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Navy Gets 8-Megajoule Rail Gun Working 650

Posted by ScuttleMonkey
from the high-flyers dept.
prototypo writes "The Free Lance-Star newspaper is reporting that the Navy Surface Warfare Center in Dahlgren, Virginia has successfully demonstrated an 8-megajoule electromagnetic rail gun. A 32-megajoule version is due to be tested in June. A 64-megajoule version is anticipated to extend the range of naval gunfire (currently about 15 nautical miles for a 5-inch naval gun) to more than 200 nautical miles by 2020. The projectiles are small, but go so fast that have enough kinetic punch to replace a Tomahawk missile at a fraction of the cost. In the final version, they will apex at 95 miles altitude, well into space. These systems were initially part of Reagan's SDI program ("Star Wars"). An interesting tidbit in the article is that the rail gun is only expected to fire ten times or less per day, presumably because of the amount of electricity needed. I guess we now need a warp core to power them."
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Navy Gets 8-Megajoule Rail Gun Working

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  • by lecithin (745575) on Wednesday January 17, 2007 @02:34PM (#17650726)
    But I was thinking, is this a possible way to launch orbiting vehicles? I first think no, as the initial force necessary to 'shoot' something into orbit would probably destroy any delicate instruments needed for a working satellite.

      However, this seems very interesting as an Anti Satellite/"Star Wars" platform. If they can get the software working to intercept, this should (scaled up version) be able to knock out satellites, ballistic missiles, etc - shouldn't it?
    • Re: (Score:3, Informative)

      by Starcom8826 (888459)
      That's called a mass driver. Using em to catapult vehicles into space.
    • Re: (Score:2, Informative)

      by Anonymous Coward
      Ask someone who knows: Gerald Bull [wikipedia.org]
    • by Phanatic1a (413374) on Wednesday January 17, 2007 @02:38PM (#17650774)
      But I was thinking, is this a possible way to launch orbiting vehicles?

      No, because when you shoot a projectile, you're putting it into a orbit that intersects the earth. You need some other impulse source to circularize the orbit.
      • by HighOrbit (631451) * on Wednesday January 17, 2007 @03:28PM (#17651632)
        No, because when you shoot a projectile, you're putting it into a orbit that intersects the earth. You need some other impulse source to circularize the orbit.
        Or, the rail gun could just be used as the first stage, second stage would be a solid chemical rocket which would take it the rest of the way and shape the orbit. The hard part then is getting the rocket engine, fuel, and nav-instruments to take the inital g-force of the rail-launch. The article mentions this:
        "When this thing leaves, it's [under] hundreds of thousands of g 's, and the electronics of today won't survive that," he said. "We need to develop something that will survive that many g 's."
        From the above, I'm assuming they have a reasearch project underway that would directly translate into launch survivability for the hardware. I'm not a electrical or mechanical engineer, but I'm going to guess that electronics embedded in high-impact composite ceramics (a la tank armor) might be the ticket here. The rocket engine and the fuel are another story. My understanding is that solid rockets are relatively simple construction (compared to liquid) so they would be the best candidate for survial. Pretty much every weld or joint I can think of would come apart under those kind of forces, so the fewer parts the better.
        • by ceoyoyo (59147) on Wednesday January 17, 2007 @04:06PM (#17652328)
          The other problem is finding some sort of material that can survive the heating. If you're going to reach an orbit that doesn't take much fuel to circularize you're going to have to be going at more than orbital speed coming out of the barrel and fly at a fairly shallow angle to the surface -- through dense air. That's going to make the space shuttle's reentry look like child's play.
        • Re: (Score:3, Informative)

          by init100 (915886)

          My understanding is that solid rockets are relatively simple construction (compared to liquid) so they would be the best candidate for survial.

          Just don't rely on the fuel to provide any structural integrity, as it is not really solid like a fireworks rocket. The SRBs used to launch the space shuttle are a good example of this. They have a void in the center of the rocket running through their entire length. This is because the fuel burns at the surface, and this configuration enlarges the surface by a large factor, providing considerably more power. So rather than burning from the end of the rocket, the fuel burns from the inside out.

