Future Tech Advice and Assistance Thread [O.O.C.]

[Hittanryan]

If you miss every single time at that range, then wouldn't that simply be considered beyond its effective range? Most weapons will have an operational range beyond which they are not likely to hit, even if it is theoretically possible under tightly controlled conditions.

[Senkaku]

If you miss every single time at that range, then wouldn't that simply be considered beyond its effective range? Most weapons will have an operational range beyond which they are not likely to hit, even if it is theoretically possible under tightly controlled conditions.

Your operational range would be extremely short, is what Sunset is saying (I think), because you can only fill a given volume of space with a comparatively small amount of munitions that the enemy ship will be able to more easily avoid. If you had, say, a dozen mass drivers each firing a spread of smaller slugs, going at 0.3-0.7 c, it might be more effective and longer-ranged, because you'd fill a larger volume of space and make maneuvering more difficult, and when you accelerate something to such a high speed, it will basically obliterate anything it touches. You don't necessarily need a single gun with (comparatively) huge power requirements when you're able to accelerate projectiles to such high speeds. Nothing is going to stop, say, a watermelon-sized piece of tungsten at 0.3 c (unless you do some serious handwaving). The same goes for a piece of tungsten the size of a house moving at 0.7 c. It's just overkill that's easier to detect and dodge- better to launch four thousand watermelons and make it impossible for the enemy to get out of the way.

[Sunset]

If you miss every single time at that range, then wouldn't that simply be considered beyond its effective range? Most weapons will have an operational range beyond which they are not likely to hit, even if it is theoretically possible under tightly controlled conditions.

Your operational range would be extremely short, is what Sunset is saying (I think), because you can only fill a given volume of space with a comparatively small amount of munitions that the enemy ship will be able to more easily avoid. If you had, say, a dozen mass drivers each firing a spread of smaller slugs, going at 0.3-0.7 c, it might be more effective and longer-ranged, because you'd fill a larger volume of space and make maneuvering more difficult, and when you accelerate something to such a high speed, it will basically obliterate anything it touches. You don't necessarily need a single gun with (comparatively) huge power requirements when you're able to accelerate projectiles to such high speeds. Nothing is going to stop, say, a watermelon-sized piece of tungsten at 0.3 c (unless you do some serious handwaving). The same goes for a piece of tungsten the size of a house moving at 0.7 c. It's just overkill that's easier to detect and dodge- better to launch four thousand watermelons and make it impossible for the enemy to get out of the way.

Exactly that. Though I dare you to look up the energy requirements (and thus the power plant needed) to push a watermelon-sized piece of tungsten to .3 c in the length of a modern tank barrel (let alone the spine of a 'realistic' 200m hard FT warship). It ain't pretty. So yes - that's the weapon's Operational Range where it has a reasonable chance of hitting its target. In the case of a spinal super-heavy weapon that range is very much lower than the more plentiful medium to heavy weapons. And thus this is where it gets complicated...

How many weapons does the opponent mount? What's their possible m/s movement along all axis? How much armor do they have? Intelligence work is going to be extremely critical in preparing for any space-based Hard FT combat. You'll need to know the Operational Range of their weapons versus yours, what their acceleration is, what the local gravity is like (close to a planet there might be enough to alter a shot by some small percentage but, given the math, that's enough to go from 1/523 to 1/582). What's the theatre like? Are there civilian outposts that might get hit? What are your rules of engagement? Can you accidentally put a teratonne worth of tungsten through a civvy outpost and not expect similar retaliation?

Which is another very, very big something to consider as well. First, roaming space barbarians are not going to exist in a Hard FT setting, period. That's a lot of advanced math, higher education, personnel management, training, industrialized infrastructure... Nope, no Hard FT space barbarians. Or even industrialized nations. If you're not a Super Power (on a terrestrial scale) you're out. You might have some representatives on an allied ship but... I wander. My point is that in a Hard FT space war the target will not be the opponent's warships. It will be their bearing and lubrication plants. Their infrastructure. Potentially (depending on how rational they are about the risks and thus separating civilian military targets) their civilian population. Hard FT war is fought on a four-dimensional battlefield and there are scant reasons to target an opposing ship when you could be killing that ship's maintenance yard.

A stationary target.

So there again you might want spinal weapons because that super-heavy mass driver can be used to take out their shipyard, their station, and there's not as much they can potentially do about it. And they would then do the same to you. MAD in space. Especially in a Hard FT environment most conflicts should be solved politically because wars would be so much more incredibly destructive. Except, of course, that the Super Powers with their advantage of being the only ones who can build and maintain ships can then pop off unaligned minor players at will. Good reason for those spinal weapons. But if there are no minor players, you'd probably be more likely to find multi-gun 'warships' rather than 'siege guns'. Better to let national pride play out in a ship-to-ship duel than to risk millions or billions of casualties in a real war.

