VC05 Transmitter: DC to beam and aperture
Depth of coverage
At its target depth of L3. What the depth levels mean.
What this layer covers
DC to RF or DC to optical conversion, amplifiers, phase control, beam forming, transmit aperture
Where it ends
Ends at the aperture face; everything beyond it is VC06
Deep area
This layer is studied in more depth than most. It belongs to the deep area RF conversion and phased arrays.
Transmitter and aperture: where it stands
No source in these records reports a test of a transmitter near full scale. The transmitter turns DC power into a microwave beam. A December 2024 Japanese aircraft test aimed a 5.8 GHz beam over about 5 km, but its preliminary report gave received signal levels only, with no transmitted power, DC output or efficiency (CLM-0294). A 2026 array reached a peak of 172 W/m2 on a 1 m2 receiver at 6.5 m (CLM-0512). The 1978 US design is said to spread its beam out if the pilot signal, sent up from the ground to show the satellite where to aim, stops. Peak intensity then falls from 23 to 0.003 mW/cm2. A 1981 programme summary says this takes milliseconds (CLM-0911, CLM-1020). A 2013 review says the 230 W/m2 limit was chosen early to avoid strong interaction with the ionosphere, one of at least four accounts of its origin that disagree (CLM-0111). The same review says about 1 kW/m2 may not be critical at 5.8 GHz, while other estimates are lower (CLM-0112).
Scope. The transmitter turns direct current (DC) from the solar array into a microwave beam. It includes the amplifiers, which are tubes or transistors, the electronics that set the phase of each antenna element so the waves add up, and the aperture, the antenna face the beam leaves from. It ends at that face; the beam's path to the ground has its own page.
What is settled. No source in these records reports a transmitter test near full scale. The tests they report are small. In December 2024 a Japanese team beamed 5.8 GHz microwaves from a jet at 7,000 m to a site about 5 km below, in 40 runs. The beam shape was close to theory. The preliminary report gives received signal levels only, with no transmitted power, received DC power or efficiency (CLM-0294). A 2026 array of 112 elements measured a peak power density of 172 W/m2 on a 1 m2 receiver at 6.5 m, against a 200 W/m2 goal. It used about 672 W of microwave power, less than a millionth of a 1 GW system's (CLM-0512).
The 1978 US reference system sized itself from two limits. The first is the heat its antenna could shed. The report states the cap as 22 kW/m2, in one place as microwave power (CLM-0204), and elsewhere as about 21 kW/m2 of heat (CLM-0023). The second is a beam limit of 23 mW/cm2 (230 W/m2) in the ionosphere, the electrically charged upper atmosphere (CLM-0023). Both are design assumptions. Its design efficiency, from DC on the satellite to DC at the ground receiver, multiplied to 63 per cent. The chain does not show that 63 per cent is achievable or was ever demonstrated. It had no term for ionospheric scattering, so the design treated that loss as zero by omission (CLM-0138).
Pointing needs active correction. A 1981 NASA study states that mechanical pointing alone could miss the ground target by 10 to 30 km (CLM-0160). The design therefore steers from a pilot signal, a beacon sent up from the ground to show the satellite where to aim. Its modelled budget is 10 degrees rms (root mean square, a typical size) of phase error, meaning how far each element's wave is out of step. That would keep main-beam loss under 3 per cent (CLM-0160). This site's own calculation reproduces the 3 per cent. It also gives about 3 mm rms of random position error per element for a 0.1 dB loss (decibels; here about 2.3 per cent of the power) at 2.45 GHz. A slow, smooth bend costs less gain, but it shifts where the beam points (CLM-0901).
On paper the design fails safe. If the pilot stops, the subarrays (blocks of antenna elements) are no longer phased together and peak ground intensity drops from 23 to 0.003 mW/cm2 (CLM-0911). The 1978 report gives no time for this. A 1981 programme summary, drawing on analysis, simulation and bench tests rather than an array, says dephasing "occurs in milliseconds" (CLM-1020).
