XC03 Environment and lifecycle impact
Depth of coverage
One level below its target of L3. What the depth levels mean.
What this layer covers
Lifecycle greenhouse gas, launch emissions, land and ecological effects, atmospheric effects, the shared debris environment
Where it ends
Cross-cutting
Deep area
This layer is studied in more depth than most. It belongs to the deep area Ionospheric interaction.
Environment and lifecycle impact
Headline carbon figures for recent designs are low but incomplete. NASA's 2024 study gives 26 and 40 grams of CO2-equivalent per kilowatt-hour (gCO2e/kWh) for its two designs. NASA says these may be similar to terrestrial renewables, at 13 to 43, pending further studies. It attributes 64 to 72% of its totals to launch, though two other assessments of an older design put launch far lower (CLM-0125). A UK roadmap study models 23.6 gCO2e/kWh, averaged over 2022 to 2080 (CLM-0832). NASA leaves out the upper-atmosphere effects of launch emissions (CLM-0125). The UK study leaves out black carbon and aluminium oxide from rocket exhaust (CLM-0834). It finds ozone depletion at 32% of a planetary-boundary reference value set by the European Commission, almost all from launch. Comparing against that value is the authors' choice, and it is not a legal limit (CLM-0837). For the 1978 US reference design, the choice of carbon-accounting method changed the result about five to six times (CLM-0182). One survey found no experiment that has measured self-focusing heating of the ionosphere, the electrically charged upper atmosphere, at 2.45 GHz (CLM-0030).
Carbon estimates for recent designs are low, but each leaves out some effects of launch on the upper atmosphere, and two accounting methods disagree by up to six times on one older design. Most evidence on the beam's effects on the ionosphere and on animals dates from 1979 and 1980, and the sources call much of it preliminary.
Scope. Greenhouse gas emissions over a system's life, what launches release into the upper air, effects of the beam on the ionosphere, land use, and effects on animals.
Carbon over a system's life. Lifecycle emissions are given in grams of CO2-equivalent per kilowatt-hour (gCO2e/kWh): all greenhouse gases released in building, launching, running and disposing of a plant, converted to the warming effect of CO2 and divided by the electricity it delivers. NASA's 2024 study gives 26 and 40 gCO2e/kWh for two 2 GW design concepts that it assumes enter service in 2050 (CLM-0125, CLM-0826). NASA says these may be similar to terrestrial renewables, at 13 to 43 gCO2e/kWh, pending further studies (CLM-0125). The 13 to 43 range comes from one US laboratory dataset, as medians for five mature renewable technologies (CLM-0849). For comparison, the 2014 medians of the IPCC, the UN's climate science panel, are 820 gCO2e/kWh for coal and 490 for gas (CLM-0854). A 2022 UK roadmap study gives 23.6 gCO2e/kWh, averaged over a fleet built from 2022 to 2080. It is not the figure for one mature satellite (CLM-0832).
Two methods, two answers. An input-output study estimates emissions from spending across whole industry sectors. A process-based study adds up the materials and steps of the design itself. For the 1978 US reference design, an input-output study gave about 20 gCO2/kWh, and a process-based study gave 112 gCO2e/kWh for silicon cells and 123 for gallium arsenide cells (CLM-0182). The process study's authors give these as 5.62 and 6.13 times the older figure, though they state that figure once as CO2 and once as CO2e, which are different quantities (CLM-0813). For NASA's two 2024 designs, the same authors' process model gave 21.89 and 35.74 gCO2e/kWh, against NASA's unrounded 26.58 and 40.38. They say this "suggests" NASA's figures are overstated by 21.40 and 12.97 per cent (CLM-0826). The two comparisons run in opposite directions, and the authors do not reconcile them (CLM-0826). The authors developed the process-based tool and recommend it (CLM-0825, CLM-0826).
A space solar advocacy non-profit funded the process-based study of the 1978 design, and two of its four authors are listed under the funder's affiliation. Its carbon result does not favour the funder (CLM-0817).
The share due to launch is also contested. NASA gives 64 to 72 per cent (CLM-0125). For the older 1978 design, one study puts launch and propellant at 17.4 per cent of emissions, and another puts the receiving antenna at about 66 per cent of the total warming effect. Both studied the older design, so they are a caution about NASA's figure, not a refutation (CLM-0125).
Launch emissions in the upper air. NASA's figures leave out the upper-atmosphere effects of launch emissions (CLM-0125). The UK study leaves out soot and aluminium oxide from rocket exhaust, which its authors say "could be potentially meaningful" (CLM-0184, CLM-0834). It puts ozone depletion at 32.16 per cent of a planetary-boundary reference value set by the European Commission, against 4.74 per cent for global warming, and 99.99 per cent of the ozone result comes from launch (CLM-0837). Comparing against that value is the authors' choice, and it carries no legal force (CLM-0837). A 1980 US assessment of 375 to 400 launches a year, by rockets burning methane and hydrogen, calculated ozone changes too small to detect, and said that with few exceptions its results should be regarded as tentative. Its models included no soot, alumina or chlorine, so its figures do not transfer to any 2020s launch vehicle (CLM-1014).
The beam and the ionosphere. The ionosphere is the electrically charged upper atmosphere. One survey found no experiment that has measured self-focusing or runaway heating of the ionosphere at 2.45 GHz, the usual beam frequency. The heating facilities that have measured related effects work at roughly 2 to 10 MHz (CLM-0030). The 1978 reference design said these effects may limit the beam centre to about 23 mW/cm2 (230 W/m2), and called that threshold a theoretical number not yet verified by experiment (CLM-0039). In tests at the Platteville heating facility, run from August to October 1979 (CLM-0163), heating equivalent to that beam raised electron temperature as theory predicted, but the data seemed to show that the predicted rise in electron density did not occur (CLM-1012). Navigation and broadcast signals showed no change attributable to the heating. That null result holds only at the beam's equivalent strength (CLM-1012). On one navigation path, a single solar flare in August 1979 shifted the signal more than five times as much as the largest change between heater on and heater off (CLM-0163). Two reports of ITU-R, the radio arm of the International Telecommunication Union, and a white paper of URSI, the international union of radio scientists, give no satellite-navigation error in metres for beam heating (CLM-0164).
Animals. In 1980 tests, bees exposed for 30 minutes at up to 50 mW/cm2 (500 W/m2) at 2.45 GHz returned to their hives at rates not significantly different from unexposed bees (CLM-1066). The assessments called these results initial and preliminary, and a null result on returning to the hive says nothing about colony survival (CLM-1009). Small birds exposed at 25 mW/cm2 (250 W/m2) for 20 or 200 minutes showed little beyond occasional gaping, holding the beak open, with reduced fluffing of feathers and a possible greater tendency to rest. The preliminary median lethal exposure, the level expected to kill half the animals, was about 150 mW/cm2 for resting birds in winter, from a handful of birds. No bird was exposed in flight (CLM-1066). The risk to flying birds from extra heat was a hypothesis in the source, with no data (CLM-1010).
