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The US Army is Building Drones That Never Need To Land (technologyreview.com)

Posted by msmash on from the how-about-that dept.

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.

55 of 84 comments (clear)

  1. Can't wait for cars by brucekeller · · Score: 1

    With more efficient and invisible solar cells, to where you could travel maybe 1000 miles during the day. Way closer than you'd think. :D Repairs would be insane though!

    1. Re:Can't wait for cars by nasch · · Score: 1

      The sun provides about 1 kilowatt per square meter.

      https://ag.tennessee.edu/solar...

      A Chevy Bolt, as an example vehicle, gets "over 200 miles" from 60 kWh.

      https://insideevs.com/deep-div...

      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. That's an array 1.8 meters on a side.

      If this is happening in the next 10 years, you're right it will be way closer than I think.

  2. But what do they do? by jellomizer · · Score: 1

    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.

    --
    If something is so important that you feel the need to post it on the internet... It probably isn't that important.
    1. Re:But what do they do? by Nidi62 · · Score: 4, 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.

      --
      The only thing necessary for evil to triumph is for it to be pitted against a slightly greater evil
    2. Re:But what do they do? by Zorpheus · · Score: 1

      Solar cells are probably lighter than a battery for even a few minutes, if they use enough laser power density. And this can fly forever. Though I also wonder, what for, with this limited range.

    3. Re:But what do they do? by Sarten-X · · Score: 1

      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.

      --
      You do not have a moral or legal right to do absolutely anything you want.
    4. Re:But what do they do? by bacetech · · Score: 2

      If the drones could be deployed while airborne (without take off) then there would be no need for take off/landing equipment if they could be powered by a wireless charging method.

    5. Re:But what do they do? by drinkypoo · · 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.

      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.

      --
      "You're right," Fisheye says. "I should have set it on 'whip' or 'chop.'"
    6. Re:But what do they do? by ShanghaiBill · · Score: 1

      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" 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.

    7. Re:But what do they do? by ShanghaiBill · · 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.

    8. Re: But what do they do? by Zorpheus · · Score: 1

      Ok, sounds really great for vehicles. They just have to make sure that the laser beam isn't scattered so much that it becomes visible. This would point right to the vehicle's position.

    9. Re:But what do they do? by Nidi62 · · Score: 1

      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.

      --
      The only thing necessary for evil to triumph is for it to be pitted against a slightly greater evil
    10. Re: But what do they do? by Anonymous Coward · · 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.

    11. Re:But what do they do? by ShanghaiBill · · Score: 1

      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.

    12. Re:But what do they do? by Darinbob · · Score: 2

      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.

    13. Re:But what do they do? by Darinbob · · Score: 1

      Cheaper maybe with two drones that you cycle though.

    14. Re:But what do they do? by ShanghaiBill · · Score: 3

      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

      For drone tech, the military is trailing the COTS/hobby market.

      COTS= Commercial off the shelf (an ERMA)

      ERMA= Easily recognizable military acronym

    15. Re:But what do they do? by Slider451 · · Score: 1

      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.

      --
      Nostalgia isn't what it used to be.
  3. Why light? Why not microwaves? by drinkypoo · · Score: 1

    Is it just because shielding the electronics against the microwave transmission is difficult? Or is there some other reason why lasers are preferred?

    --
    "You're right," Fisheye says. "I should have set it on 'whip' or 'chop.'"
    1. Re:Why light? Why not microwaves? by drinkypoo · · Score: 1

      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!

      --
      "You're right," Fisheye says. "I should have set it on 'whip' or 'chop.'"
    2. Re: Why light? Why not microwaves? by Opportunist · · Score: 1

      It's fine when government and military do it.

      --
      We used to have a Bill of Rights. Now, with the rights gone, all we have left is the bill.
    3. Re:Why light? Why not microwaves? by drinkypoo · · Score: 1

      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...

      --
      "You're right," Fisheye says. "I should have set it on 'whip' or 'chop.'"
    4. Re:Why light? Why not microwaves? by XXongo · · Score: 1

      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.

    5. Re:Why light? Why not microwaves? by drinkypoo · · Score: 1

      "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.

      --
      "You're right," Fisheye says. "I should have set it on 'whip' or 'chop.'"
    6. Re:Why light? Why not microwaves? by Geoffrey.landis · · Score: 1

      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.

      --
      http://www.geoffreylandis.com
    7. Re:Why light? Why not microwaves? by drinkypoo · · Score: 1

      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.

      --
      "You're right," Fisheye says. "I should have set it on 'whip' or 'chop.'"
    8. Re:Why light? Why not microwaves? by K.+S.+Kyosuke · · Score: 1

      Transmitter and receiver size and mass, probably. Especially receiver size and mass.

      --
      Ezekiel 23:20
    9. Re:Why light? Why not microwaves? by K.+S.+Kyosuke · · Score: 1

      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.

