What's the difference?

[kilopi505]

In sci-fi fanfics, I have read about...3 or 4 (or many more, I think) energy weapons all in the same universe. Just asking, what are the differences between all these energy, or light using weapons? What's the difference between a turbolaser, a phaser, the neutron laser thingy of the Minbari, and many many others?

[Bakustra]

A turbolaser is a magical beam that shoots glowy bolts at stuff to explode them, and doesn't quite behave like anything in particular.

A phaser is a similar magical beam that acts like a laser and has the sorcerous power of disintegration.

A neutron laser is a contradiction in terms- lasers are made of light, but neutrons are not. Neutron beams are like any other particle beam- a stream of high-velocity particles. In the case of neutrons, you need magic to accelerate them to the necessary velocities. Lasers are made by bouncing light around in a chamber with only one narrow opening. Thus, the light comes out in virtually parallel paths and is coherent. High-energy lasers can cut, melt, or simply heat things. Though this seems like magic, it is not.

Ion cannons are also popular, but nobody knows quite what they do. Generally, it is assumed ions are involved, and a little magic. Sometimes, they shoot "plasma". Other times, they shoot mystery beams.

[Imperial528]

Ion cannons would short out electronics, but would otherwise act like a particle beam, which should act similar to a laser but with the difference of having more kinetic effects on the target.

[Batman]

Let's assume you have a phaser style magic desintegrator weapon that is really nifty for making matter disappear. Now let's assume it's also useless against shields due to their being no matter for it to play with. Makes having a second kind of energy weapon a pretty sensible idea, don't you think?
Turbolasers blow stuff up. Good if you want to destroy your target. Ion cannon make the target stop working. Good if you want to capture it.
B5-pulse weapons can be dealt with via interceptors, beam weapons can not. Presumably pulse weapons are kept because they have some advantage over beam weapons (smaller and thus more agile weapons mounts for example).
Then there's different weapon types to deal with different kinds of defenses (particle vs ray shields, gravity based defenses are going to work a lot better against particle beams than lasers), brute force vs technobabble, different working mechanisms meaning some weapons are better for one thing, others for another, different tech bases between the involved parties (races that haven't discovered phaser magic yet have to use more 'primitive' energy weapons), and let's not forget the possibility of cultural preferences and biases.

[Simon_Jester]

Ion cannons would short out electronics, but would otherwise act like a particle beam, which should act similar to a laser but with the difference of having more kinetic effects on the target.

There's really no reason to expect ion cannons to have any more effect on electronics than a proton or other particle beam; that's an artifact of Star Wars, not of realism. In no case is the primary damage effect of the weapon "electrical" in the "causes a nasty power outage" sense of the word. Not for weapons that are anything but stupidly ineffective.

Ions and other charged particle beams can easily be accelerated to near light-speed and are thus a fairly good candidate for space-based weapon systems if you can solve the associated engineering problems, which are broadly comparable in difficulty to those required for laser weapons, so far as I know. Their effect on a target is easily described as high-intensity radiation, many orders of magnitude higher than background: physical damage to the surface of the ship combined with irradiation of the interior due to the handful of 'leaker' ions or particles that penetrate the outer layers of hull protection.

This is a significant difference between particle beam weapons and lasers: lasers will damage only the surface of the target, while particle cannons have the potential to kill personnel or damage equipment in compartments not opened to space by brute-force melting or vaporization of the hull.

On the other hand, particle beams lose cohesion somewhat more rapidly over long distances; effective range will be shorter than that of a laser or a solid kinetic projectile at the same velocity.

[Purple]

Ion cannons would short out electronics, but would otherwise act like a particle beam, which should act similar to a laser but with the difference of having more kinetic effects on the target.

There's really no reason to expect ion cannons to have any more effect on electronics than a proton or other particle beam; that's an artifact of Star Wars, not of realism.

I second that. Why people assume that they work like that just because the almighty TV said so. I will newer know.

An ion beam is not even specific. What kind of ions? As far as I know, any sort of atom that has been charged electively is an ion. Right? So it could be firing anything from uranium to hydrogen. None of that really has the potential to short stuff out.

[Imperial528]

There's really no reason to expect ion cannons to have any more effect on electronics than a proton or other particle beam; that's an artifact of Star Wars, not of realism. In no case is the primary damage effect of the weapon "electrical" in the "causes a nasty power outage" sense of the word. Not for weapons that are anything but stupidly ineffective.

