Value chain · CLM-0020
In plain terms
The original 1978 design set the beam at 230 watts per square metre in the middle of the receiving site, about one twenty-third of that at its edge, and about one two-hundred-and-thirtieth of that at a fenced boundary further out.
The claim as recorded
The 1978 NASA and DOE SPS Reference System specifies the full ground power density profile as 23 mW/cm2 at rectenna centre, 1 mW/cm2 at rectenna edge, 0.1 mW/cm2 at the rectenna site exclusion boundary, and 0.08 mW/cm2 at the first sidelobe about 9 km from centre, at 2.45 GHz, with a rectenna 13 km north-south by 10 km east-west at 35 degrees latitude.
Scope and limits
Read directly from both primary documents, now held in the archive. The documents give the ground power density against radius only as log-log plots, not as a table or an equation, so no intermediate radius value can be quoted. Frame settled 2026-09-19: the 23 mW/cm2 and the 1 mW/cm2 edge are beam-normal figures, incident on panels tilted to face the satellite; the horizontal ground-plane peak at the reference site is 17.4 to 17.7 mW/cm2; the 13 x 10 km ellipse is the 10 km beam-normal circle over cos z (CLM-1092).
What it assumes
No assumptions are recorded against this claim.
Where it comes from
p40 verbatim: "CENTER OF RECTENNA ... 23 mW/cm2 ... EDGE OF RECTENNA ... 1 mW/cm2 ... FIRST SIDE LOBE LEVEL ... .08 mW/cm2 (APPROXIMATELY 9 Km FROM CENTER OF RECTENNA)". SRC-086 p8 verbatim: "center of rectenna, 23 mW/cm2 - edge of rectenna, 1 mW/cm2 - rectenna site exclusion boundary, 0.1 mW/cm2 - first sidelobe level (approximately 9 km from center of rectenna), 0.08 mW/cm2". Dimensions from SRC-086 Figure 1-1 verbatim: "10 km EAST-WEST 13 km NORTH-SOUTH AT 35 LAT". Conversions, factor 10: 23 mW/cm2 = 230 W/m2; 1 mW/cm2 = 10 W/m2; 0.1 mW/cm2 = 1 W/m2; 0.08 mW/cm2 = 0.8 W/m2.
Related records
- Answers question
- QST-001 not published in this release
- Supersedes
- CLM-0011 not published in this release
Cite this
energyaperture.com/c/clm-0020
CLM-0020, Energy Aperture, as of 1978.
Connected records
Other published records linked to this one. A list, not a judgement.
- Also from SRC-085
- CLM-0013The paper that modern UK studies rely on for the beam figure calls anything below 1 kilowatt per square metre safe, with 230 watts per...CLM-0023In the 1978 reference design, two limits set the size of the transmitter and the receiving site: how much heat the transmitter can shed...CLM-0039The 1978 report set the figure to protect radio and navigation systems from a disturbed ionosphere, called the number theoretical and...CLM-0045The apparent conflict between 12 and 23 was not an error. The underlying study gave a range, and the figure adopted sits near the top of it.CLM-0101The 1978 contract required the researchers to report fixes if ionospheric disturbance pushed the pilot-beam phase error past 2 to 3...CLM-0137In four major space solar power studies from 1978 to 2007, none put a number on how much of the beam's energy would be lost if the beam...CLM-0138The original 1978 government design for beaming power down from space adds up all the expected energy losses to get 63% overall efficiency...CLM-0182When two different research teams assessed the exact same 1978 space solar power design, the older accounting method (which spreads...More on the source page.
- Also from SRC-086
- CLM-0024The American standard of the day allowed 100 watts per square metre averaged over six minutes. The US had no separate limit for the public...CLM-0036The 1980 American assessment said people living or working near the receiving site, outside its exclusion boundary, would generally be...CLM-0153A 1980 US government environmental assessment argues, without a formal calculation or test, that an aeroplane's metal body would shield...CLM-1005The 1980 assessment explains where the 10 milliwatt limit came from: a heating threshold of 100 divided by a safety factor of ten. It also...CLM-1006In 1980, by the US assessment's figures, the Soviet limit for the general public was two thousand times lower than the American 10...CLM-1007The 1980 assessment worked out that a full American deployment would raise the microwave background everywhere in the country to about...CLM-1008The 1980 documents give the beam's strength at the satellite, on failure, and above and below the receiving panels. The summary and the...CLM-1009The 1980 programme tested bees because of pollination. Early results showed no effect at the beam's strength, and one preliminary report...More on the source page.