Space pirates

[someone_else]

Ok, you can pay, but it's still a lot of time to wait.

That's not uncommon. It takes several years for new oil refineries, power plants, and factories to come online too, but people still build them.

Travel times add time on top of to that. I frankly don't see a lot that makes sense economically with so long waiting times and what we have already on Earth.

I imagine space ships can be the same way - if an old design goes into mass production and is commonly available, the ship itself may be quite cheap, since it doesn't need any special development. It's all off the shelf parts.

There are surely limits on that, although I'm not able to give even eyeballed estimates. I'm pestering anyone that seems to know a little more about that to get more info.

Crashes aren't much of a problem either. Consider that the habs are millions of times more massive than ships.

I was thinking about stuff hitting structural beams and such. Since habs are spinning to generate gravity (are they?), that may cause fuckups, depending on the habitat design. And some moron using the wole fuel supply of the ship, not just 400 m/s.

With so fucking close distances (relatively speaking), playing with rockets is plain absurd. Why don't place cables and use cable-climber vehicles? Safer, and much much much more efficient.

Wow. KKVs are shit in most space settings.

This means what exactly? If most have bullshittium as main armor material, that routinely ignores anything less than a nuke (or blatantly overpowered energy weapons) does that mean anything in real life?

It just means that the writer chose to make a good story since he is writing a book that wants to sell.
KKV battles are cruise missile duels IN SPACE!!!!!
Boring, fast, deadly, humans are at home pressing buttons.
KKVs can be handled as the nukes in a Cold-War-ish scenario, but not much more.

Distances aren't nice to kinetic impactors.

Let me clarify: KKV= Kinetic Kill Vehicle.
It's not an unguided slug (you're right, those suck balls in the accuracy department).

So, it's quite the opposite. Lasers have a maximum range (determined by the size of their focusing optics and the kind of radiation you are shooting, usually less than a light-minute since otherwise there is no fucking way to hit a goddamn thing due to light lag giving it time to evade), but KKVs (as any space vehicle anyway) have a delta-v, an "endurance".
This delta-v is used only to correct their course to home on target, while the main punch is given by a booster stage or a cannon. They can cruise for decades on their course. This is what probes built 20 or more years ago did for decades, it isn't hard to do.

If the homing delta-v is higher than the delta-v that the target can expend before impact (say, you are shooting at an average-sized habitat on Mars from Earth with KKVs with 4 km/s of homing delta-v). The target is totally fucked (unless it launches KKVs to intercept your own KKVs). Impact will happen in a second or in an year but there is no escape from it (if the kkv can expend more delta-v than the target, of course).

Their mission objective probably isn't in space itself. The real targets are probably inside a habitat.

You are wasting so much space in an habitat to allow fucking aircraft in them? Why? You don't need deliriously huge heights to have a nice fun park with trees to play in.
Also, they need an airlock big enough for an aircraft.

Which is, of course, why we use computers exclusively today!

If you are talking of space things, then I'm pretty much right. All brains are at Ground Control. You don't necessarily need guys bunny-hopping on the Moon.

They might also want to keep humans in the loop for less rational reasons (or not, depends on how you look at it). Is that truck the enemy or a civilian in the wrong place at the wrong time? Is that a school house or a guerilla headquarters?

That work is called "intelligence" and involves looking at stuff, placing spies, making recon work. It is hard as hell and takes weeks.
Then you decide who deserves a bomb up his ass, and call the bomb-deliverers.

Yes, since the aircraft pilot or ship crews or tank/artillery crew's work is just to deliver the payload (bomb, missile, whatever) to a target they barely see, because someone with higher rank told them to do so. In space the bomb-delivery part can be handled by a computer, since even here on Earth unmanned flying drones are being fitted to do it.

It's US military that sometimes tends to skip on the "intelligence" part and leave the bomb-deliverer the choice on who to kill, but it isn't how it is supposed to be (and partly explains why "intelligent bombs" still kill significant amount of civilians).
Most movies don't help either.

It may be plentiful, but resources in a solar system are still finite and at some point people have to worry about that.

A good reason to not do war (if we didn't have enough already). But anyway, this argument makes sense as much as if you were saying "we should not shoot because if we do we will exaust the mines of lead".
Is that a good reason to die or suffer? I don't think it is.

Because it's rare, because we're addicted to it, because it's part of some new and exciting fad, etc.

Fun, this reminds me of a guy talking about going on mars to make Martian Wine. I still think it's one of the few things that can pay for themselves if done correctly. It is also totally ludicrous, and would make Zubrin go mad.

did you just claim that you were deliberately trying to argue with and otherwise antagonize people just as a "fact finding" exercise?

No, I'm just saying that if you state what you know with some superiority, you are going to attract the attention of those that like to think they are more right than you (which is pretty much anyone else with enough time to type).
It's fun for both sides (I like debating, and the other doesn't debate if he does not like debating), and in the end is a win-win for me. I either prove I'm right or I learn something new.

Sometimes backfires and I'm stuck debating with morons that keep repeating the same shit all over again, but on this forum it works like a charm (must be that the discussion rules are slightly stricter and such morons get banned ).

How is this better than just asking questions

I don't know why, but it seems to be so from direct experience. Must be that nitpicking is fun, or that winning a debate is fun for people.

and why is it not trolling, exactly?

Trolling is causing an emotional response for fuck's sake going off-topic, but what I say usually springs a discussion on in-topic matters (it's what I want).

[Swindle1984]

Duhhhh, I don't know, threaten to blow the ship to kingdom come if they don't comply?

That's a threat only if there is a human crew.

Or if the cargo is more valuable than the ransom.

[someone_else]

They are trivially easy to dodge or destroy unless they have bullshittium as missile drive technology

Well, I'd say it is the opposite, they are easy to dodge only if the target has a truly overpowered torch drive (and this is another very common occurrence in most modern science fiction). Otherwise there is very little to do (you accelerate at 10, 100 milligees, and the thing has a chemical rocket that can thrust at gees or more).

I could throw a coke can in it's path and let it's own speed kill it.

The countermissile has to be guided too, otherwise it won't hit a damn thing beyond a few km, and a few km for a thing doing 3-4 km/s is a second or less.
Also, the KKV swarm can contain tiny counter-counter-KKVs if the commander so wishes.
There is hopefully a lower limit on their sizes since they have to be guided.

I could possibly laser it and let its own debris throw it off course.

Killing them usually means it can no more compensate your burns and then even a fart is enough to evade it. Blowing it up with a laser is a much more time-consuming thing to do.

What a laser can reliably do, is fry their sensor optics (that must point at the target) at truly stupendous ranges. Lasers excel at eyeball-frying operations. A countermeasure is placing a laser receiver on them and remote-guide them with your sensors (that are designed to be harder to kill this way as described in my answers to Formless above).
Their operational range gets shorter (less than a few light-seconds) due to light lag now.
If you make them work as a collective swarm (again, by placing mirrors and detectors on some of them and linking them up with a photonic laser thruster, like what I said to Formless above), then they cost more but don't need a sheperd spacecraft.

So you can have "short-range" kinds and "cruise missile" kinds with (very) different prices. One-size-fits-all it's still nonsense.

If it burns just to keep up with me, that's that much less it has to hurt me or to cross the distance

The fuel is only used for homing (something else gave it the punch, either a rocket bus or a cannon). It will have some kind of "kinetic warhead" that is a solid slug of dense matter (like this), and the expected damage will have to be calculated without the fuel's mass, for obvious reasons.
That kinetic warhead also doubles as "laser armor", since the laser has to drill through it to kill the vehicle.

How sophisticated is it's rocket too? Can it start and stop over and over again?

Most rocket engines can stop and reactivate easily (the ones used on RCS, and actual modern KKVs). Only the big brawny ones have problems in doing it (since there was no reason to design them to do so), also realistic fusion torches do have some kind of problems in shutting down and reactivating on short timescales.

Cannons to push it off don't help much either.

For "cannon" I meant something like railguns or coilguns, capable of sending stuff to higher speeds. We agree on how those are either horribly hot with waste heat or horribly huge (although very very efficient), respectively.
The usual way would be another rocket stage, that boosts them to speed and then it's discarded. The average chemical rocket (in a vacuum) can give it 3-4 km/s of speed on a nearly instantaneous timescale (less than a minute) then detach.

