XC01 Regulation, spectrum and law
Depth of coverage
At its target depth of L3. What the depth levels mean.
What this layer covers
Spectrum allocation and coordination, exposure limits, aviation, licensing, planning, liability, treaty and property questions
Where it ends
Cross-cutting: tag alongside the layer it constrains
Regulation, spectrum and law
As of 2024, no international radio allocation exists for beaming power from space. Studies by ITU-R, the radio arm of the International Telecommunication Union, are due in time for the 2031 World Radiocommunication Conference (CLM-0051, CLM-0120). The agenda for the 2027 conference, WRC-27, omits the subject (CLM-0052). In its 2020 guidelines, the International Commission on Non-Ionizing Radiation Protection (ICNIRP) sets reference levels, averaged over 30 minutes, of 10 W/m2 for the public and 50 W/m2 for workers at 2.45 and 5.8 GHz (CLM-0008). In a search of 97 sources held here, the 230 W/m2 beam figure is restated from one 1978 US report (CLM-0044). Five main studies name no exposure standard, though they may rely on assessments published elsewhere (CLM-0006). The 1978 report says peak ground intensity falls from 230 to about 0.03 W/m2 if the pilot signal from the ground stops, but gives no time for the fall (CLM-0911). An early assessment gives an illustrative estimate that spreading the beam's energy evenly across frequencies, to protect line-of-sight microwave relay links on the ground, would need about 3,200 GHz, against the 100 MHz-wide band the design would have used (CLM-0951). One law article argues that an orbital slot, a position in geostationary orbit, may be a space resource under the Outer Space Treaty, and says the question is unsettled (CLM-0945).
As of 2024, no international rule regulates radiation from a power beam sent from space (CLM-0051, CLM-0120). Exposure limits exist, but a search of five main studies held here found none of them named, though those studies may rely on an assessment published elsewhere (CLM-0006, CLM-0504).
Scope. This section covers the rules a power satellite and its ground station would meet: radio spectrum, human exposure to the beam, treaty law on orbits, and debris guidance. Many sources are US programme papers from the 1970s, and the rules they read have been revised since (CLM-0952, CLM-1041).
What is settled. The ITU is the UN agency that shares out radio frequencies, and ITU-R is its radio sector. As of 2024, no ITU allocation exists for beaming power from space (CLM-0120). Resolution 910 of the 2023 world radio conference says wireless power transmission is not a defined radio service in the Radio Regulations and that no international rules regulate its radiation. It asks ITU-R to finish studies in time for the 2031 conference, WRC-31 (CLM-0051). The preliminary agenda for WRC-31, Resolution 814, prints its wireless power item, 2.2, wholly in square brackets, and a note on the resolution's title puts the whole agenda up for further consideration at the 2027 conference (CLM-1377). On its wording, the item aims to stop wireless power transmission interfering with other radio users, not necessarily to give it protected spectrum of its own (CLM-0552). The 2027 agenda set by Resolution 813 has no item on wireless power or space solar power (CLM-0052). A 2022 ITU report covers only short-range devices on the ground (CLM-0053). It leaves human exposure to ICNIRP and IEEE, the bodies that publish exposure guidelines, or to limits set by each country's own experts (CLM-0120).
On exposure, ICNIRP 2020 sets reference levels, which are power densities at the body: 10 W/m2 for the public and 50 W/m2 for workers. They apply across a band that contains both 2.45 and 5.8 GHz, averaged over 30 minutes and the whole body (CLM-0008). A system above a reference level may still comply. It must then pass a full check against the basic restrictions, which limit the heat the body absorbs: a whole-body average SAR (specific absorption rate, the power absorbed per kilogram of body, in watts per kilogram, W/kg) of 0.08 W/kg for the public and 0.4 W/kg for workers over 30 minutes (CLM-0008).
The guidelines of the IADC, the space agencies' debris committee, recommend rather than require. National licensing may adopt them as conditions (CLM-0756).
What is disputed or uncertain. Sources give the 230 W/m2 beam figure different standing. A 2019 UK paper gives it as a typical peak beam intensity. The same paper calls intensities below 1 kW/m2 safe but gives no source for that statement (CLM-0013). Separately, a preliminary draft assessment of 1978 said the minimum density apparently needed for an economic system was thought to be about at the threshold for irregularities in the ionosphere, the electrically charged upper atmosphere. It gives no number, so it does not state a purpose for 230 W/m2, and a 1981 NASA summary of tests did not confirm the threshold (CLM-0921). Two Japanese papers take other views. One, from 1982, gives an inferred ceiling of about 200 W/m2 to avoid serious ionospheric disturbance, and 10 W/m2 or less near the receiving antenna for people (CLM-0150). The other, a short review from 1994, describes a proposal to keep the density at or below 230 W/m2 so that it has no effect on people or the environment (CLM-0148). A search of 97 sources held here traced every restatement of the figure to the 1978 NASA and DOE Reference System, with no independent derivation among them (CLM-0044). These results show where the figure comes from. They do not show whether it is safe.
This site's own calculation for the 1978 reference geometry, in geostationary orbit about 36,000 km up, puts the beam density in the ionosphere within about 2 per cent of the ground value. If the effect depends on local power density, a ground figure can therefore be set against an ionospheric threshold, though that does not make any one comparison correct. It does not hold in low orbit, a few hundred kilometres up (CLM-0865).
Interference findings depend on which limit is applied. Troposcatter links carry radio over the horizon by scattering it off the lower atmosphere. A 1975 study found no problem for ordinary and troposcatter links. The 1978 draft redrew its chart with a stricter troposcatter limit and listed those links as a problem. The troposcatter criterion the 1975 study used and the one the 1978 draft's sources apply differ by about 89 dB, on a 1977 conversion, where each 10 dB is a factor of ten (CLM-0959). The draft's appendix says the 1975 noise estimate would rise about 9 dB near the carrier, the main beam frequency, and fall about 18 dB far from it (CLM-0918). All of this is modelled.