What is uncertain. The first open question is the beam limit. A 2013 review says the 230 W/m2 figure was "selected as the maximum level to avoid strong interaction with the ionospheric plasma" early in the design. It gives no source for the choice, and it is one of at least four accounts of the figure's origin that disagree (CLM-0111). The same review says recent work finds about 1 kW/m2 not critical at 5.8 GHz, and adds that the predictions still need verification (CLM-0112). One other estimate at 5.8 GHz is lower: 425 W/m2 for one stated set of ionospheric conditions (CLM-0112). The tension is unresolved. Separately, for the same antenna and power, moving from 2.45 to 5.8 GHz raises peak power density at the ground about 5.6 times, by a calculation held here for an array that focuses its beam (CLM-0862). That figure is for the peak at the ground only.
The second is the amplifier. Klystrons and magnetrons are two kinds of microwave tube. A 1981 programme office chose the klystron for gain, noise and output per tube. Boeing, a prime contractor, had called the choice "somewhat arbitrary" in 1979 (CLM-1019). A January 1980 review panel wrote that "At this time the klystron looks most favorable, but either the solid state or magnetron source may look better later". It warned that efficiency budgets had so far used only the most optimistic predicted values for turning DC into microwaves. In April 1980 the two contractors' comparison table made the magnetron design the lightest per kilowatt delivered (CLM-1063). The best solid-state (transistor) results reported to the programme in April 1980 were 72 per cent efficiency at 1.2 W and 60 per cent at 5.1 W, against an 80 per cent design figure (CLM-1064). These are 1979 to 1981 positions.
The third is a forged pilot. An analysis held here finds that most failures defocus the beam. Two do not: a forged pilot would make the array aim at the forgery, and drift in the network that carries the phase reference across the antenna would weaken and misaim the beam (CLM-1478). A 2017 UK patent for this kind of array has no authentication wording. That is weak evidence, because patents often leave security out. A 1981 NASA report says the US design included a coded pilot signal against attempts to redirect power. It describes no check that would tell a forged pilot from a real one (CLM-0899, CLM-1478).
What is missing. A test that reports transmitted power, received DC power and efficiency would start to close the gap to full scale. The 2017 patent describes sampling the pilot at scattered detectors and interpolating between them, but gives no count or spacing. A patent states what may be done, not what a built system does (CLM-0896). No source held here tests a failure mode on hardware for CASSIOPeiA, a current design (CLM-1478). Holding the structure steady covers how a kilometre-scale antenna vibrates and the detector-spacing calculation held here.
Read next. Beam intensity at the rectenna. The ionosphere limit: tested or not? Phase coherence across a flexible array. Holding the structure steady. The beam. The receiving field. Could it be attacked or misused?
Records
91 of the 106 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-0015 | An independent Japanese authority on power beaming records the American reference design's beam strength as 23 milliwatts per square centimetre at the receiving site, which is 230 watts per square metre. | T2 | MED |
| CLM-0023 | In the 1978 reference design, two limits set the size of the transmitter and the receiving site: how much heat the transmitter can shed, and an upper limit on beam strength taken from studies of the ionosphere. | T3 | HIGH |
| CLM-0111 | An authoritative 2013 review says the 230 watt per square metre figure was chosen early in the design as a cautious maximum. It does not describe it as a measured or derived limit. | T2 | HIGH |
| CLM-0112 | The same review says modern work finds about 1 kilowatt per square metre acceptable at 5.8 gigahertz, more than four times the older figure, and that commercial designs assume it. | T2 | MED |
| CLM-0138 | The original 1978 government design for beaming power down from space adds up all the expected energy losses to get 63% overall efficiency, but the list of losses does not include any allowance for the upper atmosphere scattering the beam. | T3 | MED |
| CLM-0141 | A Chinese government-linked design study calculated that, outside the main beam of its proposed satellite, stray sidelobe power on the ground would fall to about 22 watts and then 7.5 watts per square metre. | T2 | MED |
