Caltech claims to have beamed energy to Earth from satellite Researchers at a US university claim to have beamed energy from a satellite in orbit to a detector on Earth, demonstrating that harvesting energy from solar panels in space is technically possible. The eggheads at the California Institute of Technology, aka Caltech, said they used a satellite launched into orbit in January to …
In the 80s a comms technician told me that part of his job was to clear the dead pigeons away from area below a microwave link endpoint. I don't know why the pigeons were dying, maybe flying and crashing into the hard antenna for some reason, or being affected by the RF energy. If it was the latter then.... I do remember also being shown a tunnel through the foliage of a tree that had grown into the path of a MW RF link. Might have been humans cleared the hole as a pathway, or the RF dunno.
Large space-based, microwave power transmitters are generally designed for safe power densities, like 1 milliwatt per square centimeter. Further, the beams were designed lose focus if the beam strayed from the rectenna though the reference to that is eluding me.
"Further, the beams were designed lose focus if the beam strayed from the rectenna though the reference to that is eluding me."
I wish I had a handy reference, but the receiver has to continue providing a handshake with the satellite or the power beam would shut down. There's always "what happens if", but it's possible to build a system that will fail safe rather than fail in the on condition. Relying on focus could be too variable to be safe.
> 1 milliwatt per square centimeter
Converting to more conventional units, that's 10 watts per square meter. (Compare to ~1kW per square meter for direct solar irradiation)
This means you'll need a receiving antenna 100 times larger than the equivalent solar array working at peak capacity; or 10 times larger than one working at 10% capacity (e.g. on a cloudy day). There's a possibility it could work at night too, although the satellites would have to be able to keep out of earth shadow, and/or relay power between themselves.
At that power density, the "2GW" proposed from the article would need 20,000 hectares (200 km2) of receiver. Even if that can be done with a wire mesh that doesn't obstruct the sky, so the ground underneath can be used for other purposes, that's an absolutely vast construction.
And of course, you still need to buy the kilometer-square solar array, plus microwave power conversion. And more importantly, launch the whole mass into space. And then keep it in orbit (or replace it when it de-orbits).
From one extreme to another. I'm thinking:
The Eye Of Harmony on Gallifrey powering TARDIS's via their onboard collector.
Earthsearch 2 - Solaria a free will computer operating one of many artificial suns orbiting Earth in transit to a new star system (Before it decides it want's to be the boss of all the other's & threatens to start destroying cities).
Star Trek & many others transmitting power by such techniques (Even if there is no obvious collector on the recipients end).
Icon - Looking for my sonic as per example one.
There was a road near a military base that used high-powered RADAR. The signal was strong enough to interfere with car's fuel injection electronics resulting in several stalled vehicles along this road. A business nearby with a pickup truck with a carburetor with no electronics made money towing these vehicles out of range of the RADAR.
"Researchers at a US university claim to have beamed energy from a satellite in orbit to a detector on Earth."
I think the Soviet Union's Sputnik program can claim prior art[0].
For "beamed" energy, you don't have to look much past satellite television. There is a reason you can't get New York programming in San Francisco.
[0]What, you don't think my little receiver listening to the "beep, beep, beep" was an energy detector?
I think the idea was that instead of a broadcast signal, like radio or satellite TV they were claiming to have sent all (or at least the large majority) of the energy directly to the receiver.
Of course one issue with beaming electro-magnetic waves through the atmosphere is absorbtion, which did not appear to be addressed by the described test.
Of course one issue with beaming electro-magnetic waves through the atmosphere is absorbtion, which did not appear to be addressed by the described test.
It's fine. It'll be just another example of man-made climate change. To get 2GW down to the surface, a lot more energy will be absorbed by the atmosphere, which will have a measurable effect. Mainly due to the sensitivity of measuring devices. Whether that translates to any noticeable effect is, like climate science in general a whole different matter. The marketing pitch will have to tip-toe around the issue of solving global warming by heating the atmosphere.
But it'll probably follow the usual model, ie promise much, deliver little and spend the money until it runs out. Meanwhile, the money could have been better spent on Small/Medium/Large nuclear reactors instead. We know they work. But any SF fan knows there are military applications, along with a lot of prior art. One of my favorites is to spin the generating constellation to induce vortices and use it as a tornado generator. That could be lucrative. Ohnoes! Ravaged by 'natural' disasters? All your solar panels and windmills destroyed by a combination of severe winds and microwave induction? Call us now for a quote for a new power source!
>To get 2GW down to the surface, a lot more energy will be absorbed by the atmosphere, which will have a measurable effect.
The Earth gets almost two billions gigawatts from the Sun by just being there.
I don't know what you plan to use to measure the effect of adding 2 gigawatts to that, but it would have to be one hell of a sensitive instrument.
Of course, that really, really big number can vary by up to 3%, or several million gigawatts, just because of solar weather alone.
