X-37b space plane’s microwave power beam experiment(thedrive.com)
thedrive.com
X-37b space plane’s microwave power beam experiment
https://www.thedrive.com/the-war-zone/33339/x-37b-space-planes-microwave-power-beam-experiment-is-a-way-bigger-deal-than-it-seems
163 comments
For space-based solar to be efficient, ie for it to be better than just installing normal solar panels, the beamed energy would have to be at least as powerful as sunlight (1000watts per square meter). That is a very very high bar to overcome. Compared to the simplicity of solar+batteries, I don't see a future for beaming solar energy down from space. Maybe once every square meter of roof space has been dedicated to solar panels, once every city is essentially blanketed in panels, then it may be time to turn to space for more energy.
One might say that space-based solar would operate 24/7 and so is better than normal solar panels. That's isn't reality. Low-orbit satellites spend half their day in darkness too. To hit a receiver on the night side of earth a satellite would have to be at a very high orbit, reducing beam efficiency and increasing launch costs.
One might say that space-based solar would operate 24/7 and so is better than normal solar panels. That's isn't reality. Low-orbit satellites spend half their day in darkness too. To hit a receiver on the night side of earth a satellite would have to be at a very high orbit, reducing beam efficiency and increasing launch costs.
Not true. Photovoltaics are ~20% efficient, so you're looking at 200 W/m2 in full sunlight. Plus typical solar capacity factors are about 25% so you're down to 50 W/m2 average power generation, with a subjective penalty for intermittency.
RF rectification is ~90% efficient, so that same 1000 W/m2 gives ~4.5x the power density of daylight PV, plus a capacity factor of nearly 100% gives 18x the energy density of terrestrial PV - and its baseload power.
Mankins will pitch you 100 W/m2 as a useful RF energy density to be competitive with terrestrial solar. You may also be able to include photovoltaics in your receiving antenna and have it both ways.
RF rectification is ~90% efficient, so that same 1000 W/m2 gives ~4.5x the power density of daylight PV, plus a capacity factor of nearly 100% gives 18x the energy density of terrestrial PV - and its baseload power.
Mankins will pitch you 100 W/m2 as a useful RF energy density to be competitive with terrestrial solar. You may also be able to include photovoltaics in your receiving antenna and have it both ways.
If you replace microwaves with a laser, you can get much higher efficiencies out of a solar panel as solar panels really want to convert monochromatic light.
What really kills microwaves for power transfer is the minimum sizes of the transmitter/receiver thanks to diffraction. If your going from GEO to ground, I believe you need on the order of square kilometer sized arrays on both ends.
For ground to air applications, rectennas are too bulky and heavy to be practical. If you look at the last NASA power beaming challenge, all of the contestants went with optical power transfer because it was better in W/kg and in W/sq meter.
Disclaimer: I’m involved with free-space optical power transfer.
What really kills microwaves for power transfer is the minimum sizes of the transmitter/receiver thanks to diffraction. If your going from GEO to ground, I believe you need on the order of square kilometer sized arrays on both ends.
For ground to air applications, rectennas are too bulky and heavy to be practical. If you look at the last NASA power beaming challenge, all of the contestants went with optical power transfer because it was better in W/kg and in W/sq meter.
Disclaimer: I’m involved with free-space optical power transfer.
You're right about the size. The book I mentioned puts the cost of the ground antenna at 0.7 cents/kWh, so not terrible.
Lasers have definitely been considered for SPS. The main challenge is that clouds get in the way. (And you don't want the power density so high that it works as a weapon, but I imagine you can avoid that.)
Was the NASA challenge for SPS, or other applications?
Lasers have definitely been considered for SPS. The main challenge is that clouds get in the way. (And you don't want the power density so high that it works as a weapon, but I imagine you can avoid that.)
Was the NASA challenge for SPS, or other applications?
The challenge was nominally for determining feasibility of a space elevator as there was a sister challenge for making high strength/weight cables (it had a bigger problem of the DOD snapping up the promising teams to work on armor every year).
If you keep the power down to the order of 10x sunlight, it doesn’t make a very good weapon.
If you keep the power down to the order of 10x sunlight, it doesn’t make a very good weapon.
I’m sorry but 10X the sun over a square kilometer 24/7 is a incredible weapon.
You mean 0.7 cents per kW, not kWh, right? Because hydroelectric energy costs 0.7 cents per kWh everything included, including profit.
No, I mean levelized cost per kWh (estimated retail, iirc).
Hydro is quite cheap, but it's not available everywhere and only scales to about 10% of global energy demand: https://dothemath.ucsd.edu/2011/12/how-much-dam-energy-can-w...
All other sources cost a good bit more than that. The US average is over 13 cents/kWh: https://www.electricchoice.com/electricity-prices-by-state/
Hydro is quite cheap, but it's not available everywhere and only scales to about 10% of global energy demand: https://dothemath.ucsd.edu/2011/12/how-much-dam-energy-can-w...
All other sources cost a good bit more than that. The US average is over 13 cents/kWh: https://www.electricchoice.com/electricity-prices-by-state/
Well you must be getting screwed over in the US. Québec hydro is 6 cents per kWh, at your house, and is profitable. State owned nuclear energy in Europe has comparable costs.
If only the transmitter and receiver for space solar is a very significant fraction of the cost per kWh shipped at your house with profits of nuclear or hydro it can't be viable.
If only the transmitter and receiver for space solar is a very significant fraction of the cost per kWh shipped at your house with profits of nuclear or hydro it can't be viable.
13.3 cents (us)/kWh is the US national average for electricity cost, not any given region or source.
Canada's national average (this excludes the territories) is 10 cents (us)/kWh. Québec has the cheapest energy in Canada, primarily due to its proximity to hydroelectric sources, at 5.5 cents (us)/kWh. In parts of the US where hydroelectric is the dominant energy source, prices are comparable.
Including the territories Canada's average is 13 cents (us)/kWh.
Canada's national average (this excludes the territories) is 10 cents (us)/kWh. Québec has the cheapest energy in Canada, primarily due to its proximity to hydroelectric sources, at 5.5 cents (us)/kWh. In parts of the US where hydroelectric is the dominant energy source, prices are comparable.
Including the territories Canada's average is 13 cents (us)/kWh.
Right, and total cost for SPS would be around 5 cents/kWh. The receiver is a small portion of that at 0.7 cents.
13 cents/kWh is the US national average including all sources and regions, according to the link I posted.
13 cents/kWh is the US national average including all sources and regions, according to the link I posted.
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The book's cost estimate is for a satellite in GEO. You get steady power for all but a few hours per year, and 5.4X as much energy from sunlight in 24 hours, compared to the same flat area of ground. According to the book you get about 50% power loss in transmission.
The satellite design uses a large area of mylar (or similar) reflectors, and a smaller area of solar cells collecting concentrated sunlight. Concentrated solar is costlier on Earth because the mirrors need to be a lot sturdier.
The ground collector covers a fairly large area but it's wire antenna and cheaper than solar panels.
The Falcon Heavy payload to GEO is 41% of its payload to LEO. I assumed a similar cost ratio for my estimate. Starship prices at scale aren't precisely known yet, but low enough that launch would be a relatively small portion of project cost anyway.
Large-scale grid storage is still quite expensive. Most "solar+storage" projects do not have enough storage to get through the night; if they did, it would cost significantly more than 5 cents/kWh.
The satellite design uses a large area of mylar (or similar) reflectors, and a smaller area of solar cells collecting concentrated sunlight. Concentrated solar is costlier on Earth because the mirrors need to be a lot sturdier.
The ground collector covers a fairly large area but it's wire antenna and cheaper than solar panels.
The Falcon Heavy payload to GEO is 41% of its payload to LEO. I assumed a similar cost ratio for my estimate. Starship prices at scale aren't precisely known yet, but low enough that launch would be a relatively small portion of project cost anyway.
