back to article Laser deflector shields possible with today's tech – but there's one small problem

A new paper from the University of Leicester claims that it's technically possible to build shields around a spacecraft to protect it from laser fire using available technology, but with the somewhat troubling side effect of leaving the pilot unable to see where he or she is going. The research, published [PDF] in the peer- …


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  1. Rol Silver badge

    Alternatively a thin coat of wax and a keen karate student to wax on and wax off, will also defeat evil laser wielding sharks.

  2. Big-nosed Pengie

    I'd have thought that a mirror would be cheaper.

    1. frank ly Silver badge

      re. mirror

      They have to be 100% reflective at all encountered laser frequencies, but they're not, so they would heat up, degrade and vapourise.

      1. Grikath Silver badge

        Re: re. mirror

        Eventually... So do plasma shields , as they absorb the energy, so particles will escape the containment field. So unless you keep injecting plasma, any incoming energy the shield is designed to deflect will degrade it as well.

        Maybe the idea has merit, but you're still running into the "needs humongous amounts of energy" requirement that cannot be filled currently.

      2. Trevor_Pott Gold badge

        Re: re. mirror

        "They have to be 100% reflective at all encountered laser frequencies, but they're not, so they would heat up, degrade and vapourise."

        Aye, but properly designed they not only reflect some of the oncoming fire but function as ablative armour. Plasma sheilds could be useful for a starship looking to project a field that works somewhat like a proper navigational deflector. If we could find a way to regenerate ablative reflection armour we'd have a half-decent combat hull to boot.

        Perhaps a substance that could be secreted onto the hull that would instantly harden/freeze such that it had the relevant reflective and ablative properties? The issue with both ideas (plasma shields and regenerative ablative armour) is that is having to carry the stuff around everywhere. If you get too far from port and get into the shit you have to limp back home to refill your defensive capabilities.

        Now, if you could collect the relevant elements using a bussard collector (perhaps by parking next to a gas giant, star of other friendly source of volatiles) then you might be able to make all of this lovely stuff in situ. Which brings us back to the same problem as in the paper: power.

        The magnetic confinement for plasma shielding and the bussard collectors would require enormous amounts of power. Terawatts upon terawatts. Element separation, refinement and manufacturing of polymers for your armour would also take a stupendous amount of power.

        Matter/antimatter is unlikely as a power source: even if we could figure out how to make antimatter without using a significant fraction of the output of a star, you piss away more than half the energy from the reaction as unrecoverable "energy" like neutrinos. That leaves fission and fusion. Fission because Uranium is bloody everywhere and fusion because - while fission is cute and all - fission just can't deliver the power needed.

        So, in order to play the space combat game with even the remotest chance of survivability, each starship will require at least two power plants: a fission "spark plug" and a set of truly enormous fusion reactors to output the kind of energy needed. Napkin maths say that you're probably looking at a ship so large that Kirk's Enterprise* would be considered a shuttlecraft beside it.

        Which means, quite simply, "not in our lifetimes."

        *Not the Jar Jar Trek version

        1. Sureo

          Re: re. mirror

          Sounds like a perfect application for ununseptium (element 117).

        2. dan1980

          Re: re. mirror

          @Trevor Pott

          "Napkin maths say that you're probably looking at a ship so large that Kirk's Enterprise* would be considered a shuttlecraft beside it."

          "*Not the Jar Jar Trek version"

          Well obviously not - that version could just be protected by lens flares.

      3. DJO Silver badge

        Re: re. mirror

        The trick with mirror armour would to have layers of tiny corner reflectors which would send the beam back to it's source before ablateing.

        1. Psyx

          Re: re. mirror

          Spacecraft are going to have very large delta-V, so a corner reflector bounced beam would miss whatever shot at it.

  3. Charles 9 Silver badge

    What about for unmanned stuff such as a missile? Could this combined with spin and a highly-reflective coating provide adequate defense against interception by a laser system? This can have practical implications for things like shipborne defense systems.

    1. Voland's right hand Silver badge

      No, it cannot - you cannot realistically maintain the plasma bubble under atmospheric conditions especially if you are traveling at 2Mach+. This is a space-only option.

      Also, as far as practical implementations go, this is more of a Babylon5 solution that Star Wars. Firing plasma into the path of the laser cannon in order to disperse it is something workable while trying to surround yourself with plasma probably is not.

    2. Anonymous Coward
      Anonymous Coward

      "spin and a highly-reflective coating"

      Balls. I was wondering about that too.

      Disco mirror balls, obviously. Lots of little mirrors on a ball, spinning so the mirrors get time to cool off outside the line of fire. A whole cloud of them around my spacecraft.