[SquareDisc City]

My kinda topic

These weapons are intended to be the largest capital ships' main guns, weapons powerful enough to cripple an equivalent ship in a single shot under ideal conditions, powerful enough to overwhelm a comparable ship's defenses, and with far greater range than other ships. I know the tendency in movies is to show ships blasting away at each other with volley after volley with each shot doing little damage, but really if it took that long to kill another ship, the military would seek more powerful guns. Think about RL tanks, you wouldn't consider the gun on a main battle tank to be effective if it can only kill an enemy tank with a dozen lucky hits.

The balance between attack and defence is indeed important in shaping your spacecraft and tactics, and by implication what the reaction to a ship being destroyed is. In my old blog Faster Than Sight I argued based on an electromagnetic accelerator's requirement to hold itself together against the force of firing that "in general we can expect a spaceship gun to be capable of destroying something roughly the same size as itself". Ultimately this comes from both weapons and armour relying on chemical bonds for their strength. So with a nuclear weapon, it can destroy something much larger than itself.

(My blog articles make lots of assumptions and probably ignore lots of really important factors. The results are best treated as a reasonable upper bound for hardish sci-fi stuff.)

The reason I'm agonizing a bit over this issue is that the strength of these weapons will set a sort of baseline for the setting. It will help determine energy consumption of the biggest and baddest capital ship and set a ceiling on everything below it. I don't want to find out later that something else could be far more devastating than what is supposed to be the equivalent of a battleship cannon.

It's not hugely important to RP, because whatever absolute numbers someone uses are largely ignored in the interests of a balanced story and heading off numberwanking. But it can be relevant to making your nation internally consistent. For one simple example, if starships are flinging zillions of watts around, then maybe it makes sense if domestic electricity really is "too cheap to meter".

I am attempting to determine what type of weapon is best suited to this role: a mass driver or high-frequency laser. Particle beams and plasma weapons seem to have a general problem with blooming even in space, which would make them unsuited to this specific role (though they might be used in other capacities). I have two conundrums which I wonder if harder sci-fi enthusiasts wouldn't mind taking a crack at.

Big problem 1: Range

Mass drivers theoretically outrange lasers, which diffuse over long distances despite collimation. In space, mass driver slugs will more or less maintain their kinetic energy until they collide with something, and their kinetic energy is what determines their killing power. This implies that mass drivers have theoretically unlimited range. At long range, however, a target may be able to evade mass driver slugs if they are detected early (which is likely using IR sensors) and if the delay between firing and impact is long enough for the target ship to maneuver sufficiently. If the mass driver does not fire projectiles at relativistic speeds, then the laser might be the better option at standoff ranges. The mass driver's accuracy might be too poor at that range to be practical.

If a mass driver can accelerate slugs to some substantial fraction of the speed of light (0.3-0.7c), however, it might be competitive and might be able to hit distant targets with comparable accuracy to the laser. At this point it all comes down to the laser's effective range, which I can't seem to find consistent estimates on. At what range will an x-ray laser diffuse to the point that it cannot seriously damage its target? Is this distance appreciably longer or shorter than the effective range of a relativistic mass driver?.

I discussed the issue of effective range limited by target dodging in my blog. There are a few conclusions to draw. As Sunset discussed, a small ship can take potshots at a much larger one with impunity. In response the larger ship has a few options. It can tank the hits if its defenses are strong enough, not unreasonable with a big size difference. It can have a boatload of secondary weapons to fill space with firepower to rebalance the odds. It rely on a smaller ship, or even a missile, to close down and destroy the target. All three of these and more could come into play in the design of a single craft or even in a single engagement. (And all three of those options has its own shortcomings).

Another conclusion that you've note is that if a mass driver isn't firing at relativistic speeds then it had better have some other advantage over a laser to compensate. And a third conclusion I drew is that if weaponry is travelling at relativistic speeds then you can expect engagement ranges to be large compared to planets and moons, which may well influence the way you right your space battles.

As for laser divergence, Effects of Directed Energy Weapons by Phillip E. Nielsen covers it (along with just about everything else about kinetic, laser, particle beam, and microwave weapons), though mainly considering visible light. A key equation is that in the "far field", the beam diverges with angle in radians θ ~ λ / D where λ is wavelength and D is diameter of the laser aperture. Shorter wavelength, such as with X rays, means a tighter beam but so too does using a physically larger laser. You'd have to work the exact details out yourself.

Big problem 2: Energy and heat management

Will a mass driver or laser require orders of magnitude more energy than the other for an equivalent killing power over the same range in space? Which, if either, will be able to sustain higher average rates of fire over the course of a battle? Will heat management limit a laser's rate of fire substantially compared to a mass driver?

Heat is indeed a very real problem, perhaps it ought to be the number 1 factor in spacecraft design. It's hard to way which option is better in this respect though. https://www.calvin.edu/~pribeiro/course ... 0Paper.doc states that modern railguns are only a few percent efficient, but on the other hand http://ieeexplore.ieee.org/document/4785524/ states that with a certain design and operation near 100% efficiency is possible. That ties in with developments in regular electric motors, where 95%+ efficiency has been achieved.

On the other hand today's state-of-the-art visible and infrared light lasers are targeting 85% or more efficiency, although they are not to my knowledge weapons-grade devices.