On law, the programme's 1978 legal white paper held that the geostationary level is not open to national appropriation. The same paper held that the ITU then had power over frequencies but none over orbital slots, the positions satellites hold (CLM-1041). A second 1978 paper found that a power beam does not appear to be "telecommunication", but gave the ITU competence anyway: over harmful interference from the beam's frequencies, and over the satellite's ordinary command frequencies. It also concluded, against the first paper, that the ITU would have to set orbital positions (CLM-1042). Both read treaties as they stood in 1978, and the Radio Regulations have been rewritten since (CLM-1041, CLM-1042). A 2024 article asks whether a slot is a "space resource" under the Outer Space Treaty. It poses this as a question and cites no court or tribunal ruling (CLM-0945).
What is missing. Current ITU-R reports, WRC-31 study outputs and an exposure assessment of one named design could close these gaps. The protection criteria used above, the limits that protect other radio users, are 1970s readings; the CCIR recommendations and Radio Regulations have been revised since (CLM-0952, CLM-0959). No ITU document examined mentions ionospheric effects, but only seven were searched and one more was not obtained (CLM-0054). No aviation rule was found for a beam corridor, the airspace a beam crosses. A 1980 assessment argues, without test or calculation, that a metal fuselage would shield passengers. It does not cover composite airframes (CLM-0153). The 1978 design defocuses if its pilot signal, a steering signal sent up from the ground, stops, but its report gives no time for this (CLM-0911).
Read next. QST-001 (Beam intensity at the rectenna), QST-017 (Why 2.45 GHz, and what the radio rules say), QST-019 (National SBSP programmes: money, flights and law), QST-012 (Great Britain grid connection for a 2 GW receiver), QST-011 (Threats to a GEO solar power satellite). Layers VC06 (The beam), VC08 (Getting the power into the grid), XC03 (Environment and lifecycle impact) and XC04 (Security, defence and resilience).
Records
156 of the 180 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-0006 | None of the five main studies mentions the international radio-frequency exposure limits, or any safety standard, or a restricted area around the receiving site. | T0 | HIGH |
| CLM-0007 | The UK study's own experts expect the beam to interfere with electronics in its path, and think it unlikely to have much effect outside the receiving site. | T4 | MED |
| CLM-0008 | The international exposure guideline allows 10 watts per square metre for the general public and 50 for workers, at the frequencies space solar power would use. | T1 | HIGH |
| CLM-0009 | For the UK reference design, averaging the limit over half an hour and over a whole body does not help, because the beam does not switch off and it is far wider than a person. | T0 | MED |
| CLM-0010 | At its strongest, the beam is around 23 times the level the international guideline sets for the general public, and around 5 times the level set for workers. | T0 | MED |
| CLM-0013 | The paper that modern UK studies rely on for the beam figure calls anything below 1 kilowatt per square metre safe, with 230 watts per square metre as the typical value, and cites nothing at all to support the word safe. | T3 | HIGH |
| CLM-0017 | One author, writing in an unpublished draft, says the exposure guideline must be met outside the receiving site, and that what applies inside the site is still under discussion. | T2 | MED |
| CLM-0024 | The American standard of the day allowed 100 watts per square metre averaged over six minutes. The US had no separate limit for the public in 1980, though Canada had just set one of 10 watts per square metre for continuous public exposure. | T3 | HIGH |
| CLM-0032 | In 2007 the international radio science union published a white paper saying that nobody had measured this heating effect from the ground at these frequencies, and only calculations existed. The 1978 figure was repeated not in that white paper but in the longer report attached to it, which is a separate document. | T4 | HIGH |
| CLM-0036 | The 1980 American assessment said people living or working near the receiving site, outside its exclusion boundary, would generally be exposed to much less than 0.1 milliwatts per square centimetre, and that anyone entering the site for work could be exposed to up to 23, the level at the centre of the site, unless precautions were taken. It treated space workers as a separate case with much higher exposure. | T3 | HIGH |
| CLM-0044 | Every mention of the figure in the whole collection can be traced back to the same 1978 American report, restated at least nine times over 48 years, and no source arrives at it independently. | T0 | HIGH |
| CLM-0049 | The stated design intent in a 2007 URSI white paper is that the beam would be shaped to fall to 10 watts per square metre by the edge of the receiving site, which the paper gives as the human safety limit in most countries. | T2 | HIGH |
| CLM-0051 | The international radio rules do not recognise wireless power transmission as a service, do not regulate it, and the studies that might change that are aimed at 2031. | T1 | HIGH |
| CLM-0052 | Neither wireless power transmission nor space solar power is on the agenda for the 2027 world radio conference. | T1 | HIGH |
| CLM-0053 | Power beaming is not a recognised radio service, so no spectrum is expected to be allocated for beaming power from space and no international numeric emission limit applies to it; the general duty not to cause harmful interference to radio services does apply. | T1 | HIGH |
| CLM-0054 | None of the seven ITU documents on wireless power transmission that were searched mentions what a power beam does to the ionosphere. | T0 | MED |
| CLM-0102 | A 1979 field test found no heating effect on the two navigation systems tested, but did find cross-modulation on time-signal stations and on one AM radio station. | T3 | MED |
| CLM-0103 | Solar flares during the same campaign disturbed the same navigation signals far more than any effect that could be put down to the heater, which was too small to detect. | T3 | MED |
| CLM-0113 | As of 2013 the experiment needed to check these predictions had still not been done. | T2 | HIGH |
| CLM-0120 | There is still no international radio allocation for beaming power from space, and the studies are not due until 2031. | T1 | HIGH |
| CLM-0150 | A 1982 Japanese review notes that, at the time, the American and Soviet safety limits for microwave exposure were far apart (1000 times, by our arithmetic), and that the proposed space solar power design's own human-safety figure was ten times stricter than the US limit of that era. | T3 | MED |
| CLM-0152 | Two UK industry planning documents, from 2022 and 2025, each state a beam-intensity design figure in the 230-245 watts-per-square-metre range, but neither traces that number back to any official safety or interference standard: the 2022 report gives no source for its figure, and the 2025 report, for a system planned to launch in 2033, cites only an earlier internal Frazer-Nash report. | T4 | MED |
