Effective Combat Range in Space

[doom3607]

Ray guns? From what people are saying, it'd be all kinetics and missiles... Which is fine.

And pretty good- people moving around inside aren't a problem. Evasive manuevers on the part of both you and the enemy, now...

[Connor MacLeod]

How are you setting up your combat as far as time/durations, size of the ship and its acceleration and endurance (how long can it accelerate before running out of fuel and/or propellant), and what sorts of weapons are you going for? Matters like these are always a "depends on" situation because every little detail factors into that overall capability, and it can be as generalized or specialized/optimized as one chooses to make it. (As an example, some of the "hard sci fi" groups I read over have described ranges of millions or even tens of millions of km with massive FEL X-ray lsaers in the low MW range with both sides manuvering almost very little and with milligee acclerations, but also accepting massively low hit probabilities compensated for by firing ludicrously large numbers of shots over a very very LONG period of time days or weeks of combat easily, I think.)

[doom3607]

Short and short range combat, with acceleration maxing at about net 5 gees. Size of ships... from about the size of a modern destroyer to, as stated, supermonitors that are of course larger than 15-km long monitors. I refuse to say how much bigger, for that might decrease the sheer bad-assery when they finally show up for the first time.

As for weapons... mainly mass drivers, missiles, and of course the results of the Kzinti Lesson (I.E. use your engine on them, it's a fricking fusion reactor with a hole in it after all)

Endurance... huge. I'd say enough fuel for a few weeks of continous maximum accel, and years of FTL flight. And all they need is hydrogen, which is easy enough to gather from a local gas giant. Provided the ship is big enough to carry aerospace vessels, of course.

If it makes a difference, ship actually don't come with all their guns built in- the human fleet builds ships with certain built-in weapons in the nose and some PD guns down the hull, but most weapons are mounted in pods that can be attached to certain special hardpoints on the hulls of ships. They come in heavy, medium, and light varieties, as well as a lot of different loads, from turrets to huge forward-firing guns to missiles to FTL strategic bombardment missile carriers to fighter bays to more engines...

Other races, of course, do things differently.

[someone_else]

As for weapons... mainly mass drivers, missiles, and of course the results of the Kzinti Lesson

Either mass drivers have handwaved arbitrary accuracy or anything beyond 30-50 km can only be hit with stray shots.

Missiles are fine. Although having them go ballistic and use their engines only to correct their course is generally smarter unless you have arbitrarily huge-endurance engines cheap enough to be placed on missiles.

Kzinti lesson is a myth. While your engines will annihilate anything trying to getting close to your hull (marines, shuttles, missiles) their plume dissipates rather harmlessly after at most 5-10 km.

And all they need is hydrogen, which is easy enough to gather from a local gas giant.

Is this propellant or fuel?

[Eleventh Century Remnant]

The Kzinti lesson was anticipated by some years by Dan Dare "Of course! At this range, the thing's nothing more than a glorified heat ray!"- 1960, and even earlier by E.E. "Doc" Smith in Masters of the Vortex, 1941-42. '"Doc" Smith's drives were quite exotic, but Angel's Pencil and Anastasia were both using lightpressure drives. Lasers, essentially.

Which, considering the amount of energy they need to get any momentum out of, are probably a damned sight more effective as a weapon than a drive, meaning the Kzinti Lesson kind of breaks down really. Crap drive, inversely proportional to it's (monstrous) effectiveness as a weapon.

A 15,000m ship accelerating at 50m/s/s is going to take nearly a minute to clear it's own outline- I think 54.772 seconds, but my math may be out. Lateral acceleration may matter more, but it is possible to know that, for the next fifty seconds once a target track is established, there is going to be a point in space that a bit of ship will be in. If the big ships are also fairly sluggish, and their engines can't be run up and down the power levels with minimal notice, it could be a lot further than that.

It may be that large craft can be shot by small craft at ranges far beyond that at which they can return fire effectively. Missiles seem the obvious way around this, but expect alrge shipt to take a hell of a lot of driver fire from small ships without being able to make effective reply.

