Value chain · CLM-1286
In plain terms
The 1981 congressional assessment listed who would be exposed to the beam and how strongly. Levels ran from a ten-thousandth of a milliwatt per square centimetre for the public to about 2 watts for workers at the satellite's antenna, and it said no one could yet say what was safe for workers.
The claim as recorded
OTA's 1981 report gives reference-system microwave exposure by group in Table 41. The public outside the buffer zone gets between 10^-4 and 0.1 mW/cm2, and in an aircraft flying through the beam less than 23 mW/cm2 (shielding). Terrestrial workers in the rectenna field get up to 23 mW/cm2, possibly more if reflections occur. Space workers at the transmitting antenna get up to 2.2 W/cm2. Ecosystems under the rectenna get less than 0.1 mW/cm2 outside the buffer and 0.1 to 1.0 mW/cm2 inside it; the rectenna field above the rectenna has up to 23 mW/cm2. The report states that no quantitative risk assessment for SPS workers had been done or was then possible. Occupational exposure would need adequate protective clothing, shielding and dosimeters, none of which were then available, and possibly design changes. For space workers and personnel above the rectenna it might be necessary to shut off or defocus the beam if other protection proved insufficient. Understanding of long-term effects must improve substantially before a reliable occupational safety threshold can be set.
Evidence behind this: T3, a published congressional assessment; it permits "OTA states Y". Figure 40 and Table 41 are credited to the DOE environmental assessment of August 1980.
Scope and limits
In the printed table the "above rectenna" row is ruled off below the ecosystems block, so which group it belongs to is not clear on the page; the draft places it under ecosystems. The 2.2 W/cm2 for space workers is stated without a derivation, a location on the antenna or an exposure time. By unit conversion (our arithmetic) it equals 22 kW/m2, the transmit-array peak in CLM-0204, but the report does not link the two. No row carries an exposure time.
What it assumes
The 1978 reference system (2.45 GHz, 23 mW/cm2 peak). The report says the solid-state option's densities are lower with distance and does not treat it.
Where it comes from
PDF p.213 / printed 211, Table 41, "Characterization of Exposure to Reference System Microwaves": public outside buffer zone "Between 10-4 mW/cm2 and 0.1 mw/cm2"; airplane "Less than 23 mW/cm2 (shielding)"; terrestrial workers "Up to 23 mW/cm2 (may be higher if reflections occur)"; space workers, transmitting antenna "Up to 2.2 W/cm2"; ecosystems under rectenna "Less than 0.1 mW/cm2" outside buffer and "Between 0.1 mW/cm2 and 1.0 mW/cm2" inside buffer; "Rectenna field: above rectenna" "Up to 23 mW/cm2". Figure 40: 0.1 mW/cm2 "at rectenna site exclusion boundary". PDF p.212 / printed 210: "No quantitative risk assessment for SPS workers has been performed or is currently possible"; "adequate protective clothing and shielding, dosimeters (all of which are not presently available)"; "it might be necessary to shut off or defocus the microwave beam if other protective measures prove insufficient"; long-term understanding must "improve substantially ... before a reliable occupational safety threshold can be determined".
Basis: mW/cm2 and W/cm2 by exposed group
Related records
- Answers question
- QST-001 not published in this release
Cite this
energyaperture.com/c/clm-1286
CLM-1286, Energy Aperture, as of 1981-08.
Connected records
Other published records linked to this one. A list, not a judgement.
- Also from SRC-601
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