So, no, not measurable at all. Maybe, just maybe, if we replaced all generation with space solar, there might be an effect that could be detectable, in a statistical sense over the course of decades... but then again, the benefit in getting rid of fossil carbon would be far greater.
I don't know what you plan to use to measure the effect of adding 2 gigawatts to that, but it would have to be one hell of a sensitive instrument.
That's actually the easy bit. We already have instruments that can measure energy sources that are far, far weaker, eg radio telescopes. Which presumably will be affected if they happen to be in the beam path.
Of course, that really, really big number can vary by up to 3%, or several million gigawatts, just because of solar weather alone.
Sorry, no. TSI is officially (in climate Science) a constant. In real science, it isn't, and is.. problematic, eg-
https://en.wikipedia.org/wiki/Solar_irradiance#2014_reassessment
In 2014 a new ACRIM composite was developed using the updated ACRIM3 record. It added corrections for scattering and diffraction revealed during recent testing at TRF and two algorithm updates. The algorithm updates more accurately account for instrument thermal behavior and parsing of shutter cycle data. These corrected a component of the quasi-annual spurious signal and increased the signal-to-noise ratio, respectively...
...These arise from the fact that ACRIM uses the original TSI results published by the satellite experiment teams while PMOD significantly modifies some results to conform them to specific TSI proxy models. The implications of increasing TSI during the global warming of the last two decades of the 20th century are that solar forcing may be a marginally larger factor in climate change than represented in the CMIP5 general circulation climate models.
So adjust a model using another model, then throw the results into yet another model and convince people your results accurately reflect reality. Then gloss over observable, measurable effects on components like UV, despite knowing UV has a big impact on atmospheric photochemistry.. As will adding microwave energy.
Maybe, just maybe, if we replaced all generation with space solar, there might be an effect that could be detectable, in a statistical sense over the course of decades... but then again, the benefit in getting rid of fossil carbon would be far greater.
Or not, and there is no benefit from neo-luddites depriving the world of a useful energy source. Nor is there any beneft in denying nuclear energy, yet the Green lobby does this. So a 2GW nuclear plant should cost around $10bn, a space-based microwave heater will probably cost a lot more and thanks to simple physics/reality, will have an obvious effect on atmospheric warming.. The exact thing we're supposed to be trying to prevent.
Rest is a simple engineering challenge. Start with 2GW at TOA.. how large a receiver array would you need to collect that, assuming you're using a 'safe' 0.5mW/m beam power density? Cover the Earth in chicken wire to save the planet!
"The Earth gets almost two billions gigawatts from the Sun by just being there.
I don't know what you plan to use to measure the effect of adding 2 gigawatts to that, but it would have to be one hell of a sensitive instrument."
It's not that hard to measure. The issue that will need addressing is how adding 2 gigawatts to a specific location given a wide range of weather parameters might affect the local microclimate. Changing the gross wind patterns can lead to rainfall moving to a different area which would impact local agriculture cause erosion issues, etc. This sort of problem has already been shown with the Heat Island Effect of large cities. It's subtle and the modeling, like all weather modeling, is difficult to do with arbitrary precision.
In the grand sum of things, a power satellite will often be blocking more sunlight energy hitting the Earth than it might be beaming down for a net cooling effect, but that doesn't address the local effects and the triangle of sun, Earth, sat positions. When the sat shadow is not on the Earth, there is a very slight addition to the energy striking the Earth which might be offset by not generating greenhouse gases in the production of electricity. It's all very involved and not easily hand-waved away.
It never crossed my mind before. But 2GW is a lot of energy. Radio transmitters aren't typically all that efficient. The internet tells me 70% efficiency is considered to be excellent. But let's assume that's negative thinking and that our space borne transmitter is 99% efficient. There's still 10^7 (10 million) watts (every second) of waste heat we will need to get rid of. We almost certainly can't just dump it in the nearest large body of water. How are we going to cool this thing?
We almost certainly can't just dump it in the nearest large body of water. How are we going to cool this thing?
There's also the inverse square law, which being a law, is not meant to be broken. But cooling is easy, it'll be air-cooled. Or water cooled given atmospheric water will absorb microwaves. These are however countered by modern financial laws, namely that if you create something Green, suckers will throw billions in your general direction.
To be fair, we can already detect the power of stars thousands of light-years away. Sounds like detecting power from something a few hundred miles overhead shouldn't be too much of a stretch...
This has been a science fiction staple for decades, and it does make a lot of sense if the energy is delivered at a sufficiently low power that e.g. sheep, birds, and, oh, people can wander through the collection farm without being toasted. I can get plenty of damage from a mere kilowatt per square meter of sunlight.
The scientists involved may need some of these to reduce their surface temperature --->
Also similar to the technique used in civilian phased-array radar systems or the phased-array antenna available for 5G phone signals.