        • Re: (Score:3, Informative)

          by Pentavirate (867026)
          I saw an episode of Future Weapons where they had a company developing a gps guided artillery round [discovery.com] fired from a tank. Their biggest hurdle was getting the electronics to survive. These things only go 1/10th of the distance that this rail gun is talking about so I would think it's a pretty big hurdle.
        • by raehl (609729) <raehl311@nOSPam.yahoo.com> on Wednesday January 17, 2007 @06:57PM (#17655932) Homepage
          Use the rail gun to launch a big, heavy projectile into orbit.

          Attach projectile to giant bungee cord.

          Attach giant bungee cord to object you want in orbit.

          Give object giant scissors.

          Expanding on this, you could tie one object with several rubber bands to several projectiles.
        • No, because when you shoot a projectile, you're putting it into a orbit that intersects the earth. You need some other impulse source to circularize the orbit.

          Or, the rail gun could just be used as the first stage, second stage would be a solid chemical rocket which would take it the rest of the way and shape the orbit. The hard part then is getting the rocket engine, fuel, and nav-instruments to take the inital g-force of the rail-launch.

          No - getting the hardware capable of surviving the G-forces is the easy part. The hard part is explaining to the beancounters why you are replacing a 50 million dollar first stage with a 10 billion (or most likely more) dollar accelerator - and not reducing your launch costs significantly because of vastly increased infrastructure maintenance and operations costs.
           
          There's a reason why only the lunatic fringe of the alt.space community keeps insisting that an EM accelerator is the 'only way to go'.
    • by Itchyeyes (908311)
      People have shown a few concepts of using rail guns to launch objects into space. However, they require massive amounts of electricity and, unless stretched out over several miles, the force applied due to acceleration is severe enough that it would likely destroy anything useful.
    • Launch Loop (Score:5, Interesting)

      by cutecub (136606) on Wednesday January 17, 2007 @02:43PM (#17650884)
      You're talking about a Launch Loop [launchloop.com].

      Basically, its a magnetic rail gun for launching space-craft into orbit. And in order to avoid the crushing G-forces involved, it has to be hundreds of miles long. So, while it may not be economically or politically viable, it is technically feasible. We know how to build a launch loop, as opposed to a Space Elevator, which can't be constructed with current technology.

      -Sean

    • by Maximum Prophet (716608) on Wednesday January 17, 2007 @02:43PM (#17650890)
      $1000 to launch 3.2 kilos into space. Damn straight. The price has to come down with volume. You just need to install the thing up the side of a mountain. You don't even need the fins and electronics onboard, just some end of the muzzle steering pushes should be enough to change the orbit the thing arrives in. Use it for fuel, water, and supplies that can take the G's, making it that much safer for the astronauts.
      You'd need to build a space tugboat that can hunt down and gather the payloads, then boost them to a higher orbit. No biggy, you can use robots with ion drives for that stuff.
      • Re: (Score:3, Insightful)

        by Itchyeyes (908311)

        No biggy, you can use robots with ion drives for that stuff.

        Ion drives would be worthless for your proposal. From Wikipedia:

        In practice, with currently practical energy sources of perhaps a few tens of kilowatts, and given a typical Isp of 3000 seconds (30 kNs/kg), ion thrusters give only extremely modest forces (often tenths or hundredths of a newton).

        Hardly the kind of propulsion you want to use for something that would be constantly stopping and changing direction. Ion drives are best used for crafts that travel extremely long distances with no need to change direction.

      • by dmatos (232892) on Wednesday January 17, 2007 @03:11PM (#17651370)
        Just because something gets launched to higher than the arbitrary height we have assigned to "the edge of space" does not mean that it will stay up there. The object has to also be travelling at orbital velocity. At LEO of about 200km, orbital velocity is around 7800m/s, aka ~17,500mph.