A 1980 primate study reported infant deaths of 22, 17 and 56 per cent in three small exposed groups, against a colony first-year norm of 20 to 25 per cent. Only the highest-dose group was above that norm (CLM-1067). A larger rerun had not repeated the finding, but it was not complete in 1980 (CLM-1067). In 2007 a URSI working group proposed about 250 W/m2 at the beam centre, citing bird research. Its detection premise cites no source. Its heat-stress premise cites a 1980 volume whose one bird paper reports gaping after 30 seconds, and no 30-minute heat-stress result (CLM-0460).
Land. The 1980 reference site for one 5 GW satellite would take about 200 square kilometres, including a 2 km buffer, in a preliminary comparison (CLM-1052). By this site's own arithmetic, the 29 W/m2 in a UK report is the electricity delivered per square metre of land, not the strength of the beam (CLM-0005).
What is missing. The UK study's comparisons with terrestrial energy had not had, as of 2022, the third-party critical review set out in ISO 14040/14044; its authors stated then that this was still unfulfilled (CLM-0832). No uncertainty values were calculated for the re-run of NASA's figures, and both re-runs come from the tool's developers (CLM-0825, CLM-0826). The 1980 records include no in-flight bird exposures, and the bee longevity study was incomplete (CLM-1066, CLM-1009).
Read next. QST-008 (lifecycle carbon), QST-004 (carbon against other sources), QST-009 (ionosphere), QST-001 (Beam intensity at the rectenna), QST-007 (land). Layers XC02, VC06, VC07 and XC04.
Records
157 of the 173 records tagged to this layer are published. The rest are not yet published. A record is published only after a second reader has checked it and it has passed every publication check. What the gate checks.
| Record | In plain language | Tier | Confidence |
|---|---|---|---|
| CLM-0005 | A second figure of 29 watts per square metre appears in the same report, but it measures electricity produced per unit of land, not beam strength. The two are different things and must not be compared. | T0 | HIGH |
| CLM-0030 | A 2026 search found no test of the effect at the frequency space solar power would use. The facilities that can heat the ionosphere work at radio frequencies a thousand times lower. | T2 | MED |
| CLM-0039 | The 1978 report set the figure to protect radio and navigation systems from a disturbed ionosphere, called the number theoretical and untested, and said experiments were underway. | T3 | HIGH |
| CLM-0125 | On carbon, NASA found space solar power within the range of five renewable ways of making power on the ground (wind, solar, solar thermal, hydro and geothermal), and far better than coal or gas. NASA also counted nuclear power in that group, though nuclear is not renewable; it sits at the low end, level with wind. | T3 | HIGH |
| CLM-0163 | On the exact same navigation-radio circuits used to test simulated space-solar-power heating of the upper atmosphere, a single ordinary solar flare produced a signal disturbance several times larger than anything the simulated heating produced. | T3 | MED |
| CLM-0164 | Two international radio-regulation reports and a radio-science white paper on beaming power from space never mention GPS-type satellite navigation in connection with heating the upper atmosphere, and none of them gives a figure in metres for how far off such navigation could be thrown. | T2 | MED |
| CLM-0182 | When two different research teams assessed the exact same 1978 space solar power design, the older accounting method (which spreads emissions across whole economic sectors) found about 20 grams of CO2 per kWh, while a newer, more detailed method that traces actual physical processes found 5 to 6 times more - showing that the choice of carbon-accounting method and what it covers can swing a headline SBSP carbon number by a factor of five or six. | T5 | MED |
| CLM-0184 | This study's headline carbon-per-kWh figure for a UK space solar power programme leaves out the possible climate effect of soot and aluminium oxide particles released high in the atmosphere by rocket launches, because the science on that effect is still too uncertain to model - and the authors say this gap is normal for this type of study, not unique to theirs. | T2 | HIGH |
| CLM-0185 | In a 2022 life-cycle study commissioned by the UK Space Energy Initiative, the lightweight CASSIOPeiA design it used as an example for the initiative's planned programme was estimated to be far cleaner per kWh than the old, heavy NASA/DOE design, and in the same broad range as wind and solar on this measure, though above nuclear's 5.1-6.4 range - but the same study found that almost all of a completely different, non-carbon environmental impact (ozone depletion) came from rocket exhaust during launch. | T2 | MED |
| CLM-0192 | The full list of assumptions behind the headline result of NASA's 2024 study, that space solar power would cost far more than ground alternatives, includes a launch cost of $850-1,000 per kilogram, only a 10-year satellite lifetime, and a solar cell efficiency of 35% - each of these, not just launch cost, is doing some of the work in producing the high headline cost figure. | T3 | HIGH |
| CLM-0193 | To get to a competitive cost, NASA's own 2024 analysis needs launch costs to halve, solar cells to get much more efficient, satellites to last half as long again, and manufacturing to get cheaper faster, all at the same time, not just one improvement on its own; and there is a small but real inconsistency inside the NASA report itself about exactly how low the resulting cost estimate for the smaller design (RD1) is - Table 3 says 4 cents per kWh, the summary text says 3 cents. | T3 | HIGH |
| CLM-0315 | Even though NASA's own figures say space solar power's carbon footprint is about as good as five renewable sources of power on the ground (NASA also counts nuclear with them, though nuclear is not renewable), that similarity means paying extra for space solar power buys almost no additional carbon saving compared with those low-carbon sources - and even compared with gas, the implied price per tonne of carbon saved is extremely high, about 1,250 to 1,400 dollars. | T0 | MED |
| CLM-0317 | Two studies of how much land US ground-mounted solar farms need, the second drawing most of its measurements from the first, indicate once converted to the same units that the receiving antenna of a space solar power design already in the register would need roughly a quarter to a fifth as much ground per unit of electricity delivered. | T0 | HIGH |
| CLM-0460 | The URSI working group's report proposes about 250 watts per square metre on bird-welfare grounds, and says the figure does not change with frequency. | T2 | HIGH |
| CLM-0754 | ESA's 2026 report projects that collisions between existing pieces of debris will keep making more debris in low Earth orbit even if nothing else is ever launched, and it makes no such projection for geostationary orbit at all; nothing in the register says whether the same runaway effect would happen up there or not. | T3 | HIGH |
| CLM-0810 | A 2020 modelling study estimated that, across its whole operating life from 2040 to 2100, the 1978 NASA/DOE space solar power design would produce about 112 grams of CO2-equivalent per kilowatt-hour for the silicon version and about 123 grams for the gallium-arsenide version, counting emissions from the rocket launches. | T5 | HIGH |
| CLM-0811 | In a 2020 modelling study of the 1978 NASA/DOE space solar power design, the carbon per kilowatt-hour fell the longer the satellites were assumed to keep running, because the fixed launch and manufacturing emissions spread over more electricity; but the paper says it would take 67 to 77 extra years beyond the 30-year base case before that design matched ground solar panels, which it calls hard to envision. | T5 | HIGH |
