
Navy Sets World Record With Rail Gun - gibsonf1
http://www.foxnews.com/scitech/2010/12/10/navy-railgun-shoots-bullets-electromagnet/
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essayist
This is great! When the Soviets come roaring through the Fulda Gap, or the
Japanese descend on Pearl Harbor, we got 'em!

Oh, wait. We're preparing for the last war or even the one before that, all
over again.

How does this help in the world of asymmetric warfare, failed states, nukes in
container ships, and Stuxnet? (I'll bet the Maginot Line was pretty cool
technology in its day as well.)

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nickpinkston
Well, you may be surprised by the increasing relevance of naval forces in our
modern world. Even though big ships fighting Bismarck style is rare, big ships
are still very useful in securing seaways for shipping. This is why China,
India, S. Korea are all building up their navy. Sure, SpecOps / "terrorists"
grab the headlines, but remember that countries have many other threats and
don't openly promote them without cause.

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stcredzero
Yes, spending $569,000 on a cruise missile to take out a merchant vessel of
comparable cost wouldn't be good economic warfare doctrine. If the navy can
develop weapons that can sink merchant vessels from 200 miles away with dirt-
cheap munitions (like a dozen $1000 ceramic slugs) then this makes for a more
credible threat.

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nickpinkston
They probably wouldn't be blowing up merchant vessels like U-Boats, but they
certainly would still spend whatever money it takes though: Mark 48 torpedos
are a cool $1M to $3.5M.

<http://en.wikipedia.org/wiki/Mark_48_torpedo>

I think the main advantage for rail guns are that they allow a much higher
volume of fire and faster time to engage more targets. It just happens to use
cheaper ammo - I'm sure the gun will be much more expensive to make than a
standard machined barrel.

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stcredzero
_They probably wouldn't be blowing up merchant vessels like U-Boats_

But a part of the point is that they _could in theory_.

 _they certainly would still spend whatever money it takes though: Mark 48
torpedos are a cool $1M to $3.5M._

This would be dandy for blowing up a submarine or major warship which costs a
lot more. This might also be viable for "demonstrating" your capabilities one
or several times. Sinking a major merchant marine fleet this way wouldn't be
cost effective.

 _It just happens to use cheaper ammo - I'm sure the gun will be much more
expensive to make than a standard machined barrel._

With a 200 mile stand-off range, a much more expensive gun would still make
sense. The extreme range would make such a weapon more survivable. There would
also be applications for land to shore fire support.

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vl
Lets get bunch of rails into the low polar orbit. Once a 1000 or so is
deployed, there will be an almost-instant (20 minutes) strike capability for
any location on the earth. The good part is that kinetic energy of re-entering
rail will be unmatched by any railgun.

On the serious note, they didn't specify the weight of the projectile, and
this is quite important factor. Comparison of the energy delivered at the
target range to the energy delivered by the conventional winged missile would
be useful as well.

Blog of the guy who build portable supersonic railgun at home (in Russian):
<http://railgun.org.ua/> Check out his video page:
<http://railgun.org.ua/video/>

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icegreentea
You already have 20-30 minute strike capability for any location in world.
You've had it for decades.

What you want is 20 minute strike with less warning than existing ICBMs. And
also banned. The nuclear weapons reduction and restriction of weaponization of
space treaties are some of the successful treaties with regard to controlling
weapons that anyone, let alone the United States has been involved with.
Violating said treaty will bring ridicule and anger to whoever breaks it, and
a non-miniscule chance of the other major nuclear powers launching all their
nukes.

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smhinsey
As much as I would prefer otherwise, it seems pretty clear that space has
already been weaponized. Between the Shuttle the X-37, and whatever else
exists, for all we know there are already satellites in orbit armed with
kinetic kill vehicles.

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jerf
All satellites in orbit are already kinetic kill vehicles, just with varying
degrees of sophistication. Everything in space is a kinetic kill vehicle. The
idea that space can somehow _not_ be weaponized is sheer physics ignorance. In
some ways this is the largest challenge to space exploitation, which is
rapidly becoming relevant as commercial spaceflight recently passed a
milestone. A corporation that can retrieve an asteroid for mining purposes is
a corporation that can drop that asteroid on your capital. There aren't very
many realistic treatments of this scenario in "the literature". ("The Moon is
a Harsh Mistress", at least the base scenario if not the details of the
superintelligent computer, is one of the few.)

