Value chain · CLM-1296
In plain terms
A 1977 paper suggested that a solar power satellite's beam, if moved to a frequency that water vapour absorbs, could heat water vapour, cloud and rain to change the weather. It took the beam at the ground to be 100 to 1000 W/m2, which is roughly half to four times the later 230 W/m2 design centre.
The claim as recorded
A 1977 Journal of Microwave Power paper describes the NASA space solar power laboratory concept as a 2.3 GHz, 10 GW transmitter that could deliver 100 to 1000 W/m2 at the Earth's surface, and proposes retuning it to 22.2 GHz so that atmospheric water vapour, cloud and rain absorb the beam to modify the weather. For a beam column modelled as a cylinder 3.5 km in radius and 20 km high at 870 W/m2, it computes a heat release of 4.5 x 10^11 cal per minute under total absorption, and concludes that the method has potential for controlling weather and climate.
Evidence behind this: T1-a 1977 journal article; the density figures are the authors' statement of a NASA concept, not a measurement or a design document.
Scope and limits
A 1977 PROPOSAL AND HAND CALCULATION, NOT AN EXPERIMENT. The authors report computer experiments as in progress (PDF p.5), with no results. Recomputed: 870 W/m2 is 1.25 cal/min/cm2 (paper 1.2). Over pi x 3.5^2 = 38.5 km2 it is about 33.5 GW, which gives about 4.8 x 10^11 cal/min (paper 4.5 x 10^11). That beam power is more than three times the 10 GW transmitter (PDF p.1) and the 10,000 MW raw power in Fig. 1 (PDF p.2), so the paper's column-heating case is not consistent with its own system figures; this is not resolved here. The paper gives the frequency as 2.3 GHz in the abstract and 2.4 GHz in the introduction (PDF p.1). Units: 100 to 1000 W/m2 is 10 to 100 mW/cm2.
What it assumes
No assumptions are recorded against this claim.
Where it comes from
PDF p.1 (abstract): "a 2.3 GHz, 10 GW" transmitter; PDF p.1 (introduction): absorption of the microwaves "with a power density of 100 to 1000 W m-2" (the abstract's own figure is garbled in the text layer). PDF p.4: the beam modelled as "a vertical cylinder 3.5 km in radius and 20 km in height", with 870 W m-2 assumed as what "is the power density in the 22.2 GHz beam"; release of 4.5 x 10^11 cal min-1 (read at render, paraphrase). PDF p.5: the method shows a potential "for controlling weather and climate".
Basis: W/m2 at the ground; GHz; GW
Related records
- Answers question
- QST-001 not published in this release
Cite this
energyaperture.com/c/clm-1296
CLM-1296, Energy Aperture, as of 1977.