| CLM-0812 | A 2020 modelling study of the 1978 NASA/DOE design estimated that its ozone-depleting emissions, almost all from burning rocket fuel at launch and averaged per year over the 60-satellite programme, would be several times the yearly ozone-depleting impact of all human activity in the reference figures it used, and would exceed the planetary safe limit for ozone for the silicon version and come close to it for the gallium-arsenide version. | T5 | HIGH |
| CLM-0813 | The paper's detailed component-by-component calculation gives a carbon figure five to six times higher than an older top-down calculation of the same 1978 design, and the paper is itself inconsistent about whether that older figure counted carbon dioxide only or all greenhouse gases. | T5 | HIGH |
| CLM-0814 | A 2020 conference paper's own cost model put the whole 60-satellite programme of the 1978 US reference design at about 3.86 trillion US dollars in present-value terms for either version, and the cost of launching each kilogram of hardware at about 407 dollars for the silicon version and 375 for the gallium-arsenide version. The paper never says which year's dollars these are, although it gives its cost per kilowatt-hour for the same system in 2015 dollars. | T5 | MED |
| CLM-0815 | The 2020 study of the 1978 NASA/DOE design did not count any warming from the microwave beams themselves, saying that is too hard to express as a CO2 figure and, on an outside estimate it quotes, would warm the planet by only about six thousandths of a degree even with thousands of satellites; it also assumed that at end of life the ground receivers are dismantled and the satellites recycled in orbit, an assumption the authors added because the original 1978 design never specified one. | T5 | HIGH |
| CLM-0816 | In their 2020 study of the 1978 NASA/DOE design, the authors list their own weak points: only whole-system detail rather than part-by-part, a background database built mainly on European data and patched with substitutes, social impacts assessed only for supply-chain actors and workers because organisations would not share data, and seven impact categories that lacked weighting factors and could not be checked against any global or planetary-limit yardstick because none had then been defined for them. | T5 | HIGH |
| CLM-0817 | The authors state openly that a space-solar-power advocacy non-profit paid for this study, that part of the reason was to test or support the environmental marketing claims made for the technology and potentially justify funding future missions, and that the lead researcher says the work was kept rigorous regardless; two of the four authors work for that funder. | T5 | HIGH |
| CLM-0818 | A 2002 Japanese input-output study estimates that building and launching a 1978-design fleet of 60 solar power satellites would release about 20 grams of carbon dioxide for every kilowatt-hour they generate over an assumed 30-year life, counting carbon dioxide only rather than all greenhouse gases, and counting only production and launch rather than operation. | T5 | HIGH |
| CLM-0819 | A 2002 Japanese input-output study estimates that if each new satellite were built with electricity from those already working, a fleet of 18 sized to Japan's 1995 electricity supply would come to about 11 grams of carbon dioxide per kilowatt-hour over an assumed 30-year life, roughly half the study's baseline, counting carbon dioxide only. | T5 | HIGH |
| CLM-0820 | For comparison in the same units, a 2002 Japanese study of space solar power reports about 22 grams of carbon dioxide per kilowatt-hour for nuclear, 631 for gas, 846 for oil and 1,225 for coal, which it bases on earlier work by a Keio University research group rather than deriving them in the paper. | T5 | HIGH |
| CLM-0821 | In a 2002 Japanese study of the 1978 US design, a table splits the estimated carbon dioxide from building and launching the system by part: solar cells are the biggest share at 57 per cent, the ground receiving antennas next at 25 per cent, propellant 11 per cent, the space transport vehicles 6 per cent (almost all of it the vehicle that moves cargo between orbits; the launch rockets themselves are under 1 per cent), and the satellite structure and the space bases under 1 per cent each. | T5 | HIGH |
| CLM-0822 | In a 2002 Japanese study of the 1978 US design, building the launch rockets and the vehicles that move cargo and crews between orbits accounted for only about 6 per cent of the estimated carbon dioxide from building and launching the system, and adding their propellant brings the combined share to about 17 per cent, a sum the study itself does not give. | T5 | HIGH |
| CLM-0823 | A 2002 Japanese study's carbon dioxide figures for space solar power come from Japan's 1990 economic input-output tables, with 405 industry sectors; they cover only building and launching the satellites, not running or maintaining them or delivering the power, and assume the satellites run for thirty years at full output around the clock. | T5 | HIGH |
| CLM-0824 | This is a 2002 discussion paper that says it summarises two 1998 discussion papers by an overlapping group of authors, does not point to any later peer-reviewed version of itself, and cites none of the later UK-led work, which it predates, that redid the analysis by a different method, counting other greenhouse gases as well as carbon dioxide, and got a much higher figure. | T5 | MED |
| CLM-0825 | The authors argue that the cost-based way of estimating carbon is too coarse for a custom-built industry like spacecraft, and they conclude that their own materials-and-process method should be preferred for space studies. | T5 | HIGH |
| CLM-0826 | When the authors redid NASA's own 2024 figures for two satellite designs using their materials-based method instead of NASA's cost-based one, the carbon per unit of electricity came out about 11 to 18 per cent lower, and they say this suggests NASA's published figures for these two designs are too high. | T5 | HIGH |
| CLM-0827 | The authors say NASA's 2024 carbon figures for two satellite designs came out of a model built on NASA's own cost estimates, and that NASA had not used this kind of model for a space solar power study in roughly twenty years, a period in which European researchers had developed methods NASA's assessment did not draw on. | T5 | HIGH |
| CLM-0828 | The authors say ESA's own space life-cycle guidance advises against the cost-based method because it tends to overstate environmental impact, and the authors then add that the same method's lower level of detail can also cause it to understate impact. | T5 | HIGH |
| CLM-0829 | The authors leave alumina, black carbon and water vapour from rocket exhaust out of their own carbon study because the atmospheric effects are too uncertain to quantify, even though in an earlier study of theirs almost all of the ozone damage came from exactly those launch emissions. | T5 | MED |
| CLM-0830 | The authors say an environmental claim about a space technology counts for nothing unless a proper standardised life-cycle study backs it, and that whoever makes the claim should be able to hand the evidence to anyone who asks without making it hard to get. | T5 | MED |
| CLM-0831 | This is a conference paper from October 2024 that does not claim to have been independently peer reviewed, states that it calculated no uncertainty figures, and argues it did not need the independent review that the life-cycle standards normally ask for because it says it is comparing methods rather than making an environmental claim. | T5 | MED |
