The Practicality of various futuristic weapons.

[Anna]

I actually did mention it. And the edit was because I realised I wasn't being clear.

Might simply be easier to have drones catch meteors and hurl them into things. You don't need to be going super fast of you're already super huge.

Forgive me for missing this one throw-away line among your many paragraphs of giant railgun wank.

See, I dig giant railguns. I dig giant lasers. But if you want to get down to the nitty-gritty of what would be realistic weaponry, it'd be anything that can fire fast and travel fast for ship-to-ship weaponry, and shit like giant fucking rocks for wrecking planets.

And frankly that makes for only mildly entertaining sci-fi.

[Noctis]

things

Admittedly I wasn't clear, sorry about that. I really should have emphasized that I meant for the Kinetic stuff to be used on planets. Probably should have also said more about the meteor thing, since its much easier.

The reality of it that it will probably be either a shot gun of marbles that completely blankets a large area or a powerful laser and good targeting programs. I dunno, but to me it seems like humanity will never really (at least in any time soon) get laser weapons to really work. Maybe I'm just cynical but the idea of hurling a rock (admittedly not as fast as I talked about) seems alot more feasible then laser weapons.

In fact, the most realistic thing I can imagine would be something like just a big machinegun that peppered a large area and hoped that it would work.

[Talhydras]

Yes, building a massive laser and shining it at a planet for a few days is much better than strapping thrusters to a rock, with some caveats.

Kinetic projectiles ARE a much cheaper weapon system, because you trade initial investment (thrusters and freighters for hauling the thrusters and combat engineering ships for mounting the thrusters on rocks while under the threat of fire from the defenders vs. a doom laser) for time. The biggest attraction to using a massive kinetic impactor is that you can accelerate it for weeks, months, or even years if you've achieved local space superiority. This constant investment of thruster power turns into a deadly planetbusting weapon relatively quickly; but it can only be used exactly once.

As long as you have a working power supply and a big fat radiator, you can bake planets to your heart's content with a doom laser. It's also possibly a lot quicker depending on the relative positioning of the system's asteroid belt and the target; distance you'll have to cross with your massive impactor + thrusters. If this is a few hundred million kilometers like in our solar system and you're NOT pulling 10s or 100s of gs of acceleration (which you won't be because it's a massive rock you're pushing) it will take time. If all you need to do is put a hole 100 km deep in their capitol building, a doom laser can do it from faaaaar away.

Now, time to settle this 1 ton shell at the speed of light nonsense for good. Particles moving a significant fraction of the speed of light have enormous kinetic energy but unless you're shooting at a planet with a few thousand km of rock to absorb this energy you don't WANT dense penetrator. You want something light that will convert it and the surface of the target it hits into a shower of very energetic particles (kaboom). A neutronium pellet or even a depleted uranium slug at the speed of light will convert its impact surface into a shell of energy and then punch right through anything smaller than Ceres, wasting all that energy you put into accelerating it.

A conductive crate loaded with styrofoam packing peanuts moving at C-fractional speeds is much better; relativistic KE is given by sqrt(p^2 * c^2 + m^2 * c^4); p being momentum, m being rest mass, and c being c. p = m*v / sqrt(1-(v/c)^2). Let us assume the mass of a packing peanut is one gram, and v = 0.75 c (a truly irresponsible velocity). p then = 339,932.695 m*kg / s. Plugging that into our KE formula, we get... 1.359E14 joules per packing peanut.

4.184E9 joules is a ton of TNT, so each packing peanut in our hell-volley is hitting at 14 kilotons of TNT, which is a lot. Enough to give a good nudge to your target, and scoop a nice big crater out of his hull; but another important note is that the energy release of an impact like this is not directional like a laser; it's omnidirectional and thus a lot is lost to space (as the bullet doesn't strike inside the target, but on the surface).

EDIT: I've been informed by colleagues that the note about directionality of damage in the preceeding paragraph is pants-on-head wrong. Both lasers and kinetic impacts don't fully transfer their energy into the target; some laser energy is reemited, and the laser impact will produce explosive effects as well that are not all focused on the target. END EDIT.

