Value chain · CLM-0539
In plain terms
A UK consultancy, working for the European Space Agency and using the same design as its reference point, actually published a full weight breakdown -- something the original 2019 paper never did. It comes out lower than the headline claim, at about 0.70 kilowatts per kilogram rather than 1, even though it leaves out several categories of weight altogether. It also rates one of the satellite's power-conversion stages as barely more than an idea on paper, and its input notes say the lightest case for the radio equipment is an expert's judgement, not something anyone has measured or built.
The claim as recorded
Frazer-Nash's 2022 ESA-commissioned cost-benefit study, using CASSIOPeiA as its reference architecture, publishes a subsystem mass breakdown (Table 3-1) for a de-risked 1.44 GW-to-grid variant reaching approximately 0.70 kW/kg overall (PV 65.4% of mass, WPT 17.4%, structure 9.0%, reflector 7.7%), while omitting thermal management, power management and distribution, harness and margin entirely; the same report's Table 3-2 rates "Satellite convert" at TRL 2 and rates satellite structure, satellite transmit and in-orbit assembly each "Very High" development difficulty; the underlying Annex B text says that "SME judgement" sets the lower bound of the WPT mass per unit area "a factor of 10 smaller than the maximum likelihood value" taken from its 2000 MW reference estimate, a judgement rather than a measurement or a citation to built hardware; Annex B's input table prints that parameter as uniform 0.12 to 0.15 kg/m^2, a range that contains a tenth of the text's maximum-likelihood value (0.145 by this record's arithmetic) and none of the 1.45 to 2.78 kg/m^2 that the text's own division gives (see limits).
Scope and limits
This is a de-risked, "slightly simpler" variant of CASSIOPeiA by the report's own description, not the most aggressive 1 kW/kg variant Cash's own paper describes; the report was commissioned using International Electric Company's own design input, so it is independent of Cash personally but not fully independent of the company's own design assumptions. ON-027, recorded 2026-09-24 (VER-1452): SRC-019's Table B2 (PDF 4 render, printed Page 4 of 16) prints WPT Mass per Unit Area (kg/m^2) as Uniform, lower bound 0.12, upper bound 0.15, with no maximum-likelihood value, while its PDF 9 text puts the lower bound a factor of 10 below the maximum-likelihood value. The text's own arithmetic, 12,125,000 kg over 8,370,000 and 4,360,000 m2, gives 1.45 and 2.78 kg/m^2, and a tenth of 1.45 is 0.145, so the table's 0.12 to 0.15 matches the reduced case rather than the text's range. This is recorded as a suspected transcription or editing difference inside SRC-019, not as a disagreement, until the model files or the authors settle it; this record does not say which value the model ran. Table 3-2's "Satellite convert" is not defined in the held text; the report's energy chain (section 3.2.2.4) runs "through high-concentration photo voltaic (HCPV) conversion efficiency, to transmission (DC to RF efficiency)", so DC-to-RF is not read into the convert row here. Annex B ties the 2000 MW estimate to reference [19], but its reference list (PDF 13) prints [19] as an NREL cell-efficiency chart; that reference is not relied on.
What it assumes
The external research's own arithmetic converting mass-share percentages to implied specific power per subsystem, cross-checked against the report's own stated 2,064,200 kg total mass for 1.44 GW to grid (giving 698 W/kg overall, consistent with this document's own figure).
Where it comes from
External research summary, 2026-09-03, quoting SRC-078 Table 3-1 mass figures verbatim and Table 3-2 TRL ratings, and SRC-019 Annex B: "SME judgement is that the mass per unit area of alternative designs could be a factor of 10 smaller than the maximum likelihood value, which forms the lower bound." (SRC-019 PDF 9, printed Page 9 of 16). Re-read 2026-09-24 (VER-1452): SRC-078 Table 3-1 at text pages 20 to 21 and Table 3-2 at text page 23 of the held text file; SRC-019 Table B2 at the PDF 4 render.
Basis: subsystem mass share (%) and specific power (W/kg), 1.44 GW-to-grid CASSIOPeiA-derived design
Related records
- Answers question
- QST-002 not published in this release
Cite this
energyaperture.com/c/clm-0539
CLM-0539, Energy Aperture, as of 2022; 2021.
Connected records
Other published records linked to this one. A list, not a judgement.
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