Page 224 - James Rodger Fleming - Fixing the sky

Space mirrors and dust

In July 1945, a classified U.S. Army Air Force memorandum on the subject of
German liquid rocket development included speculations on “future possibili-
ties,” including ideas on intercontinental ballistic missiles, Earth-orbiting satel-
lites, space station platforms, and interplanetary travel. Significantly, a section of
the memo titled “Weather Control” cited a 1923 proposal by Herman oberth
to launch large mirrors, a mile or so in diameter, into orbit to be used to concen-
trate the Sun’s energy on the Earth’s surface “at will,” and in this way influence the
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weather. Time further popularized oberth’s idea in 1954, describing the space
mirror as made of “shiny metal foil reinforced with wire” and spinning slowly
around a space station as its hub. The space mirror would be positioned in such
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a way as to illuminate the Earth’s nighttime hemisphere. It would bathe cold
countries in reflected sunlight, making them productive and habitable. Areas
with excess rainfall could be heated and dried with the mirrors. Conversely, rain-
fall might be generated in an arid region by concentrating the Sun’s rays on the
nearest lakes to evaporate water and form clouds. Then the rain clouds could be
directed toward arid regions by thermal currents and pressure gradients gener-
ated by “proper manipulation of the mirrors.”
The army report speculated that these mirrors could be used by “the world
group of nations” against a country that became aggressive or obnoxious to per-
suade it “to be more friendly and reasonable by the concentration of intensive
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heat on their country,” but did not discuss other possible hostile applications of
these death rays. Time was considerably more blunt in its account: “If war should
start on the earth below, the ‘aggressor’ . . . could be handily incinerated by mak-
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ing the mirror concave to concentrate its beam.” Time also reported that the
Nazis gave serious consideration to a space mirror for military purposes during
World War II.
other radiative effects on climate were also being considered. Beginning in
1913, William Jackson Humphreys explored the idea that volcanic dust might
control the climate. Two decades later, astronomer Harlow Shapley and his
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associates realized that space is filled with interstellar dust that might be influ-
encing their calculations by obscuring distant stars. Astronomers Fred Hoyle and
R. A. Lyttleton further speculated that space dust may affect the solar constant
and thus cause climatic change. 50
Early in the space age, Leningrad mathematician Mikhail Aleksandrovich
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Gorodskiy proposed creating an artificial dust ring passing over both poles.
Shaped like a flat washer with its lower boundary at an altitude of 750 miles
and its upper boundary at 6,000 miles, the Saturn-like ring would be made of

fearS, fantaSieS, and PoSSibilitieS of Control | 207