[Simon_Jester]

As for weapons... mainly mass drivers, missiles, and of course the results of the Kzinti Lesson

Either mass drivers have handwaved arbitrary accuracy or anything beyond 30-50 km can only be hit with stray shots.

Or, guided artillery rounds- essentially, a gun-launched missile with enough delta-v that it can correct its own course to track a maneuvering target, but which is fired from a launcher that imparts a high velocity relative to the total delta-v of the missile.

Range also depends in large part on muzzle velocity- doubling muzzle velocity doubles how far your rounds can travel to hit a target before that target gets out of the way. If you're firing many shots to saturate the region the enemy can dodge into, the advantage is even greater- halving the time the enemy has to get out of the way reduces the area of the patch of sky they could wind up in by a factor of sixteen.

Statistically speaking, this means you get to hit the enemy sixteen times more often.

Between x = 0.5at2 and A = πr2, high shot velocities are strongly favored over low ones for unguided weapons. This is one of the reasons ray guns (particle beam weapons or lasers, if we stick to hardish SF) are so appealing; their muzzle velocity is approximately c, so they can travel much farther before the target is able to sidestep (especially at hardish SF accelerations)

Granted, dispersion is an issue, which lowers their potential to inflict damage at long range, but at least they'll be hitting the target reliably well before the target can hit back unless it is similarly armed.

Missiles are fine. Although having them go ballistic and use their engines only to correct their course is generally smarter unless you have arbitrarily huge-endurance engines cheap enough to be placed on missiles.

This can overlap with guided artillery rounds- it might be a good idea to build your long range missiles as two-stage weapons, with a high-delta-v booster stage deploying one or more smaller missiles with more limited delta-v. Or to impart significant initial velocity to the missile using 'catapults' on the launching ship.

Incidentally, the two stage missile also overlaps with the AI fighter mission; in softish SF where you don't have to worry too much about reaction mass (i.e. reaction mass is a small percentage of the mass of the craft), there are arguments for making the missile bus reusable, at which point it turns into an AI-controlled fighter launching ordnance, or can do so at any rate.

Kzinti lesson is a myth. While your engines will annihilate anything trying to getting close to your hull (marines, shuttles, missiles) their plume dissipates rather harmlessly after at most 5-10 km.

In the original story, Niven had the Kzinti ship doing exactly that. The Kzinti had superior acceleration and ultimately wanted to board.

A 15,000m ship accelerating at 50m/s/s is going to take nearly a minute to clear it's own outline- I think 54.772 seconds, but my math may be out. Lateral acceleration may matter more, but it is possible to know that, for the next fifty seconds once a target track is established, there is going to be a point in space that a bit of ship will be in. If the big ships are also fairly sluggish, and their engines can't be run up and down the power levels with minimal notice, it could be a lot further than that.

It may be that large craft can be shot by small craft at ranges far beyond that at which they can return fire effectively. Missiles seem the obvious way around this, but expect alrge shipt to take a hell of a lot of driver fire from small ships without being able to make effective reply.

Yes. On the other hand, if they can mount superheavy beam weapons that would be impractical on a smaller platform due to space constraints, they can even up the score- beams outrange guns, and missiles potentially outrange both if their performance envelope is good enough. Though that's unlikely in a hardish SF setting, where beams can kill missiles at any point in a wide engagement envelope.

Incidentally, you got me thinking about this in the first place, so thanks.

[Connor MacLeod]

The other thing with projectile weapons in space is it depends on whether you need a direct hit or just need to get close enough. Some weapons are either just warheads, or have some standoff attack capability, which can mitigate accuracy. (although to be fair that might fall under missiles or guided shells. I'm not sure there's always much of a difference.)

Also, if fuel or propellant is an issue (and its not impossible outside of a hard sci fi setting. Fuel usage is a huge issue for SW warships since they can at best accelerate for a few hours at top power generation.) a ship may not dodge much or at all. Or depending on the weapons you use, space combat may become a matter of "who runs out of propellant first".

