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DARPA program sets distance record for power beaming
- janalsncm 1y agoCould this also be a viable alternative to HVDC lines for civilian applications?
- theamk 1y agoNo. 800 watts (vs megawatts for HVDC). 5 miles vs thousands of miles. 20% efficiency optical to electrical - so electrical vs electrical is much worse - vs 90%+. This is so much worse in every aspect it's not really compareable.
- naruhodo 1y agoIt's great if you hate birds, though.
- other_herbert 1y agoThe key thing they aren't saying is how much power it took to "send" 800 watts 5.3 miles...
- bracketfocus 1y agoThey mentioned that it was 20% efficient at a closer distance. So likely much lower than that.
- throwaway81523 1y agoWow that's a long way from the proposals for sending GW of microwave power from satellites.
- pfdietz 1y agoLaser power beaming from space could be useful at lower power levels than that, for example for powering aircraft.
- conradev 1y agoBut pretty close to powering drones from ground stations
- aurizon 1y agoThose sat to ground power sources use gallium arsenide switched FETs = synchronous rectification, avoiding the voltage drop of diodes has been tested on a small scale, the 10GW orbital 35% efficient solar arrays, maybe next week... Solar boilers, end to end, are more efficient than solar cells, but mechanical complexity(leaks, corrosion, worker avarice) made one US plan in the South West non viable. As we sit silicon-perovskite tandem solar cells will top out around 42-45% - unless Schockley is end runned? Ternary -??. A good lecture = https://www.youtube.com/watch?v=Ft0VJX0_Td0&t=2s&ab_channel=PV1xSolarEnergyEngineering%3APhotovoltaicEnergyConversion https://www.youtube.com/watch?v=Ft0VJX0_Td0&t=2s&ab_channel=...
- PaulHoule 1y agoSolar thermal as well as solar-chemical systems have the problem of start-up. PVs do not have any problem starting up, they produce less than full power with less than full illumination but they produce something and once the illumination is full they produce full power immediately. Many solar thermal power plants are fired with natural gas in the morning to get them spun up to the point where they can take advantage of the solar energy. Without that they'd probably lose a few hours of production.
- PaulHoule 1y ago20% efficiency in terms of light -> electricity. A 50% laser efficiency (electricity -> light) is really good, possible for some diode lasers, if you pump a fiber laser with diodes to get a high quality beam for cutting materials or weapons purposes maybe you get 25%. That demo would require about 45 kW of laser power with good beam quality which would be totally possible with a fiber laser https://www.rp-photonics.com/wall_plug_efficiency.html https://www.rp-photonics.com/wall_plug_efficiency.html
- HenryBemis 1y agoI was thinking of"how much is enough" so they can power 'instruments'. I am also thinking of 'how can we use this tech to revive space-instruments (the next generation of 'Voyagers' may be equipped with such receivers?) I also wonder how difficult/impossible would it be, and the 'throughput'. Assuming that you want to recharge a recon drone (or the 'next generation of Voyagers flying in space) that flies over XYZ area/country/etc. Would it take 1sec or 10seconds 'of beam', and the accuracy/waste/total amount one would have to 'dispense' in order to give that drone the X seconds of 'juice' to keep it running for 1000x X seconds of flight duration. And what about clouds/mist/rain/snow/birds/etc. 'Infinite energy' for a drone (I mean no dependency to come down to refuel) is a game changer. Would that work with 'instruments buried underground? And at what depth? ('War of the worlds' scenario). Could someone bury a device, with only the receiver protruding from the ground, with a battery to keep it alive, and waiting to be activated by a satellite passing by giving it the "10 seconds beam" to fully charge it and.. (I am thinking of the recent drone-related incidents/attacks within Russia and Iran)(if you park a drone for 10 months, its battery will deplete, right?)(I don't have a drone, but batteries are batteries). A second thought on the matter, can one 'program' the light to be also transferring data? Park the drones in <insert foreign territory>. No programming. In the middle of nowhere (no 4G-5G). You fly a satellite over it, beam down the 'juice' (together with the instructions - no interception of the transfer is possible). Someone finds it 'before', they only get the hardware but no info/intel. "The possibilities are endless" (and so are the nightmares)
- _fizz_buzz_ 1y agoThis can only be used where efficiency doesn't matter, like military applications for powering a drone. The overall efficiency i.e. grid -> laser -> pv -> grid would be atrocious.
- jauntywundrkind 1y agoThe application to drones seems most clear: beam drones some extra power as needed. Or continually! I wonder how big that receiving apparatus is. Whether the receiver is gimballed, or whether the drone itself has to fly a heading to aim at the sender: TBD.
- larodi 1y agoAnd have a great opportunity to drill some holes in birds heads. Sorry I really fail to recognise how beaming 1kw of excited particles is a safe thing to do just like this…
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- ChocolateGod 1y agoIt must not be safe to be out in the sun then.
- _Algernon_ 1y agoLast time I forgot sunscreen at a UV index of 10 my skin started peeling of after half an hour so...
- ben_w 1y agoDensity (and wavelength), rather than total power, is important. Sun's 1kW/m^2, and even then you shouldn't look directly at it, and being out in it all day without protection leads to sunburn.
- nkrisc 1y agoIt’s not, for an extended period of time. Now imagine it was collimated rather than diffuse.
- b00ty4breakfast 1y agoThis seems very silly. It's either a death ray project in a fake mustache or somebody had earmarked a bunch of money that they had to spend before it expired.