A proton would be as a technicality an ion, as it is also a hydrogen without an electron, thus it is a charged atom. So a proton beam could be called an ion cannon, or to be more precise an ion beam.

As for electronics, NASA worries a lot about ions when it comes to their spacecraft. It's why almost all satellites sent into orbits where they will be exposed to the solar wind or significant radiation use electronics invented over thirty years ago. Older processor designs use overall larger parts (, larger transistors (micro scale rather than nano), and the like, which means that there is little chance a few ions slipping past shielding and hitting the board will actually damage the components, or in some cases hitting shielding and knocking particles off of the shielding on the interior.

If you put a Pentium IV in space on a satellite, it'd stop functioning in days (or less). Sure, the batteries and all of the larger electronic components would still work, but with no command computer you're in deep shit. Good bye million-dollar satellite and hello brief meteor shower. So unless you have magic shielding around your ship's computers, a decent burst of ions will corrupt the programming or even just plain destroy it.

[Purple]

There are several problems with that line of reasoning.

Firstly, the source of the bombardment (the sun) is many orders of magnitude above what any reasonable ship can be expected to put out. (Unless you want each ship you make to put you one step higher on the Kardashev scale)

Secondly, the sun bombards these satellites day and night continuously. Any reasonable weapon could not match that.

Furthermore, any ships (even in star trek) will not have the size constraints of commercial satellites so they can put up a lot more protective insulation around any vital computers. Also any reasonable combat starship is going to have to be equipped with heavy duty protection already. Simply because it is expected to operate in outer space. And in outer space it can expect to be continuously bombarded by ions from stars.


So in conclusion. Any reasonable starship will already have to be protected against something that is both in duration and output per unit of time several orders of magnitude above what any weapon can produce. Hence, ion weapons will not work as advertised.

[Imperial528]

Purple, the flaw in your logic is that the Sun's bombardment is not as dense as a weapon's blast. In Star Wars, ion cannon blasts are always visible, which means that the ions must either be close enough together or be in such a high energy state that they glow. The iron nuclei that the sun spits out exhibit neither of these. The sun is not a focused source, a weapon is. Your analogy is like saying that because a birdshot cartridge puts out more shots than a single bullet, the birdshot cartridge is thus more powerful.

And, since ion weapons are otherwise particle beams, the disabling effect doesn't have to be the main focus, just a handy by product. Not to mention that in order to disable an engine, you don't have to disable the computer controlling it, you can just disable the sensor equipment which relay data back to the control computer, which could cause many things, from engine malfunction to shutdown, most likely shutdown.

[Purple]

Purple, the flaw in your logic is that the Sun's bombardment is not as dense as a weapon's blast. In Star Wars, ion cannon blasts are always visible, which means that the ions must either be close enough together or be in such a high energy state that they glow. The iron nuclei that the sun spits out exhibit neither of these. The sun is not a focused source, a weapon is.

But there is an immense difference between having years of 24h a day non stop bombardment to damage an unshielded satellite.
You are talking about having seconds or at most a minute to deliver much more damage to a fully functional starship that is going to be well armored against such an attack.

You are using an extremely low resistance target pitted against an extremely high output attack to prove that an extremely high resistance target could be harmed by a similar attack.

Also, can anyone find any data on how fiber optic cables handle these effects? I know they give significant resistance to EMP effects. So something like that might apply here as well.

And, since ion weapons are otherwise particle beams, the disabling effect doesn't have to be the main focus, just a handy by product. Not to mention that in order to disable an engine, you don't have to disable the computer controlling it, you can just disable the sensor equipment which relay data back to the control computer, which could cause many things, from engine malfunction to shutdown, most likely shutdown.

The only thing you could really do is disable any unshielded systems that are close to the surface. Like say sensor or communications antenna. But that can be reliably done by using conventional weapons as well. Just bombard them off.

[Imperial528]

But there is an immense difference between having years of 24h a day non stop bombardment to damage an unshielded satellite.
You are talking about having seconds or at most a minute to deliver much more damage to a fully functional starship that is going to be well armored against such an attack.

You are using an extremely low resistance target pitted against an extremely high output attack to prove that an extremely high resistance target could be harmed by a similar attack.