Large-scale grid storage is still quite expensive. Most "solar+storage" projects do not have enough storage to get through the night; if they did, it would cost significantly more than 5 cents/kWh.
Those numbers look very attractive. What was the expected lifetime of the system? Did it take increased deterioration into account from radiation/increased sunpower? What about cooling? (or are they just pricing currently available satellite panel technology?)
A big issue with a project like this are unforeseen costs (being a space-based project) and engineering costs (sometimes needs government stimulus). I'm also bothered sometimes those solutions are advertised as panaceas for climate problem; while currently we have mostly a policy problem (clean energy is almost on par with carbon energy, we're just missing key incentives for the new tech and phasing out carbon plants quicker).
But indeed looks like a promising avenue of exploration.
A big issue with a project like this are unforeseen costs (being a space-based project) and engineering costs (sometimes needs government stimulus). I'm also bothered sometimes those solutions are advertised as panaceas for climate problem; while currently we have mostly a policy problem (clean energy is almost on par with carbon energy, we're just missing key incentives for the new tech and phasing out carbon plants quicker).
But indeed looks like a promising avenue of exploration.
I think they figured only 20 years average lifespan, for the reason you mentioned. I don't remember about cooling.
They had a pretty detailed cost breakdown. The low cost is only once you have mass production and a large plant. They assume several smaller projects first, which would be quite expensive per kWh and include more R&D cost. Those would have to serve communities with very expensive power, like remote northern communities or military installations.
I wouldn't call it a climate panacea since it'll be quite some time before we can do it at scale. In the meantime we should phase out fossil energy as fast as we can with existing technology.
But it looks like in 15 or 20 years we'll have a thriving industry in space anyway, and it's possible that by then we'll be running up against the practical limits of wind/solar market penetration. SPS might play an important role then.
They had a pretty detailed cost breakdown. The low cost is only once you have mass production and a large plant. They assume several smaller projects first, which would be quite expensive per kWh and include more R&D cost. Those would have to serve communities with very expensive power, like remote northern communities or military installations.
I wouldn't call it a climate panacea since it'll be quite some time before we can do it at scale. In the meantime we should phase out fossil energy as fast as we can with existing technology.
But it looks like in 15 or 20 years we'll have a thriving industry in space anyway, and it's possible that by then we'll be running up against the practical limits of wind/solar market penetration. SPS might play an important role then.
Space mirrors beaming sunlight down to earth are far from a new idea.
https://www.vice.com/en_us/article/9a3y8d/the-man-who-turned...
https://www.vice.com/en_us/article/9a3y8d/the-man-who-turned...
I'm not saying they are, I'm just describing what makes this SPS design affordable. But unlike your link, the design is to concentrate sunlight to solar panels in orbit, then beam power to Earth via microwaves.
Microwave based power transmission systems do not rely on the photovoltaic effect for the conversion of the energy in the beam into electricity. Instead you use something called a "rectifying antenna" or rectenna which can be 85-90% efficient[1]. If you put 1000 watts of power down on a square meter of a rectenna you could pull 850 to 900 watts out of it.
Most of the proposed space-based solar power systems (SSPS) posit a reasonably large rectennas (like maybe 10 - 20 acres or 4 - 8 hectares) sized fields.
The challenge is to make the field low enough density such that things flying through it aren't harmed by it. Fortunately energy density falls off with the square of the area so if you have a enough open space you can make it arbitrarily low power per square foot or meter.
[1] https://en.wikipedia.org/wiki/Rectenna
Most of the proposed space-based solar power systems (SSPS) posit a reasonably large rectennas (like maybe 10 - 20 acres or 4 - 8 hectares) sized fields.
The challenge is to make the field low enough density such that things flying through it aren't harmed by it. Fortunately energy density falls off with the square of the area so if you have a enough open space you can make it arbitrarily low power per square foot or meter.
[1] https://en.wikipedia.org/wiki/Rectenna
Low orbit sats spend far less than half the day in darkness; it is only when they are in the penumbra of the earth that they are in darkness. What makes space-based power interesting is that such sats have a line to sunlight (and therefore power) when a portion of the planet below them does not, enabling them to provide power for a period of time after sunset and also before sunrise.
> Low orbit sats spend far less than half the day in darkness; it is only when they are in the penumbra of the earth that they are in darkness.
Yes, and over 24 hours, they are 12 hours in darkness: on a 90-minute orbit, 45 consecutive minutes are spent in Earth's shadow => half the day, they are in darkness.
On the upside, they get full insolation during those 12 hours, unlike ground-based solar. On the downside, at night, the satellite will be in Earth's shadow whenever it's above the ground station, so LEO solar power satellites can't supply power at night (unless they carry batteries).
Yes, and over 24 hours, they are 12 hours in darkness: on a 90-minute orbit, 45 consecutive minutes are spent in Earth's shadow => half the day, they are in darkness.
On the upside, they get full insolation during those 12 hours, unlike ground-based solar. On the downside, at night, the satellite will be in Earth's shadow whenever it's above the ground station, so LEO solar power satellites can't supply power at night (unless they carry batteries).
> Yes, and over 24 hours, they are 12 hours in darkness: on a 90-minute orbit, 45 consecutive minutes are spent in Earth's shadow => half the day, they are in darkness.
FWIW I don’t think that’s correct. The effect isn’t significant in really low orbits but going by my hasty maths even at the ISS’ orbit of 350km a satellite spends - at worst - about 10 hours a day in darkness. I say at worst because the plane of the orbit also has an effect here. I make it that you can roughly calculate it as: 24 * ((asin (EarthRadius/OrbitRadius) *2) / (2 pi radians)).
FWIW I don’t think that’s correct. The effect isn’t significant in really low orbits but going by my hasty maths even at the ISS’ orbit of 350km a satellite spends - at worst - about 10 hours a day in darkness. I say at worst because the plane of the orbit also has an effect here. I make it that you can roughly calculate it as: 24 * ((asin (EarthRadius/OrbitRadius) *2) / (2 pi radians)).
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>Low-orbit satellites spend half their day in darkness too. To hit a receiver on the night side of earth a satellite would have to be at a very high orbit, reducing beam efficiency and increasing launch costs.
Pedantic, but for LEO there are dawn-dusk SSO orbits that ride the terminator [1] so they get continuous sunlight, you could power some peoples evenings depending on how far the grid spans into the dark side. Not a solution for getting power at 2am though.
Might be able to compete if the cost if a rectenna is cheaper/kwh than solar panels (and free as sunlight). Then you can use your same battery solution for night time.
[1]: https://en.wikipedia.org/wiki/Sun-synchronous_orbit
Pedantic, but for LEO there are dawn-dusk SSO orbits that ride the terminator [1] so they get continuous sunlight, you could power some peoples evenings depending on how far the grid spans into the dark side. Not a solution for getting power at 2am though.
Might be able to compete if the cost if a rectenna is cheaper/kwh than solar panels (and free as sunlight). Then you can use your same battery solution for night time.
[1]: https://en.wikipedia.org/wiki/Sun-synchronous_orbit
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Solar panels only recover around 20% of the sunlight that hits them under optimal conditions. Typical installations average to about 10-15% of their peak capacity, so they only harvest less than 4% of the ~1000W peak insolation if you average over a year. So if you manage to recover a larger fraction of the microwave beam you can get away with much less than 1kw/m^2. Plus you save on storage costs.
There are groups and conferences dedicated to Space-based solar power systems (SSPS)[1] That the Navy is going to fly this test vehicle is a pretty good endorsement of the concepts.
[1] https://attend.ieee.org/wisee-2020/wp-content/uploads/sites/...
[1] https://attend.ieee.org/wisee-2020/wp-content/uploads/sites/...
> The Case for Space Solar Power by John Mankins
Wired ran a story featuring him last year:
https://www.wired.com/story/how-to-get-solar-power-on-a-rain...