      --
      Ezekiel 23:20
    10. Re:Why light? Why not microwaves? by Geoffrey.landis · · Score: 1

      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 possible, you want high current density to turn on. Solar cells are large area.

      A good diode for a microwave rectifier would be a lousy solar cell, and vice verse.

      --
      http://www.geoffreylandis.com
    11. Re:Why light? Why not microwaves? by MightyYar · · Score: 1

      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.

      --
      W..w..W - Willy Waterloo washes Warren Wiggins who is washing Waldo Woo.
    12. Re:Why light? Why not microwaves? by MightyYar · · Score: 1

      I'll help you out a little: NASA uses it when speaking baby-talk to the public.

      Gem from that website:

      Eventually, X-rays were found to be another form of light. Light is the by-product of the constant jiggling, vibrating, hurly-burly of all matter.

      Careful what company you keep.

      --
      W..w..W - Willy Waterloo washes Warren Wiggins who is washing Waldo Woo.
    13. Re:Why light? Why not microwaves? by K.+S.+Kyosuke · · Score: 1

      That's a quantitative difference, though. I'm aware of the variety of diodes in practice. It just doesn't scream "different technology" to me.

      --
      Ezekiel 23:20
    14. Re:Why light? Why not microwaves? by drinkypoo · · Score: 1

      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.

      --
      "You're right," Fisheye says. "I should have set it on 'whip' or 'chop.'"
    15. Re:Why light? Why not microwaves? by K.+S.+Kyosuke · · Score: 1

      Aren't masers still low-power devices? I don't see how you could use them power transmission.

      --
      Ezekiel 23:20
  4. How come the Navy didn't do this first? by Nkwe · · Score: 1

    Oh right. Land sharks.

  5. Obligatory Nicolas Cage by DontBeAMoran · · Score: 2

    The process creates a lot of heat, which could risk melting the drone. And lasers come with additional risks.

    You don't say?

    --
    #DeleteFacebook
  6. Oh goodie by H3lldr0p · · Score: 2

    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.

    1. Re:Oh goodie by drinkypoo · · Score: 1

      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.

      --
      "You're right," Fisheye says. "I should have set it on 'whip' or 'chop.'"
  7. What about return fire? by shayd2 · · 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?

    1. Re:What about return fire? by Nidi62 · · Score: 1

      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.

      --
      The only thing necessary for evil to triumph is for it to be pitted against a slightly greater evil
  8. Lasermotive did this already by XXongo · · Score: 4, Informative

    I should note that Lasermotive (now renamed "Powerlight Technologies") did that laser-powered-drone demonstration several years ago: https://www.youtube.com/watch?...
    (home page: https://powerlighttech.com/ )

  9. <3 by tobiasly · · Score: 1

    If you love your drone, set it free. If it comes back it's yours. If not, it was never meant to be.

  10. Re:what they are best at by XXongo · · Score: 1

    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.

  11. Re:what they are best at by drinkypoo · · Score: 1

    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...

    --
    "You're right," Fisheye says. "I should have set it on 'whip' or 'chop.'"
  12. Laugh all you want to... by kaizendojo · · Score: 3, Insightful

    .. but this is exactly how Skynet and the Matrix started. And neither of them worked out to well for us.

    1. Re:Laugh all you want to... by jfdavis668 · · Score: 1

      They both made lots of money. I say it worked out very well, at least for the people who made them.

  13. What could POSSIBLY go wrong? by Rick+Schumann · · Score: 2

    Firing high-powered lasers into the air, what could possibly go wrong?

  14. Re:what they are best at by Alain+Williams · · Score: 1

    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.

  15. Microwaves aren't light by XXongo · · Score: 1

    Not exactly. Light = Electromagnetic radiation (Microwave, X-ray, visible light, gamma, etc)

    No dictionary I am aware of defines microwaves as "light".

  16. Some EM bands are more light-like by tepples · · Score: 1

    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.

    1. Re:Some EM bands are more light-like by drinkypoo · · Score: 1

      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.

      --
      "You're right," Fisheye says. "I should have set it on 'whip' or 'chop.'"
  17. little bird by themusicgod1 · · Score: 1

    "the only time when she touches the ground / is when that little bird / dies"

    --
    GENERATION 26: The first time you see this, copy it into your sig on any forum and add 1 to the generation.
  18. stellar! by citylivin · · Score: 1

    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 do with it?
    Cooper: I'm gonna give it something socially responsible to do, like drive a combine.
    Young Murph: Can't we just let it go? It wasn't hurting anybody.
    Cooper: Listen, this thing needs to learn how to adapt, Murph, like the rest of us.

    --
    As a potential lottery winner, I totally support tax cuts for the wealthy
  19. Re:what they are best at by K.+S.+Kyosuke · · Score: 1

    But at 500 meters, this can be almost ignored (except for, for example, foggy weather).

    --
    Ezekiel 23:20
  20. Re:what they are best at by K.+S.+Kyosuke · · Score: 1

    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.

    --
    Ezekiel 23:20