| CLM-0160 | A 1978-81 NASA design study calculated that simply pointing the satellite's structure accurately enough, without any electronic correction, would miss the ground target by 10 to 30 kilometres - which is why the system needs a self-correcting radio-steering mechanism, and that mechanism's own error budget keeps beam losses under 3% and keeps the beam within a quarter of a kilometre of its target 99% of the time. | T3 | MED |
| CLM-0204 | In this 1978 design, heat from the power-conversion tubes, not the RF electronics themselves, set the top limit on how much power the transmitting antenna could handle per square metre. | T3 | HIGH |
| CLM-0294 | In December 2024 a Japanese team beamed 5.8 GHz microwaves from a business jet flying at 7,000 metres down to a receiving site about 5 kilometres below, 40 times over four flights, and the measured beam shape matched theory closely. The report gives the strength of the received signal only in decibels, and states no transmitted power, no received electrical power and no efficiency, so it shows that the beam could be formed and aimed at that range, not that any useful amount of power was delivered. | T4 | MED |
| CLM-0501 | A 2024 Chinese satellite design concept plans to beam down microwaves twice as strong as CASSIOPeiA's own typical figure, and its designers do not appear to have considered the upper-atmosphere stability question at all. | T2 | MED |
| CLM-0511 | The first real, built, and measured version of CASSIOPeiA's beam-steering hardware converts electricity to radio power at 42%, against about 80% for the amplifier alone and 65% for the amplifier with its circulator, once every real component is counted rather than just the amplifier chip. | T2 | HIGH |
| CLM-0512 | The small prototype achieved a beam strength close to what a real system would use, but only over an area the size of a small table, using about 672 watts of radio power. | T2 | MED |
| CLM-0513 | The most credible real, flown demonstration of space-based wireless power transmission achieved milliwatts of power over centimetres inside a single small satellite, at a little over half its own predicted efficiency, and its own scientists do not attempt to say what this means for a full-scale power station. | T1 | 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-0539 | A UK consultancy, working for the European Space Agency and using the same design as its reference point, actually published a full weight breakdown -- something the original 2019 paper never did. It comes out lower than the headline claim, at about 0.70 kilowatts per kilogram rather than 1, even though it leaves out several categories of weight altogether. It also rates one of the satellite's power-conversion stages as barely more than an idea on paper, and its input notes say the lightest case for the radio equipment is an expert's judgement, not something anyone has measured or built. | T4 | MED |
| CLM-0692 | The Chinese design's own summary table adds up: the parts weigh what the total says they weigh. Its claimed 12.3 per cent efficiency is sunlight-to-grid, which checks out against the area of the panels and the strength of sunlight in space. The antenna is a long thin strip, 100 metres by 10.5 kilometres, at 5.8 gigahertz. | T2 | HIGH |
| CLM-0860 | An open-source antenna modelling package puts the first side peak of a beam in the right place, to better than three parts in ten thousand, for the one antenna layout tested. A separate finding about how strong it reports one feature to be has been withdrawn, because it reversed when the aperture was reconstructed in an equally reasonable way. | T0 | HIGH |
| CLM-0861 | A published software package ships its main engine to the wrong folder, so the package cannot find its own engine, and the installation reports success either way. | T0 | HIGH |
| CLM-0862 | Switching a power satellite to the higher of the two candidate frequencies makes the beam five and a half times more intense on the ground, not less - but only if the antenna can keep its beam actively focused on the receiver. | T0 | HIGH |
| CLM-0863 | A published figure suggesting that modelling a solar power satellite beam needs ten million million times more rays than the available software could handle turns out to describe the cost of one way of doing the sum, not the difficulty of the problem. | T0 | HIGH |
| CLM-0871 | A table in the 1978 report has two arithmetic slips, and the report's own column total is enough to show which figure is wrong in each case. | T0 | HIGH |