        Not to say that this gun cannot fire projectiles into orbit, just to say that firing something into space and having it stay there is much harder than just firing something into space.
      • by Anonymous Coward on Wednesday January 17, 2007 @03:12PM (#17651384)
        Parent recap:

        1. *some idea*
        2. "use robots with ion drives for that stuff"
        3. profit!
    • by wolfgang_spangler (40539) on Wednesday January 17, 2007 @02:44PM (#17650906) Homepage

      However, this seems very interesting as an Anti Satellite/"Star Wars" platform. If they can get the software working to intercept, this should (scaled up version) be able to knock out satellites, ballistic missiles, etc - shouldn't it?
      Ronald Regan suggested exactly that same thing, which is why we have the railgun that was tested.
  • by winkydink (650484) * <sv.dude@gmail.com> on Wednesday January 17, 2007 @02:35PM (#17650730) Homepage Journal
    if you can only fire 10 per day.
    • by ackthpt (218170) * on Wednesday January 17, 2007 @02:39PM (#17650808) Homepage Journal

      if you can only fire 10 per day.

      I'd be very careful accounting for winds over a distance of 200 miles, particularly where chinese embassies are located. Must be a hell of a job to be spotter for this kind of weapon.

      • Re: (Score:3, Insightful)

        by Smidge204 (605297)
        I doubt the actual rounds used in a battlefeild scenario would be dumb-fire lumps of metal, for just that reason. They already have laser guided munitions that an aircraft (or unpiloted drone) can spot for, so adding GPS to get within a mile of the target then using laser guidance the rest of the way seems prefectly doable.

        =Smidge=
        • I doubt the actual rounds used in a battlefeild scenario would be dumb-fire lumps of metal, for just that reason.

          You are correct, sir! (*DING*)

          Unless something has changed in the last year or so, the railguns will fire Extended Range Guided Munitions [globalsecurity.org] - a type of GPS-guided "smart" shell.

          On another subject, it seems I was right [slashdot.org] when I suspected that these ships would be unable to maintain a high rate of fire. I never expected it to be this bad, though. Seems our DD(X) class is going to need a fleet of tanker escorts shoud a real war break out. :-/

          *grumbles something about failure to improve nuclear generators for destroyer use*
          • *grumbles something about failure to improve nuclear generators for destroyer use*

            There's nothing wrong with the nuclear reactors we have now; you could easily fit one of them into a destroyer without any problems. I'm sure Westinghouse Nuclear would be happy to draw you (assuming 'you' have a few billion bucks to spend) some plans of how it could be done. Much of the space optimization has already been done, for submarines. There are several basically standardized designs that you could build the ship around, and then plop one in when you got everything else ready. It's totally doable.

            The Russians have several nuclear powered ice breakers that aren't much larger than destroyers, and they used to have several nuclear-powered cruisers as well (although I think they've all been decommissioned).

            The reason that surface ships haven't been built with nuclear reactors has more to do with the perceived economics of fossil fuels, rather than any real technical limitations. And for that matter, I've seen analyses that show that bulk supertankers could be economically driven by nuclear reactors -- if the NS Savannah was around today, and upgraded to use containerized cargo instead of manually loaded stuff, it would probably make money due to the high cost of bunker and diesel.

            If it's really electricity that's the problem with the rail gun, putting a nuclear reactor on a smaller ship wouldn't be more work than breaking out some old plans, or making a long-distance phone call to a retired-engineer's home in Russia.
      • by dan828 (753380) on Wednesday January 17, 2007 @02:53PM (#17651060)
        GPS and computer controlled fins. It'd just be a matter of developing a system that can withstand launch Gs and the electromagnetic forces. Maybe difficult, but probably not impossible.
        • Re: (Score:3, Interesting)

          by Kadin2048 (468275)
          They already have such systems for conventional artillery. I'm not sure of the G forces involved on a railgun projectile versus a conventional one, but we've managed to put fairly sensitive electronics in the noses of conventional artillery projectiles since World War II, so I think we can probably figure it out.

          The GPS-guided artillery shells that I've seen actually don't use "fins" in the same way that a missile does, but little pop-up retarders that change the shape and aerodynamic characteristics of the
      • Re: (Score:3, Interesting)

        by physicsphairy (720718)
        I'd be very careful accounting for winds over a distance of 200 miles

        "they will apex at 95 miles altitude, well into space."
        There are no winds in space. For that matter, the atmosphere thins out considerably before then. If it didn't these long range railguns would be pretty useless because most of the kinetic energy would be lost. And at the velocities we are considering the time spent in the deeper atmosphere is miniscule. Neither do we know how much spin the projectiles will have (a major stabilizi

    • Well (Score:5, Insightful)

      by everphilski (877346) on Wednesday January 17, 2007 @02:39PM (#17650810) Journal
      How many million-dollar cruise missiles are you firing a day?

