About the SA Blog Network



Opinion, arguments & analyses from the editors of Scientific American
Observations HomeAboutContact

Navy Unleashes Its Electromagnetic Railgun outside of the Lab [Video]

The views expressed are those of the author and are not necessarily those of Scientific American.

Email   PrintPrint

Just weeks after the U.S. Navy trotted out images and a few short videos of its devastating electromagnetic “railgun” (EM Railgun) blowing a fiery hole in a target at the Naval Surface Warfare Center in Dahlgren, Va., a new and longer video has begun to make the rounds (see below). Whereas previous testing had taken place in the lab, this video indicates the Navy has moved the technology one step closer to combat.

For the uninitiated, a railgun fires projectiles using electricity instead of chemical propellants. Magnetic fields created by strong electrical currents accelerate a sliding metal conductor between two rails to launch projectiles at about 7,200 to 9,000 kilometers per hour, compared to perhaps 5,400 kilometers per hour for a conventional gun. By equipping ships with railguns rather than standard artillery, the Navy could eliminate the hazards of having high explosives on board ships.

The Navy is evaluating two EM Railgun models. A 32-megajoule prototype built by BAE Systems arrived at the Naval Surface Warfare Center the end of last month. (A megajoule of energy is equivalent to the kinetic energy of a 900-kilogram car moving at about 160 kilometers per hour.) General Atomics—best known as the maker of the Predator and Reaper drones—is building the second launcher, scheduled for delivery in April. The Navy says that the railgun project, initiated in 2005, will yield a 20- to 32-megajoule weapon that shoots a distance of 50 to 100 nautical miles (roughly 90 to 185 kilometers).

The Navy has contracted BAE and General Atomics to develop thermal management systems for both the launcher and pulsed power source  to increase firing rates  from a single shot to 10 rounds per minute.

U.S. Navy railgun photo by John F. Williams/Released
Video provided by the U.S. Navy

Larry Greenemeier About the Author: Larry Greenemeier is the associate editor of technology for Scientific American, covering a variety of tech-related topics, including biotech, computers, military tech, nanotech and robots. Follow on Twitter @lggreenemeier.

The views expressed are those of the author and are not necessarily those of Scientific American.

Rights & Permissions

Comments 12 Comments

Add Comment
  1. 1. And Then What? 7:49 am 02/29/2012

    Fascinating piece of technology, I have many questions, a few of which I list below, and a comment to make.
    1. Where does all the fire and smoke come from?
    2. Is there and recoil to deal with and, if so, is it equivalent to conventional Guns?
    3. Why is the projectile the shape it is?
    4. What is the power supply and how big is it?
    5. Is the technology similar to that behind the LHC?
    6. Where are the little grey Asgard guys and how much did they charge for the blueprints?
    My comment is simply this: I have often wondered if the technology used in the LHC could be used to launch Vehicles into Space. The way I see it all you need do is tilt the equipment and aim it skyward. Then Instead of smashing beams of Protons into each other you design a form of a Magnetic coupling system to transfer the beam energy to the vehicle and send it round and round until it finally reaches launch velocity at which point it is decoupled and sent into Space. Think of a Magnetic lift Train system with a much smaller train that would be “de-railed” in a controlled fashion.

    Link to this
  2. 2. realist1 11:29 am 02/29/2012

    …and one EMP weapon will turn a ship equipped with these fancy-schmancy railguns into a floating target. Well thought out. The guys with the old-fashioned gunpowder weapons still win.

    Link to this
  3. 3. TTLG 11:42 am 02/29/2012

    I don’t know that I trust the improved safety claim. A joule is a joule no matter how you store it. My experience with capacitors and what I have read about Li batteries says that neither is a big safety improvement over chemical explosives, especially at very fast discharge rates like this gun will require.

    Link to this
  4. 4. TTLG 11:52 am 02/29/2012

    To: And Then What?

    Good questions. The idea of electromagnetic guns and launchers have been around for quite some time. Check out “railgun” and “coilgun” on Wikipedia. To use an EM launcher you need to keep the acceleration low enough not to damage the payload, so you need a fairly large gun. You also want to have it as high in altitude as possible to limit the energy loss and heating as it goes through the atmosphere. You also want to have it as close as possible to the equator to get a boost from the Earth’s rotation. So the possible launch points are fairly limited.

    Link to this
  5. 5. compassghost 12:01 pm 02/29/2012


    To be fair, most modern ship guns and missiles are all electronics-based as well, having targetting computers and calibrations and the like. An EMP would ruin any modern ship, no matter what its weaponry. However, the railgun increases its standoff range significantly. You have to be able to hit the ship with the EMP to disable it, and if it’s 50 to 100 miles away, you’re probably going to have to throw something at it, and those to pull off the EMP, and ships tend to have conventional counters to those threats as well.