| CLM-0891 | The 1978 design says the size of its transmitting antenna was set by how much heat the array could shed, and elsewhere gives that limit as about 22 kW/m2 of radio power at the centre of the array. Working through the design's own numbers puts the centre at about 21.9 kW/m2, right at the limit, so the limit did set the size. Counted instead as waste heat from the transmitter tubes, the design would produce only about a fifth of the limit, but the report gives the number as radio power, not heat. | T0 | MED |
| CLM-0896 | The patent describes measuring the incoming steering signal at scattered sensors, not at every antenna, and working out the values in between. The patent does not say how far apart those sensors are, which is the number that decides whether the method works. | T3 | HIGH |
| CLM-0897 | The satellite aims its beam by listening for a low-power signal sent up from the receiving station, measuring the shape of that arriving wave and transmitting a time-reversed copy of it. The patent says in terms that this is what lets the structure be floppy. It is in the patent's claims, the part that sets what the patent protects, not just the explanatory text, and it stayed in the claims of the patent as granted, which was published in 2021. | T3 | HIGH |
| CLM-0899 | The patent never says the steering signal is protected in any way. There is a difference between scrambling that signal so nobody can read it and signing it so the satellite can tell a fake from the real thing. Only the second would stop someone aiming the beam. The patent has neither. | T3 | 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-0901 | Each antenna must hold its position along the line to the receiver within about three millimetres for a tenth of a decibel. The whole 1970s design budget, converted to the same units, was 3.4 millimetres. One metre of structural bending is nearly three thousand degrees of phase, and if that is not corrected the antennas stop adding up at all - a billion of them lose ninety decibels, which is everything. | T0 | HIGH |
| CLM-0903 | The shared clock tells every sensor to take its reading at the same moment. How precise that clock must be depends on how fast the thing being read is changing. If the reference tone is at the same frequency as the incoming signal, the reading changes only as the structure bends, and milliseconds are plenty. If the two differ by megahertz, the reading spins at megahertz too, and nanoseconds are needed. In the built prototype the two differ by 10 MHz, but it tracks the signal continuously and takes no separate readings, so this timing requirement does not arise there in this form. | T0 | HIGH |
| CLM-0904 | Nothing the satellite distributes to itself is free. Each distributed signal reintroduces a small part of the error the steering trick removed, and the size of that part is just how far its frequency sits from the ground signal's. Two separate effects that looked unrelated turn out to be one rule. | T0 | HIGH |
| CLM-0905 | Sharing a clock is not the same as being told what to do. The clock and the carrier tell the antennas nothing about where to send the power - that comes from the ground signal, and each antenna works it out for itself. If the shared signal fails, the beam does not go somewhere wrong, it stops being a beam. | T3 | HIGH |
| CLM-0907 | No source held here gives a computed model of how a kilometre-scale structure of this kind bends: its modes and their shapes. Two separate calculations here both stop at the same point for want of it. Until somebody models that structure, both answers stay as ratios rather than numbers. | T0 | MED |
| CLM-0908 | There are two different ways the scheme can fail and they are usually confused. One is that the structure has moved so far the satellite cannot tell which wave crest it is looking at. The other is that the values worked out between sensors are not accurate enough. The second gets better as the sensors get denser, but the first does not get better at all, so a well-sampled design runs into the first problem, not the second. | T0 | HIGH |
| CLM-0910 | The problem of not knowing which wave crest you are looking at is solved by sending a second tone at a slightly different frequency. The beat between them repeats only every fifteen metres instead of every six centimetres, which is more than enough to tell the crests apart. Measuring the structure directly would also work, and needs about two hundred picoseconds rather than the ten that would be needed to do the whole job. | T0 | MED |
| 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-0912 | How far apart the sensors may sit depends on how smoothly the structure bends, not on how big it is. The answer comes out as a fraction of the distance over which the bending stays similar to itself, and that fraction shrinks as the square root of how much the structure moves. Spacing them more than about 2.35 times that distance apart is worse than not correcting at all. To turn any of it into a number of metres somebody has to model how a two-kilometre structure actually flexes, and nobody here has. | T0 | HIGH |