Imagine a ton of styrofoam peanuts. Using 1 gram as our earlier mass, that's a million of these little tiny projectiles in an expanding cloud. Certainly massively deadly if you can achieve it, and much more likely to hit a manuevering target at range. However... you're not going the speed of light. Any linear accelerator capable of pumping a target up to that speed is going to be big (several hundred to several thousand km of track length needed, if not much more) and dump a lot of heat; firing is going to be obvious. And since that firing radiation is going lightspeed, it can be dodged.

You can't dodge a laser blast, and a laser turret's a lot smaller. Plus, lasers work faster than massive asteroids, and at much longer ranges.

Now to address your silly ideas about course correcting projectiles. In space there is no atmosphere to use as a working medium to change course, so you can only change course with an engine. This engine takes mass and reaction mass, which is substantial. Let's call it a missile now, because that's what a guided projectile is. Assuming I am firing at a target near pluto, he's going to see the muzzle flash and have well over an hour to let that decision influence his maneuvering strategy. However, the laser I also fired arrives at the same time as he sees me firing.

Constant maneuvering is good in space and at ranges over a few light seconds will make you extremely difficult to hit unless you're flying New York (the state). However, it uses fuel, generates waste heat (which require radiators to dump and thus massively enlarges your thermal signal), and is probably really uncomfortable for the crew. Unless the ship is expecting engagement at any time and thus has enough thruster power to dodge for the VERY LONG TIME it would take to go from pluto to Earth using reasonable acceleration power (about ten gees), they're not going to be maneuvering.

Now the real reason why lightspeed weaponry is so badass becomes evident; unless you are willing to dodge all the time a sufficiently large array can zap you. FTL change the game up a lot and gives linear accelerators and missiles a new lease on life for ship to ship combat (they're both superior to lasers for instant property destruction at knife range) but as long as light is the information speed limit lightspeed weaponry is the ultimate.

Because if I can cut your ship in half with a single pulse from anywhere in the solar system you have to either stay away or constantly dodge. I just need to keep feeding fusionables or antimatter into my reactor and stay away from the heatsink.

EDIT:Oops, noctis said something ludicrous while I was away. The technology to build massive linear accelerators would enable massive free electron lasers, as both are about array of magnets accelerating stuff. The FELs use the radiation emitted by accelerated electrons. Thus, super mass drivers enable doom lasers.

[Noctis]

more words

Just out of curiousity, which do you think has a greater chance of being invented/ used first? Both large Kinetic weapons and large lasers seem rather unlikely anytime in the near future, but I may be wrong.

[Talhydras]

Rocks have been running into things since the dawn of time, and lasers have been around for a minute. Free electron lasers in the x-ray frequencies are being built in Europe and many other places. Though the European xray FEL is firing waaay higher energy photons than the 88 kEV I was thinking of. It's a lot harder to focus short wavelength photons, according to awesome laser guru Luke Campbell the short wavelengths interact with individual atoms so you need to use diffraction to focus the beam. Going too much higher energy (and shorter wavelength) and it becomes truly annoying to get focus.

In short: they're both already invented, doofus.

[Noctis]

In short: they're both already invented, doofus.

I know that both lasers and kinetic weapons are in existence, but I highly doubt that one like the 8 TW monster you described exists or will exist in any near future, considering we can only generate about...I think 22 TW a year.

I'm just asking which you believe will be scaled up to truly devastating effect first. I assume lasers.

I can admit that it sure seems more and more like lasers would be the better choice. Perhaps Heinlein was wrong.

[Talhydras]

The 8 TW doom laser would probably require mature fusion reactors to power and probably special crystals to do the diffraction focusing; those will require a lot of investment in nanoscale engineering. Power in space is not a big problem; piles of solar collectors closer to the sun than mercury could really kick ass, and I mean... fusion is awesome too.

