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Navy Gets 8-Megajoule Rail Gun Working

ScuttleMonkey posted more than 6 years ago | from the high-flyers dept.

Hardware 650

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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95 miles altitude is space..Way Cool (5, Interesting)

lecithin (745575) | more than 6 years ago | (#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: 95 miles altitude is space..Way Cool (3, Informative)

Starcom8826 (888459) | more than 6 years ago | (#17650760)

That's called a mass driver. Using em to catapult vehicles into space.

Re: 95 miles altitude is space..Way Cool (2, Informative)

Anonymous Coward | more than 6 years ago | (#17650770)

Ask someone who knows: Gerald Bull [wikipedia.org]

Re: 95 miles altitude is space..Way Cool (4, Insightful)

Phanatic1a (413374) | more than 6 years ago | (#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.

Re: 95 miles altitude is space..Way Cool (0)

iamacat (583406) | more than 6 years ago | (#17651024)

Well, you could use Moon for a gravitational slingshot to reshape the orbit.

Re: 95 miles altitude is space..Way Cool (1)

Itchyeyes (908311) | more than 6 years ago | (#17650818)

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.

There should be an admissions test for moderating (-1, Redundant)

Anonymous Coward | more than 6 years ago | (#17650858)

Launch Loop (5, Interesting)

cutecub (136606) | more than 6 years ago | (#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

Re: 95 miles altitude is space..Way Cool (4, Interesting)

Maximum Prophet (716608) | more than 6 years ago | (#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: 95 miles altitude is space..Way Cool (2, Insightful)

Itchyeyes (908311) | more than 6 years ago | (#17651084)

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.

Re: 95 miles altitude is space..Way Cool (4, Informative)

wolfgang_spangler (40539) | more than 6 years ago | (#17650906)

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.

Re: 95 miles altitude is space..Way Cool (1)

radarsat1 (786772) | more than 6 years ago | (#17651102)

People seem to often forget that being in space and being in orbit are two different (though related) concepts.

I don't see them replacing crusie missles (4, Interesting)

winkydink (650484) | more than 6 years ago | (#17650730)

if you can only fire 10 per day.

Re:I don't see them replacing crusie missles (0)

Anonymous Coward | more than 6 years ago | (#17650796)

Immediately? Of course not.

This is like saying voice activated computer control crap won't replace the light switch, because it doesn't recognize your call for lights when yer drunk.

Sure - not yet. Technology will improve, however, and eventually we'll have ships with railguns and houses that can alert us that we're about to trip over a cat in a drunken stupor and break some important bones.

Re:I don't see them replacing crusie missles (5, Funny)

ackthpt (218170) | more than 6 years ago | (#17650808)

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 (2, Insightful)

Smidge204 (605297) | more than 6 years ago | (#17650958)

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=

Re:I don't see them replacing crusie missles (1)

wolfgang_spangler (40539) | more than 6 years ago | (#17650962)

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.
Travelling that fast....how much wind effect would there actually be?

Re:I don't see them replacing crusie missles (2, Informative)

ackthpt (218170) | more than 6 years ago | (#17651056)

Travelling that fast....how much wind effect would there actually be?

Well, wind is only one factor. Moisture density (clouds) could come into play as well. You're talking 200 miles, where only a very slight variation on forces acting on a small mass, (3.2Kg) could be enough to miss by a city block. At least the Tomahawk has guidance systems. Hitting the chinese embassy in Beograd was an intelligence failure, not guidance.

Re:I don't see them replacing crusie missles (1)

dan828 (753380) | more than 6 years ago | (#17651170)

Hitting the chinese embassy in Beograd was an intelligence failure, not guidance.



That was the claim, anyways. If I remeber correctly, there had just been some incident with the Chinese over some damned thing shortly before that. Funny how embassies have a habit of getting unintentionally targeted when the US is pissed at someone. Remember how the French embassy was accedentally hit, during the Libia bombing in the 80s, when they had refused airspace clearance for the strike force to fly over their territory? Oops. Our mistake. Sorry.