| CLM-0153 | A 1980 US government environmental assessment argues, without a formal calculation or test, that an aeroplane's metal body would shield passengers from most of a space solar power beam's intensity if the aircraft flew through it. | T3 | MED |
| CLM-0282 | A 2022 ESA-commissioned study modelled that, from 2022 to 2070, space solar power for Europe could deliver a net economic benefit of about 183 billion euros, counting avoided costs of building, fuelling and running power plants on the ground, avoided carbon emissions and other benefits. It also modelled that private investors would not fund the first satellite alone unless the government paid for a large share of development: roughly 58 percent if investors need a 20 percent return, or roughly 30 percent if they need a lower 15 percent return. | T4 | MED |
| CLM-0287 | In 2023 and 2024, the UK government awarded about GBP 5.5 million in grants to 9 projects to develop space-based solar power technology and components, through a competition that opened in 2022 and was funded by the UK Space Agency and the old BEIS department. These are awards with named recipients and amounts, not just a plan. The government page lists award values; it does not report how much was paid out. | T3 | HIGH |
| CLM-0288 | In 2025, a House of Lords committee looking at UK space policy received written submissions from two space-based-solar-power advocacy organisations, Space Solar and the Space Energy Initiative, asking for more UK government funding and support. The committee published its final report in November 2025, and the government responded in January 2026. | T5 | MED |
| CLM-0290 | On 29 May 2025 UKAEA, the UK's national fusion energy research organisation, published a press release saying that it and the company Space Solar had finished a demonstration in which robots assembled a small test section of the kind of structure a solar power satellite would need, part-paid for by a UK research council grant whose amount was not published. We have the press release and nothing else; no independent party has confirmed the demonstration or what it showed. | T6 | MED |
| CLM-0291 | As of February 2026, the UK government's own webpage on space-based solar power describes the two studies it has paid for and links to its earlier innovation competition. It does not announce any new funding or a plan to build anything. | T3 | HIGH |
| CLM-0503 | Under the international radio rules as revised at the 2023 world radio conference, there is no radio-frequency allocation for beaming power from space to Earth at either of the two frequencies CASSIOPeiA-type designs use. The international studies that might lead to one are due to report to a conference in 2031, a year after the first working system that a 2025 UK report forecasts for 2030, and before its 2033 and 2036 steps; the report says its dates are estimates. | T4 | MED |
| CLM-0504 | None of the main CASSIOPeiA-related documents in the register mentions any named safety or exposure standard, or describes any restricted area around the receiving site, anywhere in nearly 300 pages. | T2 | HIGH |
| CLM-0515 | Nearly half of the grant money the UK government announced in 2023 and 2024 for its space-based solar power innovation competition was awarded to three projects named after the CASSIOPeiA design; none of the other six awards was tied to a named satellite design. | T3 | HIGH |
| CLM-0516 | Public money funded a real piece of hardware that was built and tested, not just another report -- a rare outcome in this field -- even though what it found was not entirely flattering to the design. | T3 | MED |
| CLM-0518 | As last updated in February 2026, the UK government's own webpage on this topic describes two research reports it paid for and links its earlier grant competition, with no announced plan to fund anything further. In 2025 an advocacy group that had praised past government support warned that, without visible support and significant funding, UK leadership would fade. | T5 | MED |
| CLM-0519 | The UK government has not announced any money for the next stage of this design since its 2022-2024 competition, and its own webpage, last updated in February 2026, promises none. | T0 | MED |
| CLM-0552 | The international study planned for 2031 is aimed at stopping wireless power transmission from disturbing other radio users. It is not, on its own wording, aimed at giving wireless power transmission its own protected slice of spectrum the way other radio services get. The item is printed in brackets and is due to be reconsidered in 2027, so it is not yet settled. | T1 | MED |
| CLM-0756 | The international space debris guidelines are advice, not law: ESA's own report says they are a starting point for national rules and technical standards, and that it is up to each country, operator and manufacturer whether and how to apply them. | T3 | HIGH |
| CLM-0764 | A 2020 US presidential directive sets out what good cyber security for satellites looks like, including making sure a satellite only obeys commands from an authorised sender, but it says agencies and operators "should" do these things and states in its own text that it creates no legally enforceable obligation. | T1 | HIGH |
| CLM-0787 | The UK harmonic planning levels for networks above 230 kV set total waveform distortion at 3 per cent, with the largest single-harmonic level being 2 per cent at the fifth and seventh harmonics. These are levels for the network as a whole, and each connection gets only a share of them. The document is a recommendation, and it is careful to say which of its words are mandatory. | T1 | HIGH |
| CLM-0791 | In 2024 the EU was moving towards putting grid-forming behaviour into its connection code, following a December 2023 recommendation, but the draft wording required it only where the national system operator asks for it. Britain and Australia already had their own versions. | T3 | HIGH |
| CLM-0792 | Under the UK's retained version of the EU connection code, any generator connecting at 110,000 volts or more, or above 75 megawatts, faces the strictest category of requirements. Its reactive power envelope is capped, and synthetic inertia is something the system operator may ask for, not something the generator must have. | T1 | HIGH |
| CLM-0798 | The American standard often named as the comparator, IEEE 1547, covers generators joining local distribution networks. A gigawatt-scale ground station would join the high-voltage transmission network instead, so a different standard applies, and that one was not obtained. | T4 | MED |
| CLM-0865 | For a power satellite in high orbit, the beam is almost exactly as concentrated where it passes through the ionosphere as it is at the ground, so the two figures can be compared. For a low-orbit satellite they cannot. | T0 | HIGH |
| CLM-0876 | A common way to measure how long spectrum takes to reach users is to count the years from an international conference to the national licences. For the UK's 2018 3.4 GHz award that count may start from the wrong conference: the 2015 conference added no new footnote identifying that band for the UK's region; it amended an existing footnote that, as amended, identifies it, and the 2015 text does not show whether the identification itself was older. What these conferences do is identify bands for use, not for study. | T1 | HIGH |