| CLM-0832 | A UK-commissioned study modelled the whole planned 2022-2080 fleet of space solar power satellites and found that, spread across all the electricity it would ever deliver, each unit of power would carry about 23.6 grams of CO2, which the authors say is similar to other renewable energy technologies. | T2 | HIGH |
| CLM-0833 | This 2022 life-cycle study spells out exactly what it counted: the UK Space Energy Initiative's whole 2022-2080 roadmap, from early prototypes through to 25 full-size 2-gigawatt satellites, including their rockets, ground control and the receiving antennas on Earth, with each full-size satellite assumed to operate for about thirty years. | T2 | HIGH |
| CLM-0834 | The authors say their model does not count the soot and aluminium oxide that rockets release into the upper atmosphere, because the science on how much these matter at different altitudes is still too uncertain, and the results table duly shows exactly zero for that category everywhere despite the study listing a method for it. | T2 | HIGH |
| CLM-0835 | In a 2022 study, the research team compared its estimated carbon footprint per unit of electricity for a planned UK Space Energy Initiative programme, modelled on CASSIOPeiA satellites as an example design, with its own earlier assessment of the old NASA/DOE satellite design, made with the same calculation tool, which came out about five times higher, and said the newer design's much lower estimate was mainly because it needs far less steel, aluminium and concrete for its receiving antennas and can be built without astronauts. | T2 | MED |
| CLM-0836 | A 2022 life-cycle study set its estimate of 23.6 grams of carbon dioxide equivalent per kilowatt-hour for the UK Space Energy Initiative's planned programme against an average of 233 grams for the UK energy fuel mix in the government's 2020 figures, and quoted a 2021 United Nations commission report's global ranges for coal, gas, nuclear, hydro, solar and wind to show roughly where that programme would sit among them. | T3 | MED |
| CLM-0837 | Although the study's headline number is about carbon, its own results show ozone damage is the far bigger relative problem, at about 32 per cent of a safe planetary limit against under 5 per cent for carbon, and almost all of it comes from exhaust released during the rocket launches. | T2 | HIGH |
| CLM-0838 | The authors of a 2022 life-cycle study of the UK Space Energy Initiative's planned space solar power programme said that, if the whole programme's emissions were spread evenly across its 58-year life, the electricity generated would pay back that carbon debt in under six years against the average carbon intensity of the UK energy fuel mix in the government's 2020 figures, which they called a hypothesis in the body of the paper but stated as a result in its summary, and the paper gave no equivalent energy payback time. | T2 | MED |
| CLM-0839 | A 2022 European consultancy study for ESA calculated that launching one space solar power satellite of the SPS-Alpha type would release about 2.6 million tonnes of greenhouse gas, from roughly 760 Starship flights each responsible for about 3,400 tonnes. | T4 | MED |
| CLM-0840 | This 2022 ESA-commissioned study gave a total tonnage of greenhouse gas for launching a satellite but never converted it into emissions per unit of electricity, and apart from one sentence giving nitrogen oxides a carbon-dioxide-equivalent factor it did not assess the high-altitude effects of rocket exhaust. | T4 | HIGH |
| CLM-0841 | This 2022 study was written by two European firms under contract to the European Space Agency, and it cites none of the earlier life-cycle carbon studies of space solar power from Strathclyde or Japan, so on the evidence of its citations it is a separate line of work, not another voice from those research groups. | T4 | HIGH |
| CLM-0842 | Nobody has yet cited the paper arguing that published space-solar-power carbon figures were produced by the wrong method, on either of the two citation databases checked, more than a year after it appeared. | T5 | MED |
| CLM-0843 | Other research groups around the world are publishing on space solar power, but none of the works this search found takes a position on the argument about which carbon-accounting method is right, and this search found no new carbon-per-kilowatt-hour figure published since 2023. | T5 | MED |
| CLM-0845 | NASA states in its own report that its carbon figures come from a method that converts money spent, by industry sector, into emissions, combined with terms based on mass and area. | T3 | HIGH |
| CLM-0846 | NASA's report says its carbon figures leave out the effects of rocket exhaust released high in the atmosphere, and in several places says those effects are assumed to be worse than releasing the same emissions at ground level, but it never says how much worse. | T3 | HIGH |
| CLM-0849 | The range of 13 to 43 grams that NASA compares its satellites against comes from one US laboratory's dataset, and the two ends are the middle values for two different technologies, wind and solar, not the spread of possible values for either. | T5 | HIGH |
| CLM-0850 | NASA does test how its carbon figures move if assumptions change, and under its most favourable combination they fall by roughly 86 to 89 per cent, to around 4 grams per kilowatt-hour; but the report prints that best-case number differently in three places. | T3 | MED |
| CLM-0851 | NASA itself warns that its method assumes cost and emissions move together, which may not match what is actually measured, and that costs can fall without emissions falling; it describes the whole study as a first approximation and never states a carbon payback time. | T3 | HIGH |
| CLM-0852 | Checking the study's own sums, its headline carbon-per-kilowatt-hour figures are averages across all sixty satellites over the whole programme's life, not the figure for one satellite, and the numbers add up correctly. | T5 | HIGH |
| CLM-0853 | The wide range of published carbon figures for space solar power is not simply disagreement: most of it separates into two causes, which calculation method was used and which satellite design was assessed, and the method effect does not even point the same way in every case. The lowest published figure also counts carbon dioxide alone, while the others count all greenhouse gases, so part of the spread is a difference in what was counted. | T5 | MED |
| CLM-0854 | The IPCC's fifth assessment gives typical whole-life carbon figures per unit of electricity of about 820 grams for coal, 490 for gas, 12 for nuclear, 24 for hydro, 27 for concentrated solar, 41 to 48 for solar panels and 11 to 12 for wind. | T3 | HIGH |
| CLM-0855 | A 2024 peer-reviewed study says earlier life-cycle assessments of rockets may have understated their climate impact by a hundred to a thousand times, because they left out what exhaust and burning-up aluminium do high in the atmosphere; but it measures whole launch programmes rather than emissions per kilogram launched. | T2 | HIGH |
| CLM-0936 | The IAA's 2011 assessment says that enough solar power satellites to supply the whole world would warm the Earth by less than 0.006 degrees C. A footnote gives the full method, and redoing the sum with the source's own numbers gives 0.0062 degrees C, slightly more than the bound the sentence states. The same footnote's other figure, for a single satellite, does check out. So the method is sound and the word "less" is wrong: it should say about 0.006 degrees C. | T4 | HIGH |
