Value chain · CLM-1283
In plain terms
In 1981 the US Congress's technology office worked out that keeping the edge of a receiving site to the Soviet limit would make each site about ten times bigger, close to 1,700 square kilometres. That limit is ten times stricter than the American design boundary.
The claim as recorded
OTA's 1981 report states that the microwave power density at the edge of the reference system's exclusion boundary would be 0.1 mW/cm2. This gives about 174 km2 of land per rectenna site, with the rectenna edge at 1.0 mW/cm2 and 2 km added on each side for the buffer zone; the report's land table gives the same site as 35.0 km2 per 1,000 MW, or 1,280 m2 per MW-yr at a 30-year lifetime and a capacity factor of 0.9. If the power density at the edge "could not exceed 0.01 mW/cm2 (the Soviet standard)", each site would need almost 1,700 km2. The report gives 10 mW/cm2 of infrared at the edge of the laser design's buffer zone. It says more stringent microwave standards could increase SPS land requirements.
Evidence behind this: T3, a published congressional assessment; it permits "OTA states Y". OTA cites the land figure to a 1978 DOE siting contractor report and does not compute it.
Scope and limits
The 0.01 mW/cm2 called "the Soviet standard" is the Soviet occupational value in the report's own Table 42. The Soviet public value there is ten times lower, 0.001 mW/cm2, and the report does not state the land needed at that level. The 1,700 km2 is cited to a 1978 siting report (footnote 39, held as SRC-512), and that report was not checked. The ratio of 1,700 to 174, about 9.8 times the land, is our arithmetic. The figures cover receiving-site land only; transmission lines, mining and transport are excluded. Note b's printed "(117 km2)" is 9 x 13, the bounding rectangle; the 9 by 13 km ellipse is pi x 4.5 x 6.5 = 91.9 km2, so the 117 is not used (our arithmetic). The 9 by 13 km rectenna plus 2 km on each side is a 13 by 17 km ellipse, pi x 6.5 x 8.5 = 173.6 km2, which matches the 174 (our arithmetic). The table's other figures are OTA's roundings of the 174: 174 / 5 = 34.8 against the printed 35.0, and 174 km2 over 5,000 MW, 30 years and 0.9 is 1,289 m2/MW-yr against the printed 1,280 (our arithmetic).
What it assumes
The 1978 reference system beam profile and a land rectenna at about 34 degrees latitude.
Where it comes from
PDF p.199 / printed 197: "the microwave power density at the edge of the reference system exclusion boundary would be 0.1 mW/cm2"; "if the power density at the edge could not exceed 0.01 mW/cm2 (the Soviet standard), then each site would require almost 1,700 km2 of land" (footnote 39); laser "infrared power density at the edge of this zone would be 10 mW/cm2". PDF p.200 / printed 198, Table 35, Reference row, read at the render (zoom 3) and notes a and b in a zoom 5 crop (extract/derived/SRC-601/crop/p0200-table35-note-a-b.png): 174.0 km2/site, 35.0 km2/1,000MW, 60 sites and 10,400.0 km2 for 300,000 MW, 1,280 m2/MW-yr. Note a: the reference and solid-state values assume a 30-year lifetime and a capacity factor of 0.9. Note b: the rectenna at 34 deg latitude covers a 9 km by 13 km elliptical area, printed "(117 km2)". Note b: edge of rectenna "1.0 mW/cm2"; "If an exclusion boundary is set at 0.1 mW/cm2, then the total land per site is approximately 174 km2 (2 km extra on each side for buffer zone)". PDF p.214 / printed 212, Table 42: U.S.S.R. occupational 0.01 mW/cm2 (workshift), public 0.001 mW/cm2.
Basis: mW/cm2 at the site boundary; km2 per site
Related records
- Answers question
- QST-001 not published in this release
Cite this
energyaperture.com/c/clm-1283
CLM-1283, Energy Aperture, as of 1981-08.
Connected records
Other published records linked to this one. A list, not a judgement.
- Also from SRC-601
- CLM-1284In 1981 the US Congress's technology office said there was not enough evidence to judge the health risk of living near a power-satellite...CLM-1285In 1981 the Soviet limit for workers was a thousand times stricter than the US one, and the US had no public limit at all. Congress's...CLM-1286The 1981 congressional assessment listed who would be exposed to the beam and how strongly. Levels ran from a ten-thousandth of a milliwatt...CLM-1446The 1977-80 US government programme did not decide for or against power satellites. It said questions on technology, environment and cost...