Mass drivers?

[Asst. Asst. Lt. Cmdr. Smi]

Well, given a choice between losing his head and losing his package, a man woukld choose losing his head. Did you ever see that scene in "The Man With the Golden Gun" where Bond tried to get a lead from someone by threatening them by aiming a gun for people bwith 3 fingers at his crotch?

[Master of Ossus]

Originally posted by Alyrium Denryle
I know they arent practical, but it would be very demoralizing to a planetary population to have asteroids hitting major cities

One other advantage of a mass driver that I think is plausible is that unlike nuclear weapons they don't tend to irradiate the area where they are used. You can totally destroy and cripple a planet, but after the dust settles down, you could move your own population in without fear of radiation. Is this right?

Assuming that the eco-system is not significantly altered by the attack. That would be doable, or you could just terra-form the planet after you had destroyed it, but that would be easier to do with more conventional weapons.

Mass Drivers are not practical, even with very advanced magnets or some other method of propulsions.

[Asst. Asst. Lt. Cmdr. Smi]

And aren't the guns that use the trigger, firing pin, and the like more reliable than hydraulic or electromagnetic systems, and cheaper?

[Master of Ossus]

And aren't the guns that use the trigger, firing pin, and the like more reliable than hydraulic or electromagnetic systems, and cheaper?

Maybe they are today, but the mass drivers that they always show on TV shows and in games are always VERY reliable. Actually, magnets and hydraulics are extremely reliable. I do not know why this would be true today, but it is possible.

[Graeme Dice]

It's hard to get more reliable than a railgun, in terms of basic construction of you have some kind of magnetic field already available. All you need is two straight pieces of metal, a small conductor, and lots of direct current. The only moving part in the weapon itself is the projectile.

[Darth Wong]

It's hard to get more reliable than a railgun, in terms of basic construction of you have some kind of magnetic field already available. All you need is two straight pieces of metal, a small conductor, and lots of direct current. The only moving part in the weapon itself is the projectile.

Sort of. It depends on what you mean by "the weapon". Since this particular weapon requires a very large power source, that becomes part of the weapon, and it will have lots of moving parts, so the weapon has lots of moving parts.

As for reliability, keep in mind that purely electronic components can fail too, even with no moving parts. In this case, there would be high voltage and high current, which will both cause wear and tear on the circuits. There would also be cyclic stresses and strains in the railgun itself, due to reaction forces from the acceleration of the projectile (reaction forces always exist, even if they are coupled magnetically rather than through gas pressure, as in a conventional firearm). If the magnets are supercooled for superconductivity, you will have coolant circulation systems, cryo-refridgeration systems, etc. This thing will be more complicated than it may appear on the surface.

[Crown]

Ha! I knew I would find it! The article that I was talking about is entitled "The shape of things to come", it can be found in the September 2001 issue of Popular Science, it's that month's cover story.

To be fair, it doesn't have that much information on the proposed railguns, but to quote a snip;

"The ship carries more than 12,240 projectiles for it's rail guns, which use electromagnetism to accelerate the rounds to a speed of Mach 10. Despite the guns' smaller size, this velocity gives them the explosive impact of shells from the 16-inch guns on an Iowa-class battleship"

Sounds exciting!

I will point out though, that it doesn't state that any of this has actually been built, I think that it's just more like a proplosal of sorts, you know like the Navies pipe dream.

[Graeme Dice]

Sort of. It depends on what you mean by "the weapon". Since this particular weapon requires a very large power source, that becomes part of the weapon, and it will have lots of moving parts, so the weapon has lots of moving parts.

Sure, but a synchronous generator is not exactly an unreliable piece of equipment. It _does_ need to be protected from mechanical shock, but then if that's a serious problem there are other less efficient ways to generate electricity.

As for reliability, keep in mind that purely electronic components can fail too, even with no moving parts.

I'm an ee student, so I do realize this.

In this case, there would be high voltage and high current, which will both cause wear and tear on the circuits.

