The US Army is Building Drones That Never Need To Land (technologyreview.com) 84
It's using lasers to power the aerial machines. An anonymous reader writes: According to New Scientist [paywalled], the US Army is firing lasers at photovoltaic cells on drones to deliver power from a distance. Eventually they hope to power the devices from 500 meters away. How it works: The method is similar to the way University of Washington researchers are powering their mini insect robots. The process creates a lot of heat, which could risk melting the drone. And lasers come with additional risks.
Can't wait for cars (Score:1)
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The sun provides about 1 kilowatt per square meter.
https://ag.tennessee.edu/solar... [tennessee.edu]
A Chevy Bolt, as an example vehicle, gets "over 200 miles" from 60 kWh.
https://insideevs.com/deep-div... [insideevs.com]
Let's assume batteries get better, and it could get 500 miles from the same 60 kWh. So you would need another 60 kWh from the solar cells to go 1000 miles. At an average of 60 mph, that's almost 17 hours. 60 kWh in that time means 3.5 kW of power from the solar cells, so 3.5 square meters if the cells are 100% efficient.
But what do they do? (Score:2)
There is a trade-off for this wireless charging method, which will add weight and bulk, which could had been used to add a camera, or a weapon or something else.
Re:But what do they do? (Score:5, Insightful)
But what do they do?
Provide jobs for defense contractors and pad the resume for whoever is running the project when they are up for their next promotion.
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Provide jobs for defense contractors and pad the resume for whoever is running the project when they are up for their next promotion.
This is a big problem with DoD contracts. The military "contract liaison officer" assigned to the project will spend years of his career working on it, and has a HUGE vested interest in seeing it not fail. Notice that I didn't say "succeed", just "not fail" ... continuing indefinitely in limbo is good too, as long as the funding continues.
So the military officer assigned to oversee the project will never recommend that the project be cancelled.
It is not just his promotion at stake, but his "consulting" jo
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This is a big problem with DoD contracts. The military "contract liaison officer" assigned to the project will spend years of his career working on it, and has a HUGE vested interest in seeing it not fail. Notice that I didn't say "succeed", just "not fail" ... continuing indefinitely in limbo is good too, as long as the funding continues.
So the military officer assigned to oversee the project will never recommend that the project be cancelled.
It is not just his promotion at stake, but his "consulting" job with the contractor after he retires from the military. Military retirement is after 20 years of service. So if you sign up at age 18, you can retire with a pension at 38.
If it is a military officer like you say, it is unlikely they would be an officer at 18 years old.
No, that's 20-21 for Army assuming they go to West Point. So you could retire at 40-41 after 20 years, all as an officer.
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If it is a military officer like you say, it is unlikely they would be an officer at 18 years old.
It is 20 years total, not 20 years "as an officer".
Plenty of people enlist at 18, and are commissioned later.
With parental consent, you can even enlist at age 17.
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Actually, if they come right out of ROTC, there is a good chance they are 2nd LT. (or 3rd LT "butter bars") around 19-21 years of age. And just because you are not an officer at 18, does not mean your years of service do not count toward retirement 20 years into your service.
Commissioning in the US armed forces today (historical exceptions notwithstanding) requires a bachelors degree. Few have that at 19 years old.
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Don't forget the senators who will fight tooth and nail to keep that project alive and well if it's in their district. The natural forces that would otherwise cause a badly thought out and badly managed project to fail do not operate in this domain.
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Re:But what do they do? (Score:5, Insightful)
Though I also wonder, what for, with this limited range.
Static defense would be an obvious application. You have drones hover and circle your base 500 meters out to watch for approaching infiltrators.
Another would be convoy defense. You mount the LPU (laser power unit) on the top of a vehicle and have drones to your front and flanks to watch for ambushes, or soil disturbance that could be mines.
They could provide low cost over-the-horizon views to armor, allowing tanks to avoid bounding overwatch, and move much faster. In defense, tanks could remain in full defilade while the crews watch the video feed from the drone rather than exposing their cupolas.
Re: But what do they do? (Score:2)
Re: But what do they do? (Score:1)
The precence of drones indicates vehicles anyway. So does the noise, tanks are not stealthy. And when fighting starts, you turn off drone charging beams anyway.
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Cheaper maybe with two drones that you cycle though.