I'm not. I used the sun and satellites as an example of how fragile powerful electronics are when they are exposed to ions, or radiation in general. And even then, the sun relative to the satellite is a low output source, since the satellite has almost no surface area when compared to the area which the sun's radiation covers. And may I note that in the case of the satellite the length of time the bombardment has been going on does not matter. Any modern electronics would be destroyed in days, hours, or less, even with shielding, due to how fragile the components are, not how powerful the bombardment source is (fridge magnets come to mind), as compared to the equipment in use now, which is far older in design, and can withstand said bombardment, and usually fridge magnets.

You are also ignoring that any ion weapon would be designed with killing in mind. I am suggesting that one could use a dialed-down setting or a carefully placed shot to disable a ship without as much damage to the ship's structure as a conventional weapon would do for the same effect. Let's say I want to disable a ship by disabling control to its engines. Destroying the engines is a non-option since my ship doesn't have the equipment to move or tow the other one, and I'd like to take it relatively intact, meaning as little damage to the hull as possible. I have the ability to repair damaged systems but not replace destroyed ones. Let's say I have three weapon types available for the job, all of equal power. I have a kinetic weapon, a laser weapon, and an ion weapon. The kinetic weapon could do the job, but to do so it needs to go through armor, and has the possibility of damaging the systems beyond repair or minimal functionality. The laser weapon is a bit better, because it won't tumble inside the target systems, but it needs to go through the armor as well, and it could burn enough of the system that I can't salvage it. However, the ion weapon does not need to go through the armor, since an ion hitting the exterior of the armor will propel an ion from the interior of the armor into the ship, which means I could either kill the crew and disable the computer systems without actually doing much damage to the hull. If I want the crew alive, a glancing hit to the engines would disable the control systems and sensors that tell the engine control computer what's going on, and unless Leah Brahms designed this ship, the most likely occurance is that the computer will cut power to the engines since it doesn't know if the engine is overheating or if something else is happening. If the crew then try and fly the ship manually, the run the risk of destroying their engines and cutting off their escape anyway, and as a bonus I am now angry at them.

Also, can anyone find any data on how fiber optic cables handle these effects? I know they give significant resistance to EMP effects. So something like that might apply here as well.

Assuming the cable itself isn't rendered inoperable by the kinetic factors, it should be fine.

The only thing you could really do is disable any unshielded systems that are close to the surface. Like say sensor or communications antenna. But that can be reliably done by using conventional weapons as well. Just bombard them off.

Unless, of course, you want them intact.

[Purple]

You are making an assumption that the armor would behave the way you do. There is no reason to believe that. Not all materials are conductive, and not all materials will just spit out an ion because they were hit by one.

And proper insulation can stop any sort of ion bombardment.
The reason why modern satellites lack proper insulation is because they have a fixed limit on mass. And each kilogram costs a lot. On a starship, you could presumably have meters thick layers of insulation material embedded into the hull.

You are also assuming perfect knowledge of the internal disposition of major systems. But how would you possibly know what place to hit? You are also assuming a complete lack of redundant systems.


However, I think we should wait to see what others say as well. For all I know I might be wrong.

[Imperial528]

Even if the ions weapons do not behave the way I'd like on the enemy armor, they'd still act like a particle weapon does, since that's what they are.

Also, I would hope that the enemy is smart enough to put engine control equipment and sensor on their engines, rather than say, the mess hall. 'Cause if they're not I need to change my propaganda campaign...

But I digress, yes, let's hear others' opinions.

[kilopi505]

Wow. Thanks everybody! So...which energy weapon is the most likely we will be using in real life when we get spaceships? Or will we go to mass driven weapons and nukes only?

[Imperial528]

Lasers. Ion weapons and particle beams are nice, but too costly for anything in a hundred-five-hundred years I'd say, and that goes even more so for plasma weapons.

And I doubt we would use nukes, since they are still highly destructive in space as they are on the ground and there's a lot of collateral damage possible. Things like neutron bombs would work better, or EMPs.

Any kinetic weapons could very well be gunpowder based, since rail guns are bulky things, and coil guns are rather inefficient.

[Rabid]

Wow. Thanks everybody! So...which energy weapon is the most likely we will be using in real life when we get spaceships? Or will we go to mass driven weapons and nukes only?