| CLM-0913 | When the satellite corrects its own bending by listening to the ground signal, what is left over is not how far the antennas moved. It is only the part of that movement the scattered sensors could not see. A structure that bows a metre smoothly, with sensors close enough to follow the bow, is barely affected; a millimetre of movement between sensors costs the full millimetre. If the frequency scaling is exact, the frequency of the ground signal drops out of the answer. | T0 | HIGH |
| CLM-0915 | The leftover error does two different kinds of damage and they need separate budgets. A uniform tilt across the antenna does not weaken the beam, it moves it; everything else weakens it. Missing the receiver by 250 metres from geostationary orbit means pointing to about one and a half seconds of arc, and the steering system has to do somewhere between forty and a hundred and twenty times better than the structure can be pointed mechanically - depending on whether you take the whole structure or an individual sub-panel. | T0 | HIGH |
| CLM-0916 | The built prototype gives every single antenna its own steering circuit rather than sharing one between a group. The steering signal arrives at one frequency, the power leaves at another 20 megahertz away, and a third frequency midway between them is piped to every antenna by cable as the common reference. The paper quotes two sets of these frequencies - what it designed for and what it actually measured, one megahertz apart - and taking one number from each set is how a reader gets the wrong answer. It kept the beam locked while the whole array was physically rotated. | T2 | MED |
| CLM-0917 | Sensors placed too far apart do not merely help less. Past a certain spacing they make the beam worse than doing nothing, because each is reporting a bend that has nothing to do with the antenna it is being used to correct. That point is about two and a third times the distance over which the structure's bending stays similar to itself - not, as first drafted, one times it. | T0 | HIGH |
| CLM-0933 | In 1988 the leading experimenter listed three numbers side by side: the best efficiency physics allows for beaming power and converting it back, 76 per cent; an experimental figure, 54; and what a solar power satellite design assumes, 58 to 72. The design range is above the experimental figure, and its top end is close to the limit. | T3 | MED |
| CLM-0935 | The IPCC's chapter on energy systems mentions space-based solar power once, in a single sentence, among a list of alternative solar technologies that includes solar chimneys. It says the concept takes advantage of continuous sunlight but faces a formidable obstacle: getting the power down safely, efficiently and cheaply. It gives it no cost, no potential figure, no table row and no section of its own. | T3 | HIGH |
| CLM-0942 | Three documents held here give three different sizes for the same satellite's transmitting antenna. The patent says 1 to 1.5 km across and explains why. A 2026 paper says about 2 km by 2 km, citing someone else. A 2024 law review says 2 km across. The last two use the same number for different shapes, and a 2 km circle collects a fifth less than a 2 km square. | T3 | HIGH |
| CLM-0954 | The 1975 designers worked out how much their kilometre-wide antenna would bend, precisely so they could decide how good the beam-steering correction had to be. The biggest bend came from building it slightly wrong in the first place - roughly three quarters of a metre to a metre and a half at the edge, depending on how the stated angle is read - and that does not move. Heat bending could be held to a few centimetres if the top and bottom of the truss were kept within four degrees of each other. | T3 | HIGH |
| CLM-0955 | The earlier formula for how much beam error is left after interpolating between sparse sensors turns out to be pessimistic by somewhere between 20 per cent and a factor of three, when the structure is modelled as a handful of bending modes rather than as random roughness. So the sensor spacings it permits are on the safe side, by 10 to 70 per cent. | T0 | HIGH |
| CLM-0956 | If the antenna structure bends by the amounts the 1975 design allowed for - millimetres to a few centimetres from heating - then sensors every 10 to 18 metres, which is the size of the building blocks it was made from, are far more than enough to keep the beam within its error budget. They would only become too sparse if the bending reached tens of centimetres. | T0 | MED |