Re:I don't see them replacing crusie missles (0)

Anonymous Coward | more than 6 years ago | (#17651242)

Hitting the chinese embassy in Beograd was an intelligence failure, not guidance.
Let's review, the US was really pissed at the Chinese for opposing UN Security council support for US operations against Serbia and someone from the CIA "accidentally" put their embassy in Serbia in a target list for airstrikes. Sure mistakes can happen, but it is very hard to believe that this incident was a mistake. The Chinese certainly didn't think so.

Re:I don't see them replacing crusie missles (1)

maxume (22995) | more than 6 years ago | (#17651100)

It also travels far. The wind won't affect it's range much, but it could easily push it sideways a bit.

Re:I don't see them replacing crusie missles (4, Interesting)

dan828 (753380) | more than 6 years ago | (#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:I don't see them replacing crusie missles (2, Interesting)

Kadin2048 (468275) | more than 6 years ago | (#17651312)

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 projectile just enough to produce a change in direction. Allegedly they can be quite accurate.

I think the technology where I heard about the GPS-guided artillery was something to do with the Crusader mobile artillery system. Basically, it was the Army's way of competing with the Air Force as a "surgical strike" capability. Unfortunately then Iraq really happened, and people's interest in surgical air-strikes went out the window with "shock and awe," or at least it seems like it.

And don't forget (1)

plopez (54068) | more than 6 years ago | (#17651128)

The rotation and curvature of the Earth. Accurate long range ballistics can be demanding mathematically.

In traditional artillary tolerances in gun tubes, rifling bands, propellant charges and shell mass also have an impact; which is why it is usually used for area fire. But as other posters have pointed out, GPS and/or laser and/or radio guidance can help out.

Re:I don't see them replacing crusie missles (2, Interesting)

physicsphairy (720718) | more than 6 years ago | (#17651296)

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 stabilizing factor). But it's hard to imagine any such simple and fundamental thing would be overlooked by the scientists involved.

Well (4, Insightful)

everphilski (877346) | more than 6 years ago | (#17650810)

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 (0)

Anonymous Coward | more than 6 years ago | (#17650888)

If you need to fire more then just add another gun.

Waste of money (0)

Anonymous Coward | more than 6 years ago | (#17650932)

Great! And how will this weapon solve the Iraq debacle or get rid of suicide bombers?

Re:Waste of money (0)

Anonymous Coward | more than 6 years ago | (#17651110)

This is a weapon to be used against future enemies, like China. Democratic Congress has already solved Iraq problem -- we are going to bugout.

Re:I don't see them replacing crusie missles (4, Interesting)

drinkypoo (153816) | more than 6 years ago | (#17650946)

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 (4, Insightful)

SydShamino (547793) | more than 6 years ago | (#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.)

Not electricity (4, Informative)

SamSim (630795) | more than 6 years ago | (#17651032)

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 (4, Informative)

PIPBoy3000 (619296) | more than 6 years ago | (#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:I don't see them replacing crusie missles (2, Interesting)

Absolut187 (816431) | more than 6 years ago | (#17651148)

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?

Re:I don't see them replacing crusie missles (1)

Chris Burke (6130) | more than 6 years ago | (#17651264)

That's 10 per day per rail gun. You wouldn't need very many in a carrier group to easily match some of our largest cruise missle attacks in the past; it isn't as though we fire them willy-nilly, because they're expensive and designed to hit specific high-value targets and require some programming for each mission. Once you've built the 'rail gun cruisers' to work with/replace the missle cruisers, the primary cost is the energy. The ammo for each shot is cheap as can be, can be stored in greater numbers, and doesn't suffer from the 'secondary explosion' problem of other armaments, and even as a side effect is not vulnerable to anti-missle tech.