| CLM-0937 | A 2024 law review article quotes a 2011 assessment's figure for how much solar power satellites would warm the Earth. The assessment said "less than 0.006 degrees C". The article says the systems "would likely cause a 0.006 degrees C rise". Dropping "less than" turns a ceiling into a prediction, and it is not flagged as a change. Everything else about the citation is correct, and by luck the changed version is nearer the true figure than the original was. | T4 | HIGH |
| CLM-0945 | The article asks whether the orbital slot a solar power satellite sits in counts as a "space resource" under the Outer Space Treaty. If it does, the Treaty's rule that nobody may appropriate outer space applies to it. The authors argue orbit is finite because it is getting crowded, and that one country or company taking the best slots could amount to the exclusive control the Treaty was meant to prevent. | T2 | HIGH |
| CLM-1005 | The 1980 assessment explains where the 10 milliwatt limit came from: a heating threshold of 100 divided by a safety factor of ten. It also records that the limit had no enforcement teeth, that a new limit based on absorbed power per kilogram was being discussed, and that there was still no public limit at all. | T3 | HIGH |
| CLM-1006 | In 1980, by the US assessment's figures, the Soviet limit for the general public was two thousand times lower than the American 10 milliwatt guideline. The 1978 American design's fence line was set at a level that would have been legal in Canada or the United States and twenty times over the Soviet public limit the assessment gave. | T3 | HIGH |
| CLM-1007 | The 1980 assessment worked out that a full American deployment would raise the microwave background everywhere in the country to about twenty times what people were then typically exposed to, though it said the two could not be compared directly because the frequencies differ. It said a risk assessment had to be done before building. No such assessment is held. | T3 | HIGH |
| CLM-1008 | The 1980 documents give the beam's strength at the satellite, on failure, and above and below the receiving panels. The summary and the detailed report disagree by about twenty times on how much reaches the ground under the panels, which is the number the conclusions about ground animals and plants rest on. | T3 | HIGH |
| CLM-1009 | The 1980 programme tested bees because of pollination. Early results showed no effect at the beam's strength, and one preliminary report found no effect on bees finding their way home at more than twice the beam's peak. None of this was finished or published at the time. | T3 | MED |
| CLM-1010 | In the US Department of Energy's 1980 assessments the only bird numbers were from quail eggs at a fifth of the beam's peak, which hatched normally with minor blood changes. The assessments described the programme's preliminary bird report as mainly about design and facility building. The idea that flying birds would overheat in the beam was stated as a worry, not a finding. | T3 | MED |
| CLM-1011 | In 1980 the programme used two different rules to translate its low-frequency experiments to the real beam, one for heating and one for the instability. It said the rules were believed sound, and in the same document that the instability rule had never been tested. | T3 | HIGH |
| CLM-1012 | In the DOE's 1980 summary the Platteville heating tests showed no effect on the navigation and broadcast radio it listed at the beam's equivalent strength (a separate 1980 report on the trials records cross-modulation on time-signal stations and one AM station), warmed the lower ionosphere by roughly the amount theory predicted, but did not produce the density change the same theory predicted. The programme concluded 23 was safe for these systems and said bigger facilities were needed to find the ceiling. | T3 | HIGH |
| CLM-1013 | By 1980 the programme had made the upper ionosphere ripple with a heater running at what it reckoned was four to twelve times the beam's strength, and seen satellite signals flicker as a result, while a radar looking for the same ripples saw nothing. Whether any of this applied to the real beam depended on a scaling rule nobody had tested. | T3 | MED |
| CLM-1014 | The 1980 programme did the sums on what four hundred heavy launches a year would do to the upper air: a lot more water high up, a big local rise in nitric oxide from re-entries, and an ozone change too small to measure either way. Its own two volumes disagree by five times on the ozone offset from re-entry, and the later one expected the sign to flip. | T3 | HIGH |
| CLM-1015 | The 1980 assessment expected each big orbit-transfer burn to punch a hole in the upper ionosphere the size of the continental United States, once or twice a month, with smaller daily holes from the launcher, and a permanent thinned ring around the launch latitude. It could not say what that would add up to. | T3 | MED |
| CLM-1016 | The 1980 programme expected heavy launches to change local weather in small ways, to produce a ground cloud like a dirty coal plant's for a short time, and to make thin high clouds, and it labelled nearly all of its own results tentative. | T3 | MED |
| CLM-1017 | By 1981 the programme itself said the ionospheric limit it had designed to was probably too cautious, and worked out what relaxing it to more than double would be worth: nearly twice the power from a slightly larger antenna, at a third of the cost penalty. | T3 | HIGH |
| CLM-1033 | At the higher of NASA's two peak figures, the launches would have needed about 6 per cent of US daily hydrogen output and 30 per cent of its oxygen, and making the hydrogen by splitting water would have consumed about half the output of one of the satellites being launched. NASA's own report gives two different figures for how much fuel that is. | T3 | MED |
| CLM-1037 | By the end of 1980 the programme office was saying in writing that its own design limit was too cautious, that fifty or sixty might be reasonable, and that the cost case depended on raising it. | T3 | HIGH |
| CLM-1038 | In 1980 the Department of Energy calculated that a silicon space solar satellite would take six years to pay back the energy that built it, four times longer than coal or nuclear, and that almost all of that was the energy cost of making the silicon cells; with gallium arsenide cells it was a little over a year. | T3 | HIGH |
| CLM-1051 | The DOE studies compared space solar against six power-station types picked by stated rules; ground-based solar cells were put in specifically to be the like-for-like comparison, and fusion because DOE was spending heavily on it, not because it would be ready. | T3 | HIGH |
| CLM-1052 | In 1980 the programme's own numbers had a receiving site of about 200 square kilometres per satellite once a safety margin was included, roughly the same land per unit of energy as ground solar of the day and far more than a coal or nuclear plant, but with no mines or waste sites behind it; and the authors said not to add the columns up. | T3 | HIGH |
| CLM-1053 | The programme's 1980 climate study counted only what the rockets and power plants emitted in use, found the launch carbon small next to coal, flagged rocket water vapour in the stratosphere as the open question, and said the science was not good enough to decide anything on. | T3 | HIGH |
| CLM-1054 | The programme reckoned a receiving site would give off about as much heat per square metre as a suburb, a tenth of what the sun puts into the ground, enough for a degree of local warming in still air; one of its two reports prints the figure a hundred times too small, and the climate report suspects that the structure's roughness and reflectivity matter more than the heat. | T3 | MED |