The main news in it was this:
https://www.robins.af.mil/News/Article-Display/Article/19980...
Wired ran a story featuring him last year:
https://www.wired.com/story/how-to-get-solar-power-on-a-rain...
The main news in it was this:
https://www.robins.af.mil/News/Article-Display/Article/19980...
Has anybody looked at station-keeping issues (briefly searched, found nothing)?
A space based solar power array is a large solar sail. As it orbits, its angle of incidence to the solar wind will change, perturbing its orbit.
Lightsail 2 [1] showed the solar wind can be used to raise orbit. I wonder if such effects would be critical for space-based power systems, or just another design constraint.
[1] https://www.planetary.org/explore/projects/lightsail-solar-s...
A space based solar power array is a large solar sail. As it orbits, its angle of incidence to the solar wind will change, perturbing its orbit.
Lightsail 2 [1] showed the solar wind can be used to raise orbit. I wonder if such effects would be critical for space-based power systems, or just another design constraint.
[1] https://www.planetary.org/explore/projects/lightsail-solar-s...
Wouldn't such a system still require storage? Their nights might be a little shorter by virtue of being in GEO, but they'd still spend a chunk of each day in Earth's shadow.
Less than you think, because of the planet's axial tilt. You put your satellite in orbit over a fixed spot on the equator:
> satellites in geostationary orbit will spend some time in the shadow during what we call “eclipse seasons.” Each eclipse season lasts 44 days, during which the time that a satellite spends in eclipse (shadow) builds gradually from about a minute or two at the start of the season, to a maximum of 72 minutes at each equinox. It then gradually retreats over the next 22 days, at which point the solar arrays are again in the sunlight on a 24×7 basis.
https://corpblog.viasat.com/how-satellites-are-affected-by-t...
So you do have a little bit of downtime, but so do coal, gas, and nuclear plants. The few hours of shadow per year still leaves a capacity factor of over 99%.
> satellites in geostationary orbit will spend some time in the shadow during what we call “eclipse seasons.” Each eclipse season lasts 44 days, during which the time that a satellite spends in eclipse (shadow) builds gradually from about a minute or two at the start of the season, to a maximum of 72 minutes at each equinox. It then gradually retreats over the next 22 days, at which point the solar arrays are again in the sunlight on a 24×7 basis.
https://corpblog.viasat.com/how-satellites-are-affected-by-t...
So you do have a little bit of downtime, but so do coal, gas, and nuclear plants. The few hours of shadow per year still leaves a capacity factor of over 99%.
What would it take to power an airliner?
Wireless power transmission would be ideal for a lot of applications, transportation (electric cars, planes, maybe trains, UAVs, boats) chief among them.
You could shave a lot of weight out of an electric plane by reducing its battery capacity to an emergency supply. This would also greatly reduce the carbon impact of flight transportation, while making a case for bootstraping a beamed power constellation and ecosystem.
I guess that's something Nikola Tesla first envisioned :)
Unfortunately, from what I know, microwaves are not really harmless, unless diffused over a large area, and you then need a large collector. An airliner could do, if big enough. I don't know either if a beam can be steered fast enough, and what would the economics behind be.
Wireless power transmission would be ideal for a lot of applications, transportation (electric cars, planes, maybe trains, UAVs, boats) chief among them.
You could shave a lot of weight out of an electric plane by reducing its battery capacity to an emergency supply. This would also greatly reduce the carbon impact of flight transportation, while making a case for bootstraping a beamed power constellation and ecosystem.
I guess that's something Nikola Tesla first envisioned :)
Unfortunately, from what I know, microwaves are not really harmless, unless diffused over a large area, and you then need a large collector. An airliner could do, if big enough. I don't know either if a beam can be steered fast enough, and what would the economics behind be.
http://large.stanford.edu/courses/2013/ph240/eller1/: “The power required to keep a Boeing 737-300 flying at a constant altitude and speed is 7.2 × 10⁶ watts.”
So, ballpark 7 MegaWatts, more during ascent, and add a bit if passengers want to watch movies, eat hot meals, drink soft drinks, etc.
On the plus side, if the airplane doesn’t have to carry fuel, carrying capacity could go up (with some redesign to make the plane strong enough to land fully loaded), so that 737 might be equivalent to a 747.
That 737-300 has about 125m² of wing area, and, guessing, about the same are for the body, so that would be 7MW/250m² = 28kW/m². The sun delivers about 1,400W/m², so that’s 20 times what the suns delivers on a cloudless day.
Now, most of the time, the ground station (or solar space array) beaming the energy wouldn’t be directly below/above the plane, so the required power/m² could go up a lot ⇒ I would make sure that any windows in the plane wouldn’t let the microwaves through.
Doable? Possibly, but on ground level, I guess it would be wise to use a lot more area for sending that amount of power up, to prevent killing birds.
So, ballpark 7 MegaWatts, more during ascent, and add a bit if passengers want to watch movies, eat hot meals, drink soft drinks, etc.
On the plus side, if the airplane doesn’t have to carry fuel, carrying capacity could go up (with some redesign to make the plane strong enough to land fully loaded), so that 737 might be equivalent to a 747.
That 737-300 has about 125m² of wing area, and, guessing, about the same are for the body, so that would be 7MW/250m² = 28kW/m². The sun delivers about 1,400W/m², so that’s 20 times what the suns delivers on a cloudless day.
Now, most of the time, the ground station (or solar space array) beaming the energy wouldn’t be directly below/above the plane, so the required power/m² could go up a lot ⇒ I would make sure that any windows in the plane wouldn’t let the microwaves through.
Doable? Possibly, but on ground level, I guess it would be wise to use a lot more area for sending that amount of power up, to prevent killing birds.
Thanks for the figures. I'd guess that most of that power is used to combat drag, which can be lowered by going slower. The rest is probably used to combat gravity, especially during ascent, which should be improved by lowering the amount of fuel.
A small battery, and/or a ground station at the airport could provide a bit of extra power during ascent, and the battery recharged during flight. I guess the extra power shouldn't amount to a lot more than 10kW...
Depending on the wavelength, it should be fairly easy to have the plane act as a Faraday cage to shield its passengers. I guess the geometry could be slightly tweaked as well to make a larger surface area, possibly using trailing metallic wires to improve the energy collection area at a minimal cost (I get that cylindrical wires are the worst aerodynamic shape, but it should be less of a problem behind the wing).
If the wavelength is low enough, a coarse mesh could collect power quite efficiently, but you'd have to worry a lot more about radio interference.
A small battery, and/or a ground station at the airport could provide a bit of extra power during ascent, and the battery recharged during flight. I guess the extra power shouldn't amount to a lot more than 10kW...
Depending on the wavelength, it should be fairly easy to have the plane act as a Faraday cage to shield its passengers. I guess the geometry could be slightly tweaked as well to make a larger surface area, possibly using trailing metallic wires to improve the energy collection area at a minimal cost (I get that cylindrical wires are the worst aerodynamic shape, but it should be less of a problem behind the wing).
If the wavelength is low enough, a coarse mesh could collect power quite efficiently, but you'd have to worry a lot more about radio interference.
Drag and lift are related. Wings work by literally displacing lots of air towards the ground.
If you go slower, you need bigger wings (also no one really wants longer, slower flights in cramped airplane cabins).
If you go slower, you need bigger wings (also no one really wants longer, slower flights in cramped airplane cabins).
Unless it's cargo. Cheaper than "normal air" / faster than sea shipping is a reasonable niche.
I don't know if it's a big enough niche. There are quite a lot of costs to air cargo aside from marginal fuel efficiency and somehow developing novel cargo-specific aircraft has to translate into both increased profits for Boeing/Airbus and decreased costs to shippers. Keeping in mind that these slower craft would be unsuitable for some of the most profitable uses of air freight today. I'm not sure it makes sense.
I guess that's part of the reason we still see propeller planes around (often with the military).