In my opinion :

- Long range ( R >= 10 000 Km) : Laser. Note that it could theoretically have a range of more than an Astronomical Unit, but at this distance, the focus, or should I say the lack of focus of the ray will render the weapon ineffective : A laser ray is a very straight cone, not a perfect cylinder, and the concentration of energy at this distance is likely to be awful.
- Medium range (500 km < R < 10 000 Km) : High acceleration missile (Kinetic or nuclear, most probably kinetic if a direct hit is possible, else nuclear for proximity damage)
- Short range (100 Km < R < 500 Km) : Mass driver more than 2-3 Km/second fast, at least (should be able to shoot an incoming missile going at ludicrous speed and acceleration, and that is possibly maneuvering - picture a missile going about 50 G during 30-60 seconds, that is able to dodge what you shoot at it, do the maths, be afraid)
- Close combat ( R < 100 Km) : At this distance, it's boarding or ramming (the later is obviously a desperate and suicidal move, if I am to point the obvious). So, either plasma weapon (a cartidge with proximity fuse or meant to penetrate armor than go *boom* plasma hot), either mass driver (not a tremendous rate of fire, but a great punch), or the good old gas proppeled ammunition if you need to saturate an area with tungstene.


That's just my opinion, though.

[Rabid]

Laser are neat when you have time to sufficiently heat a particular zone(difficulty to aim ? Too bad...) of the hull of the ennemy ship to induce damage ; But if it is covered with thermal resistant material like the one on the belly of the space shuttle, and the ennemy as a disrespectful tendency to take evasive maneuver (like rotating to avoid the overheating of a particular zone, or something like that), it's going to be a sloooooow kill, if it has ever any chance to succed.

On the other hand, a missile can be shot down, yes (by, let's say, a laser), but it can dodge what is aimed at it to compensate for that, and it carry a very concentrated destructive energy time wise (the total energy carried goes *boom* on the target in typically less than a second).

I'd say that, counter-intuitively, the weapon of choice would become the missile, the laser being used for long range point-defense (if it is practical).

[Rabid]

But then...

If you have an X-Ray laser, or better, a Gamma Ray laser, you can try to kill/sterilize the organic life inside the hull... Let's just hope the ennemy ship is not equipped with some sort of AI "dead man switch" that try to ram you with the ship. That would be bad...

[Rabid]

I concede the point : if you can focus that kind of beam beyond the operationnal range of a missile, you have a good chance to succeed. But I note that your tactic rely on superior number as much as a sufficient engagement distance.

While the later, in interstellar space, is easily obtainable, the second, well... Let's just say that when you're trying to invade/raid your neighbour, at least you try to come in number, if you don"t want your surprise party to be spoiled by a crushing defeat.

If we suppose armament and number parity, in interstellar space, I suggest this plan for the attacker :

As soon as you can, begin to engage the defending force with laser. As soon as you can, shoot a salvo of one missile per attacking vessel, or per defending ship worth of the punishment. This will occupy the defender long enough for you to continue to rush, launching missile salvo after missile salvo for them to concentrate their laser on, while continuing to laser them, and either dodging the missile they are themselves shooting at you, or shooting them down with your close quarter defense.

The goal is to force them to stay on the defensive, while you stay on the offensive : If they stop shooting laser at the missile, they are destroyed by the missiles ; If they continue to shoot down missile, the portion of their armament they can dedicate to hurting your ships instead is lowered, giving you the edge.

In a way or another, I think that Spatial Warfare is very straightforward and go to the one with either the biggest dick, or the best way to dodge the punishment the ennemy try to deliver to it while succesfully delivering its own to the ennemy.

Wadda'ya think about it ?

[Rabid]

To summarize what I'm thinking about, I think in ship to ship battle, there's going to be three main way to gain the edge, be it on the defensive or the offensive : Defense is only offense where you aren't the first to shoot.

First way is to have superior number : Even an ennemy with better armament is only able to have so many gun. He will not be able to dodge or shoot any incoming menace if you overwhelm him with more missile and laser that he can reliably shoot down before they are too close that he can't doge them. If the ennemy as the magitech to do this, well, you are basically screwed. But then, we are talking about what we can realistically expect from human-on-human space warfare, not The-Attack-Of-The-Q or something like that.

