Navy Gets 8-Megajoule Rail Gun Working

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."

95 miles altitude is space..Way Cool

[lecithin (745575)]

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?

Launch Loop

[cutecub (136606)]

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

Re: 95 miles altitude is space..Way Cool

[Maximum Prophet (716608)]

$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: 95 miles altitude is space..Way Cool

[wolfgang_spangler (40539)]

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.

I don't see them replacing crusie missles

[winkydink (650484)]

if you can only fire 10 per day.

Re:I don't see them replacing crusie missles

[ackthpt (218170)]

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:I don't see them replacing crusie missles

[dan828 (753380)]

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.

Well

[everphilski (877346)]

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.

Re:I don't see them replacing crusie missles

[drinkypoo (153816)]

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.

Re:I don't see them replacing crusie missles

[SydShamino (547793)]

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.)

Not electricity

[SamSim (630795)]

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

[PIPBoy3000 (619296)]

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:I don't see them replacing crusie missles

[arivanov (12034)]

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.

Where can I get one?

[by Anonymous Coward]

I'm a member of the NRA, I didn't see this in the last catalog.

Power Sources

[nick_davison (217681)]

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?

sooo...

[by Anonymous Coward]

by June they'll get the quad-damage powerup working?

More nuclear ships?

[TheWoozle (984500)]

So, do the electrical power requirements for this mean that the Navy will once again be building nuclear-powered ships?

physics of railguns

[smellsofbikes (890263)]

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?

Re:physics of railguns

[sjaskow (143707)]

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.

Not sure about this

[thewils (463314)]

It will allow the US Navy to miss targets from much further away.

Slight correction?

[Civil_Disobedient (261825)]

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.

Amount of power (energy really)

[Beryllium Sphere(tm) (193358)]

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.

Admiral Gates

[by Anonymous Coward]

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.

power not the problem

[EricBoyd (532608)]

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.

Forget Replacing Cruise Missiles...

[Wandering Wombat (531833)]

... 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. :)