Some of the most powerful real-world lasers are chemical lasers, deriving their power from a chemical reaction. While this will have short endurance compared to a laser powered electrically from a nuclear reactor, I wonder if it might lend itself to open cycle cooling - simply vent the reaction products overboard taking their heat with them.

On bomb-pumped lasers: Would a bomb-pumped laser beat the mass driver (or vice versa) in electrical energy consumption (without sacrificing killing power or range)? If a bomb-pumped laser would be more efficient in terms of energy consumption, wouldn't it also lose its supposed logistics advantage for its gain in energy efficiency over the mass driver? That is to say, if a nuclear warhead had to be detonated for each firing, wouldn't the logistics and maintenance burden of a bomb-pumped laser be appreciably greater than that of a mass driver?

Well a bomb pumped laser doesn't have significant electric energy consumption. In terms of using nuclear fuel efficiently, I suspect it's worse than a well designed nuclear reactor just because the bomb has a lot less control. And yes, it means using single shot warheads with all the difficulties that entails. On the other hand it also means you can stick it on a missile which addresses your range concerns.

[Hittanryan]

Good thoughts from everyone. If nothing else I think this has helped determine that a light-second is effectively out of range for ship-to-ship combat with active maneuvering. Between the light lag and the need to hit a fast minuscule target, the only hope of hitting anything would be spray and pray. Since there's a fixed energy budget, these dozens of guns would have to be considerably smaller and wouldn't inflict enough damage. I'm disinclined to go with this solution. I did think of using a fragmentation warhead in the large mass driver; at some distance the shell breaks apart into smaller (but still relativistic) fragments that cover a wider area.

I'm also aware that these ship-to-ship engagements are not the end in itself, only a means to an end. An enemy nation's strategic resources (i.e. helium-3 extraction facilities in gas giants, antimatter factories near stars, shipyards) would be targeted from the word go. Unless your enemy is an idiot or weak (in which case they're also idiots for failing to negotiate), those resources will be defended. Military strategy in this setting will naturally be largely centered around attacking and defending these key assets.

This doesn't mean all engagements will take place right next to them. After all, if all defenders ever did was park their fleets on top of space station and wait for the enemy to come to them, they would be utterly predictable and therefore sitting ducks. Similar to modern naval tactics, early warning systems would likely be in play, and fleets would likely be actively patrolling a given orbit once hostilities commence.

[Senkaku]

Since there's a fixed energy budget, these dozens of guns would have to be considerably smaller and wouldn't inflict enough damage.

If you hit something with really anything going at a significant fraction of the speed of light, it's probably going to die, unless it has a mind-bogglingly large mass of armor to protect it or is ridiculously large. Same with a direct hit from a multi-megaton yield H-bomb (which would introduce an ammunition budget but get rid of your fixed energy budget). Even a few kilotons is probably enough to wipe out or cripple most targets, really, barring mind-boggling size or levels of armor (or handwaved energy shields ). Orbital battle stations built into asteroids or something might be made of tougher stuff, but killing ships probably wouldn't be that difficult with sufficient impact energies or explosive power.

[Hittanryan]

By "smaller" I meant these railguns would not be able to propel a slug at relativistic speeds. Dozens of guns all propelling tungsten watermelons at 0.3c would probably break the energy budget.

[SquareDisc City]

Since there's a fixed energy budget, these dozens of guns would have to be considerably smaller and wouldn't inflict enough damage.

If you hit something with really anything going at a significant fraction of the speed of light, it's probably going to die, unless it has a mind-bogglingly large mass of armor to protect it or is ridiculously large.

Or the projectile's really small. An object massing 1 nanogram - for comparison, about the size and mass of a human cell and over trillion times the mass of any atom - travelling at 0.5 [i]c/i] would carry energy similar to a modern day rifle round, and while the terminal ballistics is going to be very different I still think it could be quite practically armoured against.

[Vocenae]

Relevant.

[Senkaku]

If you hit something with really anything going at a significant fraction of the speed of light, it's probably going to die, unless it has a mind-bogglingly large mass of armor to protect it or is ridiculously large.

Or the projectile's really small. An object massing 1 nanogram - for comparison, about the size and mass of a human cell and over trillion times the mass of any atom - travelling at 0.5 c would carry energy similar to a modern day rifle round, and while the terminal ballistics is going to be very different I still think it could be quite practically armoured against.

I was speaking of macro-sized projectiles. If I accelerated a water bottle or a Hallmark card or a flatscreen TV (or items with equivalent masses) to 0.5 c, shit would go down.

[Olimpiada]

Or the projectile's really small. An object massing 1 nanogram - for comparison, about the size and mass of a human cell and over trillion times the mass of any atom - travelling at 0.5 c would carry energy similar to a modern day rifle round, and while the terminal ballistics is going to be very different I still think it could be quite practically armoured against.

I was speaking of macro-sized projectiles. If I accelerated a water bottle or a Hallmark card or a flatscreen TV (or items with equivalent masses) to 0.5 c, shit would go down.