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smhinsey
Maybe I shouldn't have used that term. I am aware of the basic physics of the
situation, but that's not what I was talking about. I think it's likely there
are already devices in orbit with the capability of launching "dumb" (i.e.,
non-explosive ) munitions to either take out other satellites or small targets
on earth.

When people discuss the weaponization of space in terms of the treaties,
implying ignorance because it isn't about basic physics doesn't provide any
constructive input, and is frankly just needlessly hostile. These treaties are
about weapons in a military sense, with the ultimate issue being the presence
of nuclear weapons in orbit. I don't think it would be news to anyone that the
whole business is inherently dangerous and that anything in orbit can come
down anywhere on earth with little warning.

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jerf
But that's the point. Anything nontrivial in space already is a military
weapon. (Though most satellites are trivial by this measure, I'm really
talking about the mid-term future.) It doesn't even have to be nuclear. It is
not possible to really seriously _use_ space without it being intrinsically
weaponized. There's no such thing as non-weaponized space.

And no, I seriously doubt our political leadership really understands this at
a gut level. You might even find some people in such positions that could pay
lip service to the idea, but still don't really get it. You don't even need
"nukes", which, frankly, are redundant pretty quickly and would only add a
psychological scare factor.

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smhinsey
I am absolutely with you in thinking that politicians don't get this at all.
My main point is that there is a context in which those terms are used that
doesn't immediately mean that anyone who uses them doesn't realize that mass
in space == potential big boom somewhere.

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ahi
A big rail gun is nothing new. The hard part, the part they still haven't
figured out, is firing the thing without blowing it up at the same time.

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hugh3
Pretty awesome.

There's an unfortunate focus in the admiral's comments on ship-to-ship
warfare, which really isn't something we get a lot of nowadays.

What's deliberately _not_ mentioned is how useful this might be for shooting
down a missile at launch. It is, as they say, hard to hit a bullet with a
bullet. But hitting a bullet with a much faster bullet...

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iuhjyftgrd
That's their main use

With a missile coming toward you at Mach 2-3 you don't want to be shooting
subsonic cannon shells at it.

The rail gun ammunition is much smaller so you can carry much more of it and
make a much more mobile gun turret because it doesn't need to store tonnes of
shells or have a feed back to a magazine.

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Estragon
But if you look at the video, it's clear they're a long way from making any
kind of agile turret out of this. It's HUGE.

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scdlbx
It is not that big compared to the guns on a destroyer or a battleship. It is
still large and bulky, but not that far off.

Current destroyer's gun:
<http://en.wikipedia.org/wiki/5%22/54_caliber_Mark_45_gun>

Iowa Class gun: <http://en.wikipedia.org/wiki/16%22/50_caliber_Mark_7_gun>

~~~
tsotha
Yeah. The part of the turret you can see when you look at the ship is only the
tip of the iceberg.

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pingswept
"[A] railgun offers 2 to 3 times the velocity of a conventional big gun, so
that it can hit its target within 6 minutes."

I'd expect that most projectiles decay exponentially toward a terminal
velocity, so the impact of shooting a bullet faster is negligible when it's
going to be in flight for 6 minutes. Anyone know whether that's true for long
range projectile weapons these days?

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cperciva
Railgun ammunition is designed to lose as little kinetic energy as possible.
After all, there's no point hitting someone with a non-explosive projectile
unless it's moving fast.

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pingswept
This suggests that the terminal velocity of a rail gun projectile is around
Mach 5:
[http://www.globalsecurity.org/military/systems/ship/systems/...](http://www.globalsecurity.org/military/systems/ship/systems/emrg.htm)

I guess I can spend my time worrying about other things!

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zoomzoom
What is the possibility of using these for space launches?

edit: obviously would have to be slower then these for the sake of any fragile
cargo (including people)...

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dasil003
Hard to imagine anything useful withstanding that acceleration. You could make
a longer launch tower, but how tall would it have to be?

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SerpentJoe
Why not aim for the horizon? That way your track can be on the ground, and
even better your impulse is spent approaching orbital speed rather than
struggling against gravity drag. Even traditional space rockets turn east as
quickly as possible, and a (semi) ballistic launch can do it from the start.

That said for human payloads you'd need a really long track, tens or hundreds
of kilometers. I wouldn't want to live near the launch end. (edit: to get a
useful amount of speed; still assuming rockets to get us the rest of the way)

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burgerbrain
You either lose energy to gravity during the launch or while in the air.
Either way you lose that energy, it really doesn't matter when.

Rockets turn sideways because when you're in orbit, you're moving sideways.

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SerpentJoe
You're right, but look up gravity drag. Every second you're standing on your
boosters you're wasting fuel. Imagine wearing a jetpack and wasting all your
fuel hovering an inch off the ground. If you turn horizontal the thrust is
invested rather than spent, but first you have to build enough speed to not
crash.

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stcredzero
Actually, once you get to a high enough altitude, it doesn't take that much
fuel to maintain your speed. The "Pop-up" trajectory (first stage up, 2nd
stage forwards) is one that's actually practical and has been proposed for
TSTO.

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gvb
_"We're also eliminating explosives from the ship, which brings significant
safety benefits and logistical benefits," Ellis said. In other words, there is
less danger of an unintended explosion onboard, particularly should such a
vessel come under attack._

The first half (logistics benefits) is a good statement. The rephrasing the
the second half is bogus.

Joules are joules the world over. If the enemy fire hits the caps full of
joules, it ain't gonna be good for the good guys even if there are no
conventional explosives involved.

