlimited solar irradiation, and
we have terrestrial power networks to
transport the generated power around the
globe.
Next, consider that solar cells are quite
inefficient; today’s best are at about 15
percent, and they age in space. Satellite
designers know better. In my opinion,
heating water is more efficient, and it is
done in California, Arizona, Spain, Japan
and elsewhere without rocket technology.
Then there’s the issue of energy loss as
power is transmitted to Earth. Anyone
who has heard about electromagnetic
waves knows that the power decreases due
to propagation in proportion to inverse
square. In a power distribution, a “good”
efficiency is more than 80 percent. The
experts claim that the power will be fo-
cused and collected by huge antennas. A
typical good satellite antenna has about 50
percent efficiency. And the free-space
power loss at 2.45 GHz over 35,000 km is
~190 dB, otherwise 1020. What kind of
power efficiency can you expect?
Finally, I have asked some of the ex-
perts how to get those wonderful antennas
that amplify power. I would use them in
microwave and millimeter-wave commu-
nication systems. Nobody has responded.
All this is a hoax and pure fantasy, and
moreover not based on natural laws. Those
space solar concepts are pure nonsense.
Jiri Polivka
Santa Barbara, Calif.
Editor’s response:
As a science writer, I cover subjects that I
think will be of interest to our readers and
make no claims as to the success of a
technology or marketing concept. We do,
however, appreciate readers keeping us
informed of the many issues surrounding
such a controversial topic.
Thin-film question
I read with great interest Caren B. Les’
article in the July issue on p. 28: “Image
sensor market: Looking forward to better
times.” I am curious about a statement in
your article: “A third generation of devices
based on polymeric thin films … also
could be developed.”
Are there companies or start-ups in this
space?
Erik Bodegom
Professor of Physics
Chairman, Department of Physics
Portland State University
Portland, Ore.
Response:
I’m not sure of any companies that might
be involved, but think PARC [Palo Alto
Research Center] and the University of
California, Santa Barbara, might be working on polymer-based image sensors.
Charles E. Spear
IntertechPira
Portland, Maine