*shit would go everywhere

[Tahar Joblis]

No miscommunication. If you do the math and figure out how large that fire envelope is, that spinal mounted weapon - no matter how 'carefully' targeted it is - will miss essentially every single time. Let's say you're engaging at 1 light second - 300,000 kilometers rounded - and the target has a potential movement from maneuvering thrusters alone of 300 m/s. That's what the shuttle had. So in that 1 second that it would take for your radar (or even the light bouncing off the target ship) to return to your sensor system and -assuming- no particular computational latency, movement of the weapon housing (whole ship in the case of a spinal weapon), etc, that ship (the elderly space shuttle) has now potentially moved anywhere inside a 600 m circle (parallel to your own ship). The shuttle is only 9m in diameter, 60m long. It now fills only 1/523rd of that circle.

This is not particularly appropriate as a model.

That is modeling a shuttle whose velocity is known to within 300 m/s, with the error distributed linearly (increasing as you go outward). This is an implausible error structure.

You have several sources of error leading to a "bubble" of outcomes.

(1) Error in the measurement of current position and velocity. These will tend to have a multinormal distribution.
(2) Angular precision of the weapon / observation system. At 1 light second, an error of one arc-second corresponds to almost a mile of distance. For reference, the Hubble Space Telescope's maximum theoretical resolution is 50 milli-arcseconds.
(3) Correct prediction of acceleration of the object in the time after observation.

If lateral position error is distributed uniformly, the center has the same density as everything else. If lateral velocity error is distributed uniformly, the center has a little under triple the density (you're taking the center core of a cone). If lateral acceleration error is distributed uniformly, the center has about four times the density.

If you have an error in lateral acceleration of 0-1 g, uniformly distributed in angle and magnitude, this makes for a "bubble" 20m in radius, with the center region having a significantly higher overall density. If the target shuttle is a 5m radius cylinder as viewed from tail-on, with no error in accuracy and a 2 second cycle between target observation and the beam weapon passing through the target, accuracy exceeds 10%.

This, by the way, would be considered pretty good accuracy for historical wet-navy battleships trying to hit other moving battleships. Not surprising considering we're talking about a net "flight time" of two seconds, as opposed to tens of seconds.

No matter what, all weapons you fire are going to be subject to the same accuracy constraint, which means that your statistical expectations of total energy delivered to target are not going to increase if you use multiple small shots. There are some factors that affect the efficiency of small vs large shots, but this is not one of them:

(1) "Overkill" energy. If the large weapon delivers more energy than needed to disable the target, that creates inefficiency. (This includes includes partially disabling - if smaller weapon hits will degrade target maneuverability, ability to fire back, etc, that is all the more reason to have more shots in the air, so to speak.)
(2) Accuracy gains. Larger weapons will generally have higher levels of angular precision, so if this is the important factor, it favors larger weapons. Against a non-mobile target, "ranging" shots could favor small weapons.
(3) Delay from firing command to actual firing. If this is non-trivial and varies between larger and smaller weapons, it will probably favor smaller weapons.
(4) Non-linear resistance to damage, such as is present in actual armor. If you deliver a couple hundred megajoules of kinetic energy into the USS Missouri in the form of a hail of 9mm pistol rounds, you will do little more than scratch the paint. Do so with a single AP round, however, and you stand a reasonable chance of penetration.

Between (1) and (4), there are generically very good incentives for using a weapon that is of a specific level of energy tailored to the target; and in some circumstances, good reasons for using mixed-yield weapons (lower-yield weapons intended to degrade the target's more fragile systems, combined with heavy weapons that have the ability to actually disable the target).

For the most part, if you have small targets you are trying to hit on a realistic tech base with unguided weapons, basic resolution on your sensors and similarly fine angular control of your weapon (arcseconds are tiny when you're on an erratically moving platform with vibrating machines) are the main obstacles to hitting something smaller than a giant NSBattleship at a light-second of range.

If you can conquer those (e.g., Star Trek level sensor tech and precision), you can have perfectly decent hit rates on an evading target with an average unpredicted acceleration rating in units of m/s^2 that is on the order of its radius in meters at a full light second. That's not necessarily overall acceleration; that's the component of acceleration that is not predicted.

This isn't a linear process. An object twice as far away has twice as long to accelerate... which increases the diameter of the position bubble by a factor of four, which increases the cross-sectional area by a factor of sixteen. If you're doing a drunken walk or (on the other end) have some macro-level objective that narrows your field of possible evasions, all of those will tend to concentrate your position towards the center of the bubble more relative to time than a uniform draw of acceleration, so it's realistically closer to a cube than a fourth power spread.

[Hittanryan]

New input is always good, although it seems we're still a bit bogged down on a conceptual level here, so maybe it would help if I clarified how these weapons and ships would be used and my rationale behind them. I should probably mention that I intended these main guns to be used primarily against relatively large, better-protected targets that play a key role in an enemy fleet (carriers, destroyers, arsenal ships, opposing capital ships). It would be total overkill to use these big guns on smaller targets, and what's more the ship would probably carry other weapons which can deal with these more effectively. To reduce it to World War II naval terms, it would be like using a battleship's 16 inch gun battery to hit a PT boat or an airplane in flight. Like the battleship, the ships with the big guns would have no purpose outside of conventional warfare between great powers. They're not used for patrol, anti-piracy, counterinsurgency, or search and rescue. Other smaller, cheaper ships can perform those roles equally well barring extreme circumstances.