LOL. Businesses can't plan predictable deliveries ahead of time, but militaries can?

Whut? I only said business won't make a profit on chemical rocket timescales. Planning a route is just (complex) math.

Anyway, how mobile are your settlements? More often than not, they cannot leave orbit (they can change their orbit, but that's no big deal). That's enough for overkilling them with a rain of KKVs. Although structures like dyson spheres (the swarm-of-stations kind, not the shell kind that makes no sense) and your cones would require a prohibitive amount of KKVs.

Why wouldn't you? (allowing aircrafts into habitats)

Maybe it's just because it's useless, all this air makes airborne hazards much more complex to stop (it is going to be recycled much more slowly, so airborne stuff will linger for a longer time), and you also have the problem that stuff closer to the axis has far higher tangential velocity than the stuff on its "ground". That's gonna cause some interesting phenomenon in such air.

Also, because in most habitat designs, aircraft can be hit from anywhere on its surface (the hab has air in the middle and surface on all the sides, there is no horizon to hide the aircraft and you can shoot at it from "above" so flying low is pointless.). Wheel-shaped ones don't have this problem, but flying in a bycicle wheel has its limits.

Moreover, the open spaces provide buffer, so if the planners are imperfect, no big deal. There's extra air, extra water, etc. It lets nature take its course.

Compressed air seems to need less space (duh!). This means that I can have much more redundancy with much less space.

Open spaces with ceilings higher than 50 meters make very little sense unless you have very big trees. And that's pretty low for an aircraft.

Blow something open in the middle of nowhere to minimize collateral damage and fly right in.

yeah, let's depressurize the park for fuck's sake. There is no way to stop the depressurization other than bringing with you a big badass patch.

Or if the cargo is more valuable than the ransom.

That is going to be always the case if there is no crew. Otherwise it won't make any fucking sense to pay the ransom.
If you refuse to pay the ransom, then the pirate just acquired your cargo, but that doesn't mean he just made a profit.
If you were shipping say 1000 tons of nutmeg, those aren't going to be easy to sell for him.
Piracy makes sense if you are carrying valuables like gold bars, that are easily sold.

Also, unless piracy is running wild, there will likely be insurances to cover such loss.

[Bakustra]

Some problems that I have:

Moreover, the open spaces provide buffer, so if the planners are imperfect, no big deal. There's extra air, extra water, etc. It lets nature take its course.

Compressed air seems to need less space (duh!). This means that I can have much more redundancy with much less space.

Open spaces with ceilings higher than 50 meters make very little sense unless you have very big trees. And that's pretty low for an aircraft.

What about for psychological purposes, or for generating natural weather? Surely those might come into question in a space habitat intended for long-term use.

Blow something open in the middle of nowhere to minimize collateral damage and fly right in.

yeah, let's depressurize the park for fuck's sake. There is no way to stop the depressurization other than bringing with you a big badass patch.

What pressures would the habitat ordinarily be operating at? If it operates at natural air pressures then it could take years before the loss of air becomes dangerous, and air can be imported from Earth if necessary.

Or if the cargo is more valuable than the ransom.

That is going to be always the case if there is no crew. Otherwise it won't make any fucking sense to pay the ransom.
If you refuse to pay the ransom, then the pirate just acquired your cargo, but that doesn't mean he just made a profit.
If you were shipping say 1000 tons of nutmeg, those aren't going to be easy to sell for him.
Piracy makes sense if you are carrying valuables like gold bars, that are easily sold.

Also, unless piracy is running wild, there will likely be insurances to cover such loss.

You are aware that most pirates have had, historically, access to free ports where they could sell cargoes? See Tortuga, Malacca, Madagascar, Port Royal- I specifically mentioned that as a condition for piracy to arise for a reason.

[Alerik the Fortunate]

For large rotating habitats, such as O'neil cylinders, it makes little sense to install a second cylinder inside as a ceiling to limit the internal air volume, when it would be simpler, more psychologically helpful, and probably less costly than simply filling the remaining space with air to maintain one atmosphere at ground level. As has been pointed out, full size habitats will be a couple of kilometers in diameter just to maintain gravity at a reasonable rate of rotation. Earlier versions, such as ASTEN will probably consist of smaller prefab modules attached to rotating rings and tethers, and likely have ceilings only in the tens of meters in height.

As space development progresses, there may be waxing and waning of piracy. In the early days, there might not be enough material of value actually in space to make piracy worthwhile, since initially it will be very costly for pirates to set themselves up if the majority of the population and available craft are based from earth. Later on, as colonies become established and far flung, there will be a space based population and infrastructure from which to draw pirates from who might find it profitable to divert some of the by then increasing shipping of material across the solar system. Especially if enforcer authorities are not widespread in some of the newer developments. Possibly later on as the system becomes fully developed and exploited with extensive habitats, shipping might decrease while local authorities would be relatively more powerful. I imagine piracy as we know it would decrease considerably in favor of other forms of theft, assuming society hasn't really really changed by then, since this final scenario would probably take thousands of years to achieve.

[SpaceMarine93]

This whole idea of space piracy is rather silly

First, assuming that FTL is possible, and it is recently considered possible with the verification of the quantum entanglement theory, it would be nearly impossible for space pirates to get the transported cargo - after all, an effective FTL system would allow a ship full of cargo to go from one star system to another with pin point accuracy, meaning that they could, for example, teleport their ship right into the safety of the space dock, or less preferably in the destination planet's orbit, where it would be in protection of the planet's defense systems and space fleets of the authorities. Since most piracy occurs while the ship en route to their destination, far from any protection other then themselves and thereby vulnerable to the pirate ship's weaponry and speed, an effective FTL system in a space opera setting would render piracy too dangerous for the pirates.

And even assuming that the FTL system is inefficient, or non-existent, in hard sci-fi settings, one must consider the economic factors - first, a fully fueled spaceship in itself is already very expensive, in addition to fact that it would have to make maximum use of all available cargo space, a human crew with a fully functioning self-contained life sustaining system that could sustain life for years would drive costs over the roof. So a cargo ship would logically be automated, with no life-support - which makes boarding actions impossible. The life support expenses would apply to pirate ships themselves, so how would it be possible for some poor space pirates to be able to reap economical profits from pirating? (And before anyone starts about automated pirate ships with robotic drones for boarding action, think about how pirates would afford, or be able to get, such advance AI systems in the first place)

Then we have to consider the fact that the lack of a human crew on a automated cargo ship would make room for more, in efficiency and quantity, defense systems, making space piracy far more dangerous for the pirates

The fuel requirements for spaceships in such settings, whether it be normal rocket fuel, solar sails, ion drives or antimatter, would also render one of the main advantages of pirate ships - speed - moot.

Then there are far more other factors I had not thought of.

So, in conclusion, space piracy would not be considered feasible or economical even in a sci-fi settings, thus silly. Anyone here got a counterpoint?

[Samuel]

Travel times add time on top of to that. I frankly don't see a lot that makes sense economically with so long waiting times and what we have already on Earth.

It depends on what you are shipping. If it is a good that is relatively constant (this years metal is a good as last years metal) and the demand is relatively constant and predictable, the long transit times aren't a show stopper. Although they do slow down your cash flow compared to if you could mine them and immediately sell them.

There are surely limits on that, although I'm not able to give even eyeballed estimates. I'm pestering anyone that seems to know a little more about that to get more info.

It depends heavily on how ships are built.

Tanks for example cost millions of dollars. Fighters and bombers even more. Cars however are cheap and most are in the tens of thousands. It depends on how hard the parts are to manufacture, how difficult it is to put them together, etc.

If you are making a spaceship that is inflatable, with an engine and life support attached, I imagine it would be alot cheaper than an atomic rocket.

[SpaceMarine93]

"There are already 70 posts about that"

Well, damn. Sorry about that

[Connor MacLeod]

Dude, its not really fair for you to be mocking when you basically indicated that an entire society could be so accurately modeled that you could dictate whether or not criminal enterrpises would be practical or not.

[bz249]

Travel times add time on top of to that. I frankly don't see a lot that makes sense economically with so long waiting times and what we have already on Earth.