| CLM-0900 | The satellite can point its beam far further than there is Earth to point at, so moving power from one receiving station to another is not limited by the antenna. It is limited by other things, including whether a receiving station has been built there and whether that country has allowed it. | T3 | HIGH |
| CLM-0911 | If the steering signal from the ground stops, the 1978 design's beam does not carry on pointing somewhere. It falls apart, and the power on the ground drops by a factor of about eight thousand, to below the Soviet guideline plotted in the report. The size of that drop turns out to match the number of independently steered pieces the antenna has, which suggests the same arithmetic could give a rough estimate for other designs. | T3 | HIGH |
| CLM-0918 | The 1978 study of what a solar power satellite would do to the radio spectrum found two things. Its transmitter NOISE would exceed what radio astronomy and deep space tracking are protected against. And its HARMONICS would breach recommendations and in one case the international regulations - though for the harmonics it said it could not make the comparison properly, because that figure had no bandwidth on its scale. It was a preliminary draft. | T3 | HIGH |
| CLM-0919 | In 1978 there was no rule allowing a solar power satellite to transmit power, and the industrial band everyone assumed it would use permits unlimited power only on the exact frequency while separately forbidding the spurious and harmonic emissions the same report expects. A ground-based industrial heater interferes to the horizon; a satellite covers half the planet. | T3 | HIGH |
| CLM-0920 | The 1978 study says a solar power satellite cannot keep its beam entirely on the receiving station - the physics of beams forbids it - so some energy reaches everywhere the satellite can be seen from. Most equipment is partly protected by its metal case and could be made to work with care. Microwave receivers are the exception it leaves open, because a receiver is built to be sensitive to exactly what is spilling; they could be modified, but nobody had worked out at what cost or how well. | T3 | HIGH |
| CLM-0921 | The 1978 report says the power density a solar power satellite apparently needs to make economic sense was thought to be about the same as the density at which heating starts to produce irregularities in the ionosphere. So the design was thought to sit at that threshold, not below it, and the report says understanding of the interaction was not adequate to predict the severity of all its effects. | T3 | HIGH |
| CLM-0927 | The 1978 review found an interference route the report it was reviewing never considered: the power beam bouncing off rain, hail or blown sand into a ground microwave receiver that happens to share the frequency. It calculated the result and found it far above what international rules permit as unwanted signal. It also picked out the third harmonic, at 7350 megahertz, as the one most likely to cause trouble, because it lands in a government satellite band. | T3 | MED |
| CLM-0929 | A search of the 2011 international assessment finds no power-density limit set by the ionosphere, and it mentions the ionosphere only twice in substance: once to say that tests from low orbit to the ground would be useful for understanding the beam's interaction with it, and once in a historical table of past experiments. The search used set terms and could miss a limit written in other units or other words. | T4 | MED |
| CLM-0931 | A 1989 NASA workshop records that the receiving antenna on the ground is not just a receiver - it radiates too. One contribution lists harmonic radiation as a negative feature of the current design. Another reports that on a microwave-powered aircraft, by inference the Canadian SHARP aircraft that first flew on microwave power in 1987, the receiving antenna was noisy in three different ways, and that Canadian regulators nearly stopped the test flight over interference concerns. | T3 | MED |
| CLM-0932 | A 2010 paper making the case for a national space solar power programme never works out a cost per unit of electricity, and its main system cost comes from an unpublished manuscript; one endnote does a rough fleet cost and return-on-investment sum. It also says the ionospheric and safety concerns look answered at a basic level, without giving a number. | T4 | HIGH |
| CLM-0944 | A 2024 legal article about the law of space solar power talks about radio spectrum exactly once, in half a sentence, and gives no source for it. It names the International Telecommunication Union, but as the body that allocates orbital positions - the word "frequency" is only part of the name of the ITU's mechanisms. Across all 308 pages of the volume the words bandwidth, GHz, MHz and Radio Regulations do not appear at all. | T2 | 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-0946 | A rectenna under test emitted a spurious signal. The cause was the resistor they hung on its output, not the rectenna itself, and swapping the resistor made it stop. The diode's own harmonics were measured separately and plotted. | T3 | HIGH |
| CLM-0949 | There is a standard international curve describing how quickly an antenna's stray radiation should fall away off-axis. The SPS pattern stays under that curve everywhere except at its grating lobes - the repeating spikes caused by building the antenna out of subarrays - and the report says that because of those spikes the standard curve cannot be used to describe the SPS safely. | T3 | HIGH |
| CLM-0950 | A solar power satellite in geostationary orbit cannot make its beam any tighter than its design figure, because it is too far away to focus more sharply. The same antenna in low orbit could concentrate the beam a thousand times harder, and what stops it is the air breaking down at about 45 km up rather than anything in the satellite. | T3 | HIGH |
| CLM-0951 | The usual way to stop a strong transmitter interfering with other radio users is to smear its power across a wide band. For a solar power satellite the report calculates that the smear would have to be about 3200 GHz wide to satisfy the protection limit for microwave relay links - about 32,000 times the 100 MHz band the satellite would use. The beam is strong enough to overload a relay receiver even at frequencies well away from its own. | T3 | HIGH |
| CLM-0952 | A solar power satellite would have to stay below published interference limits, and the limits differ by who is being protected. Microwave relay links get a limit per 4 kHz of bandwidth. Radio astronomy and deep space research get limits stated per hertz, which cannot be ranked directly against the relay limits. The radio astronomy and deep space limits are recommendations rather than binding rules, and the report says what protection radio astronomy really has is not clear. | T3 | MED |
| CLM-0959 | The original 1975 calculation found the satellite's radio noise would be fine for ordinary and troposcatter radio links and a problem only for radio astronomy. The 1978 review that redrew its chart swapped the two "fine" limit lines for stricter ones and then listed troposcatter as a problem. The disagreement is over which limit to apply, not over the arithmetic. | T3 | HIGH |