| CLM-0957 | The idea was to listen to the pitch of the reference signal at each antenna element, work out how fast that element is moving, and add it up to get where it is. It fails three ways: the pitch cannot be measured finely enough over the time the structure takes to move; the 1981 design's own timing system deliberately cancels exactly that pitch change at the element; and the reference signal travels along the structure, not along the beam, so it barely notices the bending the beam cares about. | T0 | HIGH |
| CLM-0958 | What is left of the idea is useful but narrower: the timing system already tracks how the reference path stretches, and the fast part of that stretching is the structure's vibration. It cannot give the slow bending that the sensor-spacing question is about, but it could tell you how the vibration is shared between modes - which is the one thing the modelling could not settle. | T0 | MED |
| CLM-0968 | The 1975 antenna study worked out how hot the middle of the transmitter gets depending on how efficient the tubes are and how tightly they are packed. With the tubes at 70 per cent efficiency and an aluminium frame, it found they had to be spread almost evenly across the whole kilometre to stay within what the frame could take. | T3 | HIGH |
| CLM-1019 | The programme gave three reasons for choosing the klystron; the company that designed the satellite said the choice was more or less arbitrary and the magnetron might be better. The 85 per cent tube efficiency that every cost chain uses is the contractor's estimate. | T3 | HIGH |
| CLM-1063 | In 1980 the magnetron satellite was the lightest per kilowatt on paper and the most efficient tube on the bench, the klystron was the panel's safer bet on noise and voltage, and the panel warned that every efficiency budget so far used the most optimistic number for the tube. | T3 | HIGH |
| CLM-1064 | The best transistor anyone had measured in 1980 was 72 per cent efficient at one watt and 60 per cent at five; the satellite designs assumed 80, and were heavier than the tube designs. | T3 | HIGH |
| CLM-1143 | Japan's flagship 2015 ground test: a solid-state GaN array of about one and a half square metres sent 1.8 kilowatts 55 metres and 335 watts of DC came out, under a fifth of the microwave power and about one-fifteenth of the DC that went in, with the beam self-steering onto the receiver. | T2 | MED |
| CLM-1176 | Each transmitting element on the satellite is a small cluster of three short rod antennas standing a quarter of a wavelength apart, all pointing along the long axis of the helix. They pass through a flat layer at their middle, which feeds them and acts as their ground plane. | T3 | MED |
| CLM-1177 | The flat layers that carry the antennas must be stacked at least a quarter of a wavelength apart, but not so far apart that neighbouring antennas are more than about six-tenths of a wavelength away, or the beam grows unwanted side beams. The layers are very thin, less than a twentieth of the gap between them. | T3 | MED |
| CLM-1178 | The antenna is one twisted surface, like a ribbon turned half a turn from top to bottom. Looking down its axis you see a complete circle; from one side it looks like an hourglass, and it presents the same area to the Earth whichever way it faces. | T3 | MED |
| CLM-1182 | In this study the huge twisted surface is tiled with small six-sided panels, each about 0.6 to 1.1 metres across. Each panel is a little staircase of thin strips a few centimetres apart, with the antennas standing between the steps and solar cells on both faces of each strip, except near the centre where the strips would shade each other. | T5 | MED |
| CLM-1186 | The patent describes an existing kind of solar collector whose layers step up like a staircase, with risers that can be panels that shed heat; it does not say its own helical design has such risers. In the helical design the rows are typically 14 millimetres apart, and the whole thing may be hundreds to thousands of metres across and tall, so it has many thousands of rows. | T3 | MED |
| CLM-1190 | The study's reference design uses four satellites about 2,500 km above the Moon, each about the size of a space station (148 by 58 m): a 58 m square microwave antenna between two solar wings. Between them they beam a steady 1 MW to the base at 100 GHz, with batteries on board for when a satellite is in the Moon's shadow. | T3 | HIGH |