Unlike the battleship in the modern era, however, there is the potential here to outrange and outgun fighter craft. In the modern era, both a shell fired from a 16 inch cannon and an anti-ship missile can cripple virtually any ship with one good hit. The USS Missouri's 16 inch guns had a range of about 32 kilometers. Modern carrier-based fighter aircraft can range out hundreds of kilometers from their carrier and fire an anti-ship missile with an additional few hundred kilometers. The disparity gets even worse for land-based aircraft; in addition to submarines, Cold War Soviet doctrine called for strategic bombers to use air-launched cruise missiles against efforts to resupply Europe via the Atlantic. That's why in 2016, big guns--and the battleships that carry them--are obsolete.

To justify the existence of the guns I proposed in my original post, they need to have both range and killing power, same way a direct hit from both an Exocet and a 16 inch shell can cripple or sink just about any vessel in the modern era. Now, a light-second might be out of range. That's fine, it just means that ships will engage at closer ranges. I'm flexible, I'm still building the world, I'm not married to the idea of engagements at 300,000 klicks. These guns just have to outrange most other weaponry including those launched by fighters.

The original question, however, was about lasers vs. mass accelerators as primary long-range weapons. I've received some feedback on this so far but would like a few more thoughts. Again, the sticking points are the effective ranges of x-ray lasers and differences in energy/heat efficiency.

[SquareDisc City]

To justify the existence of the guns I proposed in my original post, they need to have both range and killing power...The original question, however, was about lasers vs. mass accelerators as primary long-range weapons.

On the other hand, there's still a third option: missiles as primary long range weapons. As became the case in real life air warfare and to an extent naval warfare. Of course that spoils your spinal-mounted gun fun, so you might need some reason they aren't used all the time. Cost is an obvious one, there's a lot of advanced technology going into a missile and it's single use, even in real life that was seen as a bit of an issue when the USA was using expensive cruise missiles to hit cheap targets. But it might not be the only drawback.

[Hittanryan]

To justify the existence of the guns I proposed in my original post, they need to have both range and killing power...The original question, however, was about lasers vs. mass accelerators as primary long-range weapons.

On the other hand, there's still a third option: missiles as primary long range weapons. As became the case in real life air warfare and to an extent naval warfare. Of course that spoils your spinal-mounted gun fun, so you might need some reason they aren't used all the time. Cost is an obvious one, there's a lot of advanced technology going into a missile and it's single use, even in real life that was seen as a bit of an issue when the USA was using expensive cruise missiles to hit cheap targets. But it might not be the only drawback.

Guided missiles with big enough warheads will probably need a great deal of fuel to cross the kinds of distances involved and still maneuver to their targets. Not only that, modern-day carrier groups already have layers upon layers of missile defenses including fighter CAP carrying air-to-air missiles, guided missile cruisers and destroyers carrying scores of long-range SAMs, and CIWS for last-ditch point defense. Given that these lessons are likely to be retained by future generations, I imagine missiles would be somewhat easy to target and intercept using FT weaponry.

Missiles I imagine would be most effective at relatively short range, fired en masse. That gives the defenders a shorter reaction time and, if enough missiles are fired, a chance to simply overwhelm their defenses. The naval wargame exercise Millennium Challenge 2002 did demonstrate that it was possible to overwhelm a US Navy carrier strike group's defenses through massed missile attacks, as long as it could be coordinated without the fleet catching on. It took a massive barrage at short range from all angles to do it though.

Incidentally, CIWS (Close-In Weapon System, point defense) is where I would expect laser weaponry to shine in particular. Current CIWS isn't all that effective, it's largely a last-ditch hope that you can shoot a quickly-maneuvering missile with a big radar-guided machine gun. At close range I imagine that dodging lasers would be nigh-impossible.

[Senkaku]

To justify the existence of the guns I proposed in my original post, they need to have both range and killing power...The original question, however, was about lasers vs. mass accelerators as primary long-range weapons.

On the other hand, there's still a third option: missiles as primary long range weapons. As became the case in real life air warfare and to an extent naval warfare. Of course that spoils your spinal-mounted gun fun, so you might need some reason they aren't used all the time. Cost is an obvious one, there's a lot of advanced technology going into a missile and it's single use, even in real life that was seen as a bit of an issue when the USA was using expensive cruise missiles to hit cheap targets. But it might not be the only drawback.