      Is it worth owt? Patentable?

      1. Chris T Almighty

        Re: "spin and a highly-reflective coating"

        If "Moving your finger from one place to another on a touchscreen" is patentable, then I'm sure "Airbourne cloud of discoballs to defeat attack by lasers" would have been worth a punt. And it would certainly liven up the afternoon at the Patent office.

        Sadly, by making your idea public, we're all now free to clad our spaceships in 70's sparkle, and you won't get a bean. You'll be kicking yourself one day.

        1. Mage Silver badge

          Re: "spin and a highly-reflective coating"

          No, still a chance as the USPO largely ignores publications and prior art.

        2. qwertyuiop

          Re: "spin and a highly-reflective coating"

          Sadly, by making your idea public, we're all now free to clad our spaceships in 70's sparkle

          What's the betting that Apple will still be able to get a patent on it?

      2. Anonymous Coward
        Anonymous Coward

        Re: "spin and a highly-reflective coating"

        Disco mirror balls, obviously. Lots of little mirrors on a ball, spinning so the mirrors get time to cool off outside the line of fire. A whole cloud of them around my spacecraft.

        AFAIK you can't hear Staying Alive in space. Just sayin' ..

        1. Vic

          Re: "spin and a highly-reflective coating"

          > AFAIK you can't hear Staying Alive in space. Just sayin' ..

          "In space, no one can hear you cha-cha-cha"


          1. AOD
            Thumb Up

            Re: "spin and a highly-reflective coating"

            Vic, have a +1 from me for working in a Dwarfer's reference.

            Episode "Confidence and Paranoia" if my memory serves...

            1. Mad Chaz

              Re: "spin and a highly-reflective coating"

              And that would be Dave's confidence talking. Gave him an upvote too

      3. Anonymous Coward
        Anonymous Coward

        Re: "spin and a highly-reflective coating"

        "Is it worth owt? Patentable"

        I think you'll find apple have a patent covering that already.

        I mean.. They're bound to have something broad enough to cover it...

        1. JonP

          Re: "spin and a highly-reflective coating"

          "No, still a chance as the USPO largely ignores publications and prior art."

          "on a mobile device."

          5. Profit.

        2. d3rrial

          Re: "spin and a highly-reflective coating"

          "I mean.. They're bound to have something broad enough to cover it..."

          Maybe they'll patent patenting itself. The ultimate Apple victory.

      4. Marketing Hack Silver badge

        Re: "spin and a highly-reflective coating"

        @disco balls AC

        Would the ships computer play "Disco Star Wars" when you raise shields?

        1. Anonymous Coward
          Anonymous Coward

          Re: "spin and a highly-reflective coating"

          "Would the ships computer play "Disco Star Wars" when you raise shields?"

          Surely it would play "Start wrecking, across the Universe"?

          DO NOT CLICK:

          Ye canna change the laws of physics.

          1. Bakana

            Start wrecking

            That was "Star Treking across the universe."

            Star Wreck is a Fan Group in Finland that put out a Full Length Babylon 5 / Star Trek crossover parody movie. Check them out at:

            The movie is (or was) available on DVD.

            1. Fred Flintstone Gold badge

              Re: Start wrecking

              Star Wreck is a Fan Group in Finland that put out a Full Length Babylon 5 / Star Trek crossover parody movie. Check them out at:

              The movie is (or was) available on DVD.

              The first release you could download from their website - the whole merchandise thing came later. It's still available on Youtube too - well worth it IMHO :).

  4. DougS Silver badge

    All you need is one frequency that can pass through

    Then you can have a swarm of drones around it (or in the vicinity, away from all the nasty laser beams) to be your "eyes".

    That means the enemy will need its own drones to take our your drones. The stockholders will like this plan: Give the deflector shield option away for free, but charge for the drones. At least, that's what will happen if Gillette expands into starships.

    1. Michael Habel Silver badge

      Re: All you need is one frequency that can pass through

      At least, that's what will happen if Gillette expands into starships.

      LMFTFY: If Hewlett Packard ever get into 3D Printing Starships....

  5. frank ly Silver badge

    If an ultra-violet camera can see out ...

    .. then an ultra-violet laser can vapourise in.

    1. Vic

      Re: If an ultra-violet camera can see out ...

      > then an ultra-violet laser can vapourise in.

      Don't you just modulate the shield harmonics to get around that?


      1. picturethis

        Re: If an ultra-violet camera can see out ...


        You rotate the frequency until it matches the shield modulation frequency:

        1. DougS Silver badge

          Re: If an ultra-violet camera can see out ...