Answering to a cousin comment, buses and trains can't compete when you need to cross water :)
Answering to a cousin comment, buses and trains can't compete when you need to cross water :)
Well, there are boats. Passenger sailing as a means of travel is not especially popular these days.
If slower meant cheaper tickets I can guarantee that people would want to use it.
The lower cost, slower mode niche would have to compete with buses and trains, with the added penalty of TSA security theater. I'm not saying you're wrong, but I'm still not sure the financials work out.
https://en.wikipedia.org/wiki/Lift-to-drag_ratio#Examples_of... says the jumbojet, at cruising altitude, has 17 times as much lift as drag.
So it seems drag isn’t taking most of that power.
Also, “I guess the extra power (for ascent) shouldn't amount to a lot more than 10kW” seems unlikely to me. It’s too low compared to the 7MW used at cruise height.
Also, if my math is correct, 1kWh lifts one kilogram about 360,000 meters, or 36,000kg (less than the weight of an empty 737) by 10 meters. So, 10kW would lift the plane by only 100 meters in an hour.
So it seems drag isn’t taking most of that power.
Also, “I guess the extra power (for ascent) shouldn't amount to a lot more than 10kW” seems unlikely to me. It’s too low compared to the 7MW used at cruise height.
Also, if my math is correct, 1kWh lifts one kilogram about 360,000 meters, or 36,000kg (less than the weight of an empty 737) by 10 meters. So, 10kW would lift the plane by only 100 meters in an hour.
I love posts like this that remind me that I'm on HN and that HN can solve world problems based on assumptions.
Take a scenario. Give it best-case figures. See if it works. If it doesn't, then it's impossible. If it misses the mark by just a bit, it's a remote possibility. If it works, try the worst case figures and the average case ones. Of course, you can also start with the worst case ones and show that it works.
I like to approach problems this way. Plus, one can have dreams, can't they?
Once you've shown it can theoretically work, it's time to consider the side effects: best/worst. With the above, someone now controls a multi-gigawat orbiting power source.
Upsides: well, it can power useful stuff just about anywhere on (two third of) earth when there's nothing else to do. That would be really useful to compensate renewables, or other grid fluctuations. One could even imagine making airplanes slower of faster depending on demand.
Downsides: well, somebody really does control that :)
I like to approach problems this way. Plus, one can have dreams, can't they?
Once you've shown it can theoretically work, it's time to consider the side effects: best/worst. With the above, someone now controls a multi-gigawat orbiting power source.
Upsides: well, it can power useful stuff just about anywhere on (two third of) earth when there's nothing else to do. That would be really useful to compensate renewables, or other grid fluctuations. One could even imagine making airplanes slower of faster depending on demand.
Downsides: well, somebody really does control that :)
I don't know if you could kill birds with this, considering that the beam would move at something like 250 m/s during regular flight. Is microwave radiation more deadly than solar radiation?
Might be a problem at the base station, but there should be multiple of those for greater fault tolerance anyway.
Might be a problem at the base station, but there should be multiple of those for greater fault tolerance anyway.
Sun light is about 1kW/square meter.
A 737 has a wing area of 125 square meters. To deliver 7.5MW to those wings will need 60kW/square meter.
That's a far greater energy density.
As for "time in beam" of a moving beam. Presumably one end of the beam is fixed, and depending on the target's velocity the beam might not be moving much at all (oncoming plane).
A 737 has a wing area of 125 square meters. To deliver 7.5MW to those wings will need 60kW/square meter.
That's a far greater energy density.
As for "time in beam" of a moving beam. Presumably one end of the beam is fixed, and depending on the target's velocity the beam might not be moving much at all (oncoming plane).
The beam’s horizontal motion speed goes down linearly with height if the beam is sent from a fixed location.
So, picking 30,000 feet for flight height and 250m/s for the plane’s speed, at 900 feet the beam’s speed would be 7½ m/s. That’s quite doable for birds.
More importantly, if the beam isn’t sent from directly below the plane, and the plane flies more or less directly towards or away from the beam’s source, the speed at which it moves horizontally goes down considerably (1/cos(α), where α is the deviation from the vertical, I think), and its width when flying through it in the direction of the beam’s source at constant height will go up considerably.
The beam’s width, and, with it, intensity, will likely be larger on the ground, but my gut feeling is this won’t be enough to correct for both these factors in all cases (corrections welcome)
So, picking 30,000 feet for flight height and 250m/s for the plane’s speed, at 900 feet the beam’s speed would be 7½ m/s. That’s quite doable for birds.
More importantly, if the beam isn’t sent from directly below the plane, and the plane flies more or less directly towards or away from the beam’s source, the speed at which it moves horizontally goes down considerably (1/cos(α), where α is the deviation from the vertical, I think), and its width when flying through it in the direction of the beam’s source at constant height will go up considerably.
The beam’s width, and, with it, intensity, will likely be larger on the ground, but my gut feeling is this won’t be enough to correct for both these factors in all cases (corrections welcome)
I started writing a complex demonstration, but the intercept theorem, (Thales' theorem) indeeds shows quite nicely that from a ground station, tracking a plane flying at (𝒽1,𝓋1) means the beam goes at 𝓋2=𝓋1*𝒽2/𝒽1. So, 5 m/s for a bird at 200m.
That said, I was mostly imagining space-based stations.
In the above case, I talked about ground-based stations at airports. Unfortunately, those would require high angular velocities, but would already be in bird-restricted areas (airports use all sorts of tricks, including drones, sounds, people chasing them, etc, to scare away birds). You could also conceivably drastically lower the beam energy output by using multiple beams that concentrate at a single point.
Now, a fun calculation: what would be the tipping point between birds saved by not emitting carbon dioxide and birds killed by the towers, if there is one?
One last point: I'd hazard that the bird is likely to change direction if it starts running into a beam and it has time to (ie, it is not killed "instantly"). This drastically lowers the dangerous altitude range, as the bird is less likely to fly in the same path as the beam (how likely was it in the first place? One would need to go faster than the other to catch up, but not too much to actually dispense the lethal dose? I haven't done the math, but I'd say it's quite unlikely).
That said, I was mostly imagining space-based stations.
In the above case, I talked about ground-based stations at airports. Unfortunately, those would require high angular velocities, but would already be in bird-restricted areas (airports use all sorts of tricks, including drones, sounds, people chasing them, etc, to scare away birds). You could also conceivably drastically lower the beam energy output by using multiple beams that concentrate at a single point.
Now, a fun calculation: what would be the tipping point between birds saved by not emitting carbon dioxide and birds killed by the towers, if there is one?
One last point: I'd hazard that the bird is likely to change direction if it starts running into a beam and it has time to (ie, it is not killed "instantly"). This drastically lowers the dangerous altitude range, as the bird is less likely to fly in the same path as the beam (how likely was it in the first place? One would need to go faster than the other to catch up, but not too much to actually dispense the lethal dose? I haven't done the math, but I'd say it's quite unlikely).
I'm pretty sure the beam would be traveling at 299,704,644.54 m/s. It is electromagnetic energy.
The point where the beam is aimed would be moving with 250m/s. (or about so) Therefore the hypothetical bird which crosses the beam would only get the energy for a fraction of a second.
I don't know if this reasoning is correct or not, but definitely has nothing to do with the speed of light in air. I'm not even sure why you are bringing it up.
I don't know if this reasoning is correct or not, but definitely has nothing to do with the speed of light in air. I'm not even sure why you are bringing it up.
I think he's referring to the motion of the beam to track the target.
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7MW in cruise, but keep in mind the power margins that are required for a transport category aircraft.
Beam steering can be done at pretty high speed, essentially limited by the weight of the mirror. And the further the mirror is the faster the effective linear speed of the 'spot'.
But the safety question is more serious. The beam is dangerous to birds, unshielded aircraft, and persons on the ground. I don't think it's great giving the US military even more power to start a fire anywhere on earth with zero warning.