~~~
1053r
Joules are joules, but what you are failing to account for is the form the
joules might take. If the enemy hits the caps and they explode, an amount of
energy equal to one projectile launch is liberated.

If, on the other hand, you take out a magazine, you liberate an amount of
energy equal to all the shots the ship is capable of taking ALL AT ONCE.

The energy necessary to fire all those shots is probably still on board, but
it is likely in the form of a nuclear pile in the reactor, which is shielded
up the wazoo. Even if the ship is running a conventional generator, diesel
fuel doesn't have a tendency to explode in quite the same way as gunpowder.

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bigiain
That's true, but 33megajoules is almost exactly the amount of energy in 1L or
1/4Gal of gasoline. I don't know how much explosive a typical ship mounted
canon requires for propellant and payload, but even given all the
inefficiencies turning gasoline into electricity Id be quite surprised if
there's quite a bit less energy on board to supply the rail gun.

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zitterbewegung
200 pound of tnt is 30.2 mJ in the M107 round you have 14.6 lbs of tnt in that
shell. So basically 14 shells would equal about that many mJ. I'm sure that
the ship has more than 14 shells.

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dstorrs
Ok, granted, this is cool. And I see a lot of utility for space launch and
other applications, so I support the research.

My question: does it actually have practical utility as a weapon of war for
the modern US Navy? This seems like fighting the last war -- this is about
building a weapon that goes on giant ships, when the new war is all about
information and special forces strikes.

~~~
essayist
Yup. See the "Maginot line" discussion above.

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CallMeV
When they started putting big guns on battleships, they came up with a new
term: "gunboat diplomacy." When the Easter Uprising began in Ireland, the
Royal Navy just sat their gunships in the bay and started shelling them from a
safe distance.

So I guess they're hoping that they can bring back gunboat diplomacy in a form
more suited to the 21st century. And if they're aiming for ranges of two to
three hundred miles, I guess that theoretically means that no part of the UK
would be entirely safe except maybe Birmingham, and that's mostly because
nobody wants to go there even to blow it up.

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MichaelApproved
So it leaves the gun traveling at Mach 7 and can go 100 miles but how fast is
it going when it reaches the target 100 miles away? By the time it reaches the
target most of it's energy is lost. The main power of this weapon is the
kinetic energy it delivers to the target but that information is nowhere to be
found in the article.

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tsotha
>So it leaves the gun traveling at Mach 7 and can go 100 miles but how fast is
it going when it reaches the target 100 miles away?

The one they plan to deploy is supposed to go something like mach 20 and have
a ballistic trajectory. Not something you could destroy a city with, but it'll
make a bigger bang than an 8-inch shell.

~~~
stcredzero
Navies still get an awful lot of leverage out of the ability to destroy
merchant vessels.

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Murkin
Wonder if a startup could get those Tomahawks down to 60,000$ a pop.

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lispm
The last thing we need is new weapons.

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kahawe
I am sorry, I have to say this... my Quake bits won't let me rest otherwise.

"Now they just have to figure out the Quad Damage and it's going to be insta-
gibs on any target!"