| CLM-0960 | The 1975 study found the satellite's harmonics - the multiples of its transmit frequency - would trouble radio astronomy at the second and third harmonic, would trouble ordinary radio only at the klystron's second harmonic unless a filter was added, and would be clear at the fourth. A later reading of a redrawn chart says all three harmonics exceed everything. The original does not say that. | T3 | HIGH |
| CLM-0961 | Everything in the 1975 interference analysis is for one satellite. The study itself says that a hundred of them would raise the noise and harmonics a hundredfold - 20 decibels - and that nobody had looked at what that would mean. | T3 | HIGH |
| CLM-0988 | The rule that radio astronomers hold the satellite to is a specific international report, and its limit near the satellite's frequency is 87 dB, about five hundred million times, below the noise the 1975 transmitter design would put on the ground. The rule also says nothing about noise just outside the protected bands, which is where most of a wideband transmitter's noise would fall. | T3 | HIGH |
| CLM-0989 | The same figure, minus 160, appears in two 1970s papers meaning two different things: in one it is the noise reaching the ground, in the other it is the noise of a single tube compared with its own signal, which after adding up ninety thousand tubes and the distance to the ground comes out 27 decibels lower. Anyone quoting "minus 160" has to say which. | T3 | HIGH |
| CLM-0990 | The extra twenty decibels of noise suppression for a fleet assumes a hundred satellites. The government's reference plan was sixty, which needs about eighteen decibels; the hundred was a convenient round figure that the workshop papers used and said so. | T3 | HIGH |
| CLM-0991 | In 1978 the frequency band the satellite was to use was an industrial free-for-all band in the West, where users must put up with each other's interference, but the Eastern bloc had its equivalent band shifted 75 MHz lower, so the satellite's frequency was not inside it there. | T3 | HIGH |
| CLM-0992 | The receiving field on the ground makes its own harmonics: the diodes that turn microwaves into electricity also generate signals at two, three and four times the frequency and send some of it back out. Early measurements put the strongest of these at about three hundred times weaker than the main beam. | T3 | MED |
| CLM-1000 | By 1981 the government's own compatibility study said the satellite's frequency band had not actually been allocated to it, listed which services each harmonic would land on, and concluded that radio telescopes could not work within about 150 km of a receiving site. | T3 | HIGH |
| CLM-1001 | Besides the deliberate beam and the tubes' noise, the satellite's fifty square kilometres of warm solar array glow faintly at radio frequencies; the 1981 study put that glow at a level far below anything else and noted that the tube noise would change if magnetrons or other tubes replaced the klystrons. | T3 | HIGH |
| CLM-1002 | The 1981 study tells you exactly which international rulebooks it measured the satellite against, report by report, and warns that the second harmonic lands in the working band of America's biggest radio telescope even though no rule formally protects it there. | T3 | HIGH |
| CLM-1003 | For a transmitter built from millions of small solid-state amplifiers instead of tubes, the 1980 study worked its noise budget down to the ground and found about 27 decibels of headroom against the limit it used; it also noted that for such a large array the second harmonic's grating lobes miss the earth altogether, so the worry moves to the third harmonic, and that a separate frequency allocation for harmonics might be needed. | T3 | HIGH |
| CLM-1004 | In 1980 the systems contractor's own table said magnetrons were about three billion times (95 dB) noisier than klystrons; a year later the same contractor was quoting the tube maker's claim that a magnetron run without its heater was quieter than a klystron, while also listing proper noise measurements as work still to be done. Anyone citing "the magnetron's noise advantage" from this period has to say whose figure it is. | T3 | 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-1041 | In 1978 the programme's lawyer said nobody can own a slot but anyone can use one, sunlight in orbit belongs to everyone, the ITU allocates frequencies but not slots, and if the beam hurt someone there was already a treaty to claim under. | T3 | HIGH |
| CLM-1042 | In 1978 a programme lawyer noticed that a power beam carries no message, so the ITU's rulebook did not obviously cover it, and found the ITU's way in was through interference with everyone else. | T3 | HIGH |
| CLM-1043 | With the heater off and a tuning circuit on the cathode, one hand-picked oven magnetron was as quiet as the instrument could measure: about 197 decibels below its carrier per hertz of bandwidth, 50 megahertz away from the carrier. Detuning the cathode circuit cost 20 decibels; turning the heater on swamped the display. | T3 | HIGH |
| CLM-1044 | In 1980 the quiet oven magnetron was already beyond the instrument's reach: at least 155 decibels below carrier per hertz away from the carrier, quieter at low magnetic field and high current, unaffected by drive level. Close to the carrier its added phase noise was about 114 decibels down per kilohertz at 50 kilohertz. | T3 | HIGH |
| CLM-1045 | Raytheon's own numbers had the klystron just failing the interference limit at the band edge and the magnetron clearing it by 45 decibels, while conceding nobody had measured a klystron that close to its carrier and that near the carrier the klystron was slightly quieter. | T3 | HIGH |
| CLM-1046 | The number Raytheon wrote into the design table for the satellite tube was about fifty times noisier than its best laboratory reading, because it did not yet know where the noise came from; the only work on that question was Raytheon's own unfunded research. | T3 | HIGH |
| CLM-1047 | The oven magnetron's second harmonic came out about 70 decibels below its carrier, a tuned stub took another 40 off, and the antenna's own pattern was credited with 65 more, so Raytheon reckoned the whole satellite's second harmonic would arrive on the ground fifty decibels under the limit. The third, fourth and fifth were measured but never filtered, and the fifth was unexpectedly strong. | T3 | HIGH |
| CLM-1048 | A cheap oven magnetron run cold and hard converted 81.7 per cent of its DC input to microwaves, measured carefully by heating water. Raytheon's point was that theory said 94 and a lower-frequency tube already did 93, so the 2.45 GHz tube was leaving six points on the table nobody had explained. | T3 | HIGH |
| CLM-1050 | The interference limit Raytheon measured its tubes against is given as a CCIR requirement but never traced to a CCIR document, and one page even gets its units wrong by a factor of a thousand. | T3 | HIGH |
| CLM-1058 | The often-repeated claim that the magnetron is 188 decibels quieter than its carrier traces to a conference abstract in which the tube maker said "180 to 190" for hand-picked tubes and said his instrument could not see below that outside a 60 megahertz window. | T3 | HIGH |