- kulahan 1y agoThis is kinda surprising to read. I’ve never known anyone who isn’t incredibly excited at least at the prospect of wireless energy transfers. If you can do 800 watts over 8 km, surely we can do 150 watts across 3 feet in the household, and MANY of our most important discoveries come from DARPA essentially being a black budget skunkworks team. But much of the stuff DARPA does seems weird. It’s not about ideas with solid foundation and thorough engineering, it’s about crapshoots that might work and would pay off in some way - often any financially feasible way. They once put “cats” on guns in hopes it would surprise opponents even just for a quarter second, giving your spec ops dudes the advantage. They tried to create angled guns that could shoot around corners like 20 years ago. All kinds of crazy stuff! It would be a lot of fun to work there, I think.
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- christkv 1y agoThe germans tried the curved gun with an attachment called Krummlauf during ww2. It would break after just a couple of magazines being fired. https://en.wikipedia.org/wiki/Krummlauf https://en.wikipedia.org/wiki/Krummlauf Not sure how you would build one of those without the stress of the bullet during firing would not damage the barrel.
- alanbernstein 1y agoI'm amazed that worked for even one shot. Presumably gp was referring to cornershot or something similar, which seems like a much more reasonable approach.
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- petermcneeley 1y ago"reflects onto dozens of photovoltaic cells arranged around the inside of the device which convert the energy back to usable power." This is no different that what we were considering two decades ago for the space elevator competition. One of the problems with this approach is that as the photovoltaic cells heat up their overall efficiency decreases.
- inasio 1y ago“It’s a lot easier to send a power beam directly up or down relative to the ground because there is so much less atmosphere to fight through,” Jaffe explains. “For PRAD, we wanted to test under the maximum impact of atmospheric effects.” Super impressive! My only complain is that this was done at the White Sounds desert in New Mexico, at over 1200 meters of elevation. For maximum impact they should have done it in Florida on a hot humid day
- AndrewKemendo 1y agoThere’s no range in Florida large enough for this test otherwise I’m sure they would have. Even Eglin wouldn’t be large enough.
- madaxe_again 1y agoHumidity would most likely attenuate the beam from 20% end to end to less than 1% - water vapour absorbs energy like nobody’s business. This is a tech for arid environments - which seem to be where the US does most of its deployments these days.
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- contrarian1234 1y ago＂maximum impact of atmospheric effects＂ would be simply a foggy day...
- cryber 1y agoThe popcorn is a very nice touch
- ChrisMarshallNY 1y ago> New Mexico Great stuff. Do Seattle, next.
- Szpadel 1y agowhat concerns me is that it's wild laser beam in potentially public space. anyone that would accidentally cross that potentially invisible line could get killed or severely hurt. imagine something reflective entering this beam, it could blind people in a very large radius. for me it means that thus would still need some pipe/fiber that would protect world from this laser.
- seberino 1y agoThe eventual goal is to use it at extremely high altitude with drones so that that isn't much of a risk.
- DaftDank 1y agoThat will be quite a sight -- seeing the videos of people on the ground, filming future drone laser battles
- xattt 1y agoThe laser would ricochet from disintegrating drones (think of the props) and cause collateral damage to people on the ground. Also see this (with remaining eye): https://www.funraniumlabs.com/2024/07/how-i-got-my-laser-eye-injury/ https://www.funraniumlabs.com/2024/07/how-i-got-my-laser-eye...
- echelon 1y agoThere's danger and risk in everything worth doing. The dams could burst and drown millions. The highrise you live in could topple over or burn. The bridge carrying the train could crash into the valley. The passenger plane could lose lift and crash into a residential building. The power source in your car could catch fire. We engineer around it.
- probably_wrong 1y agoCounterpoint: We've known about global warming for almost 50 years and yet to this day the debate is divided between "eh" and "no, it isn't". Coal plants have been consistently depositing smog in our lungs with no end in sight. Boeing has successfully lobbied itself out of criminal charges for the deadly consequences of their (IMHO) negligence regarding the 737 Max. Companies have stopped pretending that they'll put human lives before profit. As a human, I am therefore beyond giving any company the benefit of the doubt that they'll "engineer around it" when it comes to safety.
- westurner 1y agoIs it possible to steer the weather by heating the atmosphere with power beaming microwaves? Is it possible to cancel the vortical formation of a tornado or a hurricane with microwave power beam(s)? Does heating the atmosphere with microwaves change the weather, or the jet stream, or the cloud cover? What sort of a fluidic weather simulator could answer this question? Is there a fluid simulation device that allows for precise wireless heating of certain points in the fluid? If so, there could be international space law to study and control for the known and presumed risks of space-based microwave power beaming.
- gus_massa 1y agoNuking a hurricane would not break it because nukes are not big enough https://edition.cnn.com/2019/08/26/weather/hurricane-nuclear-bomb-noaa-wxc-trnd https://edition.cnn.com/2019/08/26/weather/hurricane-nuclear... I think it's possible to nuke a tornado, but if someone does it to try to save a city, I expect even more destruction. I don't expect the beam to be energetic enough to change anything. The closest method I can think of is https://en.wikipedia.org/wiki/Cloud_seeding https://en.wikipedia.org/wiki/Cloud_seeding but it doesn't distribute energy, just tiny crystals to condense oversaturated vapor.
- westurner 1y agoTheoretically there is at least one point where a butterfly flapping its wings sufficiently affects seemingly nonlocal global weather. Presumably it's easier to prevent formation of vortices far before visible formation. A "cancel vortices" sim table might be more useful than the average CFD simulation.
- williamDafoe 1y agoThis will come in handy when DARPA builds the Phaser Cannon used to blast the Talosian fortress under the direction of Number One in the 23rd Century ...
- neya 1y agoFinally they decided to open up Nikola Tesla's work huh? :)))