The US Navy is hoping to use a railgun to boost missiles a long way and make a new generation of missile battleship I think, so if your definition of devastating includes that then linear accelerators win the race.

However as a weapons system that would be capable of defending the entire solar system from a fixed location, it's anyone's guess. Such a rad laser would take a massive investment as well as a pressing threat to get any kind of commitment, not to mention serious space infrastructure. It could be 200 years, it could be 2000. It could be never.

Giant coilgun cannon in space capable of boosting projectiles up to near-C velocities would require a truly ridiculously long barrel; I wasnt kidding when I said hundreds to thousands of km of track. This would require a lot of engineering too. Ultimately I'd put money on the laser, but that's because lasers are splendiferous and awesome.

[Noctis]

The 8 TW doom laser would probably require mature fusion reactors to power and probably special crystals to do the diffraction focusing; those will require a lot of investment in nanoscale engineering. Power in space is not a big problem; piles of solar collectors closer to the sun than mercury could really kick ass, and I mean... fusion is awesome too.

The US Navy is hoping to use a railgun to boost missiles a long way and make a new generation of missile battleship I think, so if your definition of devastating includes that then linear accelerators win the race.

However as a weapons system that would be capable of defending the entire solar system from a fixed location, it's anyone's guess. Such a rad laser would take a massive investment as well as a pressing threat to get any kind of commitment, not to mention serious space infrastructure. It could be 200 years, it could be 2000. It could be never.

Giant coilgun cannon in space capable of boosting projectiles up to near-C velocities would require a truly ridiculously long barrel; I wasnt kidding when I said hundreds to thousands of km of track. This would require a lot of engineering too. Ultimately I'd put money on the laser, but that's because lasers are splendiferous and awesome.

Indeed, lasers are pretty dang awesome. Because of where I got my information I was partial to RKV but then again, my knowledge of both systems is mostly from science fiction with some personal reading of actual research; ie it's pretty limited. The only really "professional" opinion I've ever gotten was from a professor that particularly loved the "rods from god" idea.

I would assume that what would probably happen is that Kinetic weapons would be developed until they reached the inherent limitations of those systems ( barrel being too long, power usage too great etc) and then the true laser development would start. I've always assumed that true laser weaponry, ie death stars but not so much planet exploding, were either pure fiction or something for the far far far future. I guess my knowledge wasn't wide enough. Thanks for the info.

[firevikin125]

I don't know what is more amazing.
That Talhydras is totally kicking Noctis's
ass with pure logical arguments,and that
Noctis is still arguing about it, or the fact that
the more stupid or useless a post is, the more people
comment on it.
you're fighting a loseing battle here
Noctis, aspect it.

Anyway, the fact is, is that depending on
the type of environment or situation it is, the enemy's
weapons and about 50 different factors, sometimes
its is best to use energy, sometimes projectiles.
Sorry, but this post has no real purpose other
than to piss the hell out of Anna.

[th15]

This is a pretty useful site:
http://www.projectrho.com/rocket/rocket3x.html

For example, this cute little tidbit:

A beam of neutrons does not suffer from electrostatic bloom since they have no charge, nor could they be deflected by charged fields. However, this also means it is difficult to accelerate the neutrons in the first place (and if you discovered a new way to do it, chances are it too could be used as a defense). Without electrostatic bloom neutron beams are only limited by "thermal bloom". Brett Evill says this will give a neutron beam an effective range of 10,000 km, but he doesn't mention the details of this estimate. Nelson Navarro is of the opinion that a science fictional heavy neutron beam could be produced by a science fictionally efficient method of breaking up deuterium nuclei.

Another problem is one shared by ion drives, the "space charge." If you keep shooting off electron beams you will build up a strong positive charge on your ship. At some point the charge will become strong enough to bend the beam. And the moment your ship tries to dock with another it will be similar to scuffing your shoes on the rug and touching the doorknob. Except instead of a tiny spark it will be a huge arc that will blow all your circuit breakers and spot-weld the ships together.

To me, the main problem with beam weapons is getting the beam focused on the same spot for reasonable amounts of time.

