Value chain · CLM-0974
In plain terms
The 1978 reference design shows every loss between sunlight and the power grid as a chain of numbered boxes, and the boxes multiply out exactly: about 7 per cent of the sunlight hitting the satellite reaches the grid. A rival 1980 design from Rockwell does the same sum and lands within about one per cent of its own published answer.
The claim as recorded
The 1978 DOE/NASA reference system sizes its solar array by an explicit end-to-end efficiency chain from 70.81 GW (silicon) or 71.77 GW (GaAlAs) of intercepted sunlight to 9.08 GW at the array and 5 GW at the utility busbar, an overall efficiency of 7.06 and 6.97 per cent. The chain reproduces at every stated box and implies a solar constant of 1353 W/m2 over a 52.34 km2 silicon blanket or a 53.04 km2 GaAlAs reflector area. Rockwell's 1980 GaAs sizing reproduces to 1.2 per cent at 352.6 W/m2 and 27 million m2 for 9.52 GW.
Evidence behind this: T3-government-report and T3-programme-review, two independent 1978-1980 sizings, both reproduced.
Scope and limits
THE REFERENCE CHAIN'S 30-YEAR DEGRADATION FACTORS ASSUME ANNEALING. Rockwell's temperature coefficient is in percentage points per degree, established by reproduction rather than stated: read as relative it overshoots the published 352.6 W/m2 by 9.6 per cent. Both sizings, the 1978 reference and Rockwell's 1980 design, use cells of 17.3 to 20 per cent.
What it assumes
SRC-085's solar constant is inferred from 70.81 GW over 52.34 km2, not read.
Where it comes from
This is the project's own working, shown in full:
Figure 5 from the render: solar 71.77 GW (Ga) and 70.81 GW (Si); summer solstice 0.9675; seasonal 0.91; reflector reflectivity equivalent 0.915; cell efficiency at AM0 28 C 0.20 (Ga) and 0.173 (Si); cell temperature degradation 0.908 at 125 C and 0.954 at 36 C; array design 0.901 and 0.951; ultraviolet and radiation 0.96 and 0.9273; 9.08 GW at the array for both; then 0.9368, 0.9995, 0.963, 0.85, 0.9653, 0.98, 0.89, 0.88, 0.97 to the 5 GW busbar; "OVERALL EFFICIENCY = 6.97% Ga, 7.06% Si". p.23: 52.34 km2 Si blanket, 26.52 km2 GaAlAs blanket, 53.04 km2 reflector. SRC-449 p.268: 1311.5 W/m2, 1.83, 20 per cent at AM0 28 C, 113 C, "0.0282%/C", a 4 per cent non-annealable loss (factor 0.96), 0.968, 0.89, 0.997, "352.6 W/m2", 9.52 GW; the area renders "2t'il06 m2" in the text layer and 9.52e9 / 352.6 = 27.0e6 m2 confirms it. Arithmetic in CALC-114 sections 1 and 2.
Basis: GW through an efficiency chain; W/m2 of blanket; km2 of blanket
Related records
- Answers question
- QST-018 not published in this release
Cite this
energyaperture.com/c/clm-0974
CLM-0974, Energy Aperture, as of 1980.
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-0020The 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...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...More on the source page.
- Also from SRC-449
- CLM-0964To build two of these satellites a year, about 300 tonnes of material had to arrive at the orbital construction site every day. Getting it...CLM-0975Depending on which published assumptions you take, a satellite needs between about 2 and 6 square kilometres of solar blanket for every...CLM-1058The often-repeated claim that the magnetron is 188 decibels quieter than its carrier traces to a conference abstract in which the tube...CLM-1059By spring 1980 the engineers, the reviewing panel and the ionosphere experimenters were all saying the beam-intensity ceiling the whole...CLM-1060The 1980 review did not agree with itself on how much of a satellite's cost was rockets: one paper said over a third, the programme's own...CLM-1061In one 1980 volume the satellite cost anywhere from about 2,300 to 3,800 dollars a kilowatt depending on who added what - and the programme...CLM-1062In 1980 the launch vehicle that everything was costed on was said by its own designers to be arbitrarily big, and they proposed a rocket a...CLM-1063In 1980 the magnetron satellite was the lightest per kilowatt on paper and the most efficient tube on the bench, the klystron was the...More on the source page.