[Sarevok]

Or depending on the weapons you use, space combat may become a matter of "who runs out of propellant first".

In "hard" scifi this is almost certain to be the case...

[Simon_Jester]

D, the definition of "close range" depends on the weapon. "Close range" is whenever you can hit what you're aiming at before it has time to get out of the way of the lethal footprint of the weapon, and when problems of targeting are comparatively trivial. For lasers and hardish-SF accelerations, the first half of "close range" for lasers is measured in light-seconds at least; the second half of the problem is a bit more challenging.

Or put another way, "close range" for a blowdart is not the same as "close range" for a howitzer.

The other thing with projectile weapons in space is it depends on whether you need a direct hit or just need to get close enough. Some weapons are either just warheads, or have some standoff attack capability, which can mitigate accuracy. (although to be fair that might fall under missiles or guided shells. I'm not sure there's always much of a difference.)

There's a continuum.

A 'pure' missile would contain all its own motive power, and can be fired from a very small platform as ordnance. It's self-contained. Its engines would be oriented to give it great forward acceleration, to close the distance to the target as quickly as possible.

A 'pure' guided shell would contain only a small fraction of its motive power, and be fired from an accelerator, 'gun,' 'catapult,' or what have you that boosted it to very near its terminal speed (say, 20 km/s, or 200 or 2000 or whatever fits the setting), and have only enough delta-v to compensate for the evasive maneuvers of the target. Thus, its delta-v might be only a few percent of the velocity imparted by the launcher, if that. What acceleration capability it has would be almost purely lateral- it's got guidance so it can sidestep to mirror an enemy's evasive maneuvers, not to significantly increase its own speed, as opposed to velocity.

Then, we can construct almost any arbitrary combination of these- a missile that is fired from a powerful 'ejector' system which gives it a boost enough to get the missile clear of the ship before it fires its main engines. This is close to a pure missile, and is quite common in real life with torpedo tubes, certain kinds of missile silos, and naval missile launchers.

Or a missile which is fired from something like the tubes that launch fighters from battlestars in Battlestar Galactica, which imparts a bit more forward motion but is still only a small fraction of the missile's total delta-v. Just an extra, mild 'kick' to assist the missile in reaching a distant target while reducing the amount of onboard energy storage it needs.

Then we can keep scaling up the launch tube more and more until we get something that looks more like a gun-fired antitank missile... or a guided artillery round of the kind that exists in real life.

[doom3607]

To attempt to respond to a few of this deluge of points (thanks, guys! )

1. There are most definitely multi-stage missiles- namely, the FTL bombardment missiles the really big ships can carry. They're huge, but they have a range measured in light-years, so you can bomb the hell out of the enemy from the sort of ranmge where his only response is in kind.

2. Yeah, the drives are high endurance- enough fuel for more than enough full burn for any reasonable fleet engagement, and if they're running low, gas giants are everywhere and all big ships have little scoop-ships. The hydrogen being both fuel and reaction mass- it's used in the fusion reactors that power the ship, but it's also fusioned in reactors with nozzles at the back of the ship.

3. Yeah, monitors and suchlike are almost immobile. They also have armor measured in the hundreds of meters. Even nukes don't hurt them much. For fighting the really big supercapital ships, you either have to just settle in for the long haul and keep firing until it finally dies, or bring out your own equivalent and its big-ass main accelerator. They build those things specifically to kill enemy supercaps.

4. Yeah, little ships can strafe big guys from beyond the range where they can effectively use their drivers to respond. Doesn't matter when it launches half a million missiles up your ass, for the first salvo.

5. I need a good reason to avoid beams, they just dodge so many things I'd like to have in. Any ideas?

6. Thanks for the math, Simon- I've decided to switch from guns that shoot big chunks slower to small chunks faster. Makes more sense.

So how much did I miss?

