Laser System Keeps UAV in Air for 48 Hours

Lockheed Martin and LaserMotive have developed a laser system that can recharge an unmanned aerial vehicle in flight potentially keeping them in the sky for indefinite periods.

Engineers with the company tested the system in its Stalker UAV in an indoor test in which the drone flew for 48 hours. The drone can recharge its 2-hour battery in flight by linking up with a laser system being beamed from the ground.

“This test is one of the final steps in bringing laser-powered flight to the field,” said Tom Nugent, president of LaserMotive. “By enabling in-flight recharging, this system will ultimately extend capabilities, improve endurance and enable new missions for electric aircraft.”

This system poses all sorts of potential for ground commanders who have constantly demanded long endurance UAVs for intelligence, surveillance and reconnaissance missions. Special forces units could especially benefit from a small, long endurance UAV when they are cut off from traditional air power.

The most recent test was done in a wind tunnel, but LaserMotive and Lockheed Martin officials are confident they can soon display Stalker’s capabilities in an outdoor demonstration.

Stalker can fly up to 15,000 feet and carry a payload of three pounds. The smallish UAV has a wingspan of 10 feet and maximum speed of 50 miles per hour. Soldiers can launch the Stalker by hand.

“We’re pleased with the results of this test,” said Tom Koonce, the Stalker program manager of Lockheed Martin Skunk Works. “Laser power holds real promise in extending the capabilities of Stalker.”

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Michael Hoffman
Michael Hoffman is the executive editor at Tandem NSI and a contributor to He can be reached at
  • DGR

    Very cool! The only downside is you have to have power to supply the laser, and you have to have line of site from the ground. So it would be great for recon over a FOB, but less for any kind of mobile unit. Still a very cool demonstration that could prove useful for a whole host of electronic purposes.

    • dubweiser101

      They might not necessarily need a direct line of sight to the UAV to recharge it with the laser. They may be able to bounce the laser off of satellites allowing the UAV to be recharged anywhere.

      • blight_

        You’d get serious energy losses going up through the atmosphere, to a satellite and then back down.

        Perhaps a mothership UAV (say a Global Hawk?) loitering over Pakistan, supplying energy to Predators that just hang out over the FATA as operators go on and off shift and destroy targets of opportunity?

        I guess this is supposed to compete with the alternative self-charging composites DefTech post?

        • majr0d

          It’s a HUGE leap to be powering a UAV w/a whopping three lb payload in a windtunnel to refueling Predators over Pakistan. By that time the Predators will have been retired. When we have tech to float and operate a laser powerful enough, we’ll likely have other tech making these type of refuel ops obsolete.

          • blight_

            I’ll laugh if the Preds become the next B-52 and we’re on Pred-H. Hah!

            They will probably disappear in all seriousness

        • Maxtrue

          blight, you’ll remember my suggestion years ago perhaps. I proposed a high altitude drone that could loiter using electrical power. This could be maintained by refueling drones equipped with lasers. When the time was right, the ultra high altitude drone could engage rockets and lift up to the height needed to unload a mass driver which would also be rocket powered to provide the speed for impact. NASA calls the steering required on the decent, hypersonic re-entry aero-manuvering which is being used for our Mars decent on August 5th.

          The question remaining is what happens on impact. Obviously to use electrical power to stay aloft, something like the WK2 would need some conversion, but I think many of the pieces of the puzzle are falling into place.

          I heard ablative problems are still troubling the X-51. 20 x the speed of sound is going to present some problems but the Mars payload will take 1500 degrees of heat moving through the Martian atmosphere. I bet the SkyCrane is a concept the DOD would love as they don’t have to worry about dust.

          • Maxtrue

            Ultra high drones would get recharged at high altitudes where there is less atmosphere. And the lifters are coming….

            Not sure why so many won’t think outside the box. The solar furnaces we could fabricate on sub orbital platforms could generate lots of energy

        • Swig

          Not just the loss from atmosphere but also the inverse sqaure law alone would mean that you would have to have one powerful laser to get all the way to orbit and back and still deliver some power.

          • 4FingerOfBouron

            The link is not that hard to close. Ever heard of RF? Can go up at -80fb and back at -120db. On a LEO sat.

    • The Batman

      Simple solution would be Solar Power.

      If we could only make a few leaps and bounds in Solar tech this could be viable. A few homes in my area have solar panels covering most of the roof. Ontop of providing free electricity to the home I imagine it keeps the harsh Texas sun off the roof, too, keeping things cooler.

      Anyways… This is incredible. Things like this are why it’s still a good thing to be American. From this laser tech will blossom a whole new generation of getting power from point A to point B. Say goodbye to extension cords. Hell, say goodbye to cords in general.

      Think about it. Instead of outlets we could have a little spherical laser projector powering the gagets in the room. The Military, as usual, inventing the next technological evolutions.

      This has made my day.

