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U.S. Navy set to test first industry railgun prototype


February 7, 2012

A 32-MJ version of the Office of Naval Research-funded Electromagnetic Railgun (EMRG) prototype at the Naval Surface Warfare Center (NSWC) Dahlgren (Photo: ONR)

A 32-MJ version of the Office of Naval Research-funded Electromagnetic Railgun (EMRG) prototype at the Naval Surface Warfare Center (NSWC) Dahlgren (Photo: ONR)

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Two years after BAE Systems was awarded a US$21 million contract from the Office of Naval Research (ONR) to develop an advanced Electromagnetic (EM) Railgun for the U.S. Navy, the company has delivered the first industry-built prototype demonstrator to the Naval Surface Warfare Center (NSWC) Dahlgren. The prototype launcher is now being prepared for testing which is scheduled to take place in the coming weeks.

Unlike weapons that rely on explosive chemical propellants such as gunpowder to launch a projectile, electromagnetic railguns accelerate a conductive projectile along metal rails using a magnetic field powered by electricity. While the muzzle velocity of gunpowder-propelled projectiles is generally limited to around 4,000 ft per second (2,727 mph/4,389 km/h), the U.S. Navy says its railgun will be capable of launching projectiles at velocities of 4,500 to 5,600 mph (7,242 - 9,012 km/h).

This kind of speed translates to greatly extended range. Navy planners are initially targeting a 50 to 100-nautical mile (57 to 115 mile/92 to 185 km) range, with a planned expansion up to 220 nautical miles (253 mile/407 km). The Navy says this will give Sailors extended capabilities, such as providing precise naval surface fire support, land strikes, and cruise missile and ballistic missile defense. The ONR is also touting the improved safety of the weapon for use on ships because it uses no explosives in firing or storage.

As you might expect, the high velocity of the armature causes a lot of friction. Add to this the resistance in the rails as the electric current passes through it, and massive amounts of heat are generated. This has made developing a weapon that can fire off just one shot without destroying itself a major hurdle - let alone one that can stand up to the stresses of multiple firings over a short period.

To address this problem, the next phase of the EM Railgun program is focused on developing automatic projectile loading systems and thermal management systems to facilitate increased firing rates of the weapon. The ONR recently awarded BAE Systems, General Atomics and Raytheon Corp., $US10 million contracts to develop a pulsed power system for launching projectiles in rapid succession. The contracts mark the start of a five-year effort to achieve a firing rate of six to 10 rounds per minute.

More immediately, however, all eyes will be on the 32-megajoule prototype demonstrator, which will begin test firing this month ahead of the delivery of a second prototype launcher built by General Atomics.

Source: ONR

About the Author
Darren Quick Darren's love of technology started in primary school with a Nintendo Game & Watch Donkey Kong (still functioning) and a Commodore VIC 20 computer (not still functioning). In high school he upgraded to a 286 PC, and he's been following Moore's law ever since. This love of technology continued through a number of university courses and crappy jobs until 2008, when his interests found a home at Gizmag. All articles by Darren Quick

To avoid friction and heat on rails, Could magnetic levitation not be considered an option?


magnetic levitation would remove the physical contact, sure. but then they\'d need another contact anyway to propel the object.

rail guns work on electric currents and the force they apply. remove the contact and you remove the circuit for that electricity.

Jacob Shepley

I dream of a day that we will invent machines of peace instead of machines of destruction.


There is immense impact of the missile due to momentum generated and counter offensive measures will take time to find out means to save a ship lest enemy get hold of this new technology

Shradhapati Singh

The thermal problem has to do with release of energy in a very short space of time in a small volume (the rails), solutions for this problem will be found in better conduction. The projectile is moved by the magnetic field generated in the rails, magnetic levitation in the direction of where the projectile must go. I wholly agree with Artisteroi, we´d be a lot better off when this sort of reseach would rise from the need to better life instead of destroying it.


I agree with Artisteroi\'s comments, however remember that something that may start as research for military/weapons use can often expand to other uses. Some of our biggest technology innovations have originated from military projects. Look at this technology and think about what possibilities it has beyond weapons.


Guys, Rail guns already utilize magnetic levitation. Once the projectile is moving it\'s not touching anything, it\'s friction from the air it\'s moving through that generates the heat.

Pete Kratsch

@Nasuti This is true as is the inverse. There is an article on gizmag about neurologically controlled weapons being developed from the research being done to enable better prosthesis for the handicapped. That is a prime example of research done for peaceful purposes being used to facilitate weapons.


i\'m with pete kratsch, why is friction a problem here? I thought it was like a maglev train, but in gun form (so magnets all around the projectile). I understand high current and resistance and heat could be an issue. What about the magnetic disturbances to everythng else on a ship, from small munitions to highly technical electronics. Also the munitions must be ferro-magnetic, which limits their technology somewhat, some of the densest (and more powerful munitions) are not magnetic. I\'ve never held any depleted uranium nor can speak on its magnetism; my tungsten ring was allowed inside a cat scan b/c it was not a risk. All military technology seems to involve hurling rocks at each other better than the other guy. Guns to me have always been high efficiency rock throwers. or H.E.R.T.s. Which, if anyone agrees, is an awesome way of thinking about it that comes with an appropriate anagram.