| CLM-1055 | The programme's 1980 look at nuisance and property effects gave space solar its worst marks on six counts, mostly because nobody knew enough about it, and said so. | T3 | HIGH |
| CLM-1056 | Measured in expected deaths per year for a big power station's worth of electricity, the programme found coal far the worst and everything else, including space solar, about equal within the error bars; space solar's risk sat in building it, not running it, and its open questions were long-term microwave exposure and a rocket coming down on a city. | T3 | HIGH |
| CLM-1059 | By spring 1980 the engineers, the reviewing panel and the ionosphere experimenters were all saying the beam-intensity ceiling the whole design hung on was too cautious; the table that priced relaxing it was published then, and reprinted unchanged in the 1981 summary. | T3 | HIGH |
| CLM-1066 | Bees exposed for half an hour at up to twice the beam's peak came home and hatched about as well as unexposed bees; small birds sat through the beam's peak intensity with little more than occasional open beaks, less fluffing of feathers and possibly more resting, and a preliminary estimate put the level that would kill half of resting birds in winter at about six times that intensity. | T3 | MED |
| CLM-1067 | The one primate experiment that looked alarming in 1980 - over half the infants dying in the highest-exposure group - did not repeat when rerun with more animals; the reviewer of the rodent work argued that a pregnant woman might absorb far less than the rats did, but that male fertility was the harder question. | T3 | MED |
| CLM-1068 | The 1979-80 heating experiments warmed the lower ionosphere's electrons by a factor of up to about two to two and a half. Theory predicted it would thin by up to half low down and thicken by up to a fifth higher up. The navigation and broadcast signals passing through showed nothing anyone could measure. | T3 | HIGH |
| CLM-1069 | Each launch would put about ten tonnes of nitrogen dioxide into a cloud over the pad, enough to breach a one-hour air standard on a bad day but not on its own, and make a shower of rain about as acid as ordinary polluted rain; the programme's own papers disagreed whether that happened 375 or 500 times a year. | T3 | MED |
| CLM-1070 | Nobody in 1980 agreed whether the ion engines' argon would be caught by the earth's magnetic field or escape: one group had most of it caught within twenty seconds, another had all but a few per cent escaping, and the third had a sixth raining back into the atmosphere. | T3 | MED |
| CLM-1074 | One set of 1980 papers said each satellite would look like Venus and sixty of them like a slim moon; the contractor who actually worked the geometry said ten times Venus, with the transmitter flashing as bright as a full moon for two minutes at the equinoxes unless the panels were tilted or roughened. | T3 | MED |
| CLM-1083 | Building and keeping sixty satellites was reckoned at fifty thousand working years in orbit, mostly at geosynchronous altitude where the radiation is worst; a preliminary estimate expected that a five-year career there might raise a worker's cancer risk by about an eighth, and nobody knew what heavy cosmic-ray ions would do to eyes. | T3 | MED |
| CLM-1102 | The receiving station the siting maps were drawn for is an oval twelve kilometres wide and, in the middle of the United States, sixteen long once its safety margin is added, about 150 square kilometres, with two and a half million panels on it; further north it gets longer because the satellite sits lower in the sky. | T3 | HIGH |
| CLM-1103 | Mapped at the scale of one receiver per cell, two-fifths of the country was not ruled out; look closer and seven in ten of those cells fail too, mostly on terrain; take out farmland and a quarter is left. The study still found enough room in every region, with the caveats that its own numbers imply. | T3 | HIGH |
| CLM-1105 | The first look, in 1978, used a coarser grid and a bigger site than the 1980 study, ruled out half to five-sixths of the country depending on how many rules were applied, and declined to name sites; three million acres is a small fraction of America but a tenth of its cities. | T3 | HIGH |
| CLM-1147 | The 1980 programme's experiments on bees, at strengths from the edge of a rectenna to about twice its centre, found nothing: eggs hatched, adults found their way home, a colony raised brood for a month under the edge-of-rectenna level, and foragers flew straight into fields nearly twice as strong as the beam centre to get at sugar water. | T3 | HIGH |
| CLM-1148 | Bee eggs, grubs and pupae zapped for half an hour at up to twice the beam-centre strength grew into normal adults at the same rate as unexposed ones; the one pattern in the egg numbers, treated slightly below sham at every level including zero, the authors trace to which shelf the combs sat on afterwards. | T3 | HIGH |
| CLM-1149 | One hive lived for four weeks, a full brood cycle, under the beam strength expected at the edge of a receiving station, and behaved like the identical hive next door with the beam off. | T3 | MED |
| CLM-1150 | Six thousand bees took part, 2,500 of them dosed, and were let go a hundred metres from home; the dosed ones found their hive as often as the undosed. Another set was watched for three weeks afterwards in glass hives and lived as long. | T3 | HIGH |
| CLM-1151 | Bees kept a full day at up to twice the beam-centre strength (fifty times the beam-edge level), alone or huddled, ate and lived afterwards like bees that had not been; in six-hour runs, single thermometer readings inside them and their clusters differed from the sham box's by up to about 7 degrees, in no consistent direction. | T3 | HIGH |
| CLM-1152 | Bees flew four hundred metres to a sugar dish sitting in a microwave field nearly twice the beam-centre strength, went in without hesitating, and made twenty to thirty round trips in three hours, with no significant difference from bees whose dish had no field. | T3 | HIGH |
| CLM-1153 | The people who ran the bee tests said so themselves: one species, in boxes whose field strength wandered by a third across the tray, with the questions of whether a warm rectenna would draw insects in winter, and birds after them, still open. | T3 | HIGH |
| CLM-1154 | In 1978 the literature said the fence-line level was well below anything known to cause disease over the short term, that no study had come anywhere near thirty years of exposure, and that there was no data at all on what happens to a bird that flies through the beam. | T3 | HIGH |
| CLM-1155 | The 1978 reviewers did the sum for a small bird flying four kilometres through the beam centre and concluded it would probably die of heat, on rat data and the physics of a bird the size of half a wavelength; nobody had flown a bird through a continuous beam to find out. | T3 | MED |
| CLM-1156 | The one worrying result at the fence-line level in 1978 was thinner eggshells in hens kept twelve weeks in a metal cage whose field strength was calculated rather than measured; the reviewers kept the worry because animals living near a rectenna would also be in reflected, uneven fields. | T3 | MED |
| CLM-1157 | The reviewers said most of the older microwave-health literature could not be trusted on how much power the animals actually got, that pulsed beams do more than steady ones at the same average, and that nobody had ever tried to assess an ecosystem. | T3 | HIGH |
| CLM-1158 | The 1978 plan put seven hundred people in orbit at a time, on ninety-day tours of sixty-hour weeks, adding up to about 270,000 tours over thirty years, and this workshop reviewed how much radiation they would get. | T3 | HIGH |