I feel like missiles or some form of missile-drone hybrid might also solve the issue of fixed power requirements. A ten-megaton nuke delivers ten megatons of explosive power regardless of how big the reactor on the ship that launched it is, can be used to pump an x-ray laser or Casaba howitzer to give it the ability to hit things far away, can be squeezed in along with several compatriots into a missile or disposable drone craft with computers, sensors, and communications to the mothership that will let it find more accurate firing solutions at a closer range than the mothership, be deployed as a submunition like a MIRV, et cetera. Or, if you invest in nuclear miniaturization, maybe you can deploy fifty-megaton bombs instead, or five hundred megaton bombs, all without needing vast power requirements on board your ships. And unlike with mass drivers, you won't have to worry about future cargo freighters or colonies going kaboom a century down the line when your car-sized tungsten slug hits them at sixty percent of the speed of light.

[Senkaku]

Guided missiles with big enough warheads will probably need a great deal of fuel to cross the kinds of distances involved and still maneuver to their targets.

Deploying a large number of warheads almost like submunitions on a large carrier drone or missile bus type vehicle (perhaps expendable, perhaps not) might be a way to get around this, as well as using x-ray lasers and Casaba howitzers to minimize the distance the missiles have to travel.

[Hittanryan]

Guided missiles with big enough warheads will probably need a great deal of fuel to cross the kinds of distances involved and still maneuver to their targets.

Deploying a large number of warheads almost like submunitions on a large carrier drone or missile bus type vehicle (perhaps expendable, perhaps not) might be a way to get around this, as well as using x-ray lasers and Casaba howitzers to minimize the distance the missiles have to travel.

And what of the layered missile defense that is likely to be used by any major fleet? Fighter or drone patrols with weapons capable of intercepting missiles, escorts with missile countermeasures, CIWS on the missile's target?

[Senkaku]

Deploying a large number of warheads almost like submunitions on a large carrier drone or missile bus type vehicle (perhaps expendable, perhaps not) might be a way to get around this, as well as using x-ray lasers and Casaba howitzers to minimize the distance the missiles have to travel.

And what of the layered missile defense that is likely to be used by any major fleet? Fighter or drone patrols with weapons capable of intercepting missiles, escorts with missile countermeasures, CIWS on the missile's target?

Well, it might end up being easier to consolidate counter-countermeasures to the missile buses, which could do its best to destroy interceptors and block enemy ECM until the missiles could get within x-ray laser or Casaba howitzer range. I would think that at such ranges CIWS wouldn't be much of an issue, though if you were trying to directly hit an enemy ship with a nuke, it would be. As for escort craft equipped with extensive anti-missile systems, presumably such craft would be targeted by the x-ray lasers and Casabas first, and I doubt any ship would stand up to more than one hit by a bomb-pumped anything.

Obviously there'd be stuff involved, but it might be better than just flinging a bunch of mass driver slugs and laser beams in the general direction of the enemy from half a light-second away (and equipping your ship with gigantic reactors to fit suitably gigantic power requirements, along with huge radiators that would fry your crew in like two seconds when you had weapons online). Lasers and mass driver systems will also need to get rid of a lot of waste heat- nuclear missiles don't.

[Hittanryan]

And what of the layered missile defense that is likely to be used by any major fleet? Fighter or drone patrols with weapons capable of intercepting missiles, escorts with missile countermeasures, CIWS on the missile's target?

Well, it might end up being easier to consolidate counter-countermeasures to the missile buses, which could do its best to destroy interceptors and block enemy ECM until the missiles could get within x-ray laser or Casaba howitzer range. I would think that at such ranges CIWS wouldn't be much of an issue, though if you were trying to directly hit an enemy ship with a nuke, it would be. As for escort craft equipped with extensive anti-missile systems, presumably such craft would be targeted by the x-ray lasers and Casabas first, and I doubt any ship would stand up to more than one hit by a bomb-pumped anything.

Obviously there'd be stuff involved, but it might be better than just flinging a bunch of mass driver slugs and laser beams in the general direction of the enemy from half a light-second away (and equipping your ship with gigantic reactors to fit suitably gigantic power requirements, along with huge radiators that would fry your crew in like two seconds when you had weapons online). Lasers and mass driver systems will also need to get rid of a lot of waste heat- nuclear missiles don't.

I dunno, these single-shot nuclear devices increase the logistics and maintenance burden by quite a bit. Techs will have to maintain the missiles and warheads, plus you'll be going through quite a bit of fissile material that way. On top of that you'll have ionizing radiation to consider as a hazard to your own personnel.

I'm also not seeing why fighter CAP couldn't simply be extended beyond bomb-pumped missile range where they could intercept them before detonation. Presumably before being able to use these weapons, fighters would have to first wrest control of the airspace (I know there's no air, but the equivalent term would be "space-space"). That's likely to involve a battle of attrition, with heavy casualties and high uncertainty.

As far as big reactors go, in this setting you basically need fusion plasma rockets for viable manned interplanetary travel. Other methods (chemical rockets, ion thrusters, non-beam propelled solar sails) are still around but they're niche-y because they're so much slower. Every capital ship, therefore, will have a helium-3/deuterium fusion power plant of varying size.