This tech can be used to, for example, send cargo to the ISS at much lower costs than we can do now.

Nacho Lotitto

I really don\'t see the advantage of rail guns for ship weapons.The projectiles would be unguided,and missiles already do the bombardment role quite successfully. Even if you rig up a system like that found on the Copperhead 155mm artillery round,I wonder if the electronics could survive launch from a rail-gun,which would have at least double the acceleration g-forces of an artillery round leaving the barrel. A good peaceful use would be to economically launch supplies (and maybe nuclear waste) into low earth orbit.The rail gun launcher would ideally be located on a mountain to minimize friction on the projectile from passage through the atmosphere,and have an orbital insertion rocket attached.


The reason for using a non-guided projectile vs a missile is cost. It is cheaper to make an expensive gun that fires cheap rounds rather than expensive missiles especially as cruise missiles are about $1 million a pop! Also, the shell for a rail gun might be cheaper because with the higher velocity, you might not need any explosives in the shell, just something hard. I\'m sure you could place a depleted uranium sabot inside a shell made of magnetic material...

Along with heat, you also need a system to generate a LOT of electrical power in a short space of time. This is one reason they haven\'t been able to out one in a tank yet...not enough room!


Nothing focuses the mind like survival. Throughout history, the greatest minds have been dedicated to creating technologies for warfare. Mazlov\'s hierarchy dictates the prioritization of service to self over that of the group. We are not evolved enough to transist to a reverse of these priorities and may never be before we snuff out.

At least something stimulates this inventiveness and then eventually we use the tech to make better TV\'s and cell phones and other necessities to enhance our reproductive parodies.


hmmmm this stuff has been around for years well over 20+ years only the size has changed and i see no reason a gps or laser seeker head could not be installed look up info of the Super gun Sadam almost had one but it was taken out in the 1st gulf war.

Leonard Foster

I still don\'t understand, how is heat generated in a maglev projectile system, apart from electricity in coils, such that it destroys the system. Air is heated too, how could that be enough.

Dawar Saify

god gawd michael_dowling, launch nuclear waste in low earth orbit, may it land in your yard, Here we are once again feeding the Military Industrial Complex that the last reasonable Republican warned us about, who was that? Dwight Eisenhower, in the 19foockingfifties, we will let our politicians kill off our race, christ.

Bill Bennett

Anything designed for peaceful purposes can be perverted into a weapon. A device for teleporting pizzas or people from place to place could also be used to deliver a bomb to your living room, a device that replicates a ham sandwich from organic waste could be used to make C4.

William Lanteigne

With that kind of range it would make the Iowa class battleships a viable warfighting platform again.

Imagine the Iowa with a keel up complete refit and modernization with nuclear power and nine railguns with ten times the range of her current 16\" guns. With current control systems the ship wouldn\'t need the nearly two thousand personnel to crew it.

The 1980\'s refit cut the required crew from ~2,700 to ~1,800. A nuclear and railgun upgrade should drop it to under ~1,000 if not less, but I\'d expect a large chunk of the freed up crew space would be taken over by the massive power generation systems for the railguns.

Gregg Eshelman

So some people are wondering why heat friction is such a problem. I think this picture is self-explanatory

Yes, it\'s a railgun projectile. Some minor homework would tell you how hot it is when it is travelling that fast.

Fretting Freddy the Ferret pressing the Fret

Apparently some commentators mentioning maglev tech above have no idea on how rail gun actually works, and are confusing it with coil gun.

Quite simply put, in rail gun, projectile is being propelled between two rails by magnetic field that occurs as electric current form the positive rail passes through the projectile to the negative rail. In order for that to happen, projectile needs to be touching both rails, and that is where LOTS of friction happens.

Appart from the huge friction resulting in heat and material wear problem, rail gun is simpler than coil gun. In coil gun, projectile is propelled by series of coils being placed in succesion around the barrel. As electric current passes through coils in timed succession magnetic field is generated in coils that propels the projectile forward. While the concept seems simple in theory, it has a few nasty drawbacks, that have been preventing large scale applications for now. I think one of the major ones has to do with the timing of coils activation, as maximum magnetic field occurs with some lag after the current starts passing through the coil. I\'m no expert, but I think there is also a problem with releasing such a huge amount of charge through each coil in such a short time.

So stop with maglev nonsense when talking about rail guns. :)

Short Fuse

It\'s a really important development to be able to murder large numbers of people at over 100 miles away.

It\'s great for the Murdering psychopaths that can\'t look their victims in the eye.


What is going to be attached to the the \"pointy\" end of the sabot. I assume it will be a large quantity of high-explosives. Otherwise a large trebuchet with a round 1-ton rock would suffice. And there might be some issue with high-explosives now possibly being in contact with extremely high magnetic fields and huge bursts of electricity. Will that effect the timers or primers on board?