Second way is to have the biggest dick, or preferably the way to spam the ennemy with so many threat that he can't dodge/shoot them all. If we are realistic, it's the kind of batlle where one missile hit mean at least mission kill, if not just ludicrous gibs, just replacing raw meat with a spaceship. So Laser to harass, missile to finish. I'd preferably target the ennemy weapon system with the laser, while just targeting the ship as a whole with the missiles, preferably the motors or the things that give it the ability to maneuver.

Third is to know how to dodge/destroy incoming threat before they pass from the status of "potential menace" to "oh crap", while being effctively able to shoot back at your attacker while doing it.


It's the non suicidal way. A desperate move, as always, is to just ram the other ship if it's a One-on-One, dodging/destroying incoming missile, while using your front hull to protect your motors from the ennemy laser (keeping your ability to maneuver), going all kamikaze-like on the ennemy, while shooting yer armament at them and screaming like a cowboy of eructing "Banzaï !" if you feel like like.

Obviously, if the ennemy ship is destroyed before you impact it, you could try to dodge its remain...

[Rabid]

And just to add a bit about the preposterous amount of damage a laser can do if we take "the hull is made of carbon nanotube" approache against a wanked up laser (after that I swear I'll try to limit the spam...) :

Pulse Parameters

Input
Material: Nanotubes/Fullerite
Pulse Energy: 20 kJ //atteinable by today's standard, energy provided by fission or fusion main reactor of the vessel
Spot Diameter: 1 cm //concentrated, so, for maximum effectiveness
Number of Pulses: 1000
Time Between Pulses: 1 ms //a pulse each miliseconds per "shot"

---

Effects of a Single Pulse
Crater Depth: 9.14 mm
Crater Diameter: 1.91 cm
Time to Excavate Crater: 0.383 μs
Diameter of Possible Permanent Damage: 1.91 cm
Depth of Possible Permanent Damage: 9.14 mm

---

Burst Effects
Burst Energy: 20 MJ
Burst Duration: 0.999 s
Drill Rate: 9 m/s //Ooch !!!
Hole Depth: 9.14 m
Hole Diameter: 1.91 cm
Diameter of Possible Permanent Damage: 1.91 cm
Depth of Possible Permanent Damage: 9.14 m

And that is not counting with the power of the explosion induced by the great quantity of super-heated plasma that has been realesed with each burst. "Great big hole in the middle of the ship", anyone ?


After that, I think I'll just recommend to use asteroïds as hull, and to stick motors and weapon on it on an individual and modular basis, as they come and to the best use we can put them. They'll probably be more durable in combat situation like that, if just a bit "slower" and less maneuverable. And at least, a big chunk of space rock is, as we suspect it, a little bit more difficult to crack with a surface burst of nuclear explosive than a typical spaceship.

As so, the prefered weapon against these hulks will become spam of high penetration high velocity kinetic energy projectiles against surface weapon system and propulsive units ; and "bombardement" by agile little fighter-bomber with thermonuclear penetrating missiles made to eat big chunk of the asteroid crust with each succesful hit (and to propagate powerful seismic damage to the whole structure of the ship).

[Simon_Jester]

There's really no reason to expect ion cannons to have any more effect on electronics than a proton or other particle beam; that's an artifact of Star Wars, not of realism. In no case is the primary damage effect of the weapon "electrical" in the "causes a nasty power outage" sense of the word. Not for weapons that are anything but stupidly ineffective.

A proton would be as a technicality an ion, as it is also a hydrogen without an electron, thus it is a charged atom. So a proton beam could be called an ion cannon, or to be more precise an ion beam.

...Just for the record, I'm a graduate student working on a Ph.D. in particle accelerator physics. That said...

As for electronics, NASA worries a lot about ions when it comes to their spacecraft. It's why almost all satellites sent into orbits where they will be exposed to the solar wind or significant radiation use electronics invented over thirty years ago...

If you put a Pentium IV in space on a satellite, it'd stop functioning in days (or less). Sure, the batteries and all of the larger electronic components would still work, but with no command computer you're in deep shit. Good bye million-dollar satellite and hello brief meteor shower. So unless you have magic shielding around your ship's computers, a decent burst of ions will corrupt the programming or even just plain destroy it.

That doesn't work well when the ships get larger. The reason satellites are vulnerable to cosmic rays and solar radiation is that they are small: there isn't enough physical mass to intercept stuff reliably. You need large thicknesses of material to absorb incoming radiation reliably; if your ship is a hundred meters across one side of it will not be affected by energetic charged particles hitting the other side unless the enemy accelerates them to truly unreasonable energies.