[Senkaku]

Well, it might end up being easier to consolidate counter-countermeasures to the missile buses, which could do its best to destroy interceptors and block enemy ECM until the missiles could get within x-ray laser or Casaba howitzer range. I would think that at such ranges CIWS wouldn't be much of an issue, though if you were trying to directly hit an enemy ship with a nuke, it would be. As for escort craft equipped with extensive anti-missile systems, presumably such craft would be targeted by the x-ray lasers and Casabas first, and I doubt any ship would stand up to more than one hit by a bomb-pumped anything.

Obviously there'd be stuff involved, but it might be better than just flinging a bunch of mass driver slugs and laser beams in the general direction of the enemy from half a light-second away (and equipping your ship with gigantic reactors to fit suitably gigantic power requirements, along with huge radiators that would fry your crew in like two seconds when you had weapons online). Lasers and mass driver systems will also need to get rid of a lot of waste heat- nuclear missiles don't.

I dunno, these single-shot nuclear devices increase the logistics and maintenance burden by quite a bit. Techs will have to maintain the missiles and warheads, plus you'll be going through quite a bit of fissile material that way. On top of that you'll have ionizing radiation to consider as a hazard to your own personnel.

Use antimatter to induce pure fusion (or just say "fuck it, the crew is dealing with space too, they have enough shielding"). If you have huge reactors, they will consume lots of fuel. If you have huge solar panels, they'll be very vulnerable to enemy fire and ineffective far from the nearest star. Either way, you'll have large radiators and heat sinks to deal with, both of which will be fragile, require maintenance, and seriously limit combat performance on all but the largest battle stations.

I'm also not seeing why fighter CAP couldn't simply be extended beyond bomb-pumped missile range where they could intercept them before detonation. Presumably before being able to use these weapons, fighters would have to first wrest control of the airspace (I know there's no air, but the equivalent term would be "space-space"). That's likely to involve a battle of attrition, with heavy casualties and high uncertainty.

"Fighters" would probably have limited delta-vee and minimal armor and would be easy to plaster with an initial barrage of lasers or mass drivers that could be less powerful, since they'd just have to shred a few millimeters of carbon fiber or whatever. Those lasers and mass drivers might not be suitable for attacking larger ships- they could be quite low energy, really. Once you've flooded the battlefield with heavy fire from kilowatt or megawatt lasers and much smaller, slower mass driver projectiles (a grape going at 1% c, versus a car going at 30% c), you send in your missile bus and rain nuclear death on the enemy. You could even turn your missile buses into full fledged drone craft and equip them with a small reactor and some lasers or something and have them zap any fighters that get too close before they deliver their payload. Since it'd probably be reasonably easy to smack fighters, I doubt they'd see widespread use.

As far as big reactors go, in this setting you basically need fusion plasma rockets for viable manned interplanetary travel. Other methods (chemical rockets, ion thrusters, non-beam propelled solar sails) are still around but they're niche-y because they're so much slower. Every capital ship, therefore, will have a helium-3/deuterium fusion power plant of varying size.

Sure, but it'll need a bigger one, presumably, to power the ship's systems, engines, and power-hungry weapons systems than it would to power just the systems and engine, or the systems, engine, and less power-intensive weapons. It'll also require more fuel, presumably, and again, I'd point out that super high-energy laser or mass driver systems will fuck you over in terms of waste heat output. The only craft that will really be able to make effective use of super high-energy weapons such as 0.3-0.7 c "spinal" class mass drivers or gazillion-watt lasers will be immobile battle stations built into asteroids or icy bodies, or planetary defenses, which will have huge heat sinks at their disposal. Your average ship will fire a few short bursts and then cook everyone inside it, or have to wait like an hour between shots or something like that.

[Hittanryan]

"Fighters" would probably have limited delta-vee and minimal armor and would be easy to plaster with an initial barrage of lasers or mass drivers that could be less powerful, since they'd just have to shred a few millimeters of carbon fiber or whatever. Those lasers and mass drivers might not be suitable for attacking larger ships- they could be quite low energy, really. Once you've flooded the battlefield with heavy fire from kilowatt or megawatt lasers and much smaller, slower mass driver projectiles (a grape going at 1% c, versus a car going at 30% c), you send in your missile bus and rain nuclear death on the enemy. You could even turn your missile buses into full fledged drone craft and equip them with a small reactor and some lasers or something and have them zap any fighters that get too close before they deliver their payload. Since it'd probably be reasonably easy to smack fighters, I doubt they'd see widespread use.

If that's the case, wouldn't missiles have the exact same problems? At the end of the day they're basically small, fragile vehicles as well, with guidance systems, engines, and a payload, all of which need to stay intact to get the job done.

[Senkaku]

"Fighters" would probably have limited delta-vee and minimal armor and would be easy to plaster with an initial barrage of lasers or mass drivers that could be less powerful, since they'd just have to shred a few millimeters of carbon fiber or whatever. Those lasers and mass drivers might not be suitable for attacking larger ships- they could be quite low energy, really. Once you've flooded the battlefield with heavy fire from kilowatt or megawatt lasers and much smaller, slower mass driver projectiles (a grape going at 1% c, versus a car going at 30% c), you send in your missile bus and rain nuclear death on the enemy. You could even turn your missile buses into full fledged drone craft and equip them with a small reactor and some lasers or something and have them zap any fighters that get too close before they deliver their payload. Since it'd probably be reasonably easy to smack fighters, I doubt they'd see widespread use.