[Sea Skimmer]

Also, if fuel or propellant is an issue (and its not impossible outside of a hard sci fi setting. Fuel usage is a huge issue for SW warships since they can at best accelerate for a few hours at top power generation.) a ship may not dodge much or at all. Or depending on the weapons you use, space combat may become a matter of "who runs out of propellant first".

If that was the case people would bring a whole lot of tankers along. I tend to think a naval action in space would be very drawn out and typically highly indecisive to the point of neither side actually destroying an opposing ship in typical battles.

[someone_else]

Or, guided artillery rounds- essentially, a gun-launched missile with enough delta-v that it can correct its own course to track a maneuvering target, but which is fired from a launcher that imparts a high velocity relative to the total delta-v of the missile.

I call these KKVs (kinetic kill vehicle) since you are basically shooting a kamikaze space vehicle (it has engines, sensors, communication systems and guidance computers). The real weapons we have are called EKV (exoatmospheric kill vehicle) and do *exactly* that.

Range also depends in large part on muzzle velocity

The main problem of using a gun to launch them is that you will subject them to huge g-forces on launch. Say 3 km/s that is pretty basic feat for a rocket, if you do it with a gun, and say it's delivered to the projectile in one second, your projectile must withstand 305 gravities.
For a solid slug it's a joke, but for a small space vehicle as it is a "homing projectile" it's a lot.

I tend to favor expendable boosters instead of cannons. They bring everything up to the final speed in a timescale you decide to be sure the payload survives it. Say it thusts at 30 gees, and in ten seconds the payload is up to 3 km/s speed.
Again, EKVs are boosted to RAMMING SPEED by a missile.

Granted, dispersion is an issue, which lowers their potential to inflict damage at long range, but at least they'll be hitting the target reliably well before the target can hit back unless it is similarly armed.

It's not only dispersion, but also the fact you are aiming a 5-10 meter mirror at stuff more than 1000 km distant or so. You need a lot of precision. You can't compare this level of performance to anything we have currently.

beams outrange guns, and missiles potentially outrange both if their performance envelope is good enough. Though that's unlikely in a hardish SF setting, where beams can kill missiles at any point in a wide engagement envelope.

The difference is that missiles are much easier to make than lasers.

Which is exactly the contrary of what missiles are here on Earth (more complex and heavier than slugthrowers with the same performance).

5. I need a good reason to avoid beams, they just dodge so many things I'd like to have in. Any ideas?

Make them more expensive than carrying loads of countermissiles (whose size can be very small and still be effective, even guided gyrojet rounds will work fine since you are using the enemy's slug speed against itself). It shouldn't be very hard nor sound particularly wrong. Given that you have torch drives, a missile-boosted slug is going to deal significantly more damage than a laser anyway.

Given how strong are your supercapital's armor, you would need a mindboggingly overpowered laser to overcome it.

While lasers doing a wide-beam sweep will easily destroy optical sensors not part of a huge formation of satellites where each mirror is so distant from the others that the energy they reflect from the laser isn't enough to damage the detector, Radars can laugh at wide-beam lasers anytime (use a mesh instead of a plate as the receiver and you are fine, something like This but much much much wider), although they don't have the dramatically huge ranges as optical sensors. Not that such huge range is necessary in a battle anyway.

[doom3607]

Point. It would take an insanely overpowered laser to overcome several hundred meters of armor that's rather tougher than the best modern stuff. And I still refuse to say just how much more armor than that the supermonitors will have. Let's just say... monitors shred everything smaller than them. Supermonitors do that to monitors. And small moons, given time.

[Sarevok]

I think space warfare will involve combined arms. There is no one magic weapon whether they be lasers, railguns or missiles. They each have their uses and weaknesses. And all of them can be countered by appropriate defenses. I think space combat will be decided by a lot by the weapons and defensive loadouts of your ship versus that of the enemy. Sort of like a boardgame. Having advance intel on an enemys weapon tech could be a potential war winner.

[someone_else]

It would take an insanely overpowered laser to overcome several hundred meters of armor that's rather tougher than the best modern stuff.