      Most likely it will end up as an augment. One of the virtues of this system being, though, it can set up a shot quicker than a Tomahawk.
    • by drinkypoo (153816) <martin.espinoza@gmail.com> on Wednesday January 17, 2007 @02:47PM (#17650946) Homepage Journal
      Ten a day per launcher, yo. A cruise missile costs a million bucks plus. These projectiles will cost about a thousand dollars (projected, maybe it'll be $2000, still negligible in comparison.) With the amount of money you save not launching cruise missiles, you can afford to build more launchers. Let's say the launcher costs a billion dollars and the projectiles are $2000. You will then "save" $998,000 every time you launch a railgun projectile and you need launch only 1002 projectiles to get your launcher and the ammo for "free". Wikipedia claims the cost of a tomahawk is 1.3 million, so depending on who's right it could be an even shorter period of time. Something like 4500 of these missiles are known to have been made, so assuming an average cost of $1M that's what, 4.5 billion dollars spent so far? Just to put things in perspective. Also, even cheaper munitions could be used for short-range firings where windage will not make a substantial difference and guidance is not needed.
      • by Chyeld (713439) <chyeldNO@SPAMgmail.com> on Wednesday January 17, 2007 @03:13PM (#17651410)
        If the limitation in firing these is generating the power to fire, it won't matter if you have 60 launchers or just 1, you still will only get ten shots off in a day. Unless you are including the cost of a whole need power plant for each launcher.

        That said, the point of "How many cruise missles do we expect to actually fire in one day?" is a good one.
        • Re: (Score:3, Informative)

          by RzUpAnmsCwrds (262647)
          8MJ is 8MW for one second. My university has a 36MW power plant, on site. The D2G reactor, which was used on nuclear destroyers in the US Navy, has a power output in excess of 150MW.

          Somehow, I don't see generating power as a huge problem. Even a 64MJ launcher operating at 1% efficiency would only require 42 seconds of power from the D2G.
    • by SydShamino (547793) on Wednesday January 17, 2007 @02:49PM (#17650986)
      Well, that's each rail gun that can fire just 10 times a day. Even if they cost $100 million each, there's little stopping the military from buying 50 of them for each coast.

      (I'm ignoring whether they are practical or not, or if they cost too much, compared to alternatives. I'm just pointing out that the military can solve many limitations by throwing money at them, and no one in the government is embracing plans to limit military spending at this time.)
      • by TFloore (27278) on Wednesday January 17, 2007 @06:34PM (#17655586)
        I'm just pointing out that the military can solve many limitations by throwing money at them, and no one in the government is embracing plans to limit military spending at this time.

        You need to read more about the DOD budget process inside the Pentagon and the White House. It isn't so much that they are proposing spending less, as there are a LOT of fights over exactly where to devote the spending, and which service gets how much, and how it is portioned out. How much goes to maintenance, how much to new equipment purchases, how much to soldiers, sailors, marines, and airmen. How much to R&D like this?

        Very high cost equipment does indeed get canceled, simply because it costs too much. Usually measured as "too much over budget" but it is related to cost. Cost does matter.

        The Navy has this as a very real problem over the next 10 years. The next generation aircraft carrier is projected to cost $10 billion. The Navy currently spends $10 billion per year building ships and submarines. A ship must be fully appropriated in the year that construction is begun. The year they start building the next-gen aircraft carrier, does the Navy simply not build any submarines, which they want to build 2 per year for a cost of $2.2 billion each? How about DDG-51 class destroyers, at a cost of $1.4 billion each? Or DD(X) (now renamed to DDG-1000) class destroyers, at a cost of about $3 billion each? Amphibious assault ships, like the LPD-17, which I don't know a cost for, probably north of $1 billion? Or LCS ships, for the low cost of about $400 million each?

        What doesn't get built the year they start the next aircraft carrier?

        The Air Force has the same problem, with F-22 aircraft that cost $200 million each... they aren't buying 600 of them like they planned 10 years ago. Instead they are getting... 190 I think. Ditto with the F-35 (JSF), which they are not buying 4,000 of, or whatever the original purchase number was, because they are also fairly pricey.