It depends on what you are shipping. If it is a good that is relatively constant (this years metal is a good as last years metal) and the demand is relatively constant and predictable, the long transit times aren't a show stopper. Although they do slow down your cash flow compared to if you could mine them and immediately sell them.

The problem with slow transit times are the following: first the effective throughput of your trade channel is low, thus it gives you a limit how much stuff you can produce on the input side (of course this can be compensated by purchasing more spaceships but that also increases the cost). Even though space is a relatively friendly environment stuff is still degraded there, the slower the stuff, the less cargo runs it can make before it has to be decomissioned, thus amortization costs increase. The ship itself as well as the cargo is a non-liquid asset something which much disliked in economics, because of the opportunity cost... and what's more it can bind even more money because of coverage issues.

So all in all having a buttload of nickel in transit is usually considered a bad investment.

[someone_else]

What about for psychological purposes, or for generating natural weather? Surely those might come into question in a space habitat intended for long-term use.

I've yet to know someone that prefers a rainy day to a sunny day, and you can have perfectly fine forests even without natural weather. Also, natural weather is complex to control, and having people killed by a fucking tornado into a space hab or having your forest ruined by a drought isn't good PR for space colonization attempts.
Anyway, even if you have trees and green stuff around (which is likely), machinery will likely be the one that you count on to save your ass, since you can place far more redundant machinery than redundant forests (not to mention how painful is to keep the fucking ecosystem working at so small scales).

I think of habs as big underground cities, with a huge common park with trees and lakes on top (on the interior surface). Building a hab multiple km wide to live in it with the density of population of a bucolic pastoral world (like depicted in most o-neil cylinder images) smells of libertarian bullshit to me.
I usually assume that "houses" are little more than sleeping and storage places and most of the free time is passed in the park playing with friends or doing stuff with a wi-fi internet connection, and people usually eat at restaurants. But this is my semi-communist utopia where social interaction is encouraged anyway.

What pressures would the habitat ordinarily be operating at?

My point was simply that I don't see the reason to blow holes in a perfectly fine hab and vent its air into space to move into it a vehicle that from a tactical standpoint makes no sense whatsoever. Aircraft in habs can be downed by anyone and their dog, due to the fact that you have the ground all around you, unless you are in a truly mindboggingly huge one.

You are aware that most pirates have had, historically, access to free ports where they could sell cargoes?

I know that most of what passed as "pirates" were in fact privateers, backed by a first-world country (of the times).
But we were talking about asking a ransom for the ship. And you don't ask a ransom when you can just steal the cargo.

Once again, consider the distances involved, especially if you're using very long distances like you seem to be assuming.
One light second is 300,000 km. It's going to take several hours for a fast missile to cross that distance.

Yup. Something going at 3 km/s will reach your hull in 300'000 seconds or 83,33 hours if started at that distance.

But what part of this long-ish voyage does actually matter?
Only when it is in range of your lasers, of course.
It isn't a given that lasers will be able to kill stuff up to light seconds and more.
Let's look at its optic system, say an UV laser (200 nm) reaches an acceptable spot size of 4.8 cm at one light-second, but with a 1.5-km-wide optic system (lens or mirror). Anything else and you do worse (visible light since it has a bigger wavelength, soft x-rays since you have to change the kind of focusing system with a barely cost-effective one).
You also need a rather stable aim. At such ranges (and at much lower ones for that matter) any kind of vibration can throw off your targeting dramatically, so that in reality you are hosing the target, not drilling it.

With something slightly more reasonable, say a 100 meter wide optics, same laser, you get a spot size of 4.8 cm at 20,000 km. So your engagement time is now shorter, around 111 minutes.

Then it all comes down to how good the single KKV's kinetic warhead is (since it doubles as laser armor), and how powerful the laser you have is.
I'm too lazy to talk of it myself, so I'll redirect you here, and also here.
And here is a calculator for pulsed lasers.

In general, even with modern tech we can make KKVs that are more or less immune to lasers with realistic power supplies (although have to be remote-guided or the laser is going to kill its sensors), see the example below.

Just hit it from another angle. A lot of space fight assumptions seem to be one vs one

And for a good reason. Say, you and your buddy have two laser cannons. How can you place your buddy in a position where he can to help killing KKVs with this trick without either going out of range ("behind" you) or becoming itself a juicier target than you ("in front" of you)?

I mean, this tactic has sense only if you have torch engines, so that you can get there faster than the KKVs (and the same engine gives you immunity to such weapons so what the hell are you doing the trick anyway?). And in any case assumes that KKVs can't change target if it is possible to do so. A software upgrade allows them to do so.

That's my point... if your missile has a beefy engine, starting and stopping may not be easy for it.

The big thrust towards the target is given by an expendable booster that works for a few minutes and is discarded, then the KKV just homes on you with thrusters while ballistic. It's a guided projectile, not a proper missile (although uses rocket engines to adjust its course).

Since it is very simple, very small and it doesn't need a friggin huge delta-v like your ship, it can mount engines with much more limited Isp, that have more thrust.

This allows it to change speed faster than you. So even if its delta-v is more limited than yours, it can match course with ease. Remember that you need a while to change your speed if you have milligee or sub-milligee acceleration.

Say, you have an arbitrarily big ship with a torch giving you 1 milligee of acceleration, and a 100 Kg KKV has a satellite thruster like this with 3 km/s of delta-v (mass ratio of 2.84, this thing is 65% fuel), with 10% structural mass and tank mass 10% of the fuel mass (fuel mass is 65 kg). It has three engines placed at the tips of a triangle to give it the ability to adjust its course better. It can carry 13 kg of payload. Say 7 kg for guidance and stuff, and 6 kg of kinetic warhead. Giving it a graphite warhead as an approximation of carbon nanotubes (best material against lasers), graphite has a density of 2.267 kg/m3 it can carry 2.6 cubic meters of the stuff. It is a rod a meter large, a meter wide and 2.6 meters thick. This thing is practically immune to lasers (more due to the huge depth than due to the material).

It can accelerate in any direction perpendicular to its course at 564 m/s, or 57 gees, although it has only 3 km/s of delta-v.
With a fucking satellite thruster.

How much time do you need to "outrun" it? (doing 3 km/s of delta-v with your engine accelerating you at one milligee) 3000/0.00981 = 305810.4 seconds or slightly less than 85 hours. 3 days and a half. Or 8 hours as you said if you have a 10 milligee torch. Because both are torches, remember.
(the calcs were done by a spreadsheet I did with Atomic Rocket's formulas)

You're the same person who attacked VASMIR for the mass of the power plant, yes?

And you're the one that doesn't read the sentence below what you quoted, where I say that railguns and coilguns are cool but usually not that practical for the same reasons of VASIMR.

Yeah, that's the order of magnitude I'd use. Be generous and round up to 10 km/s.

That's a two-stage booster. More bulky and expensive but doable.
In case the guy is getting to your planet, the relative speed target-kkv is much more. Say it was cruising at 30 km/s? If you manage to hit it before the fucker starts the deceleration burn, those are 30 km/s bonus for you. If you hit the fucker when the relative speed was only 10 km/s, that's still 10 km/s bonus for you.

Again, to get better than that you probably need some better engine, that isn't horribly expensive like fusion engines will likely be.

Or use torch-drive-equipped missile buses, that release the KKV at arbitrarily high speeds, then brake and get back home (they aren't expendable).

If you are making a spaceship that is inflatable, with an engine and life support attached, I imagine it would be alot cheaper than an atomic rocket.

Fuel and structural costs are largely irrelevant in spacecraft. It's the systems that cost a lot since they must be more reliable than the average car, and the people preparing and moving around your vehicle before it's ready to be deployed.

In general, military stuff must have much higher reliability than civilian stuff (that is just designed to fail safe). This is one of the reasons for the far higher cost.
In space, you don't want your main engine/life-support to "fail safe" you want it to stay alive no matter what.

[someone_else]

It's natural weather!