Personally I think bomb pumped beams are a lot more feasible. Putting the source of the laser close to the target solves targeting issues and the bomb provides the energy required. Hence the Teller Module in BSF.

[Talhydras]

Bomb-pumped beams do have some attractive elements, but they manage to combine the weaknesses of missiles and lasers. The missile is slower than light and thus detectable and engagable with active defenses and you carry a much smaller primary lens and dramatically reduce range. You also only use a fraction of the bomb's energy to produce the beam; the concept was originally proposed as an ultracomplex SDI tool. The russkies would launch fifty million nukes, we'd launch a few of our own with autoaiming lasing rods that would provide a fatal zap to all the incoming missiles. Atomic rocket goes into way better detail; for purposes of killing someone's fleet in deep space if your missile's traveled more than a thousand kilometers to get within bomb pumped laser range, you might as well send it another sixty or seventy more and get that juicy hull impact.

Noctis: You assume foolishly. There is no reason to believe that the first weapon in space will be a missile or a gun or a laser; it might be a giant rock placed in front of somebody else's ship (a mine). If the objective is to keep someone else from boosting up into orbit, you don't need to fire anything at them at all; their own engines will turn it into a deadly collision.

To be relevant; weapons technology tends to be a family of solutions to potential problems. Traditional powered missiles would be acceptable for attacking nasty satellites in space, but against a target thousands of kilometers away a large lens laser might be preferable to a small projectile gun or nuclear-powered missile. Lightspeed travel time for laser light again is a solid advantage at orbital ranges because if you can point the weapon at the target you will guaranteed hit it; travel time of 1/300th of a second over a range of 1000 km is really nice accuracy. Even better if you're putting 5 mm wide holes in specific components of the target.

[Sponge]

I didn't have time to read the whole thread, so I just read the first post. I love this kind of stuff, though, so I'll come back for the rest later.

I just wanted to say, and it might have already been stated, the following:

Neutral particle beams are kind of silly. Neutral particles are neutral, as in, they don't have a charge. Traditional accelerators take electrons and put them in a "tube" of super-powerful electromagnets. They alternate the charge of these magnets incredibly fast. One fraction of a second, the magnets are "pulling" the electrons forward, the next they're being "pushed," and so on, and so forth. Do this enough and you get a really fast stream. It all works because electrons are negative, and are therefore attracted to a positive charge and repelled by negative ones. Neutral particles don't have a charge. In order to accelerate them, at least with conventional methods, you need to give them a charge. This requires an inordinately large amount of power. And then they're all the same charge, and so they push each other apart, which is where your electrostatic bloom comes in. What seems more viable is to accelerate a stream of protons AND a stream of electrons (more electrons, obviously, as they're around 2000 times less massive). Both particles are easy to accelerate, and the combination of the two means you have electrons pulling on protons and protons pulling on electrons, which would largely negate your bloom effect that makes particle beams so impractical in the first place.

Lasers would probably be a better bet, in any case. The issue with lasers, though, is that when you hit a surface with a laser, you're pumping lots of energy into it. However, you're pumping lots of energy into it for a very short amount of time. If your target moves, your beam is now hitting something totally different. You'll make a "streak" across the enemy ship. You can negate this using sophisticated turrets that will compensate for enemy movement, but that's got to be one awesome turret, powered by one awesome computer to make such precision adjustments that are likely, at best, using several-second-old data. You'd need a whole array of lasers to ensure that you even got one good shot. That's a lot of power, and a lot of radiators (also true for the particle beams). Radiators suck because they're big, bulky, and terribly, terribly inefficient. Furthermore, one hit is going to fuck them up pretty bad. You need ultra-high surface area, and a chunk of metal is going to shit all over that parade. Space is cold, but there's very little in it. You're relying on radiation, not conduction, which is what we rely on down here on Earth. Your radiators will literally act like a heat "battery" that runs in reverse. Each shot you fire will start filling them up, and once they're a certain temperature, you're done firing unless you want to fry your guns. Instantaneous cooling isn't going to happen. You'll hit a point, and then you're done. Coolants, on the other hand, are pretty effective. They use conduction, and then just spew all that heat into space. The issue, then, is finding some place to store loads and loads and loads of coolant. A coolant-radiator combo may be effective, where you use radiators to absorb all your heat and then pump them with coolant if necessary. Unfortunately, this makes radiators even punier. Hit them and not only do you lose surface area, but your coolant lines get all screwed up, and now you just pump your coolant straight into space.