          Actually, rotating the shield frequency is exactly what you'd do. If you use my "swarm of drones" idea from the earlier post to do your seeing, and need one frequency to pass through to communicate with them, you'd have that frequency changing thousands of times per second.

          Think of absorption lines in a spectrum. You want a spectrum with a single absorption like, that changes constantly. The drones are synced to the ship's clock, and know how far they are from the ship, so they can change their frequency in a way that's timed to the shield frequency changing.

          Ideally, you'd only have a handful of places on the ship where even that one frequency gets through - the antenna sites the drones have their narrow communication beam (laser, probably) pointed at.

  6. DerekCurrie Bronze badge

    EM Wave Piloting Need Not Require Light

    There are other ways of piloting that don't require the observation of a light source. There are plenty of other wavelengths of EM radiation to detect out there in the universe besides the wavelengths used in lasers. I would imagine the pilot would be looking at a screen that reinterprets other EM energy into light representations on screen. A simple example would be the infrared images we all have seen, which aren't actually showing infrared radiation, but a representations of IR wavelengths into visible images. Theoretically, the same is possible for much of the rest of the EM spectrum that would not be used in lasers.

    I'd take credit for the concept, but it's not actually anything new. It's simply not in the public vernacular and hasn't had much use outside of the barbarism of war and ghost hunting.

    1. DougS Silver badge

      Re: EM Wave Piloting Need Not Require Light

      Whatever wavelength you can "see" in, the enemy can send in at a billion times the intensity and melt you. Or, at least, a thousand times the intensity and blind you.

  7. Flatpackhamster

    Flick it on and off at high speed.

    That'd give you a percentage of visibility whilst giving you protection. A bit like the black globe shields in the Traveller RPG.

    1. The Infamous Grouse

      Re: Flick it on and off at high speed.

      Glad to see someone else remembers the black globe. I was about to reference it as prior art.

  8. Truth4u

    Not just for space cadets

    I want the plasma shield for when I have to walk down the Strand. Not seeing isn't a problem as no one else is looking where they're going either.

  9. Suricou Raven

    One other problem.

    The power requirements. This thing is basically a scaled-up plasma window. The power to maintain something like that would likely be in the megawatts.

  10. Chris G Silver badge


    Have been using this method if not this technology for millions of years: hide inside an impenetrable shell relatively speaking, and wait until the danger has passed before you stick your head/eyestalks out.

    Perhaps it would be possible to pass sacrificial sensor stalks through the plasma field to see and navigate with, obviously they would be damaged or destroyed with a direct hit so a system for extending replacements would be necessary.

    You could also use optic fibre stalks passing through the field to deploy your own lasers.

    1. Charles 9 Silver badge

      Re: Snails

      The problem is that plenty of animals have found ways to enjoy their escargot in spite of the shell. Birds, for example, have their powerful beaks while racoons have learned to rap snails against rocks and the like to crack the shells.

      1. Psyx

        Re: Snails

        What we're saying is that space ravens will pick your spaceship up and drop it on a rock.

  11. Anonymous Coward
    Anonymous Coward


    Anyone checked it Apple have been granted a patent for this?

    1. VinceH Silver badge

      Re: Patent

      Well, if it's on a space craft, that would certainly count as "on a mobile device".

  12. Sir Sham Cad

    Shields Up! The Physics of WHAT?

    Star Wars mentioned "Deflector shields" and these appeared to be, essentially, invisible barriers that hugged the external contours of the ship. Every laser blast that was seen hitting the Falcon, Rebel fighters (of all designations) and Star Destroyers without doing damage (absorbed by the deflector shield) appeared to strike the surface of the ship. The only exception was the deflector shield surrounding the space around the second Death Star that was beamed from Endor and that was for a specific purpose of keeping the Rebel Fleet at super-laser range.

    Star Trek has visible shield barriers surrounding the ships at a distance as described in this paper. We know that the power output of the matter/antimatter annihilation reaction in the Warp Core of a Starship is sufficient to warp space itself whilst also powering all the ship's weapons and other power needs. Also, the phrase "Shields Up, Red Alert!" is from Star Trek.

    Yes, I am nitpicking the nerd culture references rather than addressing the science and I'm not ashamed!

    1. Don Jefe

      Re: Shields Up! The Physics of WHAT?

      Vessels in Star Trek only have visible shields when a vessel is viewed on the view screen. Definitely the Bridge screen, I'm not sure if cabin screens show shields or not. Cabin level equipment seems to be reserved specifically for getting Unionized set designers credit, and to show that sexy underwear is not compatible with transporters (or something).