I'd call it permanent tornado. To have 1 gee at 3 km (like the average O-neill cylinder), the angular velocity is 0.54 rotations per minute (spincalc).
If we look at the air 1 km from the turning axis (at 2 km from the surface), the circumference is 6280 meters. If the air is still going at the same angular velocity, that's what, 52 m/s?
An aircraft going more or less straight up will have more or less the same transverse velocity of the surface, or around 18.84 m/s.
So the relative speed would be 118 km/h.
It will get shredded by the air movement without any pity.

[someone_else]

Aircraft in habs can be downed by anyone and their dog, due to the fact that you have the ground all around you, unless you are in a truly mindboggingly huge one.

The situation is almost identical to Earth. Aircraft are already easy to spot from a big land area.

Unless they suddenly decide to fly low.

[someone_else]

Yeah, you can fly low in a hab too. It's the same deal.

Nope. They see you from "above", which is the upper surface of the hab. A hab surface is the opposite of Earth's surface, this is bound to change something.

Using them as a "read it and weep" closer is missing the point.

They set higher limits, and that's what matters for their (and our) discussion.
Then you can say "my lasers vibrate too much so their range sucks" or "my lasers generate so much heat that they have to shoot once every minute or they melt" (the real problem is removing heat from the laser components fast enough to have a decent rate of fire, dissipating heat in space is much easier) or even "optics this big cannot be done in my setting" (as there are actual engineering issues in making so big one-piece optic system or collimating enough smaller mirrors with the required accuracy), or even "KKV guidance sucks balls" (although this is somewhat debatable due to the multi-decade experience in making homing missiles and space probes humanity already has).
My point is that you cannot do better than such a situation where everything is assumed to work perfectly without handwavium.

In grade school, I remember something about a three sided shape. I think they were called 'triangles', but it was so long ago, damned if I remember. But, if my cobwebby brain is working, they came in an equilateral variety too.

Less mocking and more explanation of the master plan please.

I was thinking about hitting the KKV from a direction where it does not have the kinetic warhead (which is basically from any direction that isn't "front") to have more or less an instant-kill, but you seem to have a different plan in mind, like sending it off course with its own ejected material.

You're not even consistent with your own tech assumptions. You said in an earlier post that, and I quote "(hey, the scales involved tell that even spacecraft with the same course will have around light-minutes of distance between them)"?

The wonders of out-of-context quotes. Next time you're so desperate, check my math. It's almost guaranteed to be full of mistakes you can slap on my face.

Anyway, in the part you quoted I was talking of cargo ships going about their own business with no particular interest in each other (answering to Formless about the distances between such cargo ships for pirating purposes).

The safe distance between crafts is much less, a few km is more than enough even if you have unshielded radioactive parts.

Giving it a graphite warhead as an approximation of carbon nanotubes (best material against lasers), graphite has a density of 2.267 kg/m3

BIG mistake. graphite density is 2.267 g/cm3 ---> 2267kg/m3
The thing in the example above is

Aerogel

. Which considering its thermal and bulk proprieties, isn't so bad. But wasn't what I was selling you.

Now, with a 6 kg piece of goddamn graphite I have 2647 cm3 or 2.6 dm3 of the stuff, so a shield 30x30 cm and only 3 cm thick. Which is good only if your lasers suck (see example below).

To get what I said in the post above I have to multiply the goddamn KKV mass by 10. A 1 ton KKV with the same delta-v has 180 kg of payload, let's shave 10 kg for computers and stuff, and we have a kinetic warhead of 170 kg, with graphite a 75'000 cm3 or 75 dm3 warhead. A shield 30x30 cm and 83 cm thick.

With a 2-ton KKV we have 350 kg of kinetic warhead (already shaved the 10 kg or so of computers), 154'400 cm3 or 154.4 dm3 warhead. 40x40 cm and 96 cm thick.

With this slightly higher mass, the acceleration becomes much more manageable, in the realm of 2-6 gees. Feels much better now.

I guesstimate the exhaust velocity of this makeshift rocket to be somewhere in the ballpark of 1000 s, based on kinetic energy, really not half bad.

lol What the hell is 1000 s? Isp? You need the amount of ejected material to calculate the thrust and get an acceleration at the end. Isp just tells you the fuel endurance.

So, playing with a 100kw laser (assuming it is a laser creating a 100 KW beam, requiring likely more than 100 KW to work due to efficiency and stuff) and the laser calculator above:
100 pulses, 1 joule per pulse, 10 milliseconds between each pulse (the output of this is very close to 100 KW). With a spot size of 0.7 millimeter you have a drilling speed of 2.45 mm/s in nanocarbon/fullerite material. If you keep drilling for 6 seconds in the same spot (a 600-pulses burst) you can drill up to 1.45 cm of such armor.

45 pulses, 1 joule per pulse, 10 milliseconds between each pulse. With a spot size of 0.7 millimeter you have a drilling speed of 3.78 cm/s in "armor steel" material (whatever that may mean) and you have a max drilling depth of (aspect ratio of 20) 1.66 cm of such armor (metals give more way when drilled by lasers, so the hole is slightly larger). In this case you only have to shoot on the same spot for 0.44 seconds.

Now, let's assume the most favorable armor material for the attacker (the metal plate). In 0.44 seconds you're vaporizing a cylinder with 0.7 mm of diameter and 16.6 mm high. So, it's 10.56 mm3 of steel leaving the hole per 0.44 seconds ---> 24 mm3 ---> 0.024 cm3 of steel per second are ejected. Iron has density of 7.87 g/cm3, so that's a little less than 0.2 g of steel per second.

By Atomic rocket's equation page: F = mDot * Ve (mDot is the mass flow, in kg/s and Ve is the exhaust velocity in m/s)

Now, let's say this ejected iron is plasma, traveling at 100 km/s. It is wildly unlikely to be plasma and to go so fast, but who cares.

F= 0.0002*100000 m/s =20 newtons.

Now we can calculate the acceleration a=F/m

a (100 kg)= 20/100 = 0.2 m/s ---> 0.02 G

a (1 ton) = 20/1000 = 0.02 m/s ---> 0.002 G

How much time you need to have it miss by laser power alone?

Given a 100 KW, UV laser (200 nm) using a 100 m wide optic system, you can have the spot of 0.7 mm only if the target is at 300 km or less. Given the closing speed of 3 km/s, that's 100 seconds you can shoot at it before impact.
In 100 seconds you can only force it to expend 0.2*100 = 20 m/s from its reserves if it is a 100 kg KKV or 0.02*100 = 2 m/s if it is a 1 ton KKV.

Cold gas maneuvering thrusters are more than enough to compensate this acceleration on this timescale. Although probably something like this is what an actual designer would choose.

Ooops, the rocket wasn't designed for that kind of precision and it fires 22 milliseconds instead.

The engine I linked is an example to show how even tiny engines can give the KKV a respectable performance. Actual KKV designers will likely place engines more suited for the job depending on the laser they are designed to ignore.

(the best part about that is it's a last second clever luck thing instead of a boring "they launched 14 missiles and we can only handle 13 might as well just shoot ourselves")

What you were describing is a guidance failure. It's a little like playing russian roulette and hoping to win. You have no control on such odds. Compare to a cinematic (but nonsensical) evasion maneuver where everyone is tossed around, and you see why most authors prefer the second to this russian roulette.

the missile might know to plow into the side.

Nonsense. its speed is perpendicular to the target. It can do a near-miss, leaving a scratch of varying depth/lenght on the hull (if you have a hull anyway), or it can miss.
To plow into your side it must expend its whole delta-v in less than a second. Doable for a nuke (maybe), but not for a rocket.

The thing is 100 kg total, quite large if you ask me.

Big as a projectile but well within antiship missile sizes.
The corrected KKV above at 1-2 tons is within the sea-based torpedo weight scale. Call them Space Torpedoes if you wish.

[Beowulf]

The corrected KKV above at 1-2 tons is within the sea-based torpedo weight scale. Call them Space Torpedoes if you wish.

Your KKV is coming up on the size of my fighters!

Shit, the lightest modern fighter is around 7 tons in weight. Your average medium range air-air missile weighs around a quarter ton.

[someone_else]

In *both* cases there's threats from above. The difference is in a habitat, the size is constrained. Only things inside will get you, since outside stuff have the hull between you and them.

Yup. It's the kind of threat from above that changes. On Earth the only threats from "above" are other fighters, and those have a upper limit in both altitude and number the enemy can realistically field (for relatively high-tech modern versions, that is).