| CLM-1072 | In 1980 the radio astronomers expected to lose a twenty-degree circle of sky around the satellites and two of their bands, the spectrum managers found the beam's skirts spilling into the neighbouring broadcast band and its third harmonic into a government satellite band, and the military found the transmitter's hundred thousand tubes would together hiss over a five-hundred-kilometre radius. | T3 | HIGH |
| CLM-1073 | A satellite flying through the beam would get a few seconds of noisy pictures and garbled data and then recover; with a hundred satellites up, one would cross a given beam about monthly; and the rectennas would have to keep fifty to a hundred and fifty kilometres from observatories, radar ranges and airports. | 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-1086 | The number 2.45 GHz has a birthplace: a 1975 study for NASA that swept frequency from 1 to 5 GHz against cost, found a broad flat region near 2 GHz, and picked the industrial band sitting in it. The atmosphere was checked separately and found nearly transparent below 3 GHz. | T3 | HIGH |
| CLM-1087 | When the programme wrote down why it used 2.45 GHz, its reasons were consistent: each time it named the industrial band and how the beam passes through the atmosphere, and some documents added rain, good efficiency, antenna size or the outlook for the equipment. | T3 | HIGH |
| CLM-1088 | By 1980 the programme remembered its first study as having picked 2.45 GHz. The first study's report says it picked 3.3 GHz. The 2.45 GHz decision was made three years later. | T3 | HIGH |
| CLM-1089 | The higher industrial band would have shrunk the receiving field to a fifth or a third of its size, at the price of a satellite that could not shed its heat, a bigger electricity bill, and a beam that rain could knock out. Every time the programme costed it the answer was the same and 2.45 GHz stayed. | T3 | HIGH |
| CLM-1090 | The programme's two printed tables of how much beam the weather eats do not agree. One has the ionosphere numbers the wrong way round, and its rain and hail figures are a million times too small for the unit printed over them. The other is internally consistent. | T3 | HIGH |
| CLM-1091 | The people running the programme said 2.45 GHz was sensible and also said, in the same breath, that nobody international had agreed to it and the choice was open. Their own account of the 1979 world radio conference is that no frequency was given and one might be, if the environmental case were made. | T3 | HIGH |
| CLM-1095 | The three harmonic numbers the register has carried since the 1978 conference paper come from one rectenna element on a bench at five watts, measured at its input with the antenna replaced by a matched line; the fourth is the meter's floor, not a reading. Filters and a metal shield on the element cut the second and third by 25 and 15 decibels. | T3 | HIGH |
| CLM-1104 | The siting maps kept receivers 150 km from radio telescopes, 100 km from NASA's deep-space stations, 60 km from air traffic radars and 50 km from nuclear plants, on asserted distances; because those places are mostly excluded for other reasons too, the electromagnetic rules only cost about seven per cent of the country. | T3 | MED |
| CLM-1112 | The paper says this colour of infrared is good because the air lets it through and the eye-safety rules allow more of it, but it cites other papers for both and never gives a number for either. | T1 | HIGH |
| CLM-1204 | A 1981 US government study worked out what happens when an airliner flies through the beam. Its wings would reflect some of the beam, mostly away from the cabin. It judged the passengers' exposure insignificant, because the windows are small and the plane is in the beam for under a minute. | T3 | MED |
| CLM-1205 | A 1981 US study worked out what a satellite in low orbit feels when it flies through the beam. For a craft like LANDSAT, the strongest part lasts about a second and the whole crossing about 13 seconds. In tests, one of its cameras failed completely when enough of the beam's power shone into it. The study suggested such satellites could pause commands during a crossing for now, and be redesigned later. | T3 | MED |
| CLM-1207 | The 1980 paper that estimated how often a satellite would meet the beam used a simple picture: the beam turns with the Earth once a day, so a given satellite gets about two chances a day to cross it, and whether it does depends on where in its orbit it happens to be. The paper does not say how wide it took the beam to be, or show its sums. | 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-1233 | The design's beam would be very intense at the receiver, about two thousand times stronger than sunlight, so the site would need a fenced zone a few hundred metres across. At the fence, the study says, the infrared light would be far below the eye-safety limit of the day. A passing jet would warm slightly, but a slow light aircraft might be harmed. | T3 | MED |
| CLM-1235 | Studies from around 1980 used an infrared safety limit of about one-tenth of strong sunlight for long, whole-body exposure, and ten times that for brief exposure of small areas. Meeting it meant fencing off a zone a few hundred metres across around each receiver and keeping aircraft out of the beam. | T3 | MED |
| CLM-1242 | TerraSpark says it will first use wireless power on the ground, where cables are hard to lay, and move parts of the system into space later. The article suggests Luxembourg could become a financial centre for such projects. It gives no dates. | T6 | MED |
| CLM-1243 | The company says it is lining up partners in Japan, the US, Saudi Arabia and Canada, and working with the European Space Agency. It pitches beamed power as something Britain could offer its allies, including for defence and polar sites. It says the ground receivers would be cheap enough to finance even in poorer countries. None of this is backed by named deals or figures in the post. | T6 | MED |
| CLM-1244 | TerraSpark posted a lab video of power sent without wires across half a metre, with words of praise from a former British energy and defence minister. The post gives no numbers on how much power was sent or how efficiently. | T6 | MED |
| CLM-1247 | Japan's 2023 national space plan lists space solar power research, led by its science and industry ministries, and aims at eventual practical use without giving a date, size or budget. | T3 | HIGH |
| CLM-1260 | In 2009-2011 California's regulators took a contract to buy power from a space solar company through each formal step: the energy commission accepted a 200 MW space solar receiving station as a renewable source in principle, and the utility regulator signed off on the contract's emissions terms. None of these papers shows the satellite or the station being built. | T3 | HIGH |
| CLM-1261 | In 2009 California's largest utility signed a deal to buy up to 200 megawatts of power from a space solar company for 15 years, starting in June 2016, from a receiving station in central California. It agreed to pay more than the usual benchmark price, and the details were kept confidential. | T3 | HIGH |
| CLM-1263 | In 2003 ESA planned a two-year set of paper studies to help its member countries decide whether space solar power was worth pursuing. The plan aimed to compare it fairly with solar power on the ground and to pick a few demonstration missions to study, not to fund hardware. | T3 | HIGH |