If that's the case, wouldn't missiles have the exact same problems? At the end of the day they're basically small, fragile vehicles as well, with guidance systems, engines, and a payload, all of which need to stay intact to get the job done.

Missiles have one purpose: get the payload to an enemy target. Fighters are trying to shoot down enemy missiles, avoid hitting friendlies, and do a bunch of other stuff. Hell, missiles you could probably slap some basic armor or ablative coatings on them and sacrifice more delta-vee than a fighter, since you don't have a pilot and life support stuff to worry about. Even a drone fighter is going to have to do more maneuvering than a missile probably would. All the missile has to worry about is getting the warhead from the launch point to the detonation point.

Also, that's why I suggested missile buses- somewhat hardened things with maybe some ablatives or basic armor, enough delta-vee that they could manage armor and still go fast and stuff, stuffed full of submunitions that would then be released and fire a bunch of xasers or Casabas.

I'm sure you'd lose some missiles, but my point is that they'd be more effective than super high-energy mass drivers or lasers, for a host of reasons (not having to deal with huge power plants, huge heat sinks that still don't do a ton to alleviate the issue, short range because they can't cover a very large volume of space, et cetera). Imo the main issue is the huge heat sinks. Gigantic battle stations built into the bedrock of asteroids would not have problems, but your average battleship is going to start getting kinda steamy inside if it blasts away on its petawatt laser batteries for too long or zaps an apartment-building sized piece of tungsten up to ninety percent the speed of light.


Anyways, I basically am of the opinion that future space wars will just be drones and smaller craft blowing each other to smithereens and trying to kill drone tender ships (which will probably be giant and carry some longer-range weaponry in addition to drone units).

[Olimpiada]

If that's the case, wouldn't missiles have the exact same problems? At the end of the day they're basically small, fragile vehicles as well, with guidance systems, engines, and a payload, all of which need to stay intact to get the job done.

Missiles have one purpose: get the payload to an enemy target. Fighters are trying to shoot down enemy missiles, avoid hitting friendlies, and do a bunch of other stuff. Hell, missiles you could probably slap some basic armor or ablative coatings on them and sacrifice more delta-vee than a fighter, since you don't have a pilot and life support stuff to worry about. Even a drone fighter is going to have to do more maneuvering than a missile probably would. All the missile has to worry about is getting the warhead from the launch point to the detonation point.

Also, that's why I suggested missile buses- somewhat hardened things with maybe some ablatives or basic armor, enough delta-vee that they could manage armor and still go fast and stuff, stuffed full of submunitions that would then be released and fire a bunch of xasers or Casabas.

I'm sure you'd lose some missiles, but my point is that they'd be more effective than super high-energy mass drivers or lasers, for a host of reasons (not having to deal with huge power plants, huge heat sinks that still don't do a ton to alleviate the issue, short range because they can't cover a very large volume of space, et cetera). Imo the main issue is the huge heat sinks. Gigantic battle stations built into the bedrock of asteroids would not have problems, but your average battleship is going to start getting kinda steamy inside if it blasts away on its petawatt laser batteries for too long or zaps an apartment-building sized piece of tungsten up to ninety percent the speed of light.


Anyways, I basically am of the opinion that future space wars will just be drones and smaller craft blowing each other to smithereens and trying to kill drone tender ships (which will probably be giant and carry some longer-range weaponry in addition to drone units).

Missiles are far too likely to get shot down by ships with small mass drivers or lasers for anti-fighter/missile purposes. Lasers can't be shot down, and a large chunk of metal flying at 0.9c is going to be very difficult to handle.

[Hittanryan]

I still remain skeptical. I'm not denying that missiles would have their place in space warfare, in fact in my setting I imagine there absolutely would be arsenal ships (missile buses) the way you described. If a fleet relied on them as its only long-range weapon, however, I can envision any number of counters. A tungsten watermelon plowing into the bridge at 0.3c before the ship can get within range would be one such counter. Joking aside, the fighter CAP is likely to be layered as well; they wouldn't just be on the outer perimeter. If you fly your ship in close enough to clear a path most of the way to your target, you're likely to find yourself in range of every other weapon in the fleet. In fact, those other weapons could be turned on the missiles as well.

Ships designed and built in the 1970s and 80s (with upgrade packages) can shoot down large quantities of missiles today. Generally the biggest obstacle is detection and targeting, but in space, early warning of missile approach is likely to be even easier since you don't need to worry about radar horizons and they're likely to have a lovely, bright infrared signal against the background of space. Combine that with weapons like lasers and the missile's prospects seem rather grim at long range. You might use them to exploit a specific situation, like if say you managed to disable the enemy fleet's carrier and smashed several of its destroyer escorts, degrading their countermeasures.

I also acknowledged that heat management is a major problem with the big guns. It's why these things can't just be mounted on small ships without the ability to disperse the excess heat. My question was which was worse by comparison, lasers or mass drivers?