The relatively limited hab volume and the fact that there is ground above and at the sides as well means that WWII-like flak cannons or more modern self-propelled stuff still make sense, since now they can all be linked to feeds from radar/IR/whatever spotters scattered on the "ground" that is all around the airspace, thus shoot in areas where the fire control computers predict your fighters will be by the time their shots get there.
They basically shoot indirect and this way even flying low is pointless (the reason to fly low is that you don't give them enough time to detect you before you are already out of the firing range, while being too fast to be tracked by their guns all the times).

Also, prey that they don't decide to install anti-aircraft lasers, or you are pretty much fucked. You can't compete with a laser cannon using the Hab's power lines.

An hab internal space is a barrel, and aircraft in it are fishes.

Now of course not all habs are going to be so well defended (although flak cannons and spotter posts can be expensive, aero-space fighters aren't going to be cheaper for sure), but hell, why using aircraft only to stomp beggars? Do we want to have AC-130-equivalents even in a space setting?

I mean, after the first successful military campaign, the other habs with money and afraid of you will likely start making flak cannons and radar/IR/visual spotting platforms.

Also, what benefits gives you an aircraft that a missile-launcher or a more common artillery gun cannot replicate in this limited spaces? You are flying with a big badass manned vehicle with a limited payload when you could use tiny unmanned drones, and use their data to call in a (very dumbed down) cruise missile or artillery shooting guided rounds, or artillery barrage of non-guided rounds.

You will have to use infantry and artillery anyway, so why adding stuff that is clearly redundant and not so useful?

The green ships are me (big dots). The big red dot is you. Both my ships are equally far away from your ship, so they are equal targets. Here, they are also equally far from each other, but this isn't always necessary. Bigger separation means bigger angles on the targets.

This assumes I have to launch the KKV from more or less laser range (Me, you and your buddy form a equilateral triangle If I understood correctly).
I can see you from much longer distances, can you tell me why should I stay so close?
I'll show you an image of what I mean, similar symbols.

I don't know the image posting rules and I'm too lazy to look them up, so here is a Link To An Image that won't upset anyone with the mod hat.

In the image linked, I'm at around 2-3 times your laser range. Note how the KKV can simply be redirected on your buddy by telling them to do a burn at the black circle point (or before, or after for that matter). Otherwise I can simply shoot KKVs at your buddy in the first place.
If this happens, you cannot help your buddy and he is fucked since the armor is now facing your buddy and you are out of range for most of the KKV's trip.
Note that I'm assuming all spacecraft are practically immobile, since that's more or less what they are when compared to KKVs. If your spacecraft can outmaneuver the KKVs, they can do this trick on a moment's notice, but if they can outmaneuver the KKV they can just evade it with ease.

The point you keep missing is that KKVs don't have a "range" like lasers but just an endurance. You can then pick the distance you want and launch them. Of course if you are already in close range and the enemy is already in this formation you are somewhat fucked, but unless you do so obvious mistakes, there is no reason for that to happen.

As a note, it's not really likely that the enemy will let you drill. If he rotates, you can't easily hit the same spot twice.

While it is a smart trick, rotating tends to complicate the maneuvering since your engines are turned around so they have to fire in pulses or be placed on canfield joints, also there are fuel settling issues so you have to design the fuel tanks and piping specifically with rotation in mind. They tried to do something like that with ICBMs but ended up as "not worth it".

A more realistic reason why it's unlikely you'll stay in the same spot is vibrations caused by machinery transmitted to the aiming optics.

In any case, what you are doing is drilling. And just like when you do it with a hand drill, if you don't have a steady hand you'll do scratches and not holes, but you are using a drill anyway.

Laser combat vs an armored target is something you're in for the long haul (unless you have god lasers), slowly melting out grooves until you hit something sensitive. This is why the speed of the KKV is such a big deal - it gives you a lot of time to zap away at it.

You're assuming you can zap from very long distances, when I said lasers don't have so huge drilling ranges as you may think. If you are thinking about "heat beam" ranges, you are just half-right. The ranges are much more, of course, but "heat beams" do close to nothing unless they are aimed at sensitive equipment or are staggeringly high-powered. See below.

Similarly, spot size doesn't matter much, since you aren't drilling anyway!

This. Is. Wrong. If your spot is too wide, you are just heating the fucker up, and doing that is kinda pointless, since to boil off the shield you have to use a buttload of energy.

Say it is a 100 kg plate of graphite, that has 117 KJ/mol of fusion and is 12.0107(8) g/mol. So to melt the block of graphite you need to pump into it:
(100000/12.0107)*117 = 974'131 KJ

Now, your 100 KW laser must shoot on it for 9741 seconds or a little more than 2 hours to melt it.
I know what you are thinking, but wait a second to declare victory.

The thing is radiating IR away as any hot object and may re-radiate away enough heat to passively cool itself after it has reached a certain temp.
Let's have a look at how much energy is re-radiated away since I have a gut feeling that you need a bigger laser.

100000/2.267 = 44111 cm3 of volume, or a 40x40x27 cm box. This box has a total area of 8000 cm2, let's say that one of the sides of the plate is in contact with the spacecraft so it cannot radiate anywhere. So we remove 2000 cm2 and are left with 6000 cm2.

Carbon sublimates (no liquid carbon? lol whut ?) at 3915 Kelvins, so that's the temp I'll try first in the radiator spreadsheet I made with the radiator formulas from Atomic Rockets.
radiator area = 0.6 m2
Radiator temp = 3915 K
Emissivity = 0.98 for graphite (from here)

The spreadsheet gives 7832.27 KW of energy re-radiated away. So you need a laser able to dump 8 megawatts or so in the plate, or it reaches thermal equilibrium much before sublimating.
Probably this kind of temp is slightly too much for the stuff behind the plate (the vehicle part), thus you'll need some kind of insulation between them and the shield. If the insulation endures half as much (say 2000 kelvins), you are still forced to dump on the plate half a megawatt (555 KW).
Still, aerogel can be made of carbon too, so its sublimation point remains pretty much the same as the shield. Thus it can do its job until the shield itself starts to sublimate, forcing you to shoot multi-megawatt lasers at it.

They say nanocarbon tubes (and graphene for that matter) should have much better heat-dissipating properties (some say like copper, some say more), but since they are still in their infancy, graphite is the best thing I can find reliable stats of (well, there are diamonds that can do better, but those are kinda expensive).

That would make it miss by a lot if it's rocket is anything less than perfect...

Why should it be so hard? Those are maneuvering thrusters, specifically designed to do very short and very precise burns. They are available today and were available ten or even 20 years ago. There are engines pointing in the opposite direction too (since turning the whole KKV to maneuver tends to take lots of time and such engines weight little), that can be fired up to correct any misfire of its companions in real-time.

It won't be 100% perfect every fucking time, but it won't be always at risk to miss due to failures either. Satellites use these kinds of engines all the time (relatively speaking), and so far the number of guidance failures is acceptably low.

You have no control over most things in a combat situation.

I was just saying that in a story it's just a deus ex machina. At the second or third time the reader will get bored. Having the crew perform something, (anything) to make the deus ex machina happen is usually better for the audience.

It just needs to hit the side with some speed and let the target's speed let the weapon rip into it lengthwise. It's not literally making a 90 degree turn.

First it doesn't have enough smarts to do a correct hit (much easier) and then tries to pull off this trick? Anyway, given a 3 km/s speed, if you have a 6 km long ship it will maybe manage to kit within the last km or so (one sec to realize the error and fire up the engines and less than one sec to land on you), if your ship is shorter, you can safely write it off as a miss.

Your KKV is coming up on the size of my fighters!

They are dangerously underweight for an aircraft. While stuff designed to work only in space like Jules Verne ATV has a pretty low dry weight (jules verne ATV is 1.5 tons empty and dry, and 20 tons fully loaded and with full tanks), and relatively low total mass if you use torch engines, an aircraft must be bigger since it has wings and turbofans, and maybe a stronger frame.
I mean, the half-ton Bede is the smallest turbojet in existence, but I doubt it has anything more than the bare-bones of instruments, and with only 200-300 kg of payload for a civilian version, it won't get very far as a military aerofighter.