| CLM-1159 | A ninety-day shift in low orbit would give a worker about 20 rad, the trip up and back about 3, and ninety days at geostationary altitude 29 to 56 rad depending on where over the Earth the satellite sat, most of it from X-rays the trapped electrons make in the hull. | T3 | MED |
| CLM-1160 | A big solar flare like August 1972 would push a spacesuited worker past the skin limit in three hours and the eye limit in two, so the geostationary base needs a storm shelter with the shielding of about 15 cm of aluminium, plus goggles and lead underwear so the shelter can be lighter; and a geomagnetic storm can make the electron belt a hundred times more intense in hours. | T3 | MED |
| CLM-1161 | The 1978 plan assumed space workers would be allowed about ten times the radiation dose an ordinary radiation worker may take, under 1970 astronaut rules that doubled a person's natural cancer odds over twenty years at the career limit; the authors said the design, and possibly the feasibility, turned on whether those rules would be tightened. | T3 | HIGH |
| CLM-1162 | A satellite would look like Venus all night, and for two minutes near the equinoxes its polished transmitter would flash a full-moon-bright spot 350 km wide across the ground at 150 km a minute; the ferries being built in low orbit would flash brighter still by day. Tilting or curving the panels and roughening the antenna face would cut the glints, though not the Venus-like glow. | T3 | HIGH |
| CLM-1163 | Between the spring conference paper and the autumn final report, Boeing's figure for how bright a satellite would glow at night fell twelve-and-a-half-fold, from ten times Venus to about Venus, and the report does not say why; the factor is almost exactly what a 4-pi slip in the diffuse-reflection formula would give. | T3 | HIGH |
| CLM-1164 | The report's worry was not that a satellite could light the ground like the sun. It was that a small bright point in a dark sky reaches an eye whose pupil is wide open. So it compared the brightness of the image on the retina with the sun's: in normal operation the transfer vehicles in low orbit reached about a tenth and the satellites far less. For an out-of-control satellite, a case the report treats as abnormal, the same comparison gives about three-tenths (the record's own arithmetic). | T3 | MED |
| CLM-1165 | In 1978 the government said plainly what it did not know about a space power station's effects: almost nothing about long, low-level microwave exposure of people, almost nothing about birds in the beam and nothing about whole ecosystems, and no numbers yet for anything else; it gave itself two years to find out. | T3 | HIGH |
| CLM-1166 | An early tally of ordinary industrial harm from building the system: about twenty-five million lost working days from injuries over thirty years, more than half of them in mining the materials, and a materials bill that would take a large slice of a year's national output of mercury, argon, hydrogen and oxygen. | T3 | MED |
| CLM-1167 | For the launches the 1978 assessment could only line up the rulebook - allowed minutes of rocket exhaust gases for the public, the EPA's day and night noise levels, the blast reach of a launcher twice as explosive as a Saturn V - and note that several launches a day would probably break the noise rule. | T3 | MED |
| CLM-1168 | In 1978 the receiving station was expected to warm its surroundings about as much as a suburb does, unless the beam went astray; one Skylab launch had already punched a 2,000 km hole in the ionosphere for hours, and only preliminary calculations existed for what daily launches would do; water dumped above 40 km was the open climate question. | T3 | MED |
| CLM-1230 | US regulators approved a test satellite with an 18-metre mirror to reflect sunlight to the ground at night, despite objections from astronomers. | T5 | MED |
| CLM-1268 | In 2003 ESA's own rough internal sums suggested space solar and comparable ground solar would cost about the same, to within a factor of ten, and that a space solar plant would return more energy than it took to build. ESA treated both as unproven and planned studies to check them. | T3 | MED |
| CLM-1283 | In 1981 the US Congress's technology office worked out that keeping the edge of a receiving site to the Soviet limit would make each site about ten times bigger, close to 1,700 square kilometres. That limit is ten times stricter than the American design boundary. | T3 | MED |
| CLM-1284 | In 1981 the US Congress's technology office said there was not enough evidence to judge the health risk of living near a power-satellite receiver for years. It expected little harm outside the site, could not rule out effects inside it, and said this research should come first. | T3 | MED |
| CLM-1287 | In 1978 a draft plan for the US satellite power programme proposed that every lab test rats the same way, at fixed microwave levels from far below to just above the beam-centre level of the later reference design, for at least four hours a day, and later for 23 hours a day. | T3 | MED |
| CLM-1288 | The 1978 draft plan said long-term low-level studies would decide whether the satellite was safe for the public, but that in the two to three years available most effort would go to checking earlier alarming reports, with three-fifths of the money on health. | T3 | MED |
| CLM-1289 | The 1978 plan aimed to find, by stepping the dose up or down, the lowest microwave level that changed anything in mice, rabbits, birds and plants, and to use the rabbit result to inform human safety standards. | T3 | MED |
| CLM-1292 | In 1966 Canadian researchers found that caged birds under a pulsed radar-band beam at roughly the strength proposed for a power beam's centre reacted within seconds, but only when the beam came from above. | T1 | LOW |
| CLM-1293 | A year later the same laboratory found chickens under a pulsed beam at a strength about twice the proposed beam centre went lame on one side or fled within seconds, and barely reacted when the beam came from beneath. | T1 | LOW |
| CLM-1294 | The fullest of the four papers: caged birds under a pulsed beam above them reacted within seconds at about twice the proposed beam-centre strength and more slowly at lower strengths, pigeons stayed drowsy for half an hour after two minutes, and birds lit from below barely noticed. | T1 | LOW |
| CLM-1295 | Wiring a chicken's muscles showed the beam made one side tense and the other go slack within moments, and the bird was back to normal seconds after it was switched off. | T5 | LOW |
| CLM-1296 | A 1977 paper suggested that a solar power satellite's beam, if moved to a frequency that water vapour absorbs, could heat water vapour, cloud and rain to change the weather. It took the beam at the ground to be 100 to 1000 W/m2, which is roughly half to four times the later 230 W/m2 design centre. | T1 | MED |
| CLM-1300 | Pregnant rats kept almost all day in a microwave field at a fence-line level (5 W/m2, about a fiftieth of the 1978 beam centre) had more pups die in the first week and pups that developed a day late. The authors called for replication. | T3 | LOW |
| CLM-1301 | The pregnant rats absorbed about 0.4 W per kilogram, the same as the whole-body figure the 1982 US standard later used as its limit, yet the litters still showed the early deaths and delays reported in the companion paper. | T3 | LOW |
| CLM-1302 | Months of night-time exposure at about a fifth of the 1978 beam centre made rats eat and drink less, but changed nothing else that was measured. The authors argue that absorbed dose, not frequency, explains the result. | T3 | LOW |