Use large enough bus bars and good breakers, and the amount of power doesn't matter too much. If you can keep the pieces from overheating, then you can usually keep them from failing. Of course, there's really no way you could use semiconductors in this at all.

There would also be cyclic stresses and strains in the railgun itself, due to reaction forces from the acceleration of the projectile (reaction forces always exist, even if they are coupled magnetically rather than through gas pressure, as in a conventional firearm).

And since we want a high-speed projectile in a short acceleration distance these forces are likely to exceed the limit where fractures don't occur.(It's been three years since my materials class, so I've forgotten it's name.)

If the magnets are supercooled for superconductivity, you will have coolant circulation systems, cryo-refridgeration systems, etc. This thing will be more complicated than it may appear on the surface.

I left the magnets out for just this reason, as the level of magnetic field needed is a real pain to create.

[TrailerParkJawa]

Obviously, you've never gone to the James Bond Super-Villain school of pointlessly impractical uber-weapons

Make sure you dont forget to protect said weapon with the "one inept guard".


So far the discussion has revolved around using mass drivers on a large scale. Destroying cities and such, what about using a smaller device. Mabye something that throws smaller sized rocks for targets like critical overpasses, dams, ships sitting at anchor, trains, etc. Would this precision be possible? Would it be easier to use a more conventional weapon? What'cha think?

[Mechwolf]

The tactical advantage a mass-driver has over nukes, at least presented in Babylon 5, is that Orbital Defense Satellites would destroy the nukes being fired form orbit long before the nukes could reach their target. The asteroids that the Centuri used were too big to destroy before hitting their targets. Also, as someone pointed out earlier, asteroid bombardment did not irradiate Narn as badly as would using enough nukes to do the same amount of destruction. If the Centauri had used nukes, Narn would be an irradiated hell hole unable to support life. The Centauri wanted to occupy Narn, nukes were out of the question.

[phongn]

So far the discussion has revolved around using mass drivers on a large scale. Destroying cities and such, what about using a smaller device. Mabye something that throws smaller sized rocks for targets like critical overpasses, dams, ships sitting at anchor, trains, etc. Would this precision be possible? Would it be easier to use a more conventional weapon? What'cha think?

You could, but you'd have to put some sort of guidance package on it, like INS+GPS (which has been proposed for ERGM). You'd get a nice standoff range, but such attacks would be easily detectable via radar and in the future could be shot down by systems similar to THEL.

Critical targets should be left to cruise missiles or stealth aircraft which are less likely to be shot down and harder to track.

[Darth Wong]

The tactical advantage a mass-driver has over nukes, at least presented in Babylon 5, is that Orbital Defense Satellites would destroy the nukes being fired form orbit long before the nukes could reach their target.

That's no advantage, since the launching platform itself (the ship) must be much larger in order to handle the large, heavy equipment necessary for this mass driver. Therefore, the orbital defense satellites (if they exist) could destroy the ship itself rather than worrying about picking off its projectiles.

Compare this to nukes, which could be loaded onto any little fighter. Could an orbital defense platform stop a swarm of fighters and their missiles? If I were designinf an orbital defense platform, I'd much rather have a few big mass driver-equipped battlewagons to shoot at.

The asteroids that the Centuri used were too big to destroy before hitting their targets. Also, as someone pointed out earlier, asteroid bombardment did not irradiate Narn as badly as would using enough nukes to do the same amount of destruction.

The radioactive fallout point is a good one, although I would point out that very high yield nukes in airbursts do not create any appreciable fallout. It's the low-yield "tactical" nukes which are the dirtiest.

[Crown]

Originally posted by Darth Wong
The radioactive fallout point is a good one, although I would point out that very high yield nukes in airbursts do not create any appreciable fallout. It's the low-yield "tactical" nukes which are the dirtiest.

I agree, but can a fighter carry the, one assumes, very heigh yeild nukes?

[Darth Wong]

I agree, but can a fighter carry the, one assumes, very heigh yeild nukes?

Two megatons is high yield. A two megaton warhead in B5 is small enough for a guy in a spacesuit to lug around by hand. They can put that on a fighter.