Something like the japan's suicide bomber Yokosuka MXY7 Ohka (so much for those that thought W40k's grot bomb launchas were fiction... damn Japan and their sillyness ) is another aircraft in the same size category (2 tons or so). You have 1.2 tons of payload (the warhead in the original design) that can be used to make it airtight and give it a short-endurance life support Mercury capsule after reentry weighted 1 ton, dump the reentry shield and pilot weight already included in the aircraft and it's in the 0.6-0.7 ton range).
This leaves you with 0.4-0.5 tons of actual military equipment, radars and other stuff.
As an aside, they built 750 of these things, launched a hundred or so and sunk just one ship? (and damaged a bunch of others) I'm impressed by the huge effectiveness. What a waste of lives.

Serious aircraft, like these are within 10-30 tons when fully loaded.

It all comes down on how good materials and engines you have and how lightweight your systems are, but since you are going to make them both space and atmospheric-capable, that will add mass for systems that will be unnecessary in either one or the other environment (say radiators or heat-distribution for your machinery).

[someone_else]

Possibly. Depends how many there are, if I can destroy or surprise them, etc.

With your cone of habs unbelievably close and loads of stuff jumping from a hab to another, you should be able to surprise them easily.
Although flak cannons aren't going to fall so easily as lascannons, due to the sheer number of such platforms and their spotters (while lasers being much more expensive will not have this advantage).

Thankfully this madness doesn't apply on my habs. The "ground" is the recreational park, while the "underground" is the place where everything worth capturing is (railroads, fabs, homes). It is mostly a slugfest for infantry, at most riding bicycles due to relatively tight quarters that don't allow vehicles (other than trains anyway).

Aircraft can go in first, see more, and hit specific targets to clear the way.

This works (poorly) on Earth, when you can stay out of the antiaircraft defenses by flying high (also flying high helps spotting since your horizon is farther). In habs you are well within flak cannon and SAM range and you cannot get higher than that. Also, with spotters placed outside of the hab hull in the window sections you see all you need to see.

I say it works poorly since gathering intel about stuff is more about “look what goes on for a few weeks” than “send an already armed vehicle that will look at stuff for less than half an hour before shooting”.

If you care about civilian and friendly-fire casualities, that is.

Even the change you depicted in the picture is a delta-v of maybe 2km / sec depending on scale and speed assumptions.

Yeah, Realized it afterward that it's kinda stupid to not launch the KKV directly to your buddy.

I'm your intellectual superior in every conceivable way.

Hardly difficult, really. What I'm trying to do is learn something while trying to demonstrate that you are wrong. Being smart (or claiming to be such) does not make you automatically right.

I say I'm stupid because I should have disregarded how I handle the KKVs in my own setting (where lasers suffer some drawbacks I imposed them to feel them realistic, or at least different from the mainstream) and used immediately the standard answer.

Give up the armor (armoring the whole thing isn't impossible even without making them more massive since there is no reason to have a 80 cm thick frontal shield against a pathetic 100kw laser like the 1-ton and 2-ton KKV specimens have), leaving a reasonable kinetic warhead to simply boost numbers.

Say that to kill a semi-naked KKV you need 3 seconds (sum of eyeballed target acquisition and lasing time, feel free to say otherwise)

For each 10 KKVs you kill, I bought 30 sec for the others.

So, given that you will likely be able to kill them from say 900 km even with a 100kw laser since they are nearly naked, the closing time is 300 seconds.

So, I need to deploy 100 KKVs per laser to buy time for all the others above the 100th to make hull contact.

In this case, the KKVs are going to be rather simple and lightweight (relatively speaking) affairs.
You may remember Rick called them “Soda Cans of Death” in his blog.
And here I'm using your mass-production claims against you, for the cost of doing so.

Let's say a KKV masses 30 kg, Some real ones mass 60 kg so I think it can be done.
It has less than one Kg left for kinetic warhead (1.57 kg of total payload), but it doesn't matter much. three DST-100A give it a 0.3 G acceleration, 3 km/s of delta-v.

Their booster stage is a fuel tank with this engine and a KKV guidance system. It can boost 300 kg at 3 km/s. It weights 1.5 tons (payload included), and carries a hundred of such KKVs.

With 3 tons I overwhelmed your 2 "hose" lasers, and any KKV launched after them will likely hit (if your lasers are your main defense anyway, at this point is more cost-effective to pack anti-KKV and leave lasers at home).

In comparison, the 1 ton and the 2-ton KKVs would have massed 5 or 10 tons (respectively) with their booster stage included.

If you launch early enough, I can fire my engines and outrun them. Stalemate.

Not necessarily. How much delta-v do you have in your tanks? I mean, Ok you outrun them but you expend the same amount of delta-v as their maneuvering thrusters (3 km/s in this case).

For example, I shoot a KKV swarm (let's pretend it is a credible threat for the sake of this example) at you, you evade it, I shoot a second KKV swarm at you, you evade it, and so on and so forth.
If I shoot 10 KKV swarms piecemeal like this I forced you to waste 30 km/s of delta-v in evasive maneuvers.

You must plan to carry more fuel for such evasive maneuvers, or you are going to end with dry tanks while you haven't yet done the deceleration burn. (i.e. die in deep space)

For example, a torchship able to thrust at 4 milligee and go to Jupiter in 3 months and a half, capable of carrying around 500 tons of payload and with enough fuel only to do the Earth-Jupiter trip has 400 km/s of delta-v.

Since you are likely going to engage it during the deceleration burn, it will have only 200 km/s left (those 200 km/s are all needed to brake it down and enter planetary orbit, but anyway).

To exhaust its delta-v supply you only have to launch 66 KKV volleys more or less piecemeal. Each volley is composed of say 300 Soda Cans Of Death+booster stage, total mass of 4.5 ton per volley. That's 297 tons total (and if launched together less than 1/4 of that scores an overkill and likely 1/2 of them piecemeal is more than enough to force it to expend too much fuel even for abort courses). Compare to the mass of your laser.

If you launch too late, you're already killed by my own weaponry. You lose.

If you launch in the middle, I might kill you, kill your weapons (whether by laser or counter-missile), or I might throw it off course. Could go either way.

Again, why should anything other than KKVs get in your range at all? I have longer range than you.
If I'm trying to defend my planet from your incoming armada, you are half-right, since it is a head-on charge and when I'm after you I cannot do a U-turn to follow you (nor launch any KKV at you). Still, it doesn't mean the crewed ships ever get in range (they can move laterally and you can bet your sorry ass that after they deployed the KKVs they are going to be a great deal lighter).

But that ain't the only possible battleground (and technically it would be a massivley advantageous battleground for KKVs, due to the fact that it's likely to be an encounter with massive speed difference between combatants, more than 10 km/s total even with chemical rockets).

Note the rotation doesn't have to be fast or tumbling; it can simply spin very slowly and still work.

Any kind of rotation will push the propellant around with its centrifugal force, causing fuel settling problems. Any rotation makes maneuvering a pain since your engines are moving as well.

Anyway, if a laser can shoot in a single point so precisely that rotating the whole thing is useful, then you can move the laser's focus as well to stay on the same spot even if the thing is rotating.

but conduction isn't infinity, not even in graphite.

Not to nitpick, but that's exactly what you are assuming for your lasers. Your laser assembly will lose heat to the coolant at the conduction speed of its material. This is one of the reasons why lasers in my setting aren't "hoses" that keep shooting for hours. They need time to cool down after some shots. Or do you assume electric-motor levels of efficiency?

Plugging in your numbers for depth, I estimate my spot size will have to be a diameter of < 7 cm to heat the impact area faster than it can conduct heat away.

Can you write how you reached this conclusion? I'm interested in the heat formulas part.

wtf. Shooting down the enemy with your standard weapons isn't what comes to my mind when someone says "god". It seems to me to be more like "standard procedure".

You have a short memory, I'll show you how this side-thread started. You said: (the best part about that is it's a last second clever luck thing instead of a boring "they launched 14 missiles and we can only handle 13 might as well just shoot ourselves")

If you count on guidance failure to save your ass from the 14th, then it's a deus ex machina that happens because God (the writer) Wants It. You may make it look natural, but it's just a show of dumb luck (and not of skill) of your charachters. Not something you can abuse of in a story.