| CLM-1264 | The plan had three steps. First, check whether space solar makes sense against ground solar, what the law allows, and whether it could power Mars missions. Second, compare system designs and pick up to three. Third, study two or three small demonstration missions in enough detail for ESA to decide whether to go ahead. | T3 | HIGH |
| CLM-1272 | In 2000 NASA sketched a path from small demonstrations around 2006 to a first full-size power satellite prototype between 2025 and 2035, and very large systems after 2050. None of it was funded, and none of the dated steps has happened in a held source. | T5 | HIGH |
| CLM-1278 | A 2026 expert commentary points out that the upper atmosphere would scatter a small share of a power beam, as it does a research radar's signal, but far more strongly, so it needs checking against Wi-Fi limits. Rocket tests that made the beam produce other radio signals measured them only close by, so how far those signals could travel is unknown. | T2 | 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-1285 | In 1981 the Soviet limit for workers was a thousand times stricter than the US one, and the US had no public limit at all. Congress's technology office expected US limits to tighten and said the design should be checked against that. | T3 | MED |
| CLM-1286 | The 1981 congressional assessment listed who would be exposed to the beam and how strongly. Levels ran from a ten-thousandth of a milliwatt per square centimetre for the public to about 2 watts for workers at the satellite's antenna, and it said no one could yet say what was safe for workers. | T3 | MED |
| CLM-1290 | A 1963 US aviation agency study set the safe level for an aircraft flying through a radar or radio beam at the then human exposure limit, 10 milliwatts per square centimetre, and ten times lower for aircraft carrying explosive devices. | T3 | MED |
| CLM-1291 | The 1963 study assumed an aircraft crosses a radar beam in a few seconds at most, too short to wear out its radio parts, though a switched-off radar set could still be damaged by a strong pulse. | T3 | MED |
| CLM-1297 | In the 1970s the East set microwave limits about a thousand times lower than the US. Against the later 230 W/m2 beam centre, the Soviet public limit is 23,000 times lower and the Polish general-population limit 230 to 2,300 times lower. Poland banned any human exposure above 100 W/m2. | T3 | MED |
| CLM-1298 | In 1982 the US limit at SBSP frequencies was halved, from 10 to 5 mW/cm2, and for the first time it was meant to cover the general public as well as workers. The 1978 beam centre of 230 W/m2 is 4.6 times this limit. | T1 | HIGH |
| CLM-1299 | The 1982 US limit was set by taking the lowest dose at which animals' trained behaviour was disrupted, about 4 W/kg, and dividing by ten. The standard admits the factor of ten was a safety margin without a quantitative justification, and one biologist dissented on that point. | T1 | HIGH |
| CLM-1314 | The international radio-astronomy standard says how weak a stray signal must be before it spoils a sensitive observation. In the radio-astronomy bands just above the 2.45 GHz and near the 5.8 GHz power-beam frequencies, that level is about 10^-24.7 and 10^-24.1 watts per square metre per hertz. Longer observations and satellites in geostationary orbit make it stricter still. | T2 | HIGH |
| CLM-1315 | The 1975 estimate of the satellite's radio noise, taken at its own frequency, is about a hundred million times above today's threshold for spoiling radio astronomy. The noise in the astronomy band itself would be lower, by an amount nobody has yet read from the 1975 study. | T3 | MED |
| CLM-1319 | The two frequencies power satellites would use sit in bands set aside for industrial and medical equipment, where radio services already there must put up with interference. The treaty's limits on how strong a satellite's signal may be at the ground do not cover either band. | T1 | HIGH |
| CLM-1320 | The radio regulator's 2026 report on beamed power now has a section on power satellites, built around a UK design, and repeats that UK and European studies found it workable. It says nothing about effects on the upper atmosphere. | T1 | MED |
| CLM-1322 | Around 1970 an author at Atomics International (North American Rockwell) reviewed Soviet research and asked why Soviet limits were up to a thousand times stricter. He found the Soviets took non-heating effects seriously, reported long-term symptoms in workers, and turned that concern into lower limits through shorter lines of communication than the US did. | T5 | LOW |
| CLM-1323 | By 1970 most western countries used a limit of 10 milliwatts per square centimetre, first chosen in 1957 for lack of better data. The Soviet Union and Poland allowed a thousand times less, because they accepted evidence of effects that do not come from heating. | T2 | MED |
| CLM-1324 | In 1981 two US officials said America still had no enforced microwave exposure standard and that its proposed limit was among the most permissive in the world. They reported the view of some that the gap with the Soviet Union came from different evidence and different readings of it, and said closer medical checks on Soviet workers may explain why Soviet studies report many mild, reversible symptoms at very low levels. | T5 | LOW |
| CLM-1325 | In 1979 American and British radiation officials worked out that the then-standard limit of 10 milliwatts per square centimetre was safe at 2.45 GHz (the frequency planned for power satellites; our context, not on the page), about nine times below the level that warms the body by 1 C (our arithmetic). They said it was too loose at much lower frequencies, where the body absorbs more. | 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-1330 | A 1964 Polish study found that workers exposed for longer to weak radio and microwave fields reported more headaches, sleep problems and similar complaints, and argued that safety limits based only on heating were too lax. | T2 | LOW |
| CLM-1332 | By the mid-1980s Western limits were set from the energy the body absorbs, with a tenfold margin below the level that upset animal behaviour. The Soviet limit for a working day stayed far lower. | T2 | MED |
| CLM-1333 | By 1986 one early long-term rat study had hinted at more tumours at the level US rules called safe, but it was unconfirmed. Eastern European reports of nerve symptoms had not been confirmed by careful studies, and experts said there was no theory to predict any non-heating effects. | T2 | LOW |
| CLM-1334 | In 1978 the US environment agency calculated that the American safety limit of the time could, at some radio frequencies, heat parts of the body far more than normal metabolism does. It found that a cautious heat-based limit would land close to the much stricter Soviet limit. | T3 | MED |
| CLM-1335 | In the 1970s most city dwellers in the US received radio-frequency exposure more than a hundred times below even the strictest heat-based limits the note considered; only people next to big transmitters came close. | T3 | MED |
| CLM-1336 | An old reviewer's note says the US microwave limit came mainly from a heat-balance calculation for an average man, after an earlier limit ten times higher, and not from laboratory evidence of harm. | T3 | LOW |