Rockets seem so much better. Yes, they have slow acceleration (what's with this "delta v" shit? It's acceleration. lrn2physics), but they also have high destructive potential, require fairly minimal launching facilities, and generate virtually no heat. Further, they have the advantage of on-board computer systems, which they can use to act like a "hive mind," tracking their enemy, adjusting course individually and in real time to ensure highest hit chances. Chemical fuels are pretty effective propellants. They wouldn't fly for long distances, but they'd work very well for mid-range engagements (at, around, or less than 1 Ls). The idea would be to launch a large amount of small rocket-guided ordinances, each with a sophisticated computer system. They co-ordinate amongst themselves, such that some overcompensate in this direction, others that. Some undercompensate here and there. Some aim dead-on and try to mimic the enemy's movements. They've got a lot less mass, and so are a LOT more maneuverable than a hulking ship. The destructive potential in one small rocket is immense. They could be anything from bomb-pumped lasers (an effort to bypass point defense) to antimater warheads. They could be both. You could include a few small "counter point defense" ordinances, that the device could use when necessary. You could even send some sort of anti point defense craft along with the swarm to provide cover.

I would think space warfare would be a battle of mid-range missiles and huge amounts of point defense. Lasers and other directed energy weapons use lots of power, and make lots of heat, which is difficult to get rid of.

[Talhydras]

As soon as your "rockets" have multiple entry vehicles, complicated onboard computers capable of making tactical decisions without user input, counter countermeasures, fuel to accelerate for hours, armor to protect against whatever, light weapons, escorts, communications systems, and a warhead, you're no longer talking about a cheap spammable weapon. You're talking about an entire fleet that can only be used in one engagement before being depleted, because all your warships have bombs strapped to them.

Low acceleration means increased interception time, and a manhole cover in a several km/sec collision with an expensive distributed network AI bomb pumped laser kill vehicle is an effective countermeasure. Sure that's what you bring anti point defense guns and escorts for, but those are more expensive than lots more chunks of metal or cat litter that stay between the target and the missile. Takes a lot less energy on the defender's part to keep his physical shield between the incoming supermissiles and him.

Waste heat and massive radiators become less of a problem when the other guy is already dead and his low acceleration missiles are still three months or whatever away, assuming a modest doom laser and tracking system. Additionally, the defender can't hope to outmaneuver the incoming missiles and doesn't need to generate heat dodging like crazy. Mr. Missile spam needs to be dodging like crazy if he's inside missile range, because small aperture high intensity beams make holes, and where there's holes in a spaceship, there's trouble.

Now of course on the scale of Earth's orbit, missile spam is a LOT better. You can hide behind Earth and there's a lot less time for the doom laser to pick off incoming missile, or more logically pick off the command vehicles and countermissile the "rockets". Still, thousands of kilometers is a long way to travel and light goes a loooot faster than a missile.

[Noctis]

I don't know what is more amazing.
That Talhydras is totally kicking Noctis's
ass with pure logical arguments,and that
Noctis is still arguing about it, or the fact that
the more stupid or useless a post is, the more people
comment on it.
you're fighting a loseing battle here
Noctis, aspect it.

Anyway, the fact is, is that depending on
the type of environment or situation it is, the enemy's
weapons and about 50 different factors, sometimes
its is best to use energy, sometimes projectiles.
Sorry, but this post has no real purpose other
than to piss the hell out of Anna.