        Just because the military works with large budgets, doesn't mean that the cost of equipment doesn't matter. It matters very much.

        And they really do care about limiting costs, because it really does affect how many they can buy.
    • Not electricity (Score:5, Informative)

      by SamSim (630795) on Wednesday January 17, 2007 @02:52PM (#17651032) Homepage Journal

      I'm almost positive the main issue is not electricity generation but rail friction. The best rail guns I'd heard of until today needed completely overhauling after each test firing because the rails themselves are damaged so badly as the projectile passes. Coil guns are better in this respect, as the projectile doesn't have to touch the coils...

      • Rail damage (Score:5, Informative)

        by PIPBoy3000 (619296) on Wednesday January 17, 2007 @03:06PM (#17651282)
        Excellent point. Here's a quick reference from the Wiki article [wikipedia.org]:

        Full-scale models have been built and fired, including a very successful 90 mm bore, 9 MJ (6.6 million foot-pounds) kinetic energy gun developed by DARPA, but they all suffer from extreme rail damage and need to be serviced after every shot. Rail and insulator ablation issues still need to be addressed before railguns can start to replace conventional weapons.
      • Re:Not electricity (Score:5, Informative)

        by JesseL (107722) on Wednesday January 17, 2007 @03:30PM (#17651692) Homepage Journal
        The problem isn't friction, it's spark erosion.
        The projectile in a rail gun should barely be touching the rails at all so it doesn't get welded in place. You end up with the equivalent of a huge arc welder traversing the rails with several thousand degree plasma.
    • Re: (Score:3, Interesting)

      by Absolut187 (816431)
      I'm guessing the problem is that such a large current would be difficult to re-capture into a battery?
      But couldn't the electricity from the first launch simply be routed to a second rail-gun, achieving a chain of launches from one burst of current?
    • by UnknowingFool (672806) on Wednesday January 17, 2007 @03:08PM (#17651324)
      That's 10 per gun. A cruise missle takes about 2 months to build, I think. And a ship/sub only carries a limited number of them. It might augment cruise missile in that the missiles would be for highly selective pre-planned attacks while a rail gun is for close support like artillery.
    • by arivanov (12034) on Wednesday January 17, 2007 @03:10PM (#17651358) Homepage
      10 a day is better than ten in total. You will be surprised how few Tomahawks (or Granits in the Russian case) are actually carried by most ships capable of launching them.

      The contract is awarded to a nuclear shop so I suspect that the thing will have an integrated reactor which makes it even more interesting.

      What goes around, comes around. After realising that missile tech is too expensive, Iraq tried to build the Babylon gun with a 1000 miles range. For the same reason (the missiles being too expensive) Russians have now developed a gun launcher (forgot the name) to fire high altitude atmospheric probes instead of the old missile system . US nearly did that with the HARP, but heavy lobbying by the aerospace industry killed that. And now we come full circle with US looking at long range guns for cost reasons.
  • by Anonymous Coward on Wednesday January 17, 2007 @02:35PM (#17650734)
    I'm a member of the NRA, I didn't see this in the last catalog.
  • by ackthpt (218170) * on Wednesday January 17, 2007 @02:37PM (#17650758) Homepage Journal

    What happens to the projectiles in these things? Such a gauss density I would assume, beyond simply the accelleration of the projectile has to be considerable. The coin shrinker is only 1600-2500 J [delete.org]

    Assuming 2500 J in a space of 3 mm does to an object the size of a quarter, 8 mega Joules would have an equivilent magnetic density spread over a gun 96 metres in length. Or me math is fscked...

    • by noewun (591275)
      What happens to the projectiles in these things?

      They transfer their kinetic energy to whatever poor sumbitch they happen to hit?

      My dad worked on a similar weapon for the DoD in the late 80s and early 90s. Since it's a kinetic weapon the projectile as such doesn't matter much. It's basically just a hunk of solid metal aerodynamic enough not to miss the target.

  • by nick_davison (217681) on Wednesday January 17, 2007 @02:38PM (#17650776)
    An interesting tidbit in the article is that the rail gun is only expected to fire ten times or less per day, presumably because of the amount of electricity needed.