| CLM-1191 | The study sized its transmitting and receiving antennas with a standard beam formula, assumed about half the transmitted power would be caught on the way down, and found that above 35 GHz the antennas are small enough that they stop mattering much to the total mass, and that going beyond 100 GHz gains little. | T3 | MED |
| CLM-1193 | A 1979 study for NASA drew the pilot transmitter's beam about three-quarters of a degree wide, a few hundred kilometres across by the time it reaches the satellites, and argued that with 100 satellites spread along a sixth of the orbit only one would sit in each pilot beam; the others would see a site's pilot only through its much weaker side lobes. | T3 | MED |
| CLM-1195 | The design builds one thin, nearly kilometre-wide disc out of many metre-sized flat satellites, each with solar cells on one side and radio transmitters on the other; the first project's disc is 967 m across. | T4 | MED |
| CLM-1197 | The company beams at 10 GHz and claims its beam loses nothing in space on the way down, where the other designs in its own table lose between a sixth and a half. | T4 | MED |
| CLM-1201 | Caltech's design has no single large structure. Many separate square craft, each 60 metres across, fly side by side in geostationary orbit and act together as one antenna 1.6 kilometres wide. Each craft is launched rolled up into a drum about 2 metres wide and 1.5 metres tall, and unrolls in orbit. | T2 | MED |
| CLM-1214 | The company says its beam will be on 99.9 per cent of the time, and that a 2 million dollar development agreement with a US government energy agency (ARPA-E) supports its work. It plans a public power-beaming demonstration in March 2027 and says it expects record efficiency. None of this is independently confirmed. | T6 | LOW |
| CLM-1220 | The receiving site sends a guide signal up to the satellite, and the satellite's many small transmitters use it to line up their beams on that site. The design uses 2.45 GHz microwaves. | T3 | MED |
| CLM-1225 | A US start-up said in late 2025 that it had beamed power from a plane to the ground, and planned an orbital test in 2028 and its first megawatt from space in 2030. | T6 | MED |
| CLM-1227 | China's state broadcaster said in 2022 that China planned a 10 kW orbital test in 2028, 10 MW by 2035 and a 2 GW commercial plant by 2050. | T5 | MED |
| CLM-1228 | A US start-up said its first power-beaming satellite would launch in October 2026 and try to send power to another spacecraft. | T6 | MED |
| CLM-1232 | In 1978 a NASA contractor designed a satellite that would turn sunlight into an infrared laser beam and send it, by way of a mirror satellite high above the equator, to a ground station about 30 m across. The ground station would use the beam as heat to run turbines. On paper, about 5 to 6 per cent of the sunlight collected in space would reach the grid as electricity. | T3 | MED |
| CLM-1234 | A second NASA-funded study in 1980 imagined the standard power satellite with its microwave transmitters swapped for about twenty very large infrared lasers. On paper, about one-seventh of the electricity made on the satellite would reach the grid, a bit more on mountain sites. The receivers would again turn the beam into heat. | T3 | MED |
| CLM-1238 | In 1978 the US energy department asked whether lasers could replace the microwave beam. Its review said the lasers of the day were not good enough, mainly because they wasted too much electricity, but that they might become good enough in time. | T3 | MED |
| CLM-1240 | In 1999 a US national laboratory sent infrared light from a bank of laser diodes across a lab room onto ordinary solar cells and got a few watts out, enough to turn a small motor. The beam was patchy and the run was cut short, so less than one per cent of the electricity put in came out at the far end. | T3 | LOW |
| CLM-1248 | By December 2025 Japan's space roadmap said hardware for a large-structure test had been handed over for a supply-ship flight, and a satellite to beam power from low orbit to the ground had been built. | T3 | HIGH |
| CLM-1249 | Japan's December 2025 space roadmap plans to launch a solar power demonstration satellite, OHISAMA, on a private Kairos rocket in the year from April 2026, to beam power from low orbit to the ground. | T3 | HIGH |
| CLM-1250 | In a 2015 ground test in Japan, a 1.8 kW microwave beam sent over 55 m delivered about a third of a kilowatt when the steering corrected a deliberate panel misalignment, and about 90 W, roughly a quarter of that, when it did not. | T5 | MED |
| CLM-1274 | NASA said its programme had built a test solar panel that it expected to lead to arrays more than three times lighter per watt than the best of the day, kept its power beams to about a tenth of midday sunlight for safety, and found that the very high voltages assumed in 1979 would not work in space. | T5 | MED |