But the safety question is more serious. The beam is dangerous to birds, unshielded aircraft, and persons on the ground. I don't think it's great giving the US military even more power to start a fire anywhere on earth with zero warning.
> I don't think it's great giving the US military even more power to start a fire anywhere on earth with zero warning.
They already have hydrogen bombs :-)))
They already have hydrogen bombs :-)))
Couldn't phased arrays ensure that everywhere (within region) but the target gets only a small amount of power?
In theory, yes, but practice no. The antenna required to collimate the beam from LEO, down to a person sized spot on earth, would be massive.
Single antenna apertures are limited to about 90 dB of gain, and I doubt that is near enough, but I’d have to run some calculations.
Single antenna apertures are limited to about 90 dB of gain, and I doubt that is near enough, but I’d have to run some calculations.
Think of it this way, it can be uses safely on high altitude and trans-oceanic flights which means less fossil fuel usage,less fuel-weight to carry and more flight capacity (even lower carbon footprint).
>start a fire anywhere on earth with zero warning.
Are lasers like this detectable? If not, seems like a good way of creating targeted brain tumors. Disrupting soft infrastructure nodes etc.
Are lasers like this detectable? If not, seems like a good way of creating targeted brain tumors. Disrupting soft infrastructure nodes etc.
It's not that microwaves are intrinsically harmful, it's the intensity of the beam. For example microwave ovens operate around 2.4Ghz, same as Bluetooth/WiFi. I'm not sure what power delivery operates at.
If you get hit by a megawatt beam, you're going to get burned regardless of the wavelength (unless either it's short enough to pass through you, or somehow you reflect 100% of it).
As another comment points out, you can beam steer quite fast. You only care about angular rate, and an airliner at cruise altitude moves fairly slowly (eg you can follow it with your eyes easily).
If you get hit by a megawatt beam, you're going to get burned regardless of the wavelength (unless either it's short enough to pass through you, or somehow you reflect 100% of it).
As another comment points out, you can beam steer quite fast. You only care about angular rate, and an airliner at cruise altitude moves fairly slowly (eg you can follow it with your eyes easily).
This has nothing to do with aircraft. This is about beaming power to low-orbit satellites. The problem with low-orbit radar satellites (the spy satellites tracking ships) is that they need lots of power. In the past this was done with small nuclear reactors but today that is unacceptable and virtually all satellites use solar panels. But sarge solar panels means higher drag and shorter lifetimes in low orbit. Being able to 'beam' power from a higher orbit means one could power more aerodynamic low orbit satellites.
This has nothing to do with aircraft.
Actually, yes, the article explicitly mentions the possibility of powering unmanned aerial vehicles.
Actually, yes, the article explicitly mentions the possibility of powering unmanned aerial vehicles.
>> the article explicitly mentions
Ya. The public report on the super-secret space plane touts that it is studying far-off green energy solutions when those same technologies have much more immediate military effects. It's like the USAF saying that it is studying lasers in order to build better CD players. Everyone takes such statements with a grain of salt. Nobody thinks that we are getting the full story behind these experiments and we chuckle a bit at the poor junior officer instructed to "be creative" with descriptions in public statements.
Ya. The public report on the super-secret space plane touts that it is studying far-off green energy solutions when those same technologies have much more immediate military effects. It's like the USAF saying that it is studying lasers in order to build better CD players. Everyone takes such statements with a grain of salt. Nobody thinks that we are getting the full story behind these experiments and we chuckle a bit at the poor junior officer instructed to "be creative" with descriptions in public statements.
I didn't say anything about green energy, and while the grandparent comment did, I don't think it was implied that it was the motivation of the experiment. Powering military drones for indefinite dwell time is a very plausible use case among many listed in the article.
It mentions "long-endurance unmanned aircraft", which I assume use orders of magnitude less power than most aircraft.
Umm, TFA is on the X-37B spaceplane, but it specifically speaks a lot about potentially using the power for aircraft and drones. And the potential for indefinite drone flight duration.
You're not wrong about low orbit sats in general, but it's only one of many potential military (and/or civilian) uses. And it's not the use the article focuses on.
You're not wrong about low orbit sats in general, but it's only one of many potential military (and/or civilian) uses. And it's not the use the article focuses on.
Ah, my bad. That said, beamed power could be applied to anything, and the post I wrote above is one of the better use cases, in my opinion.
I’d imagine a safety feature on the airplane to be a battery or even capacitors to help smooth out any drops in transmission. At least the batteries could be small
THIS was the missing tech to start launching iteratively what will become a Dyson's sphere.
The step zero could also be using Earth's deserts.
And then step one is using a space shell of satellites. Because the available surface at a large distance of Earth is huge, even considering the constraints of not creating too much shadow for life's photosynthesis.
Further in the future could be step two, some flotilla at Lagrange points or even directly in a solar orbital between Earth and Mars (so that this will never create any shadows to us).
The step zero could also be using Earth's deserts.
And then step one is using a space shell of satellites. Because the available surface at a large distance of Earth is huge, even considering the constraints of not creating too much shadow for life's photosynthesis.
Further in the future could be step two, some flotilla at Lagrange points or even directly in a solar orbital between Earth and Mars (so that this will never create any shadows to us).
I mean, this could happen: we deploy a microwave energy station above the Sahara, and build that space tower ...
In my idea, the energy production would be the solar-panel-satellites. Or the deserts if we are only at step 0. But for drones and other energy-receiving devices, imho the ground grid and batteries are still the best option, as the wireless powerlinks towards the ground should be reserved to where it cannot be avoided. Any smaller powerlinks from-space-towards-space would be fine though.
You know, deserts aren't empty.
My first reaction to this was Sim City 2000's Microwave Power Plant (and the occasional miss of the microwave beam):
https://simcity.fandom.com/wiki/Microwave_(disaster)
https://simcity.fandom.com/wiki/Microwave_(disaster)
In SimCity 3000, the Microwave Power Plant is also first available in the year 2020. Coincidence? I think not :)
It sounds like a test for a future space weapon. Something that, anyone correct me if I'm wrong, it's banned right now. They sell it as a new energy source and that way they circumvent the ban.
You are wrong. The Outer Space Treaty bans nuclear weapons in space, but e.g. mass drivers shooting tungsten slugs which would have nuclear-like effects aren't banned, nor is anything else.
Even if a treaty did ban these weapons it wouldn't be "illegal" for a major power in any meaningful sense. These mutual arms restriction treaties are only followed by the major power as long as they see a mutual interest in doing so.
Even if a treaty did ban these weapons it wouldn't be "illegal" for a major power in any meaningful sense. These mutual arms restriction treaties are only followed by the major power as long as they see a mutual interest in doing so.
> These mutual arms restriction treaties are only followed by the major power as long as they see a mutual interest in doing so.
Sorry, but this really rubs me the wrong way. The whole reason we have these kind of treaties is to protect nations which don't have the power to defend their interests should a conflict arise.
Saying that it is normal for a nation to just ignore a treaty they have ratified IMHO instills a very wrong mindset. If a nation ignores a treaty, the reaction should not be "Oh, that was to be expected".
Sorry, but this really rubs me the wrong way. The whole reason we have these kind of treaties is to protect nations which don't have the power to defend their interests should a conflict arise.
Saying that it is normal for a nation to just ignore a treaty they have ratified IMHO instills a very wrong mindset. If a nation ignores a treaty, the reaction should not be "Oh, that was to be expected".
> The whole reason we have these kind of treaties is to protect nations which don't have the power to defend their interests should a conflict arise.
It’s blatantly naive. The reason we have these restrictions is because it’s simply more efficient not to have an arms race.
If it was really about small countries we would already gotten rid of nuclear weapons.
Don’t forget that the amount of countries having the capability to detect the launches of nukes is even less than the amount of countries having nukes.
It’s blatantly naive. The reason we have these restrictions is because it’s simply more efficient not to have an arms race.