| CLM-1303 | Hamsters kept in a field from under half to slightly above the 1978 beam-centre level for most of each day showed small brain-cell changes under the microscope in some animals. The author thought the changes would reverse but did not test that. | T3 | LOW |
| CLM-1304 | Rabbits kept for six months in a field of about 70-100 W/m2, below the 1978 beam centre, showed no tissue damage and no clear blood changes. Their immune cells responded somewhat less to one stimulant in the test tube a month later. Four animals per group is too few to settle it. | T1 | MED |
| CLM-1305 | Six months nearly round the clock in a field of about 100 W/m2 at the head did not cause cataracts or other eye changes in four rabbits. Acute cataracts in rabbits in the cited earlier work needed more than 100 mW/cm2. | T1 | MED |
| CLM-1307 | An "energy return" figure for solar power can be stated in two ways, counting the electricity itself or counting the fuel a power station would have burned to make it, and in the worked example of the 2016 international guidelines the second is about three times larger. Any SBSP figure set beside a ground solar figure has to use the same way of counting. | T3 | HIGH |
| CLM-1308 | "Energy payback time" and "energy return" are two views of one calculation and can be converted only when the lifetime and counting method are known. Neither says how much of the sun's or the fuel's energy a system uses up; that is a separate measure. | T3 | HIGH |
| CLM-1310 | The 2016 guidelines recommend default lifetime, wear-out and performance numbers for a ground solar energy-return study, and list 16 facts every study must report. An SBSP figure can be checked against the same list to see whether it is comparable. | T3 | HIGH |
| CLM-1326 | A 1980s US federal health review of animal studies put the onset of harm at about 2 watts absorbed per kilogram of body, mostly from heating. Below about a tenth of that it found few effects and none it judged harmful, though a cancer-promotion result at 2-3 W/kg was unconfirmed. | T3 | MED |
| CLM-1327 | In 1972 the experimental evidence put the onset of microwave cataracts at about 10 times the then US limit, for acute exposures, and found the 1-3 GHz band the most effective. Nobody had tested years of low-level exposure. | T2 | MED |
| CLM-1328 | Studies of radar and microwave workers up to 1972 found small lens changes but no clear cases of cataract below about ten times the US limit. The reviewers saw no harm at the limit but said nobody had shown that years of low-level exposure were harmless. | T2 | MED |
| CLM-1329 | A 1972 US government-funded report found that cataracts in animals needed about ten times the worker limit for an hour or more, and that the range between the limit and that level had never been properly studied in people. | T3 | MED |
| CLM-1349 | NASA's report does print how much electricity each design is credited with, in its cost tables, and its carbon figures follow from those amounts exactly. An earlier reading that it had left out one design's part-time operation was wrong. | T0 | HIGH |
| CLM-1354 | Rats exposed most of every day for a whole pregnancy at about 200 W/m2, close to the 230 W/m2 design centre, had normal pups and normal grand-pups on the tests used. | T3 | MED |
| CLM-1358 | At and below 180 W/m2, rats warmed slightly but less than they do from being handled, and they slept through it. At 360 W/m2, they had to use emergency cooling. | T3 | MED |
| CLM-1359 | Rabbit eyes needed a local field more than six times the 230 W/m2 design centre, held for over an hour and a half, to form a cataract; repeated daily exposures at about four times the design centre did not cause one. | T3 | MED |
| CLM-1360 | Mice kept 16 hours a day for four days in fields around and above the design centre showed no sperm damage, though modest direct heating of the testes did cause it. | T3 | MED |
| CLM-1361 | The same lab that once reported microwaves made mice grow faster repeated the test properly and found no effect, and said its earlier result should not be relied on. | T1 | MED |
| CLM-1362 | Two hours a day at about 100 W/m2 warmed rats by about a degree and shifted blood counts for a while, without lasting harm on the tests used; 500 W/m2 overheated them quickly. | T1 | LOW |
| CLM-1379 | ESA's current life-cycle guidance tells analysts not to use the spending-based method for space hardware, because it seems to overstate environmental impact in the space sector. | T3 | HIGH |
| CLM-1398 | A 2022 survey of real US power plants found that, per unit of electricity, nuclear uses the least land and, of these six, wind farms use the most if the land between turbines is counted; if only the turbine pads and roads are counted, wind uses little land. | T2 | HIGH |
| CLM-1399 | A US government lab found that a wind farm's whole site is about a hundred times larger than the land its turbines and roads actually cover. | T3 | HIGH |
| CLM-1408 | In the late 1970s, US studies sketched receiving stations raised on posts or legs so the ground beneath could still be farmed or built on. They noted a trade-off: panels close to the ground are easier to reach for repairs. | T3 | MED |
| CLM-1410 | US government studies around 1980 thought crops might be grown under a receiving station, because its mesh lets most sunlight through and warms the ground only slightly. They also said it would make farming and repairs harder, needed design changes and had not been studied properly. One later survey suggested raising the station and screening the ground from microwaves, or building greenhouses under it. | T3 | MED |
| CLM-1411 | In 1978 nobody knew whether animals could graze, or crops be grown, under or around a receiving station, because research on what its microwaves do to people and animals was not finished. | T3 | MED |
| CLM-1446 | The 1977-80 US government programme did not decide for or against power satellites. It said questions on technology, environment and cost were still open, that a satellite would cost more to build, and less predictably, than conventional power stations, but that the range of its electricity costs was similar to that of other new options of the time, fusion and solar cells. A separate 1981 review for the US Congress said too little was known to decide, that the basic technologies had been shown to be feasible except lasers, and that, except perhaps for fusion, the up-front cost would be much higher than for other large power stations. | T3 | MED |
| CLM-1452 | By our rough arithmetic, the beam of the UK's full-size reference design would carry about a million times more power than the power-beaming tests checked here that have a stated power: a Chinese ground test in 2022 that sent about 2 kilowatts across 55 metres, and two figures of about a kilowatt reported in the press in 2026, one for a Japanese satellite that is planned and not shown to have flown (a Japanese space agency researcher's 2025 lecture shows the same plan) and one for another Chinese ground test. At the design's peak beam strength, such a test could cover less than ten square metres, against tens of square kilometres for the design, so none of these tests comes close to the full-size beam that the worry about disturbing the upper atmosphere concerns. No output power is stated in the documents held here for a third test, a US Air Force flight test that nothing held shows has launched. | T0 | MED |
| CLM-1462 | A 2020 paper's finding that its detailed method gave five to six times the carbon of an earlier, simpler study of the same 1978 design compares a carbon-dioxide-only figure with a figure that also counts other greenhouse gases, and the paper labels the earlier figure two different ways in two places. | T5 | LOW |