      • dfor

        Or take it a few steps further…a solar-powered laser on a satellite. Yes, you would have to deal with atmospheric distortion, and the political implications of putting a laser in space, but still…think of the possibilities.

        • blight_

          Tesla’s wireless power would’ve been more awesome. Though I think he would be pleased.

          In any case, I was hoping that one day houses would invert AC back to DC, and obviate the need for almost every household appliance to have a AC-DC inverter.

          • Dfens

            The funny thing is, Boeing’s 787 does away with the 28 VDC bus and runs everything off of 3 phase 400 Hz power. When you think about the fact that all your electronics have DC-DC power supplies that convert aircraft power to AC, do an AC voltage conversion, and then rectify and regulate the DC power. With 3 phase AC going everywhere, it eliminates the step (and losses) of converting DC to AC. As everything in your house gets more electronics in it, the same advantages of having AC power available will be realized. Too bad we can’t get 3 phase power in residences.

        • John Deere

          No need to use lasers on a solar satellite, simply use a microwave link; cloud cover would be irrelevant. NASA has been working on the tech since the ’70s, it’s been viable for decades.

      • Brian Black

        With a max altitude of 15,000 ft the Stalker could often find itself under cloud layers. Also, while solar power is an option for the Middle East and around the Earth’s waist, future operations could be required at extreme latitudes – there may be no sunlight for a month; even at continental Northern European latitudes a fourteen hour winter night might stretch the ability of a drone that needs power not just for flight, but for powering the various onboard communications, serveillance and/or weapons systems.

        • blight_

          Nuclear batteries! With UAVs the weight of the shielding won’t be a problem. Though you need enough shielding to prevent electronics from being fried.

  • Dfens

    Kevin Parkin, who now works for NASA, did his doctoral thesis on using microwaves to power spacecraft back in 2006 ( Microwaves could be used instead of fuel to heat air in a jet or turboprop engine in much the same way. The only difference being you don’t have to carry your reaction gas with you when travelling in air.

    • Hugh

      This very concept is in my copy of ‘Future Travel’ published by Usborne in 1978.

  • RCDC

    Just an Idea: place solar panels on it’s top wings and tires on the base wing and place a 12 hr timed rotating twin engine on its nose…

  • kim

    Interesting also from the point of civilian use; If this is possible for a small UAV moving at speed and low height, surely it must be possible for ground vehicles as well.

    • Dfens

      True, it might be cheaper than inductively coupling to power buried in the road itself. You could have towers located along an interstate, for instance, such that you’re always within line of sight to one, not unlike cell phone towers except that you wouldn’t want anything metal in between your vehicle and the beam source.

      • blight_

        It’s an overcast day, and the entire interstate of cars lost power…

        I’d love inductive coils myself. Put some solar panels into the roads and use them to power inductive coils.

        • Dfens

          If you use towers, the overcast won’t bother the transmission. Rain or snow precipitation might, which would be the advantage of using the longer wavelength microwave power. Microwaves are less effected by precipitation than light, plus I think masers are much more efficient than lasers.

          • blight_

            Blah, I was thinking about the solar powered stuff from a different posting. That said, heavy fog (like a marine layer), or rain and snow might do it.

            As for microwave infrastructure, I started thinking about the AT&T Long Lines, but that was microwave communication between nodes.

    • Matrix_3692

      sounds like Tesla’s vision of wireless power supply network, which had problems with it’s efficiency.

      • Dfens

        No, it is as straight forward as a transmitter and receiver. In this case the transmitter is a low dispersion beam and the receiver can be materials that efficiently turn electromagetic waves of certain frequencies into heat or electricity.

  • stephen russell

    Laser Team under fire
    Losing Laser Unit
    Laser unit stolen or sabotaged.
    Detonate Laser unit from falling into wrong hands?
    miccommunication to ID drone etc

    • Matrix_3692

      i think it’s safe to say that the laser unit is meant to be install in a secured location ( a FOB or a fire-base or even the HQ). so security ‘should’ be plenty, but what ever you do, there’s always the chance of a spec-ops team getting their hands on the unit, or even an artillery/mortar/missile strike could do the job, so as every other early detection/surveillance/communication systems out there, it’s the age old “pike and shield”,”defense and offense” problem.
      and about the weather, well, it’s always a major player in any warfare, and will be so in the foreseeable future, and we might as well ‘weather’ through it.
      to ID and communicate with the drone, i think the standard IFF and modern C4I systems will do just fine.

    • blight_

      There’s also the more obvious problem of precision adjusting a laser to hit a recharging element on a UAV just right from practical ranges of a mile or so. A tight beam must be very accurate, a dispersed beam to allow for some inaccuracy requires more power, which adds fatigue to the emitter and increases the required size of the unit.

      Perhaps converting a CIWS mounts direction finder to point a charging laser at the drone…?