[Crown]

Originally posted by Darth Wong
quote:
--------------------------------------------------------------------------------
Originally posted by Crown:
I agree, but can a fighter carry the, one assumes, very heigh yeild nukes?
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Two megatons is high yield. A two megaton warhead in B5 is small enough for a guy in a spacesuit to lug around by hand. They can put that on a fighter.

I stand corrected!

[Mechwolf]

Darth Wong Posted: Thu Jul 25, 2002 10:56 pm Post subject:
That's no advantage, since the launching platform itself (the ship) must be much larger in order to handle the large, heavy equipment necessary for this mass driver. Therefore, the orbital defense satellites (if they exist) could destroy the ship itself rather than worrying about picking off its projectiles.

That is why a fleet should have some ships attacking the Orbital Defense Satellites. So that they are not able to attack the ships hurling asteroids at their world.

Again I point to the episode of B5 when the Centuri are Bombarding Narn form orbit. Before the Centuri show up, G'kar is talking to his Uncle who is in charge of the Narn fleet sent to destroy a Centuri supply depot. When his uncle tells him what ships he's taking for the assault, G'kar states that will leave Narn with only a skeleton defense crew.

Fast forward to the actual bombardment that we see, there are no signs of the skeleton defense crew to be seen. To me, this suggests that the Primus-class battleships that the Centuri were using for this offensive either had support from Vorchan or Demos cruisers, & we just didn't see them, I.E. thay were off screen. Or the Primus battleships took out the Narn defenses with conventional Ion & Battle-Laser cannons before comencing with the orbital bombardment.

[AdmiralKanos]

That's no advantage, since the launching platform itself (the ship) must be much larger in order to handle the large, heavy equipment necessary for this mass driver. Therefore, the orbital defense satellites (if they exist) could destroy the ship itself rather than worrying about picking off its projectiles.

That is why a fleet should have some ships attacking the Orbital Defense Satellites. So that they are not able to attack the ships hurling asteroids at their world.

How does this change the tactical comparison between missiles and mass drivers? Either way, if you can destroy the defense platforms, you're home free. But if you can't, you've got a better chance of success with the swarm of nuclear missiles than you do with a big mass driver-equipped target lumbering into range.

[Mechwolf]

The Primus-class Battleship that was carrying the Mass-drivers was a normal sized warship for the B5 universe. It was no bigger a target than a Narn G'quan cruiser or EA Omega-class destroyer, or other Primus-class battleships.

[The Dark]

[quote="Crown"]Ha! I knew I would find it! The article that I was talking about is entitled [b]"The shape of things to come"[/b], it can be found in the September 2001 issue of Popular Science, it's that month's cover story.

To be fair, it doesn't have [i]that[/i] much information on the proposed railguns, but to quote a snip;

[i]"The ship carries more than 12,240 projectiles for it's rail guns, which use electromagnetism to accelerate the rounds to a speed of Mach 10. Despite the guns' smaller size, this velocity gives them the explosive impact of shells from the 16-inch guns on an Iowa-class battleship"[/i]

Sounds exciting!

I will point out though, that it doesn't state that any of this has actually been built, I think that it's just more like a proplosal of sorts, you know like the Navies pipe dream.[/quote]

Yeah, I remember that article. It's also supposed to be a trimaran design, if I recall correctly? I thought it sounded cool, but I don't want to think about what the recoil will do to the crew.

BTW, railguns have been tested before. I'll have to check the book out from the library again. It's called Beam Weapons (great title, no?), and while most of the book deals with lasers and such (X-Ray lasers, free electron lasers, I think it even mentions grasers), there is a section on railguns. They took a small metal discarding sabot and a plastic cube (I believe it said a child's toy cube, but I'll have to read for exact details), and shot the cube through armor plate. Of course, I will get more details, since this is very vague.

