Value chain · CLM-0862
In plain terms
Switching a power satellite to the higher of the two candidate frequencies makes the beam five and a half times more intense on the ground, not less - but only if the antenna can keep its beam actively focused on the receiver.
The claim as recorded
For a solar power satellite holding transmit aperture, radiated power and orbit constant, moving the downlink from 2.45 GHz to 5.8 GHz multiplies the peak ground power density by exactly the frequency ratio squared, 5.60433. For the 1978 reference geometry - 1 km circular aperture, 10 dB Gaussian taper, 6.72 GW, 35,800 km - the peak rises from 248.2 W/m2 to 1391.0 W/m2. This factor is available ONLY to a genuinely focused (retrodirective) array. A collimated flat-phase array of the same size achieves 5.53985, forfeiting 1.15 per cent, and the forfeit GROWS with both frequency and aperture, because it is set by how far inside the Fraunhofer distance the link sits.
Evidence behind this: T0-calculation: the stated VALUE comes from arithmetic performed here and independently reproduced by PyPO 1.2.1 (SRC-358, an artefact source). CALC-038 supplied as required.
Scope and limits
Peak on-axis ground power density ONLY. Says nothing about total delivered power, beam collection efficiency, rectenna sizing or cost, all of which move differently with frequency. The 1.15 per cent collimated forfeit is specific to this aperture and range; it is NOT a general constant and grows with both frequency and aperture.
What it assumes
That the array is retrodirective, hence focused. Established from the register rather than assumed: register/claims.md line 2629 records that every reviewed design uses a retrodirective array, including SRC-085 (1978), SRC-107 (1981), SRC-100 (2007) and CASSIOPeiA. So the focused case is the SPS case.
Where it comes from
This is the project's own working, shown in full:
Computed here and independently reproduced by PyPO 1.2.1, CPU double precision. Focused: 248.204 and 1391.017 W/m2, ratio 5.60433; PyPO 248.20 and 1391.017, ratio 5.60433153 against the exact 5.6043315285 - nine significant figures, grid-independent from 200x128 to 1600x512. Collimated: 247.582 and 1371.564, ratio 5.53985; PyPO 247.5812 and 1371.56, ratio 5.53985. The two implementations agree to six significant figures in every configuration once matched. The regime fact that makes this non-obvious: at 35,800 km the Fraunhofer distance is 16,345 km at 2.45 GHz but 38,693 km at 5.8 GHz, so R/Fraunhofer is 2.190 and 0.925 - the 5.8 GHz link is INSIDE its own Fraunhofer distance. Residual quadratic phase 0.179 rad against 0.424 rad, so the defocus penalty is frequency-dependent and f^2 cannot hold for a flat-phase array. PyPO power conservation 99.904 per cent of 6.72 GW inside 100 km.
Basis: W/m2 (ground peak power density); dimensionless (intensity ratio)
Related records
- Answers question
- QST-001 not published in this release
- Supersedes
- **Three earlier values reported by this pass for the same quantity all superseded.** em-simulation-soa.md section 3.7 gave 1 276.6 W/m2 (unfocused branch AND slant range both wrong); section 9.4 gave 1 293.5 W/m2 (focused branch still slant range); this record gives 1 391.0 W/m2 (focused sub-satellite altitude PyPO-confirmed).
Cite this
energyaperture.com/c/clm-0862
CLM-0862, Energy Aperture, as of 2026-09-05.
Connected records
Other published records linked to this one. A list, not a judgement.