Just remeber that you don't shoot trough your armor, nor you can see through your armor, nor you can communicate through your armor, and your engines must have nozzles somewhere. Although handwaving can solve all these problems.

Mission-killing these beasts is going to be significantly easier than actually destroying the vessel. Just hit an exposed system:
-weapons
-sensors
-communication systems
-engines

This is usually the reason why most sf authors resort to forcefields.

I think space warfare will involve combined arms.

It depends from how powerful each of the weapons are. For example, pike formations and mounted cavalry are totally worthless in modern warfare.

Although, yes, having 2-3 different kinds of weapons each with different strenghts and weaknesses makes a game/story more interesting. One-size-fits-all is boring after a while.

For example, in a setting where there are decent although not totally overpowered lasers, kinetics tend to be an overkill-or-nothing affair. You either launch enough and you shred the enemy or you are wasting your money. Asking a KKV to target specific parts of a vessel is usually too much for it (it has less than a second to do so). They also litter the orbital space, so their use close to a planet can be banned by treaties.

Lasers have the benefit of being more accurate (hopefully), so you can mission-kill the enemy without collateral damage.

For example, Space Terrorists have seized a vessel carrying 1000 tons of nutmeg from Mars and are aiming it at a space hab.
You don't want to shred it so KKVs are out of question. So the space hab (that planned in advance for such eventuality) will have lasers or laser-armed escorts that will go and disable that ship. Then a space tug will push the crippled vessel around until its speed is safely reduced (maybe doing some aerobrakings), then will bring it to a dock.

Lasers in that setting are something like AC-130. Good if you have space superiority, not so good against a real enemy. Asymmetrical warfare and all that means your space forces still want to have lasers on hand.
The Space Police will want some for its Space Swat.

[doom3607]

I think I'll dodge that blatant a handwave- the FTL is enough for me. At least I've bothered to say that nobody actually knows how it works and that all theoretical physics says it's actually impossible to do that...

But lasers for police work or killing light ships might make sense.

And yeah, complete destruction of a monitor is a lot harder than a mission kill. The solution is another monitor, or a supermonitor. But everything less will be trying for a mission kill, it just isn't easy since every part of the engine that isn't spitting nuclear fire is armored like the rest of the ship. As for the rest...

Sensors and comms are a good idea, but with the pod system I mentioned they tend to be all over the thing's hull- you'd need to basically hit it enough to scorch it clean. And the pods are armored, too.

Same problem affects killing weapons, not to mention there's the main gun on a monitor which is really, really hard to disable. With good reason when you consider when not in use it's covered by a few hundred meters of armor plate in the form of a blast door. And yes, the areas where it fits into the front of the ship is not a straight line all the way through, so there's no 'magic tiny unarmored spot'. There's a circle where the armor is a few centimeters thinner.

Anything I didn't consider anyone can think of? And again, thanks for all the help already- this is seriously helpful stuff.

[someone_else]

You don't even need to handwave. Just use a system that is transparent to what you want but opaque to what you don't.

It has the same problems of Trek's phased shields. If the enemy knows your armor/shield frequency you are fucked.

Fast-acting shutters with decent armor are a better idea.

[doom3607]

The problem is the thickness. You go make a shutter hundreds of meters thick. I'll go wait over there, on that other ship.

[Dwelf]

Gigantic immobile monitors only work if your FTL system has limited known FTL entry/exit points that a monitor can sit in and automatically threaten anything that tries to enter or leave the system.

If this is not the case then you can simply enter or exit the system at a point that the monitor is not covering and mostly ignore it. If you need to go through it whittle it down from well outside of it's effective range a death of 1000 cuts. With your drives and a bit of a run up you can get rounds into the thousands of km/s speeds and still have plenty of fuel for evasive manouvers.


On a completely different note.
I am left wondering if someone would get a mission kill on a monitor by denting the blast door on the main gun. Sure you might not get through it but how much would you need to warp it to make it impossible to open the doors.

[doom3607]

Monitors are mobile. As are supermonitors. Think of them as the equivalent of WW1 tanks, with everything less as infantry.