    If only we knew when lightning was due to strike some sort of a clock tower? Surely, then, we could harness the power needed.

    If that doesn't work, perhaps some new technology involving trash?
  • boom! (Score:4, Funny)

    by User 956 (568564) on Wednesday January 17, 2007 @02:38PM (#17650778) Homepage
    The Free Lance-Star newspaper is reporting that the Navy Surface Warfare Center in Dahlgren, Virginia has successfully demonstrated an 8-megajoule electromagnetic rail gun.

    Yeah, but can you headshot with it from the far platform on the Longest Yard?
  • sooo... (Score:5, Funny)

    by Anonymous Coward on Wednesday January 17, 2007 @02:38PM (#17650786)
    by June they'll get the quad-damage powerup working?

  • by TheWoozle (984500) on Wednesday January 17, 2007 @02:38PM (#17650788)
    So, do the electrical power requirements for this mean that the Navy will once again be building nuclear-powered ships?
    • Re: (Score:3, Interesting)

      by Protonk (599901)
      Eh. The reasons for dropping nuclear powered surface ships were that the regulatory and maintenance costs didn't justify the independence that nuclear fuel offered. Also, in the wake of TMI, cruisers like the Long Beach found fewer and fewer foreign ports willing to invite them.

      The Navy keeps nuclear power on submarines because the air independence is too valuable (notwithstanding the nuke/diesel arguments) and on carriers because it makes for a ready source of steam (think catapults), hot water, etc.

      Powe
  • physics of railguns (Score:5, Informative)

    by smellsofbikes (890263) on Wednesday January 17, 2007 @02:39PM (#17650806) Journal
    I have *never* understood how railguns work. Here [physicshome.com] is an explanation, although it still leaves me frowning and making funny shapes with my fingers all stretched out.

    One presumes there are sonic booms associated with this. Anyone know if they're louder or quieter than the explosions associated with heavy ship artillery?
    • by sjaskow (143707) <stuart,jaskowiak&gmail,com> on Wednesday January 17, 2007 @03:00PM (#17651184) Homepage
      Well, a little googling turned up this [howstuffworks.com] which seems to explain it better without of the nasty physics technobabble. And this [scitoys.com] is how to do it yourself.
  • Has anyone else found out about these guys [powerlabs.org]?

    It's an old site but it's still just as awesome. I almost considered trying this out myself but I'm not exactly sure if such a thing is legal.
  • by thewils (463314) on Wednesday January 17, 2007 @02:40PM (#17650840) Journal
    It will allow the US Navy to miss targets from much further away.
  • Slight correction? (Score:5, Insightful)

    by Civil_Disobedient (261825) on Wednesday January 17, 2007 @02:41PM (#17650852)
    The Navy isn't estimating a price tag at this point, with actual use still about 13 years away.

    I think they mean deployment, unless the Navy knows something Congress doesn't. Which wouldn't surprise me.
  • I wonder..... (Score:2, Interesting)

    by Prysorra (1040518)
    Perhaps a sufficiently high arc can disguise this as a meteor* strike if it goes unannounced and unnoticed by radar.

    *Meteorites leaves evidence. Meteors can explode in midair.


    Cool to think about....
  • by Beryllium Sphere(tm) (193358) on Wednesday January 17, 2007 @02:45PM (#17650920) Homepage Journal
    32 megajoules is less than 9 kilowatt hours.

    Heat might be more of an issue. That would be over 30,000 BTUs, or a 60 degree rise in a quarter ton of cooling water.
    • Yeahbut.... (Score:4, Informative)

      by Iphtashu Fitz (263795) on Wednesday January 17, 2007 @02:56PM (#17651106)
      a 60 degree rise in a quarter ton of cooling water

      A cubic foot of seawater weighs approximately 64 pounds. A quarter ton, or 500 pounds, means this thing would raise less than 8 cubic feet of seawater by those 60 degrees. (A cubic foot of fresh water is 62 pounds, so the difference is negligible) That's a miniscule amount of global warming that this thing will add to the ocean each time it fires. And with entire oceans to heat up I doubt the Navy is too concerned about that environmental impact.
      • Re: (Score:3, Insightful)

        by dbIII (701233)
        A cubic foot of seawater weighs approximately 64 pounds. A quarter ton, or 500 pounds

        Somebody please add this to the metric article as an counter example for when people are talking about how easy imperial units are to deal with.