[ClaysGhost]

I'm pretty sure I've got a (1990s) book with a picture of an aluminium block after a lexan projectile from a primitive railgun-derivative has hit it. The projectile is a lexan disc with an aluminium skirt - during firing, the skirt is vapourised by the high current flowing across it between the two rails and the expanding plasma accelerates the projectile. The target block developed a hole about six inches across and 5 deep, going by the scale they put on the picture. This isn't really a pure railgun, in which the round is accelerated by the magnetic field developed by the rail current, but it's still pretty powerful. The forces placed on the rails are indeed extreme, but of more concern is the way the projectiles tend to weld themselves onto the rails. People beat that by increasing the surface area of projectile in contact with the rail, which reduces the current density. You can turn up lots of railgun pages on the internet - for instance,

http://www.powerlabs.org/railgunprogress.htm

[SpacedTeddyBear]

That is why a fleet should have some ships attacking the Orbital Defense Satellites. So that they are not able to attack the ships hurling asteroids at their world.

You forget that under normal circumstances there would be a fleet of ships protecting the Homeworld along with the defense grid. If the attacking fleet were to go for the defense grid first there would be little or nothing left to protect the ships with the mass drivers. If the fleet were to attack en mass, the enemy would still have to dedicate a number of ships to protect the ships with the mass drivers. Then there's also the problem of storing the ammo for the mass driver.

[Jadeite]

Crown wrote

To be fair, it doesn't have that much information on the proposed railguns, but to quote a snip;

"The ship carries more than 12,240 projectiles for it's rail guns, which use electromagnetism to accelerate the rounds to a speed of Mach 10. Despite the guns' smaller size, this velocity gives them the explosive impact of shells from the 16-inch guns on an Iowa-class battleship"

Sounds exciting!

Dont tell Manji about that! Next thing we know, all his designs will have railguns instead of 16inchers.

[tharkûn]

The big advantage of the mass driver is that there are no "area effect" counters.

For instance early in the cold war there was a huge worry about the "bomber gap" the idea was that the Soviets had produced so many bombers that they could load them up with nukes, send the planes swarming into the US, preempt and obliterate the US before a full retalitory strike could commence. A counter to this was the nuclear Air to Air missile. In the event of nuclear war the US thought a great way to kill Soviet nuclear bombers would be to put a high yeild warhead on an AtA missile and detonate it in the middle of the swarm.

So what does this have to do with Sci-fi uberweapons? Well nukes are inherently weak. Take the megatonne fusion bomb, if you punch a hole in the side ... it no longer goes off (if you don't get the requisite pressure to fuse your D/Li/T/whatever you go from a bigass missile to a rather weak slug). Likewise if you fry the circuitry the thing is not going to off (at least assuming compotent design ... normally the default action is not to go boom). So if you intend to swarm with nukes one possible defense strategy is to use area effect weapons that go off in the middle of the swarm and break the missiles.

You can disable a nuke with a very small amount of work, so you set off a bigass explosion designed to spray high speed micro shrapnel, burn the electronics, even partially detonate the missile, etc. The whole goal is to get a high kill ratio with one (MAYBE two) shot kills. This does not work for NMD today because the number of area effect defensive shots is huge to begin with (something like the entire US arsenal is needed for saturation defense), and the density of incoming missiles is too low to make it more effective than point shots (i.e. Patriot type systems).

Now on the flip side a mass driver cannot be as easly stopped. It doesn't have to do anything when it reaches its target (like say send a firing sequence through the electronics, set off a primary explosion to get the activation energy needed, contain a hideous pressure/temperature chamber, etc.). In short a mass driver is fire and forget. Further your mass driver cannot be defeated with cheap work costs. Cheapest way out is fragmentation ... which still means individual fragments hit and the KE has to go somewhere. Vaporization is another option, but you still need to worry about what the hell happens to this high KE, superheated gas headed at you. To truly neutralize a mass driver you have to just as much work, if not more on it as the guy who launched it, but you don't have the luxury of working with it inside a prebuilt acceleration chamber egineered to have high efficiency. Instead you get to lob missiles at it, explode them as close to the surface as possible, and watch as a good chunk of the explosion is wasted.

Alternatively you could take shots at with your own high momentum projectiles, but if this is planetary bombardment ... you are shooting uphill out of the well, they are shooting downhill in.