| CLM-1338 | A 1970 experiment found that microwave cataracts in dogs needed the lens to heat up: the same repeated doses that clouded a warm eye did nothing when the eye was kept cool. | T2 | MED |
| CLM-1345 | A 1972 medical paper says sailors on a warship's signal bridge could stand in radar fields up to about five times the US limit of the day. Under the thinking of the time, they would still be below the level expected to harm the eye. | T5 | LOW |
| CLM-1347 | In 1972 a leading American review said microwaves were only known to harm people by heating them. It called the evidence for other effects weak, so it argued against copying the far stricter Soviet limit. | T2 | MED |
| CLM-1363 | With an aircraft's own radar aimed at the cockpit, the metal front of the fuselage kept the cockpit below what the meter could detect. | T3 | MED |
| CLM-1364 | Inside a radar aircraft in flight, crew areas got under a thousandth of the old limit from the big radars; the one weak spot was a glass dome next to a radio antenna. | T3 | LOW |
| CLM-1377 | The official 2023 text that plans the 2031 world radio conference marks the wireless power item as not yet settled. It also says the whole agenda will be reconsidered in 2027, because countries disagreed about which frequency bands to study and how to protect existing radio users. | T1 | HIGH |
| CLM-1385 | The Government's formal reply to the 2025 Lords report on UK space policy does not mention space-based solar power. None of the committee's 40 recommendations, as the reply reprints them, is about it either. | T1 | MED |
| CLM-1386 | Great Britain's grid rules put any generator joining the network at 110,000 volts or more into their top class, Type D. A gigawatt ground receiving station would join at 275,000 or 400,000 volts, so it would be Type D. | T1 | MED |
| CLM-1416 | A 2022 study for the European Space Agency put the cheapest case for space solar power at about 55 euros per megawatt-hour after adjusting for the value of its electricity, under optimistic costs, a 10% cost of capital and a 30-year life. | T4 | MED |
| CLM-1433 | In the 1975 study, at 300 dollars a kilogram to launch and assemble, a 1 GW station cost about 1.7 to 3.5 times as much per kilowatt as a 20 GW one. The large stations were cheapest at about 1.25 to 2.25 GHz, but their curves are shallow: about 1,900 to 2,300 dollars per kilowatt across the whole band for the largest. | T3 | MED |
| CLM-1434 | With launch and assembly at a third of the price and a cheaper power source, the 1975 study's costs per kilowatt fall at every size, by about 40 per cent for 1 GW and about two thirds for 20 GW. The largest stations still sit at their cheapest between about 1.5 and 3 GHz, around 610 dollars per kilowatt for 20 GW. | T3 | MED |
| CLM-1454 | The 2020 international limit for public exposure, 10 watts per square metre, is about 19 to 42 times lower than the beam strengths at which one theory says the beam might start to focus itself in the upper atmosphere (42 times uses a 2008 estimate, 19 times uses measured conditions), and 23 times lower than the 230 that a 2019 CASSIOPeiA paper gives as a typical peak. Those atmospheric figures are estimates, not hard limits. A 2026 international radio report that takes CASSIOPeiA as its example says the beam can be designed to fall below the public limit at the edge of the receiving site, with a safety zone over the beam's footprint; it gives no figure for the beam's strength at that edge, and a diagram in it shows the receiving site taking 245 watts per square metre. | T3 | MED |
| CLM-1455 | A Member of Parliament who, by his own declarations, chaired the advisory board of the Space Energy Initiative and was a non-executive director of Space Solar used House of Commons debates in April 2024 and June 2025 to argue for UK government support for space-based solar power, declaring these as unpaid interests each time. The government minister who replied in June 2025 did not promise any money specifically for space-based solar power. | T5 | HIGH |
| CLM-1456 | Japan's government roadmap for space solar power, written in 2006 and revised in 2016, as shown in a December 2024 report, planned a decision on a space demonstration around 2025, a demonstration satellite around 2030, and a commercial system around 2045 to 2050. All of these were plans, not achievements. The same report notes that its earlier record of up to 100 metres was 0.0003 percent of the 36,000 kilometres a real system would need (by our arithmetic, the 5 kilometres it planned to fly is about 0.014 percent), and gives its next step as a transmission from low Earth orbit, dated only as 2025, to be decided. | T4 | MED |
| CLM-1457 | A 2021 study for the UK government of the CASSIOPeiA space solar design used two discount rates for two questions: a tough 20 percent, the return it assumed private investors would want, for its cost of electricity, and the government's standard rate at the time, 3.5 percent, for judging whether the whole programme would be worth it for the country. It does not show that pairing the two is standard for other power stations. | T4 | MED |
| CLM-1467 | Keeping people out of the area where the beam is strong is a plausible way for a strong beam to meet the 2020 international limit for public exposure, and international exposure guidance accepts limiting access as a way to comply. Other designs have worked this out: a 2013 Japanese review plans a no-entry area 3.5 kilometres across, and a 2007 international study sizes a 4-kilometre receiver this way. A 1977 US study set aside 204 square kilometres for one receiving site, without saying in its cost table what fixed that size, and costed buying and preparing that land. A 2026 international radio report that takes CASSIOPeiA as its example says the beam can be designed to fall below the public limit at the edge of the receiving site, with a safety zone matching the beam's footprint, about 3.5 to 6.5 by 7 to 13 kilometres in the UK. A diagram in it shows the receiving site taking 245 watts per square metre, but the report gives no figure for the beam's strength at the edge and no cost for the zone. A 2021 UK cost model for a CASSIOPeiA design includes the land for the receiving site but names no safety zone. | T4 | LOW |
| CLM-1479 | A 1981 NASA summary says that if the timing across the 1978 design's antenna were lost, its beam would spread out to the width that one of its small radiating sections makes on its own, covering a very large area. Far from the receiving site the power could rise, but the summary says it would stay well below even the strictest safety limits of the time. | T3 | MED |
| CLM-1480 | A 1981 survey for the US energy department says that a beam steered by a signal from the ground cannot form without that signal. If the signal fails, the antenna's parts fall out of step, the power spreads over half the sky, and what reaches the ground is as weak as a radio signal. The survey takes this to mean the beam could not be aimed anywhere except at the signal. | T3 | MED |
| CLM-1485 | The patent behind the CASSIOPeiA design, both the 2018 application and the granted patent published in 2021, mentions 230 watts per square metre in passing as an ideal and safe figure while describing the design. Neither version sets out to show that the figure is safe, and neither cites any safety standard. | T3 | HIGH |