  • by Anonymous Coward on Wednesday January 17, 2007 @02:48PM (#17650978)
    A 32-megajoule version is due to be tested in June. A 64-megajoule version is anticipated to extend the range of naval gunfire (currently about 15 nautical miles for a 5-inch naval gun) to more than 200 nautical miles by 2020.

    Nobody will ever need more than a 64 Megajoules rail gun.
  • by Black-Six (989784) on Wednesday January 17, 2007 @02:49PM (#17650990)
    With this new rail gun technology, the US Navy now has a serious fire support asset in its Iowa and North Carolina class battleships. All they have to due is overhaul the power generation systems to handle these things and an Iowa class battleship would be capable of launching 90 16" projectiles and 200 5" projectiles a day via modifying the the main and secondary batteries for rail gun tech. In much more significant terms a Iowa class battleship would be able to deliver a broadside salvo of 9 16" rounds and 10 5" rounds on a target. Thats a lot of firepower!
  • by EricBoyd (532608) <mrericboyd@@@yahoo...com> on Wednesday January 17, 2007 @02:49PM (#17650992) Homepage
    Running a few quick calculations shows that power is not likely the cause of the delay between firings. If you have 10kW to power your system, you can fire a 64MJ blast every 1.78 hours. If you have 100kW, time to fire is only 10.7 minutes. Obviously for the smaller railguns the power requirements are even less. I'm no expert on how much power is actually available on those big boats, but somehow I doubt that 100kW is out of reach.

    I believe that the time to fire is more likely dominated by the maintenance issues - making sure that the rails are perfectly straight, the warhead is correctly placed, etc. If you're off by even a little bit that sucker could destroy the railgun on the way out, costing you millions and making it inoperative until you're back home.
    • you're right (Score:3, Informative)

      by enos (627034)
      100kW is around 134 hp. There are motorcycles capable of generating more power than that, and a single cylinder of a ship's diesel makes more than that, too.
    • Re: (Score:3, Informative)

      by hcdejong (561314)
      Current US Navy destroyers have some 70 MW installed for propulsion, and electric generators for 7.5 MW.

      The next generation of destroyers will have a turbine-electric powerplant, with the entire 80 MW available as electric power.
      And regardless of current specs, if the USN adopts rail guns, they'll find a place to park another generator, if need be. 2.5 MW generators aren't that large.
  • ... these would almost replace Navies.


    Come on, if you could fire a projectile 200 miles, you could just mount these on coastlines, serviced by ground-based power plants. True, it wouldn't replace navies ENTIRELY, but it would suddenly become extremely UN-economical to have one with even the slightest capability to get near a shoreline. Pushing back aircraft carriers 200 miles would severely reduce the flight time of the planes, which now have to fly a lot farther just to get to the coastline, let alone targets inside countries.

    On the plus side, land-locked countries can now hunt whales for food. :)

    • Think twice. (Score:4, Insightful)

      by Wilson_6500 (896824) on Wednesday January 17, 2007 @02:59PM (#17651182)
      ...these would almost replace Navies.

      I believe a Navy does a lot more than just throw shells at buildings. That aside, you'd probably have a hard time hitting an even slightly moving ship with one of these at any range, let alone finding the ship in the first place without any of your own. After all, if the ship makes a slight random adjustment to course every six minutes or so (travel time of the shell at maximum range), then they're reasonably safe--especially if we assume that each gun could only fire at the maximum noted rate of ten shots a day, which means they get a shot every few hours or they blow all their shots in a few hours. Mounting these on shorelines is a waste.
  • Accuracy? (Score:4, Insightful)

    by chiph (523845) on Wednesday January 17, 2007 @03:07PM (#17651308)
    Being able to launch one is a great accomplishment. The question is: Where will it hit? Unlike a Tomahawk, it's unlikely you can install a GPS receiver in the "bullet" because of the high launch g-forces, so using terminal guidance is probably out. You'd have to rely on the initial launch trajectory, which at a range of 200+ nautical miles, means the result will likely be a miss, rather than a hit.