Hey RealityBytes we all thought same way in our early teens

Todd Dunning

This is an interesting problem. You might think that the barrel would be a vacuum. Then you still have the same problem of making an exit from the barrel in terms of heat and air reactions. This is compounded by needing to use a magnetic metal shell. However coatings that both insulate and are non conducting may help to reduce the problem. To disrupt the atoms outside the barrel with a electric burst that was propagated through a high intensity ultra violet light beam may help to preserve the barrel however then again you still have the problem of thermal activity affecting the projectile and possibly putting it off course. Its quite simple. We know war is coming. Like the last major war we knew it would be a surprise attack and we were ready all the people at the academy had assessed the situation well. The outcome was better than anticipated thanks to the Manhatten project. Ive been pondering what I would have done if I had 200 nautical mile range rather than only 15 when attacking enemy bunkers. This weapon is a real game changer. This economy would of made Libya\'s Liberation a bit easier. Though you still have to remember that the Gun itself will use alot of Electricity. So its still going to have its draw backs. Their are only a handfull of docks that will be able to build a cruiser or other with nuclear power to run it. The waste for me is the biggest drawback.

Spriscilla the Queen of the Ocean

A lot of misinformation here.

First, the rail gun is really just a pair of rods. A conductive \'projectile is set between the two rods, Preferably touching both rails at the bottom. The, a very large charge of electricity is sent into the rails. The electric field short circuits through the projectile. The resulting electric arc forms a magnet. 1/4 Ampere Turn on each side. This results in a magnetic force that accelerated the projectile forwards. This continues all the way down the rails. It is not necessary that the projectile keep in touch with the rails, as a high enough charge will result in an arc forming between the rails and the projectile.

One result of all of this, is that the projectile gets very hot (Arc Furnace anyone?). Another is that the air in the barrel is \'pushed\' forwards by the projectile. Before the projectile leaves the barrel, it will be traveling faster than sound, so the rails and the supporting \'barrel\' must be able to withstand the pressure of the sonic boom. The power supply is one of the limiting factors. It takes a lot of power to charge up the storage medium. Charge and discharge both create a lot of heat, as does firing the thing off. You don\'t want to melt the gun. There needs to be a cooling mechanism. I would suppose that air is blown down the barrel at high pressure to cool the mechanism. This must be timed carefully, or the air blast might quench the arc.

The projectile, of course will be a glider. (more like an old fashioned \'rocket\' with very small fins). It will at range have the ability to home in on it\'s target using some kind of system to find it\'s aim point. The outer casing will be what heats up most. Inside this casing, you could pack anything. The heaver the projectile, the longer its range, and the harder it strikes.

German V2 rockets in WWII carried close to a half ton of explosives, but the impact of the rocket caused more damage than the explosives did. I would imagine that there will be a range of projectiles used, with some optimized for penetration, and some optimized for spreading out the destruction. There are more possibilities that I am sure I don\'t know about.

So, Yes, this is a weapon. There have been versions of these rail guns built for over 60 years, but it is only in the past few years that enough of the problems have been worked out to allow for velocities and ranges greater than those attained in 1900 era guns. (so called \'carriage guns\'.)

Next, this can\'t be used for supplying the ISS. The projectiles might have the speed to reach the station, but would not be on an orbit for anything like a non destructive rendezvous. The velocities quoted here are still only a little over half of orbital velocity. And remember, any orbit that leaves the surface of the earth will return to the surface of the earth. For space craft, the rockets first get them up, the \'circularize\' the orbit with a second burn at the top, so you would still need a rocket to get to a stable orbit. And, for space use from the surface, it\'s still not half fast enough.


I too agree that it is unfortunate that we must create so many tools of destruction. However, two points must be made. ..1. The defense funding, quite often, allows for amazing technologies to be developed, when there is no way to get it funded commercially. Tons of things that are created this way end up commercially viable in the end, but wouldn\'t exist if not first made for military application. GPS is a good example. 2. Reagan\'s philosophy can have some affect on deterring conflict. Not the cheapest way to avoid conflict though! If you build a huge, advanced, capable and highly motivated military defense program, psople dont want to act out against you. If they try to match capabilities with you they go bankrupt.....i.e. USSR! The cold war was won without one shot being fired !

James Palmer

What\'s with all the comments knocking new weapons tech but simultaneously promoting peace as an alternative?

That is exactly what tech like this does. Silly romantics.

Tylenol Jones

Interesting thing ... everyone is thinking about this only as a weapon. Did you ever think about it as a way of transport? With long enough rails and enough power you could actually design space catapult to launch space crafts. It should be easy to control current flowing through rails to control acceleration so you don't shred projectile / crew in it.

Cba with calculating the length of rails, but if there are companies designing skyscrapers 1000 meters high, I think that space catapult should fit in that limitation.

František Okáník

How about using cooling close to absolute zero to eliminate the resistance. This would give us a head start on the cooling needed for the friction and would eliminate the magnetic heating.

We must always be one step ahead of any potential adversary, and be aware of all threats. Since our secrets are stolen most of the time, I would concentrate on research, development, secrecy, and the ability of produce quickly if needed. If the secrets get out, then we must manufacture the weapon to stay ahead of the bad guys. This is truly a chess game and we must not fail.

chuck johnson
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