If it was really about small countries we would already gotten rid of nuclear weapons.
Don’t forget that the amount of countries having the capability to detect the launches of nukes is even less than the amount of countries having nukes.
> If a nation ignores a treaty, the reaction should not be "Oh, that was to be expected".
A nation can withdraw from a treaty instead of ignoring it. The US just withdrew from the INF treaty. In retaliation, Russia withdrew too (they were the only signatories).
In 1936 Japan withdrew from the Washington Naval Treaty and built the formidable battleship Yamato (armed with 18 inch guns, by far the largest in WW2). What was the world supposed to do? The US imposed various sanctions on Japan. At some point the sanctions became so hard that they amounted to an economic death sentence. WW2 was not averted.
The unpleasant truth is that international treaties are not worth a whole lot. For the simple reason that there's no international equivalent of law enforcement.
A nation can withdraw from a treaty instead of ignoring it. The US just withdrew from the INF treaty. In retaliation, Russia withdrew too (they were the only signatories).
In 1936 Japan withdrew from the Washington Naval Treaty and built the formidable battleship Yamato (armed with 18 inch guns, by far the largest in WW2). What was the world supposed to do? The US imposed various sanctions on Japan. At some point the sanctions became so hard that they amounted to an economic death sentence. WW2 was not averted.
The unpleasant truth is that international treaties are not worth a whole lot. For the simple reason that there's no international equivalent of law enforcement.
> A nation can withdraw from a treaty instead of ignoring it
Yes, as far as I can see both the INF and the Outer Space Treaty explicitly include the possibility for a withdrawal (with prior notice).
At least this publicly signals the intent of a nation to do something which would violate the treaty instead of just silently ignoring it.
Yes, as far as I can see both the INF and the Outer Space Treaty explicitly include the possibility for a withdrawal (with prior notice).
At least this publicly signals the intent of a nation to do something which would violate the treaty instead of just silently ignoring it.
The US withdrew because Russia violated the treaty. Russia wasn't "retaliating" because the whole issue was instigated by them.
The powerful have control and the weak unfortunately have to sit by and hope the powerful live up to their word.
Without external forces (a higher authority or some sort of coalition of the weak) to check the impulses of the strong, the strong get to make and break the rules as they please.
This is inevitable and a fundamental fact of reality.
Without external forces (a higher authority or some sort of coalition of the weak) to check the impulses of the strong, the strong get to make and break the rules as they please.
This is inevitable and a fundamental fact of reality.
>You are wrong. The Outer Space Treaty bans nuclear weapons in space
I can't count the number of times I saw the usual armchair experts confidently state online that Trump's proposed Space Force would "violate the Outer Space Treaty!".
It's one thing to not be completely familiar with the details of a treaty signed 50 years ago, but how is anyone today ignorant of the military (the US's and other countries') large presence in space?
I can't count the number of times I saw the usual armchair experts confidently state online that Trump's proposed Space Force would "violate the Outer Space Treaty!".
It's one thing to not be completely familiar with the details of a treaty signed 50 years ago, but how is anyone today ignorant of the military (the US's and other countries') large presence in space?
The Outer Space Treaty does not ban weapons in space or the militarization of space it banned stationing WMD’s (as defined in the treaty) in space.
It was designed to prevent the nuclear powers form parking their nukes in space because that would reduce the warning time to the point where MAD might break as a first strike without a chance of retaliation could then be possible.
It was designed to prevent the nuclear powers form parking their nukes in space because that would reduce the warning time to the point where MAD might break as a first strike without a chance of retaliation could then be possible.
I think it's most useful for powering drones. Microwaves can go through clouds too.
Wasn't Tesla consumed with beamed power? I seem to remember that was what Wardenclyffe was about.
https://en.wikipedia.org/wiki/Wardenclyffe_Tower
I remember reading a Repairman Jack novel about it. I think it was Conspiracies.
https://en.wikipedia.org/wiki/Wardenclyffe_Tower
I remember reading a Repairman Jack novel about it. I think it was Conspiracies.
Elon Musk giving shade to space based power "You'd have to convert photon to electron to photon back to electron. What's the conversion rate?"
[1] https://www.popularmechanics.com/technology/a8101/elon-musk-...
[1] https://www.popularmechanics.com/technology/a8101/elon-musk-...
who cares?
The practicality rests on two open questions, I guess:
1. How much power could a satellite generate, realistically? 2. How many targets could it serve simultaneously?
I imagine there is a huge difference between being able to support a single, ultra lightweight drone and, say, hundreds of reapers.
1. How much power could a satellite generate, realistically? 2. How many targets could it serve simultaneously?
I imagine there is a huge difference between being able to support a single, ultra lightweight drone and, say, hundreds of reapers.
Those questions are determined by how many solar panels and transmitters you have on the satellite?
For comparison, the ISS generates 240kW when in sunlight. So for the 7MW mentioned upthread to power an airliner (or half a Eurostar train), you need something 28 times larger than the ISS.
For comparison, the ISS generates 240kW when in sunlight. So for the 7MW mentioned upthread to power an airliner (or half a Eurostar train), you need something 28 times larger than the ISS.
1) Sun output minus conversion loses. Also you likely want nore than one, eq. a Dyson Swarm.
"Sun output" at reasonable Earth orbits for this application is maximum ~1368 W/m2, and that only when the the panels are perpendicular to the direction of the rays.
What is considered a "reasonable" orbit depends on our ability to collimate the microwave beam's rays, which is not an easy task
What is considered a "reasonable" orbit depends on our ability to collimate the microwave beam's rays, which is not an easy task
A global network of satellites beaming power to insect-sized drones near the ground? Splendid.
Remember simcity's microwave power station? Microwaves beamed down from space :)
"it's all fun and games until somebody lose an eye"
in city telecom microwave antennas on top of buildings already kill thousands of bird every day.
maintenance checklist start with "clean the dead birds from base of antenna"
in city telecom microwave antennas on top of buildings already kill thousands of bird every day.
maintenance checklist start with "clean the dead birds from base of antenna"
I don’t believe the frequencies used for terrestrial communications cause injury, but rather birds are generally killed by physical impact with towers. Much like windmills.
Please show a source if I’m mistaken.
Please show a source if I’m mistaken.
The problem is that directly in front of a microwave antenna, power output is on the KW order of magnitude. This is like standing in front of a microwave oven with the door open - in a few seconds you will have severe burns.
I can point out you're mistaken simply by saying "frequency".
it's power that kills. you can make a death ray with light, vhf, whatever, given enough power, which decay geometrically. most of the dead birds are on antennas without cover, where the birds would perch up and get fried. thousands of dead birds every day on top of builds is the sole reason all microwave antennas have that white half-cone cover on them.
it's power that kills. you can make a death ray with light, vhf, whatever, given enough power, which decay geometrically. most of the dead birds are on antennas without cover, where the birds would perch up and get fried. thousands of dead birds every day on top of builds is the sole reason all microwave antennas have that white half-cone cover on them.
Apparently birds colliding into towers is a thing.
https://en.m.wikipedia.org/wiki/Towerkill
TIL.
https://en.m.wikipedia.org/wiki/Towerkill
TIL.
Carrying one's power supply onboard a rocket in space and even on an airplane is a huge weight penalty. What if high energy density beams could power a substantial VASIMR thruster? That would make for awesome LEO to GEO orbital tugs. It would also be a good basis for a drone "space fighter" that could reduce the rocket equation penalty through ultra high ISP.
Reliable high density power beaming could enable fully automated cargo drone aircraft. These would have fundamental advantages in operations costs due to weight savings, the simplicity of electric motors, and reduced personnel costs.
If we could generate large amounts of power in space and use sufficiently large transmitters (re: diffraction limits) to beam it to VASIMR thruster spacecraft, we could substantially reduce transit times to Mars, as one example. Alternatively, we could also greatly increase mass fractions of cargo delivery to Mars.