Re:But what do they do? (Score:4)
If the drone never lands how do you re-arm them?
They carry cameras, not weapons.
And reconnaissance drones already have extended time on target capabilities.
Big high altitude recon drones are too expensive to assign one to every outpost, convoy, or patrol.
Every time one crashes some neo-barb gets access to the technology.
The tech is already available on-line to anyone with a credit card: dji.com [dji.com]
For drone tech, the military is trailing the COTS/hobby market.
COTS= Commercial off the shelf (an ERMA)
ERMA= Easily recognizable military acronym
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The trade-off is that by removing a camera, they can drastically reduce the number of landing/takeoff cycles, which means less downtime and fewer crashes. It also opens the (perhaps future) possibility of having fully-mobile drone support: A drone overhead for days as a convoy moves through unprotected space, without needing to be near a friendly runway.
Lasermotive did this already (Score:5, Informative)
(home page: https://powerlighttech.com/ [powerlighttech.com] )
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There is a trade-off for this wireless charging method, which will add weight and bulk, which could had been used to add a camera, or a weapon or something else.
Well, no. The solar panels will be thin-film, so they will take up basically no space and add very little mass. The charge controller will be smaller and lighter than the amount of battery they remove/don't install, because they don't need to maintain runtime with big batteries. They only need a small battery (or a large capacitor, which is lighter than a large battery) in order to manage power.
Why light? Why not microwaves? (Score:2)
Is it just because shielding the electronics against the microwave transmission is difficult? Or is there some other reason why lasers are preferred?
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It's fine when government and military do it.
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What? Microwave, like x-rays or visible "light", is a form of electromagnetic radiation.
Yes, but microwave is not a form of light, and light is not a form of microwave. They are of different frequencies and there are different ramifications to using them. HTH, HAND!
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"Light", especially in the physics world, is generally referring to EM.
Yeah, EM within a certain range of frequencies which doesn't include things that aren't light.
Microwaves, X-rays, visible light, etc are all forms of "light".
No, they are not. Only EM within a certain range of frequencies is called "light". Outside of those frequencies, it goes by other names.
Some EM bands are more light-like (Score:2)
To me, "light" refers to those EM frequency/wavelength bands that behave similarly to visible light in whatever way is important for a particular application. These are usually IR, visible, and UV. The 3 meter band used for FM radio, for example, isn't very light-like in how it is transmitted and received or how it interacts with the atmosphere and terrain.
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To me, "light" refers to those EM frequency/wavelength bands that behave similarly to visible light in whatever way is important for a particular application. These are usually IR, visible, and UV.
You're not the only one. That's why we have different names for LASER and MASER, for example. Otherwise they'd both just be a LASER.
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Please offer an example of someone using "light" to describe, say, an x-ray.
Yes, they are all photons, but that doesn't mean they are all "light". And the OP certainly made the context clear - only the AC that responded made it an issue of language.
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I'll help you out a little: NASA uses it when speaking baby-talk to the public. [harvard.edu]
Gem from that website:
Careful what company you keep.
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Yes, but microwave is not a form of light, and light is not a form of microwave. They are of different frequencies and there are different ramifications to using them. HTH, HAND!
Exactly. Specifically, microwaves are four to five orders of magnitude longer wavelength, and therefore have much larger spot size on target-- the laser receiver is much much larger than a photovoltaic receiver.
Microwaves aren't light (Score:2)
Not exactly. Light = Electromagnetic radiation (Microwave, X-ray, visible light, gamma, etc)
No dictionary I am aware of defines microwaves as "light".
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I'm guessing here, but since you have to use un-shielded inductor (instead of photovoltaic cells), it may be far more vulnerable to enemy's electronic attacks.
It's possible to deliberately make a solar panel which can receive both microwaves and light. But I wonder if it's possible to make a solar panel which doesn't receive microwaves... after all, it's got long conductors. If you point a microwave weapon at a solar-powered craft, you might be able to fry it that way. Unless, of course, it's designed to harvest that energy...
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It's possible to deliberately make a solar panel which can receive both microwaves and light.
photovoltaic and microwave receivers use different technology. It may be possible to co-locate a microwave rectenna array on top of a solar array, but they won't be the same receiver, just two receivers in the same place.
But I wonder if it's possible to make a solar panel which doesn't receive microwaves...