When it fails, the stupid AI single-mindely continues going after it's target. It just tries to get from where it is to where it wants to be, even if where it is isn't ideal.

This is how missiles work in computer games (where stupid single-minded AIs abound), but not in real life.
Primarily because to the contrary of computer games, missiles don't have full 360° sensor coverage due to space, mass, power and safety reasons.
In a computer game it's vastly easier to use the “move to coordinates” macro they already made for NPC spacecraft movement, so you get missiles that “home on you” regardless of any other factor, like interposing objects or the fact you can sometimes outmaneuver them.
In the case of realistic missiles, if the target goes out of their sensor arc (bigger or smaller depending on the missile performance), they lose track. Most missiles I know of self-destruct in this case (to avoid locking on the first cool-looking contact and blow up innocents).
Note that the sensor arc size is designed with missile performance in mind. Only stuff with better handling than the missile can evade it by exploiting this limited sensor arc. Usually missiles are designed to outmaneuver anything they are designed to hit. Of course missile failures and deploying countermeasures can still save your ass as normal.

This is just to say that assuming weapon designers can't do better than computer game designers is a bit of a stretch (technically the latter wants you to stay alive and have fun, designing a game that kills the players no matter how good they are is devastatingly easy even without cheating, by implementing basic fire-control algorithms and basic tactics).
Once the KKV realizes that it can no more successfully home on target (for whatever reason) its programming will likely tell it shutdown or enter hibernation mode (if they plan to recover it anyway), not do some random pointless shit.
If it can still home on the target (say the enemy vessel is unusually long), it will still try to do so even if the damage dealt will not be optimal.

Coming up on != greater than or equal to.

Sorry, didn't know that. What you wanted to say with “Your KKV is coming up on the size of my fighters!” then?

[someone_else]

Woops. Stupid math mistake. Correcting.

Their booster stage is a fuel tank with this engine and a KKV guidance system. It can boost 300 kg at 3 km/s. It weights 1.5 tons (payload included), and carries a hundred of such KKVs.

Note the bolded part. It should have been 10, since each KKV is 30 kg.

With 3 tons I overwhelmed your 2 "hose" lasers,

30 tons, not 3.

Each volley is composed of say 300 Soda Cans Of Death+booster stage, total mass of 4.5 ton per volley. That's 297 tons total

That's 45 tons and 2970 tons respectively.

[someone_else]

How do they move bulk machinery or other cargo around?

Trains mostly. It's not like the fabs, the markets and the docks change place overnight. They don't have to move stuff the size of aircraft carriers on a regular basis either, although the railroad tunnel size is big enough to accommodate something like that if necessary (those require them to stop all other trains sharing the big tunnel, just like truly oversized loads do on highways).

Keep in mind that to launch the next volley, you'll have to fire your own engines to counter my movements. So it comes down to who has more propellant left or who has a base more within reach.

Lol? I aim them to a different area of space and start the booster engines. They work like artillery, even if they use rockets instead of cannons. If you are still in their range, artillery doesn't need to move and neither does a KKV launcher.
You just dodged the bullet.

Today, space solar panels give about 100 W / kg

The SAFE (scroll down a little) is a better choice imho. To make 500 kw you need 2.5 tons, plus say 8 tons or so for thermal management. It weights a little more, but is better if you want to use the craft in the outer system too.

So about 15 tons for my whole weapon package, rounding up individual pieces available with today's technology. So, ton for ton, it looks like we're about even.

I have to disagree . You are missing a critical (and rather heavy) piece of machinery. The optics system. Without it you are shooting a laser flashlight.

It is a 100-meter-diameter beast, likely made of adaptive mirrors (to havedecent accuracy, you know) massing likely in the hundreds of tons (here the guy throws around a 30kg/m2 and says it is lightweight, the area of a circle of 100 m diameter is around 7853 m2 = 235.6 tons, being in space it can be somewhat flimsier, but yeah). Plus the support and something to protect the mirror from space debris when not in use (a fucking 100-meter wide shutter, no less).

So you have 15 tons for the machinery plus something between 100 and 200 tons for the optics and shutters.

I, with the numbers from above: mass of kkvs + booster needed to kill a single lasership with that laser is somewhere around 200, so we are looking at 200/10*1.5 ton=

30 tons for KKVs Vs 100-200 tons (and a huge surface to hit due to either cooling systems, solar panels and the mirror) for a LaZoR.

If a KKV does down in mass, it also goes down in effectiveness...

Only if you have some kind of armor. "Civilian" whipple shields are made to stop relatively tiny stuff, anything bigger than an artillery shell (going at 2+ km/s) will get through laughing.

lasers also have the advantage of being reusable, if not smashed in battle.

They are expensive and easy to damage (very big optics means you have to shield 100 meters from micrometeors and other kinds of tiny crap) and as any high tech stuff managing lots of energy they require lots of servicing and checks, while KKVs are cheap and require minimal checks once in a while.

It might be that my ships have sufficient speed to dictate the range. Either through less mass, more propellant, or coming in on a transfer orbit.

I generally tend to assume that space combat is done by blind drone warships (although laser-equipped ones use their laser as a ladar and their optics as a telescope as well) controlled by unarmed sensor-equipped crewed vessels. The crewed vessels are generally designed to easily outperform warships (not that hard, being very light in comparison), so that the command ship is practically never in danger no matter the outcome.

KKVs are most effective if you are using our high relative closing speed against me. That same situation means I'll be getting closer to you every second.

You are getting close to the unmanned KKV barges (second-hand cargo ships or similarly cheap transports). The manned vessels can stay in any of the other two dimensions (not in front, not on the back of the brages), well beyond your laser range.

If someone engineers a situation so a strategy has a high chance of failing and it fails, it's not just dumb luck.

How exactly can you put a KKV in high chances to fail? I'm curious.
I generally assume a 20% failure rate due to random malfunctions and shit (heh, mass production does this about quality), but it isn't exactly caused by the enemy.

Great, so they simply give up if I throw an obstacle at them. They just went from a 1% chance of victory to a 0% chance. Good for me.

Newsflash: KKV are remote-controlled until the last couple seconds where their sensor unshutters and activates (just like their real-life counterpart i linked above). Why? Because their sensors are tiny, and their sensor range sucks balls as a result.
Also because otherwise it's a joke to fry their sensors with a wide low-power laser beam.

Otherwise you have to make something much more complex with photonic laser thrusters, mirrors and KKVs carrying the detector. That's a cruise-KKV swarm with a far higher price tag.

Specifically, I like to put them in the ballpark of ~10 tons (give or take). If you loaded my fighter with just a handful of your missiles, you'd have doubled it's mass!

I'm pretty fine with it. How many torpedoes can a real fighter craft carry around anyway? One? Two?
Although I think that using fighter craft to deliver KKVs will eventually kill your pilots of boredom.

[someone_else]

If I just literally ran away, you've gotta make up for my backward motion or it will never connect.

If you are "running away" you are either getting far from the thing I'm protecting (so I'm fine with it) or I have already lost. In either case there is no need to shoot at you.
In any other case, it's very likely I can just point where you are headed and launch. It will take maybe a few more hours, but it's time while it is out of your weapon range anyway, so it doesn't matter a lot.

The important thing is the power to mass ratio, and you just pointed to something with a higher one

An actual space-capable reactor will likely have a worse mass ratio than your solar panels. I pointed it out because you may want your laser ship to be useful beyond Earth orbit. At mars the solar irradiation drops to 1/3 or so, and in the outer system is pratically nonexistant (it is detectable but not useful for solar panels).

note that I'm perfectly ok with a heat beam at 1000 km (and a mirror of 5 meters)

Ah, ok. Scratch the above. But you have a spot of 48 cm diameter at 1000 km (if using a UV laser) or around one meter (if using a visible light laser).

I wonder how much time do you think it will take to kill one of my naked KKV with this weapon.

I'm in no rush to take you down.

At 3 km/s (assuming KKV have only 3 km/s relative to you) 1000 km is around 333 seconds. Assuming you will need 3 seconds to take down each KKV (both target acquisition and lasing time), that's 340 KKVs needed to overwhelm such system. 340/10*1.5 is around 51 tons, say we want to land 40 hits and there is a 20% natural failure rate it's 390 KKVs. I'll round it up to 400 so it becomes 60 tons.