      I used to think it was all just a tiny forgotten detail, but I'm now quite certain it is very deliberate. When Sam Beckett was Captain they frequently showed things from a viewpoint outside the ship and the shields weren't visible but back on the bridge the shields could be seen on screen, mostly. The same occurs in all the feature length films.

      Sometimes, especially in Voyager, a view from outside the ship will show shields being energized (which makes total sense, any matter in the space where the shield actually forms would be annihilated, like a bug zapper). The Delta Flyer had shields, but they were never visible, even on screen, perhaps because the vessel wasn't Star Fleet. But Voyager also had those silly variable swing thrusters that changed position according to the amount of confidence displayed by Bridge officers, apparently, so it's hard to say why the Delta Flyer Shields weren't visible.

      1. Psyx

        Re: Shields Up! The Physics of WHAT?

        You watched Voyager?

  13. Don Jefe

    Hands Free

    It's not like there's anything to see anyway. Space was filmed solely in black and white, and even that becomes more of a white with black specs until you exceed the speed of light. If you want color you have to apply the Turner Filter.

    If FTL travel were possible there's less than any point in having a view. You'll already have plowed over whatever it was at the same moment the whatever became visible. They could probably offset the costs of voyages by just showing endless adverts to the people onboard. It would be more interesting during the vast spaces between promiscuous aliens and exciting enemies.

    At any rate, being able to see outside is not an impediment to navigation. If it were, international travel and submarines wouldn't be nearly as scary, or successful. Assuming that we found a place to visit and figured out how to get there the Hansel and Gretel breadcrumbs are still the best way to navigate. The spacecraft drops small stationary satellites behind it which are upgrade if repeat travel is desirable and other craft do the same in different directions, you end up with a huge GPS (Galaxy Positioning System).

    Incidentally, Star Trek: Enterprise does that very thing, but the idea was first floated in the 1950's. Setup temporary navigational beacons and upgrade as requirements dictate. You only need signals from two of those beacons and you let the computer (or socially awkward crewman) drive.

    1. moiety

      Re: Hands Free

      Yeah there's not a lot to run into in space; but for combat you need to know where the other guy is so you can fire stuff back. Missiles are expensive.

    2. moiety

      Re: Hands Free

      Been thinking about the 'space navsat' idea and don't think it'll fly:

      1) You'd have to cancel out any intrinsic velocity from the ship that dropped them...this would be colossally expensive

      2) Stars move; so the endpoints of your trail would get quite quickly out of date

      3) Have you seen what a paint-fleck can do to something merely in orbit?

      (#5 here: imagine something satellite-sized at the sorts of speeds you'd need for interstellar travel. Space is big and the chances are slim; but you'd be dropping large lumps of stuff directly into the path of future travellers.

  14. Scroticus Canis Silver badge

    So safe on re-entry then?

    Given the plasma flare around any current space vehicle during atmospheric re-entry will protect it from a ground based laser strike? Goody!

    1. Suricou Raven

      Re: So safe on re-entry then?

      It serves to protect the ship against radio communication. There's minimal contact during reentry, as the plasma sheath blocks signal.

    2. Don Jefe

      Re: So safe on re-entry then?

      If the reentering vessel isn't a missile you just have to wait for it to land. That whole returning to Earth thing has been the Achilles heel of any space domination hopes/dreams since the 1960's.

      Sure, it isn't sexy, or clever, but those aren't things you really want involved in any conversation about 'shooting'. Launch facilities are impossible to hide or shield and stuff coming back is even recorded by amateurs (advanced). Until something changes with our technology, a lot, there is no fear of unfriendly or unwanted space domination by any nation.

      I'm sure the boos and hisses I'll get were no worse than when the DoD guy said the same thing 50 years ago :)

  15. ecofeco Silver badge

    I direct you to...

    Yes, I know the article is only about laser shielding, but this is related in that the whole technology is moving forward.

    Check the dates as well.

  16. Adam 1 Silver badge

    May the fourth be with you.

    /here all week

  17. John Deeb

    In space nobody sees you scream

    Article: "...would also not allow light to reach the pilot".

    Note: in space it's pretty dark unless one is close enough to a light source like a star. Pilots won't steer by visible light unless they are flying in a carton cabin hung inside a well lid studio. But I guess radar beams won't go through the plasma either. Enemy ships need to be detected at least with "sub-space particles scanners" one would presume. At least in Startrek.

  18. mIRCat

    Moon Base One!

    "The other drawback is physical. Any spaceship carrying the shield would need a massive magnetic array to contain the plasma bubble, not to mention a power source capable of maintaining it."

    It sounds suitable for my future moon base! Or other ground based operation that has a large underground power plant.