Sure. Put a transparent conductor on the surface. Fine-mesh chicken-wire would do.
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But I wonder if it's possible to make a solar panel which doesn't receive microwaves...
Sure. Put a transparent conductor on the surface. Fine-mesh chicken-wire would do.
Okay, but now the fine-mesh chicken wire is receiving the microwaves, and it's got to dissipate the energy someplace. Also, if they're willing to use terahertz frequencies to attack, your chicken wire will be too coarse a mesh for defense.
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photovoltaic and microwave receivers use different technology
A PV cell is practically a large-surface diode. Guess what a microwave power receiver is in practice? Basically a rectifier.
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A PV cell is practically a large-surface diode. Guess what a microwave power receiver is in practice? Basically a rectifier.
I should sign my comments with my affiliation, maybe people won't try to teach me grade school semiconductor device physics.
Rectennas need FAST diodes with low turn-on voltage, so they're usually a Schottky diode. Photovoltaic cells are exactly the opposite: they need long minority carrier lifetime, so they aren't fast, and they need as high an open circuit voltage as possible, meaning a high turn-on voltage. Nobody uses Schottkys for solar cells. And microwave rectenna diodes need to be as small area as
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Maybe rain and fog causes more attenuation for a maser based link?
That's difficult to believe, because laser-based communications systems are well-known to have serious attenuation problems in rain or fog, and we use microwaves instead.
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How come the Navy didn't do this first? (Score:2)
Obligatory Nicolas Cage (Score:3)
You don't say? [pics.me.me]
Oh goodie (Score:3)
One step closer to Snowcrash with constantly flying, close orbit satellites. Wonder how much longer before I can walk around with goggles that show me views from above and behind? Surely becoming a gargoyle isn't that far away.
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Surely becoming a gargoyle isn't that far away.
You can do it already. Build an eyetap, wear a computer, have mobile internet. But just like in the book, people will think it's weird and gross. Google Glass proved that.
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They are doing what they are best at - waste... Consider atmospheric absorption,
The atmosphere is transparent to light. You know this because you can see.
...It would have been far more efficient to use a range that is not absorbed by the atmosphere, like directed microwaves or something.
Light is not absorbed by the atmosphere.
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Consider atmospheric absorption,
The atmosphere is transparent to light. You know this because you can see.
The atmosphere is partially transparent to light, because stuff in the atmosphere can absorb it...
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Consider atmospheric absorption, ...
If you have one of these trying to look at you: set of a few smoke bombs, the drone's cameras won't be able to see and it will soon power down.
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Consider atmospheric absorption, the efficiency of the cells and the added weight and becomes tremendously inefficient.
Solar cells are already rather lightweight, and that's without concentrated monochromatic light shining on them.
What about return fire? (Score:1)
How long until the other side builds a drone that homes in on the laser trail? (Good advise -- Don't take the tent next to the laser)
More generally, our soldiers in the field are radio wave hot spots. How long until the other side builds drones to target them?
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1. That homing drone would be fried by the laser. (remember, laser has enough power to charge huge drone quickly, it can simply increase its output and point to the enemy)
We already have laser designators and laser guided bombs. And we have ARMs(anti-radiation missiles), used to destroy the radar for AA/SAM sites, radios, and jamming equipment. Build a bomb that can detect the wavelength of the laser powering the drones, hone in on the source of the laser which is presumably on the ground (this does not involve getting in the path of the laser), and then boom, no more laser.
<3 (Score:2)
If you love your drone, set it free. If it comes back it's yours. If not, it was never meant to be.
Laugh all you want to... (Score:4, Insightful)
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What could POSSIBLY go wrong? (Score:3)
little bird (Score:1)
stellar! (Score:2)
Young Tom: How long do you think it's been up there?
Cooper: The Delhi Mission Control went down same as ours, ten years ago.
Young Tom: So for ten years?
[Cooper touches the surface of the drone]
Young Tom: Why did it come down so low?
Cooper: I don't know. Maybe the sun cooked it's brain or it was looking for something.
Young Murph: What?
[to Tom]
Cooper: Give me that large flat blade.
[to Murph]
Cooper: Maybe some kind of signal. I don't know.
[Cooper opens up the side of the drone]
Young Murph: What are you gonna d