The main problem I see is that most of our ships are no longer designed around big naval guns, instead they use missles and smaller DP guns, so a fast retro-fit may not be easy. They don't say in the article, but even the more powerful planned versions are certainly smaller than traditional naval guns, so maybe it's not a big deal.

Re:I don't see them replacing crusie missles (3, Insightful)

UnknowingFool (672806) | more than 6 years ago | (#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.

Where can I get one? (5, Funny)

Anonymous Coward | more than 6 years ago | (#17650734)

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

Might I suggest... (1)

LoganTeamX (738778) | more than 6 years ago | (#17650738)

http://www.eve-online.com/ [eve-online.com] They have a wealth of knowledge with warp cores, power requirements and railguns. I forsee great things for all... just don't use Minnie BPOs.

Projectile distortion? (3, Interesting)

ackthpt (218170) | more than 6 years ago | (#17650758)

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...

Re:Projectile distortion? (1)

noewun (591275) | more than 6 years ago | (#17650874)

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.

Replace tomahawk? (-1, Redundant)

ad0gg (594412) | more than 6 years ago | (#17650768)

So how would a railgun replace a cruise missile? A cruise missile can go hundreds of miles, a railgun is line of fire/sight. It fires a small projectile so can't exactly arc it to the destination.

Re:Replace tomahawk? (2, Informative)

Anonymous Coward | more than 6 years ago | (#17650864)

Did you read the original post? It says it can go up some 90 miles before coming back down. If thats not an arc, I dont know what is.

Re:Replace tomahawk? (1)

Wilson_6500 (896824) | more than 6 years ago | (#17650974)

Please RTFA: even the summary states that the projectiles will reach up to 95 miles of altitude. They're not just firing the thing into the air willy-nilly--that projectile is, yes, being arced to its destination. 5-inch cannon shells must arc to reach the extent of their range, so why not these projectiles?

Re:Replace tomahawk? (0)

Anonymous Coward | more than 6 years ago | (#17651116)

But then aren't most of that amazing speed (and thereby, kinetic energy) lost, or do these projectiles have guidence to steer them over the curvature of the earth, not relying on gravity?

Re:Replace tomahawk? (2, Interesting)

gnasherspants (943992) | more than 6 years ago | (#17651044)

Its advantages are obvious - each round is cheap, it doesn't get lost and end up as a technology or a munition 'giveaway' (or bad press), and as the article says, reaction time can be rapid. It means that the next class of boats are merely floating powerstations with all the 'goodies' held far away from the action. Besids, a rail gun is not just line of sight, as with any ballistic weapon, unless you can see over the horizon. I guess the main limiting factors in use would be those of ablation - both to the rail and projectile.

Re:Replace tomahawk? (1)

gstoddart (321705) | more than 6 years ago | (#17651058)

A cruise missile can go hundreds of miles, a railgun is line of fire/sight. It fires a small projectile so can't exactly arc it to the destination.

Well, if you look at the summary, it says:


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. ... In the final version, they will apex at 95 miles altitude, well into space.

Travelling 200 nautical miles, and reaching a peak height of 95 miles, I would say they plan on having something which both covers distance, and can be lobbed onto the target.

So, I think both of your issues are addressed in the summary. They will be able to shoot farther than they can now, and do it at pretty high altitudes.

Cheers

Re:Replace tomahawk? (1)

drinkypoo (153816) | more than 6 years ago | (#17651326)

So, I think both of your issues are addressed in the summary. They will be able to shoot farther than they can now, and do it at pretty high altitudes.

Just to put things in perspective, a tomahawk is capable of flying 1,500 miles, and then passing through a 1 meter square window (through which of course the wings cannot follow) and detonating its payload, which can be high explosive, a tactical nuclear warhead, an EMP device, or any of another broad assortment of items.

Granted the commanders don't expect a tomahawk to be that accurate more than one time in ten, but they seem to do it about half the time.