But charged particle beams don't have magic "fry electronic" powers. They just irradiate the hell out of things, when fired at relativistic energies. That's all there is. In that respect they are little different from an X-ray laser or a nuclear weapon.

There are several problems with that line of reasoning.

Firstly, the source of the bombardment (the sun) is many orders of magnitude above what any reasonable ship can be expected to put out. (Unless you want each ship you make to put you one step higher on the Kardashev scale)

Ah... could you show me your math, please? I'd like to see intensity for solar radiation bombarding a fixed object in space, and integrated intensity over a reasonable period of time for a fixed target in space. Compare to a 'reasonable' space-based beam weapon, operating at the kind of energies we'd take for granted in, say, a mass driver.

Furthermore, any ships (even in star trek) will not have the size constraints of commercial satellites so they can put up a lot more protective insulation around any vital computers. Also any reasonable combat starship is going to have to be equipped with heavy duty protection already. Simply because it is expected to operate in outer space. And in outer space it can expect to be continuously bombarded by ions from stars.

Now this is a leigitmate point... as far as it goes.

So in conclusion. Any reasonable starship will already have to be protected against something that is both in duration and output per unit of time several orders of magnitude above what any weapon can produce. Hence, ion weapons will not work as advertised.

Nonsense. Check the actual intensity of radiation from the Sun in space, and compare to a directed-energy weapon.

You are also ignoring that any ion weapon would be designed with killing in mind. I am suggesting that one could use a dialed-down setting or a carefully placed shot to disable a ship without as much damage to the ship's structure as a conventional weapon would do for the same effect.

Not gonna work. Solar radiation 'disables' a ship by physically irradiating the hull until the bits stop working. The reason it stops working is that it is now radioactive. This is bad for humans too, not just computers. It's also useless against targets much larger than a typical unmanned satellite.

Also, note that the behavior of kinetic energy weapons at spacecraft speeds won't look like you think. At those speeds, the collision between a projectile and the target starts looking less like a bullet punching into armor and more like a shaped-charge jet punching into armor.

Against a well protected target (one armored with protection worthy of the name), ion beams will need to do a fair amount of cutting to get into the interior, because the armor will be deep enough that particles punching into the surface will stop inside the armor, absorbing secondary radiation without frying the crew.

Unless, of course, you want them intact.

Space warfare is energetic enough, and boarding a spacecraft impractical enough, that it is REALLY difficult to contrive situations where you can capture enemy ships intact in a hard-SF context.

Wow. Thanks everybody! So...which energy weapon is the most likely we will be using in real life when we get spaceships? Or will we go to mass driven weapons and nukes only?

In my opinion :
- Long range ( R >= 10 000 Km) : Laser. Note that it could theoretically have a range of more than an Astronomical Unit, but at this distance, the focus, or should I say the lack of focus of the ray will render the weapon ineffective : A laser ray is a very straight cone, not a perfect cylinder, and the concentration of energy at this distance is likely to be awful.
- Medium range (500 km < R < 10 000 Km) : High acceleration missile (Kinetic or nuclear, most probably kinetic if a direct hit is possible, else nuclear for proximity damage)
- Short range (100 Km < R < 500 Km) : Mass driver more than 2-3 Km/second fast, at least (should be able to shoot an incoming missile going at ludicrous speed and acceleration, and that is possibly maneuvering - picture a missile going about 50 G during 30-60 seconds, that is able to dodge what you shoot at it, do the maths, be afraid)
- Close combat ( R < 100 Km) : At this distance, it's boarding or ramming (the later is obviously a desperate and suicidal move, if I am to point the obvious). So, either plasma weapon (a cartidge with proximity fuse or meant to penetrate armor than go *boom* plasma hot), either mass driver (not a tremendous rate of fire, but a great punch), or the good old gas proppeled ammunition if you need to saturate an area with tungstene.

I would argue that this should be somewhat reversed: guided missiles dominate at long range simply because the target can dodge even a laser by random sidestepping. The effective range of an unguided weapon, including a beam of light, is given by its speed times the amount of time it takes for an enemy ship to sidestep several times its own length.

At moderately-hardish SF accelerations, even for lasers that isn't more than a few light-seconds, and even small target movements can make the laser ineffective at burning holes into an armored target.