As for denting a multi-hundred meter thick door built of armor... I think anything that could do that in such a way that they can't easily clear it wouldn't need to settle for a mission kill.

[Steel]

Monitors are mobile. As are supermonitors. Think of them as the equivalent of WW1 tanks, with everything less as infantry.

As for denting a multi-hundred meter thick door built of armor... I think anything that could do that in such a way that they can't easily clear it wouldn't need to settle for a mission kill.

They may be 'mobile', but will they be as mobile as anything else?

Consider that achieving the same mobility as smaller ships will be impossible using the same materials and especially not for the same cost per kg.

Also consider that even if your super ship is mobile to the same degree as smaller ships (despite the fact that this will require massive concessions in at least one of raw combat performance, endurance and cost) it cannot be in two places at once. It sounds like someone can build hundreds if not millions of smaller ships for the same cost as your monitor, each one capable of heading in a different direction and nuking some vital industry behind your lines. While this is going on your monitor is wallowing along trying to engage 1% of the enemy fleet who know all they need to do is hold it off for long enough to let the remainder of the force fight the actual battle (against your vastly reduced forces as you built this ridiculous thing).

[doom3607]

Scenario:

Enemy builds ten thousand frigates while i build one monitor. Let's assume we each have one planet and I'm playing defence.

All his frigates attack me. Let's say five thousand decide to distract the monitor and the rest attack the planet directly, even bombing it, regardless of the fact that the industry down there is more valuable intact.

The monitor opens up with its secondary weapons. 'Secondary', by its standards, is enough to smash a cruiser in half with the first shot. Did I mention it's fricking huge? And that guns have a high refire rate? And that it has fuckloads of missiles? Wild evasion or not, the five thousand frigates going after it last maybe ten seconds.

The frigates going at the planet open fire with all their missiles. The planet's own defences shoot down or confuse (ECM) most of the missiles. The frigates then proceed to do battle with the planet's defences to try to get close enough where they can actually inflict a reasonable amount of damage with their guns. They do this for a few minutes. Then the missiles the monitor launched, being controled by the planet's defences, come flying around the planet and smash them all.

The moral of the story is, there are planetary defences. They are quite good. They are not, however, capable of stopping monitors in most cases. That is why there are monitors. The WW1 tank analogy was used for good reason.

[Steel]

The moral of the story is, there are planetary defences. They are quite good. They are not, however, capable of stopping monitors in most cases. That is why there are monitors. The WW1 tank analogy was used for good reason.

You are perfectly allowed to make it so that in your story your capital ships are so spectacularly more powerful and cost effective that everything else is worthless. I'm just saying you should think is that the most rational way to set things up.

Alternative to your scenario is that the frigates just attack from the other side of the planet, drop missiles and leave before the monitors counter fire even reaches them. You cannot ecm anything so badly that it misses a planet, and with the tech level you've specified a salvo getting through is an extinction event.

Also that scenario massively stacks the deck. What if the system has dozens of space based assets? The frigates can just pop those with impunity. What if there are 10 systems to defend? The frigates can wipe out all the planets while the monitor is sitting at one.

Then there is the way in which one act of sabotage, or one lucky shot, and your expensive monitor is crippled or lost entirely, while a whole fleet of smaller ships would be much less vulnerable.

[doom3607]

That's why monitors are about as common as WW1 tanks. Which is to say, not many. That's actually a much better analogy after further thinking through, since the only thing monitors would really seem to be useful for is attacking targets nothing less can break. But the bulk of the firepower in any fleet would be in the cruiser-battleship range, and almost everything would be such smaller ships. And planetary defences, naturally being dependant on planetary development, can be anything from nigh-nonexistant (like new colonies) to godlike and damn near invincible (like Earth).

Also, I was assuming the 5,000 frigates hitting the planet were on the other side from the monitor. If they weren't, it wouldn't need to use missiles. It's just open up with insane ammounts of cannons and shred them.