Tomahawks can also do things like be programmed to follow waypoints. You can fly one up a canyon (it uses a combination of GPS and other data, including bitmap images of the target and points along the way) and hit a target that isn't reachable by a simple ballistic trajectory. So they're not going away any time soon, we'll just use a lot less of them. A tomahawk can fly around a building and blow up a shorter one behind it, a railgun projectile can't.

Re:Replace tomahawk? (1)

Gr8Apes (679165) | more than 6 years ago | (#17651144)

it's not line of sight. Note the "suborbital" phrase in the summary?

Power Sources (5, Funny)

nick_davison (217681) | more than 6 years ago | (#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! (3, Funny)

User 956 (568564) | more than 6 years ago | (#17650778)

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?

Re:boom! (0)

Anonymous Coward | more than 6 years ago | (#17651232)

There are no headshots!

sooo... (5, Funny)

Anonymous Coward | more than 6 years ago | (#17650786)

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

More nuclear ships? (5, Insightful)

TheWoozle (984500) | more than 6 years ago | (#17650788)

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

Re:More nuclear ships? (1)

adamofgreyskull (640712) | more than 6 years ago | (#17651156)

It's pronounce nukular. Nukular.

Re:More nuclear ships? (3, Interesting)

Protonk (599901) | more than 6 years ago | (#17651214)

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.

Power required in electrical form was never really an issue. Modern gas turbines can produce power more quickly and in a denser fashion (think fuel + turbine + cables vs a whole steam engine room) than naval nuclear reactors.

Unless they decide on HUGE engine rooms and prioritize power use, i wouldn't see nuclear powered sruface ships coming back.

Re:More nuclear ships? (1)

powerlord (28156) | more than 6 years ago | (#17651260)

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


I was wondering the same thing.

Or imagine the conversion of an existing Nuclear powered Aircraft Carrier into a launch platform.

Alternatively ... I could see the Iowa or Wisconsin reactivated as a test-bed/deployment platform.

With its electrical output equaling ~10MW ( http://en.wikipedia.org/wiki/Iowa_class_battleship #Electricity [wikipedia.org] ), the introduction of a capacitor system might make them a "good fit".

The real question is how much "extra" power the system needs versus what's generated. (i.e. you don't want to be like the Yamato/Excaliber after you fire your main battery ... sitting defenseless and unpowered until the system recharges). If they CAN grab the full output for a few seconds (or most of it at least), then they could generate capacity for the "final" 64Mj version in ~7-10 seconds.

(I guarantee there are holes in this idea, so please feel free to poke them . :) )

physics of railguns (4, Informative)

smellsofbikes (890263) | more than 6 years ago | (#17650806)

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 (0)

Anonymous Coward | more than 6 years ago | (#17650964)

> 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?

It's not as if existing artillery fires at subsonic speeds so yeah, it's not going to be silent, but it will definitely be quieter.

Re:physics of railguns (5, Interesting)

sjaskow (143707) | more than 6 years ago | (#17651184)

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.

Mmmm.... I love rail guns! (2, Informative)

rhartness (993048) | more than 6 years ago | (#17650816)

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.

Re:Mmmm.... I love rail guns! (0)

Anonymous Coward | more than 6 years ago | (#17651008)

The guy that runs that site is a total asshat. He does not take any consideration into how dangerous what he's doing is, and has nearly killed himself, and others numerous times. He's a lawsuit waiting to happen.

Goodbye Iraq insurgency! (0)

Anonymous Coward | more than 6 years ago | (#17650826)

All we do is park one of these badboys off the coast of Iraq and blast the Insurgent bases to smithereens. Score one for the good guys.

Re:Goodbye Iraq insurgency! (1)

jalet (36114) | more than 6 years ago | (#17651026)

the "good guys" ?

Warp Core? (1)

FR007 (843341) | more than 6 years ago | (#17650828)

..more like ZPM.