Whereas guided missiles have a very large maximum range, especially if their drive can be shut on and off during times when the target isn't making evasive maneuvers.

Lasers and particle beams dominate at medium range where they are nigh-impossible to dodge; mass drivers at shorter ranges. Mass drivers have the advantage that you can use a time delay fuze to create a cloud of shrapnel out of your mass driver round, which has excellent applications for point defense by increasing the footprint a single round destroys.

So, on average, our laser is knocking out a groove of 5cm x 4cm every second. If we have more ships in the fleet, multiply it. It will take your missile at least 100 seconds to cross that distance. That means I can drill through meters of your ship before you can hope to even touch me. It could probably knock out your propellant tanks and mission kill you inside the first minute, then spend the rest of my time focusing those hundreds of laser shots on your inbound missiles, using the speed of light to make their evasive maneuvers generally futile. (My laser might not readjust quickly enough to stay with you though. I figure the best thing to do is a bit counterintuitive - laser the missiles furthest from you, leaving the ones close to you for the rest of the fleet to shoot down.)

As you note, this strategy relies on being able to put your laser on a given two-inch spot of a target thousands of kilometers away. Not exactly an easy task.

To summarize what I'm thinking about, I think in ship to ship battle, there's going to be three main way to gain the edge, be it on the defensive or the offensive : Defense is only offense where you aren't the first to shoot.

First way is to have superior number :...
Second way is to have the biggest dick, or preferably the way to spam the ennemy with so many threat that he can't dodge/shoot them all. ...
Third is to know how to dodge/destroy incoming threat before they pass from the status of "potential menace" to "oh crap", while being effctively able to shoot back at your attacker while doing it.

How is this different from normal warfare? All fights boil down to trying to apply superior numbers, superior weapons, or superior ability to resist an enemy's weapons.

Well, there are exceptions, but they're mostly specialized gambits (such as taking down an enemy commander).

And just to add a bit about the preposterous amount of damage a laser can do if we take "the hull is made of carbon nanotube" approache against a wanked up laser (after that I swear I'll try to limit the spam...) :

Pulse Parameters

Input
Material: Nanotubes/Fullerite
Pulse Energy: 20 kJ //atteinable by today's standard, energy provided by fission or fusion main reactor of the vessel
Spot Diameter: 1 cm //concentrated, so, for maximum effectiveness
Number of Pulses: 1000
Time Between Pulses: 1 ms //a pulse each miliseconds per "shot"

---

Effects of a Single Pulse
Crater Depth: 9.14 mm
Crater Diameter: 1.91 cm
Time to Excavate Crater: 0.383 μs
Diameter of Possible Permanent Damage: 1.91 cm
Depth of Possible Permanent Damage: 9.14 mm

---

Burst Effects
Burst Energy: 20 MJ
Burst Duration: 0.999 s
Drill Rate: 9 m/s //Ooch !!!
Hole Depth: 9.14 m
Hole Diameter: 1.91 cm
Diameter of Possible Permanent Damage: 1.91 cm
Depth of Possible Permanent Damage: 9.14 m

And that is not counting with the power of the explosion induced by the great quantity of super-heated plasma that has been realesed with each burst. "Great big hole in the middle of the ship", anyone ?

The problem with this one is hitting the same little dot every time. Remember that the target is a blip on a radar screen, not something big and nearby. If they're rotating, or making random side-to-side movements, your neat tunnel drilled at 9 m/s through their armor rapidly becomes a Gaussian-shaped crater that's drilled at speeds measuring in millimeters per second.

[Simon_Jester]

Forcing them to dodge might just win the day too - the constant pressure means they will burn through their propellant slowly but surely.

For this to matter, of course, you need a laser with an incredibly long range, which is easier said than done, but not impossible. Over the course of weeks or months, that constant random .01 m/s^2 (arbitrary number) will add up - two weeks of it match up to a Hohmann transfer to and from just about any planet in the solar system in delta-v!

Yes, but if you don't have the engine fuel economy to make that easily possible, you wouldn't be fighting Space Wars anyway. Because the logistics burden of actually putting anything militarily useful in a ship that won't be shot to pieces before reaching the target is too high. With near-future chemical rocketry, ion drives, and the like you just won't see space battles fought, not over interplanetary distances. Unless it was something weird like 'guide an asteroid to hit the target and layer it with robot gun turrets to resist deflection missions,' but that wouldn't be recognizable as a battle.