But I guess all of us imperialist warmonger commentards are going to be more familiar with the military application and it does tie nicely into the use within war-torn areas (technology giveth and taketh away).
But I guess all of us imperialist warmonger commentards are going to be more familiar with the military application and it does tie nicely into the use within war-torn areas (technology giveth and taketh away).
I'm guessing war-mongering may have delayed civilian applications because for a while, phased-array tech was rather classified. As for this application in war-torn areas, I wonder if the wires from all the expended wire-guided missiles could be used as antenna?
Building really large solar arrays in space is tricky, but I don't think it's impossible. I think there are very light solar panel materials in development; not very efficient, but in this case the weight-to-power ratio is all that really matters. I think it's feasible... technically.
Politically, it's another matter.
Anything that happens to be under a gigawatt microwave beam without being designed specifically for it is going to be screwed up very quickly, and the satellites would have to be able to target accurately as part of their normal operation. So, there is literally no way to build one of these things without it being a few radio commands away from being a weapon that's almost impossible to defend against. I can't see this happening without a rework of the Outer Space Treaty, and good luck getting that done, with international relationships being what they are right now.
Sadly, the easiest way to make this feasible would probably go through Russia or China or whatever deciding to openly build space-based missile platforms, at which point the ban on space weapons would be obsolete anyway.
I think it's feasible... technically.
That's been believed to be true for a while.
Politically, it's another matter.
There's also the minor question of whether it's economically feasible. Space Karen may have knocked a zero off the cost of lift to orbit but a 2GW orbiting SPS is still going to be literally massive and thus expensive to build. Unless that cost is less than the cost of ground based systems (possibly with battery storage included) it's a non-starter.
Your £5 solar panel only works in day time for a start
Yeh, but it works. A decent solar panel should be able to produce >300Wm^2. A microwave receiver running at safe power levels will deliver a couple of mW at most. Then you still have day/night cycles in space, with anything in the Earth's orbit being in the Earth's shadow for some part of the day. Which would happen to be at night. Even if you run a constellation of low-orbit solar collectors, if it's night time on the surface, it's shade/night time in space. Plus you'd have the challenge of reliable tracking for power delivery, or creating space-based relaying to get from day to nightside orbits and to the surface.
So it's one of those technofetish ideas slathered in greenwash and peddled to gullible politicians and investors. Better, more reliable and cheaper alternatives already exist down in the gravity well, yet neo-luddites want to ban them. There'll also be fun from the Greens who think all radiation is bad, especially the microwaves from mobile phones..
Putting nuclear to one side, I believe a 1km^2 solar panel array would generate 100MW of power, so I'm sure building 20 of these on the ground would be cheaper than trying to build equivalent power generation in space. Surely we should be looking into efficient power distribution over the planets surface, so that solar arrays on the sunny side of the planet, could be powering the dark side.
A big, orbital, photovoltaic array powered microwave transmitter with advanced beam forming ability?
Or, a big, orbital mirror?
Panel members: Concerns & Questions:
Military: What kinda body count? / What's our defense?
Engineer: Possibility/efficiency/manufacture/deployment/maintenance cycle?
Bean Counter: Monetary cost per kill, or kilowatt, delivered ( Who's paying for this? Timeshare?)
Farmer: What's it do for my crop yield?
Astronomer: [as "Mr. Bill" - apologies for the dated reference] Nooooo!!!
When will I be able to direct a space microwave to heat up my curry using a phone app?
You can do that today. Of course, nothing will happen. That may be better than Stage 2 when a beam will appear and cook something -- maybe your curry, maybe the picnic table, maybe you.
You can do that today. No "phone app" ::spit:: required.
Head for fleabay (or your favorite other tat emporium) and look up "solar oven" or "sun oven".
Putting the solar concentrater at ground level makes life so much easier by cutting out the myriad middlemen.
Easier on the ol' pocketbook, too. You can make one yourself fairly easily if you're handy (plans are available all over t'intarwebtubes), or just purchase one. Remember, you get what you pay for ... I own a couple decades-old versions from Sun Oven that still work admirably well. Recommended.
This post has been deleted by its author
Queen Mary University of London (QMUL) has been awarded £960,000 from the UK government to investigate wireless technology for spaced-based solar power (SBSP).
https://www.qmul.ac.uk/media/news/2023/se/queen-mary-to-develop-wireless-technology-to-beam-down-solar-power-from-space.html
Can we transmit power from space to the ground? We already do it, see radio communications.
Can we transmit enough power to be useful? Sure, a big mirror in space could light up disaster areas at night, and allow solar panels to power up equipment. It could be very useful in cold dark latitudes. The same mirror could direct solar insolation away from deserts and make them habitable, or simply reduce climate change.
Will it be banned? Probably, far too easy to weaponise it. Even a plane space mirror used in daytime to double solar insolation would be very difficult to defend. If you had several you can just burn out the enemy. Even with massive protections you could still get hacking or space rocks making it lethal.
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