Not sure about this (5, Funny)

thewils (463314) | more than 6 years ago | (#17650840)

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

That's What I'm Talkin' Bout! (1)

RailGunSally (946944) | more than 6 years ago | (#17650842)

High energy physics, baby! Makes me all weepy...

Slight correction? (5, Insightful)

Civil_Disobedient (261825) | more than 6 years ago | (#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.

Add favourite Kojima reference here... (1)

F-3582 (996772) | more than 6 years ago | (#17650854)

Okay, now we just need some legs for this beauty, don't we?

BFG (1)

RPGonAS400 (956583) | more than 6 years ago | (#17650862)

Soon to replace the BFG in Doom.

I wonder..... (2, Interesting)

Prysorra (1040518) | more than 6 years ago | (#17650882)

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....

Re:I wonder..... (0)

Anonymous Coward | more than 6 years ago | (#17651078)

But at those speeds, you'd have to have a radar that is currently unobtanium for a long time given the potential size of the slugs. If you can't detect the nuclear tipped 12"ers, what makes you think you'd be able to detect something far smaller, and going magnitudes faster? Whoever said the gun would be L.O.S. didn't RTFA, it's a ballistic weapon with a high arc, think mortar.

Amount of power (energy really) (4, Interesting)

Beryllium Sphere(tm) (193358) | more than 6 years ago | (#17650920)

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.

Re:Amount of power (energy really) (2, Insightful)

D4rk Fx (862399) | more than 6 years ago | (#17651088)

It's not all converted to heat. Well, assuming the projectile actually does leave the muzzle... Some early experiments ended up vaporizing the projectiles inside of the rails.

Yeahbut.... (3, Informative)

Iphtashu Fitz (263795) | more than 6 years ago | (#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:Amount of power (energy really) (1)

Sparr0 (451780) | more than 6 years ago | (#17651180)

Only 30000 BTUs if its all converted immediately to heat. I think the goal of this device is to convert as much of the power as possible into kinetic energy. Some of THAT will turn into heat in the air, which fortunately can cool itself (global warming jokes aside), but most of will still be kinetic energy when it hits something, at which point a little more becomes heat and most of it is expended breaking atomic bonds (and thereby causing damage).

It would be interesting to see the efficiency of a railgun. If it's 10% then youre right, shitload of heat to dissipate. If it's 80%, not nearly as much, esp considering that a naval ship has just a *bit* more than a quarter ton worth of water to work with :)

640 megajoules (0)

Anonymous Coward | more than 6 years ago | (#17650926)

ought to be enough for anybody.

Power Needed (1)

Dvinn (927610) | more than 6 years ago | (#17650936)

All it needs is 1.21 gigwatts

I wonder (0)

Yurka (468420) | more than 6 years ago | (#17650954)

why it increases in powers of two? Maybe, then, it should be mibijoules, so that we know for sure that we're getting our money's worth for each kibidollar of taxes?

Re:I wonder (1)

Yurka (468420) | more than 6 years ago | (#17651006)

mebi-, sorry about that.

Admiral Gates (5, Funny)

Anonymous Coward | more than 6 years ago | (#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.

Return of the Battleship (3, Interesting)

Black-Six (989784) | more than 6 years ago | (#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!

power not the problem (4, Interesting)

EricBoyd (532608) | more than 6 years ago | (#17650992)

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.

Re:power not the problem (1)

gardyloo (512791) | more than 6 years ago | (#17651086)

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.

    Think you're right. If I remember correctly, railguns are extremely nasty to themselves, due mainly to electrical arcing and the damage it does to the rails. There'd have to be a LOT of recalibration after a shot to make sure that the next shot doesn't detroy the area and/or send the projectile off in unexpected directions.

Re:power not the problem (1)

Prysorra (1040518) | more than 6 years ago | (#17651120)

You are correct. At high enough energies, the projectile is often liquefied and can cause damage to the rails.