| CLM-1311 | The 1979 design sends a sample of the reference back up each cable and adjusts until the far end matches the source. That makes cable length stop mattering. What still matters is any difference between the trip out and the trip back, and small fixed offsets in each box. These pile up from the centre to the antenna elements. | T3 | MED |
| CLM-1312 | In 1979 the contractor simulated the whole reference-distribution tree. Small, random timing errors were added at each branching level, and the simulation measured how much beam power was lost. To keep 96% of the ideal beam, the errors could add up to about 12 degrees, or about 6 degrees at each of four levels. | T3 | MED |
| CLM-1313 | An error near the antenna elements is different at each element. It averages out in pointing but scatters power. An error near the centre is shared by a whole block of the array. It tilts that block and pushes the beam off target. | T3 | MED |
| CLM-1365 | The paper's biggest design is a laser array 10 km across that would push a sail a metre wide, carrying a chip of about a gram, to a fifth of light speed in ten minutes. It would then reach the nearest star in about 20 years. | T2 | MED |
| CLM-1366 | The paper plans to build up in stages. Small ground lasers come first, then a 1 km array in orbit, and only at the end the 10 km array that its star-flight numbers assume. | T2 | MED |
| CLM-1441 | Documents give the size of the CASSIOPeiA satellite design as anything from 1 to 2 km across. For a full-size version delivering 2 gigawatts from geostationary orbit, the best supported figure is about 1.7 km, from a 2021 study for the UK government. A 2020 report gives 1.6 km and credits the designer's 2019 paper, but that paper gives 1.6 km only as a general minimum for any such antenna at one radio frequency, not as this design's size. None of these is a measured size: the satellite has not been built. | T4 | MED |
| CLM-1463 | If each antenna in a row starts its wave a moment after its neighbour, the beam leans away from straight ahead. The size of the lean follows from three things: how big the time step is, how fast the waves travel, and how far apart the antennas are. A bigger step, or closer antennas, gives a bigger lean. | T0 | MED |
| CLM-1464 | Adding antennas to a row that all send together does two things. The beam gets narrower, and it gets stronger straight ahead: twice as many antennas give four times the strength in that direction. A row 16 antennas long, half a wave apart, makes a beam about 6 degrees wide. | T0 | MED |
| CLM-1465 | If the antennas in a row are spaced too far apart, extra beams as strong as the main one go out in other directions. How close they must be depends on how far the beam is swung. Unswung, up to a whole wavelength apart is safe. Swung 30 degrees, the antennas must be closer than two-thirds of a wavelength. | T0 | MED |
| CLM-1466 | The pilot method works out of each antenna's own measurement, not out of a plan of where the antennas should be. Each antenna times its reply from when the pilot reached it. So if one antenna has moved, its timing changes by just the right amount, and all the replies still arrive together where the pilot came from. A 1980 NASA memorandum set out the principle; it does not discuss a moved antenna, but its working covers one. | T3 | MED |
| CLM-1472 | The designer of the UK's CASSIOPeiA satellite says it has no moving parts and is built from many small identical pieces, so when pieces fail it loses power gradually rather than stopping. It is meant to run for 20 years or more with no planned repairs. A 2020 UK government study repeats this and treats the satellite's upkeep as a slow loss of power rather than a repair bill. | T4 | MED |
| CLM-1478 | Almost everything that can go wrong with this design makes the beam fall apart and become harmless, which is the right way to fail. Two things do not. If someone fakes the ground signal, the satellite aims at the fake. And if the internal reference cabling drifts, the beam weakens and wanders rather than switching off. | T0 | MED |
| 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-1481 | Worked out from the 1978 report's own figures: if the design's thousands of antenna sections fall out of step, the beam does not fill half the sky. It spreads to a patch roughly 400 km wide, and the power in it, on average, is close to the report's own figure for that case, several thousand times weaker than at the centre of the working beam. | T0 | MED |