Space-based assets, now... Well, they're invariably more valuable intact. Nuking is, was, and always will be an action of last resort. The art of the boarding action is well and alive, in other words.

[Simon_Jester]

Monitors are mobile. As are supermonitors. Think of them as the equivalent of WW1 tanks, with everything less as infantry.

As for denting a multi-hundred meter thick door built of armor... I think anything that could do that in such a way that they can't easily clear it wouldn't need to settle for a mission kill.

Easy. Just hit it hard enough to warp the metal. It is a lot easier to hit a piece of metal hard enough to warp it so that it can't be fixed until you take the ship back to dockyard than it is to drill through the whole piece.

This was actually a major problem for armored warships during the Second World War, as bombs and torpedoes became more powerful. A battleship might survive a hit from a bomb pretty well- no holes blown in the ship below the waterline, crew manages to put out all the fires before anything really essential explodes, and so on- only to find that the heat from the fires had permanently warped bits of the hull so that guns couldn't fire, or that a torpedo strike had twisted the hull so that the ship now had a slight curve in it, making propeller shafts useless and limiting it to reduced speed.

Sometimes, you could take the ship back to a drydock and patch things up. Sometimes you couldn't.

Anything that is, in essence, a big steel box wrapped around thousands (millions? billions?) of tons of precision machinery is going to be vulnerable to this sort of thing. It's much, much easier to damage the hinges of a huge vault door than it is to damage the door itself.

Scenario:

Enemy builds ten thousand frigates while i build one monitor. Let's assume we each have one planet and I'm playing defence.

All his frigates attack me. Let's say five thousand decide to distract the monitor and the rest attack the planet directly, even bombing it, regardless of the fact that the industry down there is more valuable intact.

The monitor opens up with its secondary weapons. 'Secondary', by its standards, is enough to smash a cruiser in half with the first shot. Did I mention it's fricking huge? And that guns have a high refire rate? And that it has fuckloads of missiles? Wild evasion or not, the five thousand frigates going after it last maybe ten seconds.

So, tell me Doomy.

If X tons of monitor can defeat X/2 tons of frigates so easily... why can't X tons of monitor defeat X tons of frigates easily, or 2X, or 5X, or even 10X?

Why do people build anything smaller than a monitor at all, if ships built to monitor scale are the only thing that has enough durability to be considered a survivable platform? What's the point of building a ship of "frigate" scale if the only thing is can plausibly hope to accomplish is to distract one of a monitor's secondary batteries for a fraction of a second and get slaughtered along with thousands of other ships of its class in the opening minute of an engagement?

Or is your example pitting X tons of monitor against, say, X/10 tons of frigates? In which case it's hardly a fair test.

The frigates going at the planet open fire with all their missiles. The planet's own defences shoot down or confuse (ECM) most of the missiles. The frigates then proceed to do battle with the planet's defences to try to get close enough where they can actually inflict a reasonable amount of damage with their guns. They do this for a few minutes. Then the missiles the monitor launched, being controled by the planet's defences, come flying around the planet and smash them all.

It sounds to me as though ten thousand frigates are not and can never be a match for one monitor.

Why is this so? How much do those ten thousand frigates weigh, relative to one monitor?

That's why monitors are about as common as WW1 tanks. Which is to say, not many. That's actually a much better analogy after further thinking through, since the only thing monitors would really seem to be useful for is attacking targets nothing less can break. But the bulk of the firepower in any fleet would be in the cruiser-battleship range, and almost everything would be such smaller ships. And planetary defences, naturally being dependant on planetary development, can be anything from nigh-nonexistant (like new colonies) to godlike and damn near invincible (like Earth).

Um, an important point: WWI tanks weren't invincible. They bogged down a lot, their machinery broke down a lot. They were slow as fuck (to the point where people would attach horse cavalry to the armored unit because the tanks had no chance of chasing down a retreating enemy and the cavalry did). And they were nowhere near tough enough to survive hits from artillery fire- the defender could and did knock them out with heavy guns, often in large numbers.