Something doesn't add up (0)

Anonymous Coward | more than 6 years ago | (#17651004)

From the TFA "... will extend it's range to more than 200 miles and strike a target that far away in six minutes". So that's 200 miles in 360 seconds, or 2000 miles / hour. That's not really all that fast, it's a muzzle velocity of ~2933 fps, and the projectile weighs 3.2 kg

Yeah, it's a lot more than a bullet, but I don't see how something that size at that speed takes out a building. Or am I missing something?

Screenshots!!! (0)

Anonymous Coward | more than 6 years ago | (#17651018)

Where are the screenshots!

Forget Replacing Cruise Missiles... (5, Funny)

Wandering Wombat (531833) | more than 6 years ago | (#17651020)

... 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. (3, Insightful)

Wilson_6500 (896824) | more than 6 years ago | (#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.

Re:Think twice. (1)

Wandering Wombat (531833) | more than 6 years ago | (#17651306)

Please see every other comment about how they would be firing semi-intelligent fin-guided projectiles, able to make considerable course corrections over a distance of 200 miles, and let's face it, the USS Ronald Reagen ain't exactly taking any hair-pin turns here.

Re:Forget Replacing Cruise Missiles... (0)

Anonymous Coward | more than 6 years ago | (#17651298)

So I guess Marines, SEALS, and cargo will be launched by this thing, too?
The projectiles will be able to re-target midflight?

I hope you realize that the Navy does more than WWII shore bombardment.

Yeah, but the only source for di-lithium crystals (1)

Master of Transhuman (597628) | more than 6 years ago | (#17651064)

is IRAN!

Two birds in one shot? (1)

gorrepati (866378) | more than 6 years ago | (#17651134)

Now, what happens to birds when you fire a gazillion of these things into sky. On a cautionary note - please keep it away from Dick Cheney.

Railguns in Games (1)

walterwalter (777821) | more than 6 years ago | (#17651188)

From TFA: "Railguns are also portrayed in the "Stargate" TV series and in many video games, including "Halo 2."" Halo2? What that article really needed was a Quake II shout out. Damn kids...

look ma! a falling star! (1)

mennucc1 (568756) | more than 6 years ago | (#17651216)

95 miles altitude? reenter from out of atmosphere ? while carrying complex electronic for GPS navigation?
Most movies and documentaries attest that, when reentering from space, the communication between NASA and the space crew is off , due to excessive heat on the vehicle; and that gizmo is supposed to navigate out of GPS, while free falling at the highest possible speed (to maximize impact damage)?
I hope they did their math correctly, and computed the heat of air friction correctly... otherwise the navy will sport the first artificial falling star generator in history

Re:look ma! a falling star! (2, Funny)

Absolut187 (816431) | more than 6 years ago | (#17651316)

NO, NO, NO.
You're so Silly!

They will be wire-guided.

Not that much power (1)

Arnold Reinhold (539934) | more than 6 years ago | (#17651224)

64-megajoules is 17.8 kilowatt-hours. Even assuming the gun is only 10% efficient, that isn't so much power. To put it another way, to fire the gun every 64 seconds at 10% efficiency takes 10 megawatts, or 13000 horsepower. Destroyer turbine engines put out considerably more power than that. What am I missing?

Stability and Accuracy... (1)

Lohrno (670867) | more than 6 years ago | (#17651272)

How do they plan on keeping the thing stable enough to hit targets accurately 200 miles away at sea?

Platform instability (1)

dave562 (969951) | more than 6 years ago | (#17651286)

How are they going to deal with the fact that they are trying to mount these things on ships that are floating in the middle of the ocean and are subject to the rise and fall of the waves? I have to imagine that the angle of the barrel in relation to the horizon has to be changing by a pretty significant amount of degrees.

Accuracy? (3, Insightful)

chiph (523845) | more than 6 years ago | (#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.
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