Now the big drawback (tactically speaking) to the mass driver is that you need to have huge space to accelerate the thing, and this means a huge amount of dedicated mass. This means you likely need a large ship which presents one big target to gun for. However this need not be the case ... you can make a gauss gun with multiple compenents that can be spaced on several ships that just need to get in line with the shot. There are any number of systems you can use to build a mass driver that do not require a monolithic ship to propel your shot, each have their disadvantages of course, but its possible to make a mass driver with nothing but a tender to carry the slugs and small ships to incrementally push the thing.

Further mass drivers are fire and forget ... if the enemy doesn't have the ability to fragment, vaporize, decelerate, or otherwise stop/dodge the thing and time is not of the essence ... fire it from out of weapons range and wait for it to hit. Its a vacuum so there should be little loss of KE during flight and you are going downhill.

Mass drivers have their advantages ... they are a bitch to divert/stop, they are cheap (DU/iron work fine), and the defender has a massive disadvantage fighting uphill. They also have their weaknesses ... very long ToF's, huge input energy costs, and either a few big targets or multiple stage accelerations.

The tactical advantages of the mass driver vs a swarm of nuke laden bombers is going to be determined by the defender's weaponry and your defensive abilities. If his defensive weapons pack enough punch to have area effect destructive abilities (1 shot "kills" a high percentage of missiles within radius R, this space containing multiple missiles ... think of it like a nuclear SAM defense ... one shot will kill any F-15 withing say 1 km of detonation or whatever) against your fighters/missiles ... the mass driver may be a better option. If the enemy can't lob one missile into a swarm of fighters and watch large numbers die in one shot, then the missiles are likely better.

It is just another spin on the swarm vs big gun debate. The swarm wins if enough of them economically kill the target (think Sherman tanks ... cheap enough you can lose em and still beat back the Germans). The big gun wins if large numbers of swarm units can be killed with a single shot (infantry "swarms" against artillerly and HMG's) or if the platform can withstand a number of hits far in excess of whatever the swarm can throw at it (A M1 against rifle infantry).

//end pointless ramblings

[Darth Wong]

The big advantage of the mass driver is that there are no "area effect" counters.

Small consolation, since it also lacks an area effect itself, so if you don't hit your target, 100% of the energy of your weapon is wasted. In addition to all of the other weaknesses. Mass drivers are a silly idea.

Now on the flip side a mass driver cannot be as easly stopped. It doesn't have to do anything when it reaches its target (like say send a firing sequence through the electronics, set off a primary explosion to get the activation energy needed, contain a hideous pressure/temperature chamber, etc.). In short a mass driver is fire and forget. Further your mass driver cannot be defeated with cheap work costs.

Yes, it can. Move out of the way! How complicated is that? A nuke can miss you but still detonate from a proximity fuse and seriously damage or destroy your ship. But a mass-driver will fly harmlessly right by you. At anything other than short range, it's useless. At short range, the big-ass ship you need for your mass driver would have been blown to shit by swarms of nuclear missiles already.

Alternatively you could take shots at with your own high momentum projectiles, but if this is planetary bombardment ... you are shooting uphill out of the well, they are shooting downhill in.

If this is planetary bombardment, nukes are still better. You can take out all of the electronics on the entire planet with a few large-yield blasts in the upper atmosphere. Then, you start hammering the surface.

Now the big drawback (tactically speaking) to the mass driver is that you need to have huge space to accelerate the thing, and this means a huge amount of dedicated mass. This means you likely need a large ship which presents one big target to gun for. However this need not be the case ... you can make a gauss gun with multiple compenents that can be spaced on several ships that just need to get in line with the shot.

And your ships will be happy to carefully line themselves up while everyone is shooting at them?

[Enlightenment]

Line up several ships and kill in one shot.... Ahem.

Sounds like it might be time for someone to do a page on space combat brainbugs, starting with a resounding debunking of the Trek/Wars/B5 point blank range brainbug and a little primer on the vastness of space.