Reliable high density power beaming could enable fully automated cargo drone aircraft. These would have fundamental advantages in operations costs due to weight savings, the simplicity of electric motors, and reduced personnel costs.
If we could generate large amounts of power in space and use sufficiently large transmitters (re: diffraction limits) to beam it to VASIMR thruster spacecraft, we could substantially reduce transit times to Mars, as one example. Alternatively, we could also greatly increase mass fractions of cargo delivery to Mars.
24/7 availability was mentioned several times.
Does this mean it's possible to have a satellite in geostationary orbit that is never eclipsed by the Earth? Or does it mean you have more than one satellite serving a power receiver?
Does this mean it's possible to have a satellite in geostationary orbit that is never eclipsed by the Earth? Or does it mean you have more than one satellite serving a power receiver?
GEO satellites are pretty much always in the sun, minus couple hours per year when they hit the (very snall at this altitude) Earth shadow.
GEO orbit is too high for this application, since it would require an insanely collimated microwave beam (or insanely directional). The power loss is proportional to r^2. Google "spherical spreading loss"
That actually is doable. GEO is generally considered the best orbit for a solar power sat. The receiver has to be several kilometers across, but that's good because you don't actually want to fry any birds flying through.
There have even been proposals to put transmitters on the Moon, but that's stretching things.
There have even been proposals to put transmitters on the Moon, but that's stretching things.
Sure, but I thought the consideration here was about UAVs and the such :)
You can have orbits that are never eclipsed by the earth, but not GEO.
GEO satellites go dark for about an hour a night for about 6 weeks a year.
https://www.stephenmack.space/blog/geostationary-satellite-e... Contains a video of them
GEO satellites go dark for about an hour a night for about 6 weeks a year.
https://www.stephenmack.space/blog/geostationary-satellite-e... Contains a video of them
The latter. This is discussed later in the article.
>In addition, it could allow satellites to provide reliable power anywhere on the planet or even to spacecraft or other satellites in orbit.
Aka laser ASAT platform. Seems like one of those read between the lines Space Force press releases. References to laser beam UAV kills, original research by Revolutionary Munitions Directorate etc. All the remote power through atmosphere interference sounds pretty fanciful TBH, whereas crippling adversary satellites using beam energy instead of kinetic impactors (=space debris) seems like the most parsimonious application.
Aka laser ASAT platform. Seems like one of those read between the lines Space Force press releases. References to laser beam UAV kills, original research by Revolutionary Munitions Directorate etc. All the remote power through atmosphere interference sounds pretty fanciful TBH, whereas crippling adversary satellites using beam energy instead of kinetic impactors (=space debris) seems like the most parsimonious application.
It would be in line with the tradition of using "ballistic missile defence" as a pretext for developing ASAT capability.
I would question if there really is such a strong push for even more US ASAT tools in the USSF, though given the current administration I guess the "kill 'em all" mentality has a good wind in their sails.
I would question if there really is such a strong push for even more US ASAT tools in the USSF, though given the current administration I guess the "kill 'em all" mentality has a good wind in their sails.
My understanding is there's a much greater emphasis on counter-space capabilities now that US military is shifting towards peer to peer confrontations (China). ASAT... especially a concurrent global network is going to be pretty key to nullifying the Chinese missile gap in SCS by disrupting the killchain - Chinese satellites - in a manner that doesn't endanger US space assets. Also this was a month ago:
https://www.space.com/russia-anti-satellite-missile-test-202...
Beyond just needing the capability, media releases like this seems to be oblique posturing as well.
Edit: apparently posting to fast? Reply to below:
>ASAT warfare is hugely advantageous to them
Most threat models anticipate disrupting space assets in peer to peer conflicts to mitigate technological edge. All the old ASAT tests have been missiles that create debris (or potential debris in deliberate near misses), Recipe for kessler syndrome if executed at scale. So moving to beam ASAT that can disrupt / destroy sensors precisely without adversely risking the space commons might not be a terrible development in terms of space arms race.
Also if memory serves some of the new Chinese satellite used to track SCS shipping (US aircraft carriers) are in a high orbit that can't be hit by current ASAT at all. So this might be developing new capabilities. It certainly makes sense to hit other objects in space vacuum at speed of light than to power drones through clouds.
https://www.space.com/russia-anti-satellite-missile-test-202...
Beyond just needing the capability, media releases like this seems to be oblique posturing as well.
Edit: apparently posting to fast? Reply to below:
>ASAT warfare is hugely advantageous to them
Most threat models anticipate disrupting space assets in peer to peer conflicts to mitigate technological edge. All the old ASAT tests have been missiles that create debris (or potential debris in deliberate near misses), Recipe for kessler syndrome if executed at scale. So moving to beam ASAT that can disrupt / destroy sensors precisely without adversely risking the space commons might not be a terrible development in terms of space arms race.
Also if memory serves some of the new Chinese satellite used to track SCS shipping (US aircraft carriers) are in a high orbit that can't be hit by current ASAT at all. So this might be developing new capabilities. It certainly makes sense to hit other objects in space vacuum at speed of light than to power drones through clouds.
> So moving to beam ASAT that can disrupt / destroy sensors precisely without adversely risking the space commons might not be a terrible development in terms of space arms race.
Um, lowering barriers for using weapons is obviously a bad thing: it means they are more likely to be used, and cause a response by the adversary. So unless you mean that this beam-tech should be freely shared all you're doing is increasing the risk to the commons.
But my larger point is this: the incredibly costs of space weapons only make sense if you think your adversary doesn't have any counter-move, this is what I meant by my supposition that USSP thinks space warfare is advantageous.
To illustrate: remote detection can be counteracted by masking and decoys, both of with are much more mundane than ASAT capabilities but will work pretty good for a fraction of the cost and without any risk at all to the commons.
Um, lowering barriers for using weapons is obviously a bad thing: it means they are more likely to be used, and cause a response by the adversary. So unless you mean that this beam-tech should be freely shared all you're doing is increasing the risk to the commons.
But my larger point is this: the incredibly costs of space weapons only make sense if you think your adversary doesn't have any counter-move, this is what I meant by my supposition that USSP thinks space warfare is advantageous.
To illustrate: remote detection can be counteracted by masking and decoys, both of with are much more mundane than ASAT capabilities but will work pretty good for a fraction of the cost and without any risk at all to the commons.
Oh great, I sort of knew the military was all in on orbital warfare, but somehow your comment really drives home the idea that USSF truly thinks ASAT warfare is hugely advantageous to them :(
(To be clear, the USA already posses ASAT capability, demonstrated most recently in 2008)
(To be clear, the USA already posses ASAT capability, demonstrated most recently in 2008)
Anyone know what impact this will have on anything that gets in the way of these high-energy microwaves? I’m thinking birds or manned aircraft?
I imagine it would depend greatly on whether the beam was set to 'Max' or 'Defrost'.
I'm imagining a hacker pointing a bunch of microwaves beams at all the corn fields to heat them up, causing the Popcorn Famine Of 2052.
I don't know if you're referencing it but that was the ending of Real Genius: https://www.youtube.com/watch?v=rthHSISkM7A
[edit: possibly a spoiler?]
[edit: possibly a spoiler?]
That’s exactly the scene I thought of but the last time I saw that film I was 11 in 1992 and I had no idea what the title was! Thank you!
I had completely forgotten about that awesome seen. Thanks for the reminder!
According to Wikipedia the power density of various proposal to beam energy from space should be harmless for human.
https://en.m.wikipedia.org/wiki/Space-based_solar_power
https://en.m.wikipedia.org/wiki/Space-based_solar_power
Or they could just use a non-harmless power and focus it on large on-ground receiver stations. Could use some security on the satellites like interrupting automatically the beam on sensing an unpredicted movement (up to when a "continue" greenlight message is received, after needed corrective steps).