    Sharks with laser beams not included.

  19. TheProf


    Has anyone built a powerful enough laser to warrant the use of shields? Or a spaceship that needs shielding?

    Sorry if the answer was in the video but it was so boring.......

  20. CaptSmeg

    A simpler solution

    As Traveller was mentioned further up I thought I'd note another simpler approach that I recall first hearing about in that RPG about 30ish years ago. It always struck me as a very elegant and simple way to deal with directed energy weapons in space...

    Use a "sand thrower", basically a big shotgun which you fire sand in the direction of a hostile ship resulting in a large obscuring cloud between you and her. Lasers etc. are easily absorbed / scattered by the cloud. It also provides nice cover while you deploy decoys & drones. Cheap and effective. When you shoot back you are much better off using good old rail guns... Plasma or sand aren't going to stop a slug.

    I think any real space fights are going to be much more like the Wild West than Star Wars.

    1. dan1980

      Re: A simpler solution


      "I think any real space fights are going to be much more like the Wild West than Star Wars."

      I think you're right.

      I mean, right now our ability to inflict damage is far greater than our ability to prevent it. Collectively, our defense consists of destroying those assets that can harm us. US warplanes might be whizz-bang-awesome but their ability to fly unhindered is largely due to targeted strikes against warning and defense installations. This was seen to devastating effect during the beginning of 'Desert Storm'.

      Protection therefore lies not in hardening a structure against attack but preventing any potential attack getting in range.

      I suspect, actually, that if such battles were to take place at some point in the far future, that they would be more like naval battles. Each vessel would be essentially fragile, able to be destroyed with a single hit, so engagements would happen at long range, either with large guns, like battleships, or by utilising smaller fighters, as carriers do.

      In such engagements, lasers would more likely be used as point-defense to destroy incoming projectiles, just as they are being developed now.

      Or is it too much to hope that the massive effort and expense required in such ventures, coupled with the technical hurdles of powering weaponry and defenses on top of normal ship functions, would require us all to grow up a bit and focus on working together for the good of all.

      Yes, I suppose that is a bit of a stretch.

    2. Psyx

      Re: A simpler solution

      The problem with 'sandscreens' is that both vessels are travelling so fast at such a distance that a 1km cube 'sandscreen' is going to be of zero use after about a second, when it will cease to be in the firing line.

      Railguns have the disadvantage of long flight times and lack of terminal guidance. A missile is going to be slower, but can change delta-V at a rate that would turn a human crew spaceship to pulp.

  21. Allan George Dyer Silver badge

    If you surround your spaceship with a ball of plasma…

    surely your FIRST problem is dying when your ship evaporates?

  22. T. F. M. Reader Silver badge

    Cool, we have unlimted power now! Wait...

    I've read the paper. Frankly, it looks like it was written by students who attended exactly 1.5 lectures on plasma physics. And it does not contain any information that would *not* be included in the first 1.5 lectures in plasma physics in any university course.

    If they only offered any feasible way to actually contain a hot plasma shield around a spacecraft - no, "you just need a sufficiently strong magnetic field" is not good enough as magnetic field does not contain plasma in all directions, that's what you normally learn in the second half of the second lecture in plasma physics - we would have controlled thermonuclear power by now. The problem of magnetic containment is what has been hindering the fusion efforts for the last few dozen years. The Earth's ionosphere that they quote as an example is held in place by gravity, not by magnetic field...

  23. IvyKing

    Ionosphere Refracts, not Reflects

    The ionosphere refracts radio waves, were the maximum angle of refraction is roughly proportional to the wavelength times the electron density. At a low enough frequency, the refraction angle can equal 180 degrees, where the low enough is on the order of 2 to 10 MHz depending on time of day and sunspot number.

  24. sisk Silver badge

    Star Wars shields are nice and all, but where's my freaking lightsaber?

  25. Bakana

    Another option

    There IS another option. One that just requires the ship to have Really Big Hoinking Engines and a really Big fuel tank.

    Coat the entire outside of the ship with a thick coeat of Ice.

    And always Rotate the ship during combat.

    It does make Aiming whatever weapons you postulate your ship uses more difficult, but we already have weapons systems on fighter aircraft which deal with that problem.

    As always, whatever weapons & shields You have, your Enemy ships are going to have something Similar, otherwise, it's not a Battle, it's Shooting Fish in a Barrel, depending on which side has the advantage in Technology.

  26. Mike 137

    Prior Art

    '"Another possible application of this principle may be for trapping radiation inside a shell of plasma rather than excluding it" said Toohie.'

    Larry Niven and Jerry Pournelle invented this (the Langston Field) in 1974.

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