    Link to this
  6. 6. SafetyGuy 5:09 pm 02/29/2012

    Actaully @compassghost and @realist1 you are both wrong. EMP will not ruin any modern ship. The DoD has very specific standards that must be met in regards to every system and EMP.

    @TTLG I think the point is that currently Navy ships operate with both very large electricity generation capacity / storage systems and have large amounts of convential munitions. The residual risk of increasing electrical generation and storage is reduced through the elimination of conventional munitions. The rail gun might just be more practical in the sense that repair from battle damage to this system is limited to the gun. Repairing from a hit to a conventional munitions magazine is several orders of magnitude more difficult and time consuming.

    Link to this
  7. 7. mousedude 7:11 pm 02/29/2012

    The “fire” is plasma, generated by the huge electrical currnet as it vaporizes the rear portion of the projectile (or more accurately, the armature that pushes the projectile forward).
    The projectile is shaped like that because it needs to ride between the two rails. That whole oddly shaped thing they loaded was probably two parts. The front part was the actual projectile, and the rear part was the “Armature”, which is like a carriage that holds the projectile and pushes it forward. The armature completes the circuit between the rails, and may even be designed so that the electrical current vaporizes part of it (probably the part that would touch the rails), creating a conductive metal plasma that completes the circuit. That would cut down on friction, compared to having the armature physically touching the rails as it moves.

    Link to this
  8. 8. And Then What? 7:06 am 03/1/2012

    Your answers sound plausible. This makes me wonder about the cleanliness of the barrel after a few shots. I suppose they have some automatic cleaning system to handle any debris. In addition if each projectile is actually two pieces, that must be loaded separately, that should lower the rate of fire and I would imagine make each “Round” fairly expensive. I suppose increasing the accuracy could mitigate the additional cost. One of the reasons I was wondering about “recoil” is that; if such a weapon were “recoilless” it would be more suited to a Space-based launch platform than a conventional ballistic weapon of comparable capability, which would have to compensate for every shot fired.

    Link to this
  9. 9. karlchwe 12:55 pm 03/1/2012

    Thermal management, ey? That sounds like a big problem. You could cool the gun with water, even seawater, but clogged or damaged water inlets would effectively kill the gun. Air-cooling? I imagine it would take a lot of air.

    So alternatively, you could make the gun more efficient somehow, so more of the electricity consumed goes into making the steel dumbbell fly faster, and less into making things hot. Superconducting coils? Smaller armatures that have to be vaporized?

    Link to this
  10. 10. rekeba 4:01 pm 03/1/2012

    @And Then What?

    To respond to your post, each projectile can be loaded as a single piece, which acts as a two piece projectile. Consider it like a hunting rifle if that helps… In a conventional hunting bullet, you have a single cartridge which holds both the round and the powder which projects that round. Just, in this case, there’s no need for a cartridge, because neither piece is exploding, and they can simply be loaded “open-air” into the gun.

    And in response to the second part about the gun being recoilless… Unfortunately, there is no way to create a hypothetical recoilless projectile based weapon. As conservation of momentum is a physical law which can never be violated, if you shoot something one way, something else HAS to go the other direction to compensate. This recoil can be reduced as we see in many modern military grade firearms through the use of extensive spring systems embedded within the stocks of the weapons, however, recoil will unfortunately always be a factor in projectile weapons (this changes once you get into laser-based arms technology, as the photon-projectiles used therein have no mass, but thats a completely different kind of technology which isn’t nearly as far practically developed as EM armaments).

    Link to this
  11. 11. spacelobster 4:59 am 03/2/2012

    Hi folks,

    I can contribute a couple of details. According to the reps from ONR, the projectiles in the tests that are shown in the videos were engineered to be aerodynamically unstable and thus easier to recover; no need to send a copter out to, say, North Carolina to pick it up. If you look closely at the videos, you will see that the projectile begins to yaw and tumble within a few dozen meters. War shots will, they suggest, be highly aerodynamic and contained within sabots for firing. How they will ruggedize the guidance electronics to handle 45,000 Gs is another question. Holy crap.

    The flaming coming off of the projectile’s ass is, apparently, pure friction igniting anything remotely combustible in the air, like a space shuttle on re-entry. I mean, seriously, Mach 7!

    Link to this
  12. 12. spacelobster 5:27 am 03/2/2012

    Oh man! I just noticed this! The ONR motto for this project is “Velocitas Eradico”, which translates to “Eliminating (or getting rid of) Velocity”! Hysterical!! I’m sure some buffoon thought it meant “Eradicating Via Velocity”. Come on people… Google Translate is there for a reason.

    Link to this

Add a Comment
You must sign in or register as a member to submit a comment.

More from Scientific American


Get All-Access Digital + Print >


Email this Article