(Side note: random evasion like this doesn't actually send you very far off course, as you probably know. The random burns will tend to cancel each other out, on average, so on a long trip, you're only a wee bit off of the trajectory on which you started.)

Also, they don't have to be strictly random. Just random 'enough' that you can't readily outguess them.

As you note, this strategy relies on being able to put your laser on a given two-inch spot of a target thousands of kilometers away. Not exactly an easy task.

Aye, and certainly worse when the target isn't cooperating! On the other hand, making your rockets faster and faster while maintaining their guidance isn't trivial either.

100g has already been managed, but only for a few seconds (solid fuel rocketry). Might be hard to beat that without futuretech, simply because you're getting too close to the limits of chemical propellant, I guess.

As I said, I think guided weapons dominate at extreme ranges because they're the only things with a hit probability that doesn't drop with the square of the range-to-target. Unguided weapons' hit probability always will, simply because there's more room to miss in and more room for the target to dodge in.

At shorter ranges, lasers dominate if you can make them highly destructive effectively; mass drivers if not. Hypervelocity missiles (100g for several seconds, say) might do mass drivers' duty too. Mass drivers may be pure-kinetic, time delay fuzed, or (in principle) loaded with something like a shaped nuclear charge to give them a standoff attack.

[SeaTrooper]

Ion cannons would short out electronics, but would otherwise act like a particle beam, which should act similar to a laser but with the difference of having more kinetic effects on the target.

There's really no reason to expect ion cannons to have any more effect on electronics than a proton or other particle beam; that's an artifact of Star Wars, not of realism.

I second that. Why people assume that they work like that just because the almighty TV said so. I will newer know.

An ion beam is not even specific. What kind of ions? As far as I know, any sort of atom that has been charged electively is an ion. Right? So it could be firing anything from uranium to hydrogen. None of that really has the potential to short stuff out.

Aluminium ions? There has been some very interesting work done recently on cargo-shells that deliver long strands of wire or foil. This is meant to burst over someone's power lines, the strands settling over the cables themselves, and then short them out. Hardly the same affect as we see in SW, of course, and reportedly ONLY effective when used on open-air, civil power-lines.

Getting even further off-track, DW Cybermen (the old ones) were supposedly vulnerable to gold. In-universe, this soft metal (in bullet form or even as dust) was supposed to somehow penetrate their outer casings and gum up (short out?) their systems. Glitterguns, anyone?

[Rabid]

To sum up what I understand of the thread :

First of all, we aren't going to see space battle soon, if not for the fact that we aren't in space yet, but because it is in the current perspective not cost-effective to try to arm vessel, not as long as ships don't try to harm each others (and then, you could just try to go on a rendez-vous trajectory and try to board the ennemy ship, the matter then being adressed with... SPACE MARINES !!!).

Then if it become cost effective to put armament on ship, due to the great distance involved and difficulties to aim correctly on a tiny spot more than 10 000 Km away, the primary weapon on long distance engagement will become missile, or more some sort of missile bus for efficiency (in this style).

After that, all the warfare will revolve around putting down incoming menace before they reach you while shooting the one who is shooting you...

What I see, in this case, is that :

You take an asteroid in the multi kilometers range. Preferably a rocky one (not a metallic one because it is too rigid, and it breaks too good when you blow nuclear explosives in it). You carve it in a way that the hull of your ship is basically the crust of the asteroid. Do so that you have a 100 meter hull of rock. That will protect you from laser. Put point defense on the exterior of the ship to take down incoming missiles (laser or mass driver with fragmenting warhead). And finally, because this kind of hulk has the same acceleration of a dead turtle, and the manibaility of the rock it basically is, use it as a carrier for some sort of fast and maneuverable fighter/bomber that will attack the ennemy hulk by launching crust-cracking warhead at them (some sort of thermonuclear space-bunker buster missile thingy).

So, basically, you take carrier warfare, you turn it up to eleven, and you put it into space.

This, obviously, is for interplateray combat. For orbital defense, it is far more simpler :

Put on orbit automated weapon platform with long distance laser, anti-ship missiles, anti-missile missiles, anti-missile mass drivers, and kamikaze drones (glorified missiles with some wepon system on it).


Am I right or do I miss something ?