You had your laser into the 15 tons.

I can only say a KKV swarm is vastly cheaper than your vessel and that doesn't require any mainteneance.

How exactly can you put a KKV in high chances to fail? I'm curious.

Shooting at it.

So it is just a matter of numbers then. Once there are enough KKVs you lose no matter what. And we return to your initial sentence "they launched 14 missiles and we can only handle 13 might as well just shoot ourselves"

In such a situation, given that KKVs need a while to make contact (or even to get into your laser range at all), you have a while to see you have no chance and surrender. Maybe in a more desperate situation than that, say you can stop 15 and there are 30+ KKVs coming at you.

In my setting the winner usually asks the command vessels to detach their main fuel tanks (so they can no more maneuver for a while), or fire off all offensive KKVs.

Then, if the loser complies, the attacker's KKVs are redirected and the command vessels are captured (when the rest of the enemy fleet gets up to them anyway).

Spacecraft crews are officers, their value as prisoners is usually very high.

Sweet, I can focus fire on your remote controllers and take out all the drones at once.

They are called remote for a reason, you know. They won't stay anywhere near your laser range.

And as I said above, making sensors immune to wide-beam lasers (what a laser does when it is 10 or even 100 times its nominal range) is possible if you have enough space and photonic laser thrusters (and they aren't expendable).

[someone_else]

An actual space-capable reactor will likely have a worse mass ratio than your solar panels.

A clarification: that reactor generates 400 kw thermal, of which only 100 kw are converted to electrical power, so in the end you have still 300 kw thermal to place somewhere.
Scaling up, to generate 500 kw electric for your laser is generating in fact 2 MW thermal total, so there are 1.5 MW of waste heat to dump somewhere.
So, while the reactor itself may have a better mass ratio, you are wasting (much) more space in cooling systems.
Solar panels cool themselves passively most of the times (the back is always in shade after all).

[someone_else]

Or, it was my first wave of many. If you don't shoot at them, they finish the strike. If you do shoot at them, they fall back and let the next wave try again, probably from a different angle to avoid mines.

I can hold fire until you can no longer fall back without any problem. Say, your crafts have 1 milligee acceleration and my KKVs go at 3 km/s (ignoring the boosting time since it's less than 3 minutes and the timescales here are in hours), if I open fire when they are at 9'000 km from me (arbitrary distance to make math easy), the KKV will make contact in 1000 seconds. In 1000 seconds you can change your speed in any direction by at most 9.81 m/s. Big deal if you want to evade.

So, why should you split your forces in waves? That way I can overkill each wave with ease.
If they attack all toghether, a lot of them will get shredded, but the bigger is the shitstorm the more ship you should manage to slip through. You must have good numbers though.

(btw by mine I mean a kkv that opted not to fire it's rocket and instead wait there to chase down the second wave, rather than wasting their time chasing the runners)

Unfired KKVs stay onboard their carriers. Which are cargo spacecraft, with interplanetary-trip engines (fusion drives, torches, what have you). This allows them to relocate themselves with a performance comparable to your spacecraft.

It'd be quite interesting to actually put myself in orbit, so my ships can cycle the waves for free.

And my KKV can stay on retrograde orbits and go up your ass at 14+ Km/s of relative speed. Or I can just send buckets of sub-orbital KKVs (that need tiny delta-v in comparison to stuff that sends payloads in orbit) and still impact with you at around 8 Km/s using your own orbital speed against you with modern ABMs (although I have only two chances to make contact, once while outbound and once while inbound, then it reenters atmosphere).

Anything in LEO is shredded in minutes after launch, anything beyond has a few hours to surrender.

I spent a few minutes last weeking seeing if I could change my RTS to include orbits, so we could simulate this kind of thing.
Alas though, everything moving didn't jive well with the classic Warcraft style of control so it sucked. I'll have to make a new game for it. I really want to do some playing with gravity tactics though.

Orbital combat games are difficult to make due to complex math involved in most maneuvers, like say changing orbital inclination although would make a rather interesting game.
Just be sure you have a guy with some experience in orbital navigation. You can also have a look at this.
Also, if Phil Eklund's High Frontier boardgame is an example, you'll likely want to place "orbital rails" to hide the math needed to do everything.
If you have a computer game, it is much easier to give the players more freedom.

The reactor your pointed to had a better mass ratio than my solar panels...

Yup, I clarified above in a second post. Nuke plant's relatively low mass ratio is misleading. They generate a whole lot of waste heat, and don't have a so huge surface to dissipate it as solar panels, so they need much more cooling system mass, while solar panels are usually fine with passive cooling.

Another thing I can do is have multiple ships fire on the same target, blanketing it in intense heat... I figure about ten of my ships focus firing can triple their range; laser range depends on a lot of factors. (because the square root of ten - distance and area)

It is kinda expensive, but if you can't make 15-meter mirrors, it's the only choice.

You now have a megawatt over that same area (more or less, depends on precisely they can coordinate).

5 meter mirrors shooting at 3000 km (which seems to be "three times their range" that was 1000 km and 7 cm of spot, which gives me a 300 nm light) have a spot size of around 21.6 cm diameter. Say that they can perfectly focus fire and that's 1 MW on 346 cm2, or 0.00289 MW/cm2 ---> 2.89 KW/cm2

A single ship shooting at stuff at 1000 km with the same laser has a spot of 7.2 cm diameter. 100KW/40.7cm2 = 2.457 KW/cm2

I just remembered a thing, your heat rays can be harmlessly redirected by modern laser mirrors. This modern laser mirror can survive intensities of up to 500 kw/cm2, and one can go up to 1 MW per cm2. The laser guy of Atomic Rockets (luke campbell) claims they can go up to 5 MW per cm/2 but the link is broken.

Not that I advocate using such mirrors on KKVs (expensive!) but as spacecraft armor they would be awesome.

If they are too far away, they won't be able to do their sensor job very well. (remote controllers)

Not really, I can have a rather intriguing resolution at a fucking huge range without using a particularly huge mirror. "the astronomers were able to see details on the scale of one milli-arcsecond, corresponding to being able to distinguish, from the Earth, the headlights of a car on the Moon."

For remote sensor platforms the only show-stopper is light lag.

[someone_else]

Overall though, the player shouldn't have to do much math, since he can visually enter his goals and let the computer do the rest.

I like the concept, it seems like what Homeworld should have become in the future. Gimme a call when it's ready.

(it's a drilling laser at closer range, resorting to heat ray effects here due to the distance to target)

Heh, do you remember how crappy range it had in drilling mode, right? And also how pointless it is when drilling.

If you let stuff get this close, you are already dead.

With a little luck, some micrometeor impacts will ruin that beautiful surface for me

It can either be made of sections that can be changed in-flight (although not in-battle), or covered with some kind of whipple shield before the battle.

Ah! Remeber the mirror of the Venture Star (from Avatar)? The mirror could be pivoted to show a whipple shield in the direction of travel.

The trick to overcoming them is the pulse intensity or maybe the wavelength

In theory, the stated kw/cm2 number is for the wavelenght they are optimized for (99% or so). But since for all other wavelenghts they are still 97% or so reflective, it's not a so dramatical decrease in kw/cm2 resistence.

If lasers are expensive to maintain, ship armor made of laser mirrors would be nuts.

Well, since it doesn't have to focus a laser, and that it isn't an adaptive mirror, it can be far cheaper and much easier to mantain than real laser optics. Although will still be expensive and relatively fragile.

I still believe that staying out of range and launching KKVs remains a more sensible choice, given the enemy.

Looks like were back to the eyeball frying contest...

If your laser can go that far and still have a decent output. Using photonic laser thrusters makes the sensor much more resistent since each sensro now receives light from very distant mirrors. Shining the laser on all the mirrors will be impossible and targeting (due to range) will be very hard.

[Connor MacLeod]

Since I'm bored, I thought I'd just point out that I ran across a bit on the economics of piracy, which gives an insight into modern piracy. It doesn't neccesarily guarantee space pirates but it can help put the topic in context I think.