      • Brian Black

        If NASA can lase a tea-tray sized reflector 400,000km away travelling at 1km/s…

      • Maxtrue

        High altitude drones would likely have ample upper wing surfaces. Perhaps a scaled down turret could be used on recharging drone given the abilities of the Air Borne laser turret. Maybe that’s an idea in itself. Wasn’t the F-24 supposed to eventually carry a laser. And would this be point and shoot? So some form of accurate targeting was imagined, yes? Wouldn’t a targeting laser make sure bursts would happen only when source and target were properly aligned? Would stronger laser provide more power faster? And would this be the beginning of laser-absorbent material air craft will need on the underside in hostile laser environments? Would then laser fire below actually provide more power to the properly modified air craft?

        One idea I heard about was to use electrical power supplied to produce hydrogen which could keep drone ultra high with rocket bursts. Not sure how that energy balance sheet works out or the game of cat and mouse between refueling and targeted drone in that scenario. What is depicted above is a far different application.

        Too bad drones couldn’t seek and survive thunderstorms and recharge with lightening :)

        • Maxtrue

          excuse me, I meant F-35. Did we even build an F-24? :)

  • Matrix_3692

    well, if this system works as advertised, we’ll be able to clear a lot of a drone’s mission payload (by removing / shrinking some fuel tanks / batteries), good for CAP on military installations and border patrols. maybe warships could also benefit form this system, a warship the tonnage of a destroyer(maybe smaller if the tech allow) will be able to operate it’s own mini(micro)-AWACS for long periods of time, sounds good for countries that can’t afford a carrier.

  • STemplar

    Interesting way to maintain persistent surveillance over a fixed location with short ranges, like say the Straits of Hormuz.

  • EW3

    “The drone can recharge its 2-hour battery in flight”

    Problem is it will likely take 3 hours to recharge the battery.

  • Jonathan

    Wait until they come up with the idea to power drone’s from satellites and start beaming down a trillion watts over our heads, and then the guidance misses the drone by a few inches and then a grandma walking down the street gets incinerated.

    Pretty cool I admit but this stuff is not new and has been proven to be too inefficient?

    It’s sort of like the laser communication system between satellites, the aiming must be the hardest part. And aiming between two satellites is a lot easier then a drone because it doesn’t drift in the wind, have atmosphere to deal with, rain, and satellites don’t generally spin, roll, yaw, etc.

    Still cool though I am just skeptical it is the best choice for perpetual power.

  • Praetor

    It’s great R&D, but I see some drawbacks… First, the UAV must be on the “target line” of the laser, therefore it has a very limited range to go far behind enemy lines… Second, when I fire a huge blast of laser in the sky I can be saying “look bad guys there is my unarmed and very slow drone!”, even tough the laser is invisible to the naked eye (IR detectors).

    • blight_

      Depends on how much side-scatter comes off the beam. If you fire a laser in the light, you’ll usually only see the dot on the other end because there isn’t enough stuff in the air to scatter off of. If you repeat this in a smoky room or a sauna, the smoke particles or water droplets in air will scatter your Vis- laser in a spectacular, visible fashion.

      It would be a great way to keep a solar UAV in the air at night.

      “They have no sun, their UAVs will go to sleep….NOT!”

      • Praetor

        You are right blight, thanks

  • J.E. McKellar

    I got it, they just need to create a large energy source positioned high in the sky that can beam energy to multiple UAVs at the same time. If they can make the device powerful enough, they wouldn’t even have to aim the lasers, just blast out the energy in every direction. If they position the source high enough to overcome ground obstructions, they could even power ground vehicles and even whole bases. It would require a lot of power, though, maybe something on the order of a sustained hydro-nuclear reaction…

    • john Deere

      Space-based solar power (SBSP) system is the answer. Energy is transmitted by microwaves, rather than laser. There’s no need to worry about cloud cover. And, it is old, well proven, tech that was developed in the 1970s.

      • Maxtrue

        Since then various different ideas including solar furnaces that generate lasers and power have been imagines. We know things are serious when Musk fires up a small factory capable of making large sheets of solar panels and scaffolding/. No doubt space is a great place to generate energy and make things we can’t on earth.

        Such a system will bring political problems as we edge closer to effective space weapons. NASA didn’t get anywhere with their plan.

    • Dave

      ALready have that, they call it the sun…

      • blight_

        The atmospheric losses plus the inefficiency of solar panels don’t make it as favorable as it could be.

        • Dave the rug

          What do you mean by “the inefficiency of solar panels”? This is a space based system; simply by being outside the Earth’s atmosphere increases the transmission of solar energy by 144%.

          Beaming microwaves through the atmosphere loses around 15% of the energy, 85% of it still gets through. These are pretty good figures.

          • mondodoodah

            I think the technology and the location is rubbing against conservative instincts here: Solar energy is associated with tree hugging hippies, and space is Star Trek and Star Trek is Communism.