    Of course, if they get the rate of fire up high enough...

    Chip H.
  • by LordByronStyrofoam (587954) on Wednesday January 17, 2007 @03:12PM (#17651392)
    When I worked on General Atomic's Doublet-III experimental fusion rector [gat.com], in the early 80s the energy for the machine was supplied by a three-story motor-generator constructed below-ground at the site. The motor ran off 440V mains and when powered spun itself, the generator and a 400-ton flywheel at 480rpm. It took twenty minutes to get the thing up to speed.

    During a 5-second 'shot', when the stored energy was released, the motor, generator and flywheel would go from 480 to ~100 rpm, and dump 960 mega joules of energy into the coils of the experiment. You could feel the vibration in your feet anywhere you stood at the site, all the CRT's images would collapse due to the intense magnetic field generated. Then it was another twenty minutes before they could do it again.

  • Useless? (Score:4, Interesting)

    by SparkyTWP (556246) <phatcoq@[ ]ightbb.com ['ins' in gap]> on Wednesday January 17, 2007 @03:13PM (#17651416) Homepage
    I think it's great that research is being undertaken since this could be useful for other applications, but am I the only one scratching their head as to why the military is making a big push for these?

    I assume a gun like this would go onto a destroyer. I can't think of the last time a destroyer was used in any meaningful way in combat since WW2. If I remember correctly, the only reason the navy even keeps destroyers is because congress forces them to. I guess you could put it on a tank or something, but most conflicts that are fought now are on the ground and are more guerilla tactics than formal engagements. It's being shown in Iraq and Afghanistan that all the fancy new technology that the military keeps buying doesn't really mean squat when it comes to fighting a war.

    Am I missing something here?
    • Re: (Score:3, Insightful)

      by king-manic (409855)
      I think it's great that research is being undertaken since this could be useful for other applications, but am I the only one scratching their head as to why the military is making a big push for these?

      I assume a gun like this would go onto a destroyer. I can't think of the last time a destroyer was used in any meaningful way in combat since WW2. If I remember correctly, the only reason the navy even keeps destroyers is because congress forces them to. I guess you could put it on a tank or something, but mo
  • by grumpyman (849537) on Wednesday January 17, 2007 @03:24PM (#17651564)
    Wait a second... I guess the country who has the most prolific use of satellite for military is the states. So could this technology comes back and bite our own ass?
  • by Picass0 (147474) on Wednesday January 17, 2007 @03:29PM (#17651656) Homepage Journal
    This reminds me of a proof-of-concept model built by by Dr. Emmett L. Brown, except he was capable of creating greater acceleration using only twenty-one gigawatts of electricity, and he utilized flux-capacitor technology which did not require overhauls after every use.
  • alternative to nukes (Score:4, Interesting)

    by 2ms (232331) on Wednesday January 17, 2007 @03:49PM (#17652072)
    Hmm, I wonder if, instead of nuclear missiles, we could just have nuclear generation powered railguns that could lob comet-like projectiles, thereby have the same kind of initial devastating effect, but without all the problems of nuclear fallout and radiation.

    I mean, it's true that nuclear weapons have basically brought peace to modern nations through the principle/doctrine of mutually assured destruction (thats why, for example, all of Europe isn't Soviet Union now -- Russia forced to stop taking over stuff and be peaceful or else get nuked).

    Maybe a new doctrine of mutually assured destruction through the crushing of cities through colossal projectiles with ungodly kinetic energy would still provide the umbrella of traditional MAD, but without that tiny little problem (which will never go away as long as there are nuclear weapons) of the potential of some lunatic dictator, who cares more about being in power than he cares about whether or not the rest of life on planet gets wiped out by radiation poisoning, getting his hands on nuclear weapon.
  • by Randolpho (628485) on Wednesday January 17, 2007 @04:14PM (#17652486) Homepage Journal
    Wow, 200 posts, and not one complaint about railgun campers. I guess nobody plays Quake anymore.
  • by rlp (11898) on Wednesday January 17, 2007 @04:20PM (#17652656)
    I WANT ONE! (The other 10% are holding out for the 64 megajoule model).

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