Other possibility is to use stratospheric balloons as receiver stations. Could then use softer power links to the ground. Would some system of cables be doable then?
(I wrote that in the optics of a Dyson's sphere [thus connecting space solar stations to an on-ground power grid] instead of the proposed direct powering of drones.)
Other possibility is to use stratospheric balloons as receiver stations. Could then use softer power links to the ground. Would some system of cables be doable then?
(I wrote that in the optics of a Dyson's sphere [thus connecting space solar stations to an on-ground power grid] instead of the proposed direct powering of drones.)
At those intensities, microwaves seem significantly less useful than optical PV.
Microwave rectenna is more efficient than optical PV. Also, microwave is less affected by weather than visible light. As a power source, they also can have much higher capacity factor than PV.
Well, they work at night if your solar power satellite is high enough (eq. GEO).
The same applies if the beaming is done with an optical laser instead of a microwave.
Sure, that's true - I guess microwaves still could have some benefits, for attenuation in the atmosphere/weather maybe ?
Optical laser is rather inefficient at converting electricity into optical energy. Surely there are some low-powered diodes where one can get over 50%, but for powerful lasers efficiency like 1% is a good number. Consumer microwave ovens on the other hand has efficiency like 65%.
Can the effect of capturing and sending more enegry to Earth from space (than Sun does now) be compared to global warming effects from currently burning fossils?
You can position the solar panels to shade the earth which wouldn't change the total impinging power.
I was surprised to learn the rectenna was invented as recently as the 1960s: https://en.m.wikipedia.org/wiki/Rectenna
And in 2015, the optical rectenna: https://www.me.gatech.edu/featured_colarectenna
And in 2015, the optical rectenna: https://www.me.gatech.edu/featured_colarectenna
If one assumes that the beam feeding the drone is not a cylinder, but more of a cone with a Gaussian profile, then technology could get built which detects the source and the target of the beam. So no matter how much you stealth the drone, you'd have to deal with that new problem.
The power must be enormous at the source. It would degrade considerably from the source, inverse square law.
The inverse square law only applies to a point source radiating uniformly in all directions.
Laser and microwave beams, while they do suffer from losses over distance, aren't anywhere near that bad.
Laser and microwave beams, while they do suffer from losses over distance, aren't anywhere near that bad.
The inverse square law still applies to directional transmitters and optical transmitters. It's just that their transmit gain is much much higher.
I wonder how they don't fall afoul of Tesla's patents?
https://www.damninteresting.com/teslas-tower-of-power/
https://www.damninteresting.com/teslas-tower-of-power/
Thank you for that article for me this quote from Tesla so well explains the struggle of invention.
“It is not a dream, it is a simple feat of scientific electrical engineering, only expensive — blind, faint-hearted, doubting world! […] Humanity is not yet sufficiently advanced to be willingly led by the discoverer’s keen searching sense. But who knows? Perhaps it is better in this present world of ours that a revolutionary idea or invention instead of being helped and patted, be hampered and ill-treated in its adolescence — by want of means, by selfish interest, pedantry, stupidity and ignorance; that it be attacked and stifled; that it pass through bitter trials and tribulations, through the strife of commercial existence. So do we get our light. So all that was great in the past was ridiculed, condemned, combatted, suppressed — only to emerge all the more powerfully, all the more triumphantly from the struggle.”
“It is not a dream, it is a simple feat of scientific electrical engineering, only expensive — blind, faint-hearted, doubting world! […] Humanity is not yet sufficiently advanced to be willingly led by the discoverer’s keen searching sense. But who knows? Perhaps it is better in this present world of ours that a revolutionary idea or invention instead of being helped and patted, be hampered and ill-treated in its adolescence — by want of means, by selfish interest, pedantry, stupidity and ignorance; that it be attacked and stifled; that it pass through bitter trials and tribulations, through the strife of commercial existence. So do we get our light. So all that was great in the past was ridiculed, condemned, combatted, suppressed — only to emerge all the more powerfully, all the more triumphantly from the struggle.”
Possibly something to do with his having been dead for nearly 80 years?
Somebody owns those patents...
Patents expire. That's the point of patents. Instead of complete secrecy thats practically impossible to maintain we have a system where patented inventions are publicly disclosed and the inventor gets to have sole use of the invention for a limited time.
Patents are only valid for 15 years or so.
That’s the idea. I have no clue what’s going on with big companies sitting on stacks of tens of thousands of patents and litigating people for violating patents unrelated to what the company produces.
Ah yes, when he filed the limit was 17 years. I had some notion they could be renewed. I guess I was thinking of copyright.
patents expire after 20 years
Takeoff and ascension use the most power. What happens when it’s foggy and cloudy? Do you have to wait it out? Planes cannot afford the weight of large batteries.
“If we had a way to keep those drones and UAVs flying indefinitely, that would have really far-reaching implications. With power beaming, we have a path toward being able to do that.”
Why go through all this trouble when there's this?
https://www.amprius.com/amprius-silicon-nanowire-lithium-ion...
While 25 days is the record, I'm sure this thing can remain aloft for at least a week at a time.
To me the solution from the article appears expensive and suspiciously deathray-ish.
Why go through all this trouble when there's this?
https://www.amprius.com/amprius-silicon-nanowire-lithium-ion...
While 25 days is the record, I'm sure this thing can remain aloft for at least a week at a time.
To me the solution from the article appears expensive and suspiciously deathray-ish.
Because it's a superlight UAV without any instrument package or ordnance load.
I see no indication that anything heavier could be powered via the method described in the article.
The beam is on the order of kilowatts.
Noone is going to deploy satellite network just to power some semi-gliders.
Noone is going to deploy satellite network just to power some semi-gliders.
But how efficiently can the drones receive such a beam?
I checked and the Zephyr S has a 5kg payload - not much, but enough for instrumentation. And they're making an even bigger one.
I checked and the Zephyr S has a 5kg payload - not much, but enough for instrumentation. And they're making an even bigger one.
So what’s actually new here? Why can’t we test this same system on earth?
Is it a laser or a focused microwave beam? Will it hurt if a bird or airplane flies through the beam?
Is it a laser or a focused microwave beam? Will it hurt if a bird or airplane flies through the beam?
They did test it on Earth, there's a bunch of examples in the article, but you are limited to line of sight on Earth.
This would also have a great application for commercial flights. It would be also a bit easier if energy would be sent only above clouds.
anyone know what the conversion and transmission power loss is?
Seems great technology. Hope they also address any impact on ecosystem.
Lol, we are going to spend billions to possibly send down the power of a few litres of fuel to a drone a day?
Maybe targeted at someones head it might pay for itself, but still pretty sci-fi if it was possible.
Just send from a blimp.
Or send the power up to the satellite to power them, it's good as free from the ground, if this stuff is possible.
[edit] I would have ruled out this being a ruse to confuse people from the military's side, since it's so crazy no one would believe solar panels in space transmitting energy to earth was possible. But maybe not it seems..... I assume IRL it's for communications, or jamming, shooting a missile out of the air?
Maybe targeted at someones head it might pay for itself, but still pretty sci-fi if it was possible.
Just send from a blimp.
Or send the power up to the satellite to power them, it's good as free from the ground, if this stuff is possible.
[edit] I would have ruled out this being a ruse to confuse people from the military's side, since it's so crazy no one would believe solar panels in space transmitting energy to earth was possible. But maybe not it seems..... I assume IRL it's for communications, or jamming, shooting a missile out of the air?
> Just send from a blimp.
Drone Mothership
Drone Mothership
Old designs from the 1970s were monolithic beasts, and would be horribly expensive even if launch were free. The new designs use a large number of small identical components (of seven or eight types), which self-assemble in orbit. That way you can mass-produce them.
I plugged SpaceX Starship launch costs into the book's estimate and got a total system cost of 5 cents/kWh, which is pretty good for steady clean power that doesn't need storage.
[1] The Case for Space Solar Power by John Mankins