Value chain · CLM-1121
In plain terms
Half a kilogram per square metre for the working blanket, about half of it the silicon itself; per kilowatt delivered on the ground the 1977 satellite came to six or seven kilograms, and the blanket alone to about two.
The claim as recorded
Boeing's 1977 silicon blanket weighs 488.7 g/m2 with 2-mil covers and 550.8 with 3-mil: fused silica covers 107.96 (161.94), 4-mil silicon cells 231.61, copper interconnects 22.71, Kapton film 32.46, adhesives 16.00 and 14.22, a theoretical 424.96 (478.94) plus "TOLERANCES & INSTALLATION (15%)"; the GaAs blanket with 0.4-mil cells on 0.5-mil titanium weighs 345.9 g/m2 (theoretical 300.77 plus 45.13), gallium 7.4 per cent of it; 3-mil covers were used for unannealed cases and 2-mil for annealed. By arithmetic on the report's stated figures, which print no kg/kW, the 2-mil silicon blanket is 1.84 kg per kW of blanket output at the start of life (488.7 g/m2 over 264.9 W/m2 at CR 2) and 3.13 kg/kW after 30 years (over 156.1 W/m2); the whole reference satellite is 6.5 kg per kW of ground output at beginning of life (64,883 t for 10 GW) and 7.2 kg/kW as an annealed CR 1 satellite holding 10 GW for 30 years (71,728 t).
Evidence behind this: T3-contractor mass buildup by layer with the density, thickness and area factor of each, and a stated 15 per cent allowance.
Scope and limits
THE kg/kW FIGURES ARE THIS RECORD'S ARITHMETIC ON STATED INPUTS: THE REPORT PRINTS NO kg/kW FOR THE ARRAY OR SATELLITE ("kg/kW" occurs once in 349 pages, for a Brayton turbocompressor). Blanket only, no reflectors or structure, in the blanket figures; the satellite figures are Part I sizings at 10 GW with CR 2 or CR 1 as stated. The GaAs estimated weight's last digit is uncertain on the scan; the arithmetic gives 345.9.
What it assumes
Outputs per m2 of blanket from Tables 3.2-3 and 3.2-5; satellite masses exclude the 50 per cent growth allowance and the 10 GW is at the two rectennas' busbars; the density figures in g/m2 per mil as printed.
Where it comes from
PDF 190 / printed 185, Table 3.2-12 read at a zoom-5 crop, silicon: rows (columns S.G., g/m2/mil, mils, area factor, g/m2, as the crop prints them): "COVERS - FUSED SILICA" 2.20, 55.88, 2.00/3.00, 0.966, 107.96/161.94; "CELLS - SILICON" 2.36, 59.94, 4.00, 0.966, 231.61; "INTERCONNECTS - COPPER" 8.94, 227.08, 0.50, 0.200, 22.71; "SUPPORTING FILM - KAPTON" 1.42, 36.07, 1.00, 0.900, 32.46; "ADHESIVE, CELLS TO FILM" 1.40, 35.56, 0.50, 0.900, 16.00; "ADHESIVE, KAPTON TO KAPTON" 1.40, 35.56, 0.50, 0.800, 14.22; "THEORETICAL WEIGHT" 424.96/478.94; "TOLERANCES & INSTALLATION (15%)" 63.74/71.86; "ESTIMATED ACTUAL WEIGHT" 488.7/550.8; "(% SILICON WEIGHT)" 47%/42%; GaAs: "CELLS - GaAs" 5.32, 135.13, 0.40, 0.966, 52.21; "SUBSTRATES - TITANIUM" 4.50, 114.30, 0.50, 0.966, 55.21; theoretical 300.77, "TOLERANCES & INSTALLATION (15%)" 45.13, "ESTIMATED ACTUAL WEIGHT" printed 345.9 or 346.9 on the scan, "(% GALLIUM WEIGHT)" (7.4%). PDF 187 / printed 182, normalised: "15% factor applied" to both silicon and GaAs; the 75 um for nonannealed and 50 um for annealed arrays sentence as a render reading; "reduced from our previous baseline primarily by a reduction in tolerances on the silicon cells themselves" (render reading). Recomputed: every line is density x thickness x area factor (55.88 x 2 x 0.966 = 107.96; 59.94 x 4 x 0.966 = 231.61; 227.08 x 0.5 x 0.2 = 22.71; 36.07 x 0.9 = 32.46; 35.56 x 0.5 x 0.9 = 16.00; 35.56 x 0.5 x 0.8 = 14.22); 107.96 + 231.61 + 22.71 + 32.46 + 16.00 + 14.22 = 424.96; x 1.15 = 488.70; 231.61 / 488.7 = 47.4 per cent; 300.77 x 1.15 = 345.89; 0.4887 kg/m2 / 0.2649 kW/m2 = 1.845 kg/kW; 0.4887 / 0.1561 = 3.13; 64,883 t / 10^7 kW = 6.49 kg/kW; 71,728 / 10^7 = 7.17.
Basis: g/m2 of blanket by layer; kg/kW derived from stated blanket mass and stated output; kg/kW of satellite from stated mass and 10 GW
Related records
- Answers question
- QST-018 not published in this release
Cite this
energyaperture.com/c/clm-1121
CLM-1121, Energy Aperture, as of 1977-07.
Connected records
Other published records linked to this one. A list, not a judgement.
- Also from SRC-475
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