You'll note that the post directly above you contains my admission to unknowingly laboring under incorrect information, and that my opinion thus far had been refuted. I started this so that I could argue what I thought and have those arguments corrected if they were wrong. They were so I stand corrected.

Also, I only even mentioned Anna's post to give a context. I could have cared less if he saw it or not. The problem I had with his replies were that they tended to be very abusive (which I don't care about) but didn't really explain HOW anything I said was wrong. I'm more then happy to admit that I'm wrong, just not before defending my ideas and having them logically refuted.

[Sponge]

Of course, long distance is out of the question. What I'm essentially arguing is that long distance is inherently impractical. If your opponent is a light minute away, how do you know how to aim your laser? If you're off by even the slightest fraction of a degree, you'll miss a target that's sitting still. What if that target slows down? What if that target turns around? What if that target "dives?" There are so many things your opponent can do. They need move only a few meters and your shot becomes worthless. They can move in any one of an infinite number of directions, incredibly insignificantly, and you will have never had even the slightest chance in hell of hitting them. They could not even know you're there and still have an amazing chance of dodging your shot. A course change will throw you off completely. Chances are, you'll spot each other at the same time. You see an enemy, you charge lasers and change directions. Both of you, invariably, miss. At ranges in light seconds, the issue is smaller but still critical. You may not miss as much, but you get that "streaking" effect, where your burst is spread over a large area of hull, rendering is next to harmless. That is, unless you can somehow generate all that power, repeatedly, in some insignificantly small amount of time. Uncontrolled energy release like that, though, is going to be much less efficient than a controlled release. This means even more waste heat. You can try to hit a happy medium, but good luck. I doubt there is one. You either streak harmlessly across their hull or melt your radiators after a few seconds. You may kill your enemy, but you won't be killing anything else for a while.

Missile spam is probably less expensive that you may think. Nukes are pretty cheap. You only need to shield electronic components, which isn't very difficult at all. You don't need armor, because it will probably be useless against weapons of a huge ship anyway. You need one, maybe two hits, and your target is dead. Yes, you can only use this "fleet" once. Maybe old rockets could be collected and refueled, but you'd have to catch them, which may be problematic depending on how much fuel they have left. Sophisticated computer control isn't even all that sophisticated by today's standards, and is certainly much easier than coming up with some method of generating enough power to run a massive laser that slice a hole through armor in a nanosecond without melting your ship. Your manhole cover is moving at much slower than the speed of light, and can be easily avoided. NASA, even today, tracks space debris the size of softballs (in the lower atmosphere; it's basketballs up further), that they track so many objects that it boggles the mind. Long-range attempts at point defense will be seen well in advance, and handily dodged. You really have to wait until the missiles get close before you can start to engage. Yes, you have a lot of intercept time, but the bottleneck is the effective range of your weapons, NOT the accelerative capabilities of your enemy's rockets. Lasers have a pretty high effective range, and as such may see quite a bit of use as low-power point defense tools. Deathrays? Not so much.

I anticipate the end result will really just be a battle of numbers. One ship beats two, four beats three, etc. Tactics obviously come into play a bit, because to get the upper hand, you have to act before your opponent, and so don't know what they're planning. Point defense is critical, and will likely be difficult to develop such that it can out preform a sea of a hundred smart bombs.

EDIT: I didn't see your edit before making this post, but I think I hit on that a bit. Laser point defense would be very effective, but only when the missiles start to get close-- ESPECIALLY if you implement any kind of armor, which is a cost vs return thing that I can't begin to speculate on. They're better than, say, railguns, but still not perfect. They're only as accurate as your data, which is, according to the speed of light, old. Predictive models can't tell the future; they can only make educated guesses. The older your info, the less educated your guess. As such, it would be better to have a shittonne of low-powered lasers than a couple of tough ones. More shots = more chances to take down something important. Low power is okay, as long as it make missiles useless. It's your job to overcome the enemy's point defense, while making sure they can't do the same to you. If neither or both parties are successful in this, you get a stalemate, and everyone either goes home sad or doesn't go home at all.