Hypothetical Interstellar Warfare Scenario

[Zaune]

So, I'm working on some SF fanfic that hasn't been posted here yet with a plotline that is going to proceed roughly thus:

There are two civilisations; let's call them Race A and Race B for now. Race A is mostly still confined to one planet, with a handful of colonies on its moons and the next planet over and some tentative plans for space habitats. Overall technology level is intended to be about where we would have been by now if NASA's budget had stayed at 1969 levels. The only thing Race A have that we don't at least on paper (yet) are somewhat rudimentary FTL communications and a prototype Alcubierre warp drive. At the time of the events of the story, they have precisely one working FTL spacecraft which is a test-bed and research vessel converted from an asteroid mining tender, but the shipyard did find room for a warship-grade railgun and some missile-defence lasers. Refitting existing warships is probably not all that feasible, but if absolutely necessary they could probably scrounge up a dozen more of the same design as the testbed within a year and a half.

Speaking of warships, the eight or nine major spacefaring nations have about forty proper warships between them as well as roughly two hundred lightly armed patrol boats for search and rescue, anti-smuggling and general law-enforcement out on the edge of inhabited space. A handful of the richer nations have small numbers of SSTO spaceplanes that can carry some armament, and nearly every country can at least put a communications satellite in orbit. A few of the larger and wealthier nations have nuclear weapons, many others could probably acquire some without much trouble if they felt the need, but they haven't known real war in two or three generations so there's not much call for them.

That brings us to Race B. They're somewhat more advanced than Race A in certain areas; they've had FTL comms much longer and have refined it enough that their Internet equivalent is fully interplanetary, their terraforming capabilities have enabled them to put permanent colonies of some kind nearly everywhere in the system and they have artificial gravity. They don't currently have a warp drive, but as soon as they realised someone else did then a whole hell of a lot of R&D money was diverted to rectifying this deficit. Their military is much larger, capital ships numbering in the low hundreds, but it also has its hands rather full with internal security at the moment.
Politically, they're almost completely unified, though not exactly through choice; about fifty years before First Contact, one large power bloc started swallowing up some of its smaller neighbours and things kind of snowballed into forcible annexations and eventually flat-out wars of conquest... which they won. They have elections and a parliament, but actually getting -or more importantly keeping- a seat in it entails all but selling yourself into indentured servitude to your campaign contributors so describing it as a democracy is stretching it a bit. They're not particularly evil but they're repressive, imperialistic and possibly expansionist, with a side order of deeply unethical medical experiments that Race A finds out about accidentally in the course of making contact.

To say that diplomatic relations are not terribly convivial is probably putting it mildly. It didn't quite come to an outbreak of open hostilities but there was a nasty stand-off after Race A received and granted a request for political asylum that Race B were keen to contest. As Volume 1 ends, domestic opinion on Race A's homeworld is pressing hard for diplomatic overtures to be made to the remnants of the losing side in the aforementioned wars of conquest and Race B is debating whether or not they have a casus belli that will look convincing in the media. But neither of them have ever actually fought an interstellar war before and in-universe they're not honestly sure how they should go about it if and when it proved necessary.

Out of universe, I'm trying really hard to keep this as hard-SF as possible and haven't really got a plan for Volume 2 yet, so I'm hoping the collective knowledge and wisdom of this forum can help me work out something that will make sense and still be interesting.

Oh, and the Alcubierre Drive's top speed is about one lightyear a month, and it turned out that the theory about a massive and deadly energy release whenever you turn it off is absolutely true, as Race A found out when they accidentally blew up a dwarf planet. Weaponising this is off the table in-story by way of an unspoken mutual consensus along the lines of, "if you don't try and do it to our noncombatants, we won't try and do it to yours". Race B is slightly more likely to be the first one to break said agreement, having a previous history of breaking out the salted nukes to make examples of their enemies, but have never previously been in a position where they might have to take it as well as dish it out.

So... Is it possible to write a thrilling tale of interstellar space warfare and still be a harder SF writer than David Weber, or do I need to think of something else?

Oh, and I'm not naming the story, but it's online elsewhere on t'internet and if anyone guesses right I'll say so.

[krakonfour]

I'll comment as I go along.

So, I'm working on some SF fanfic that hasn't been posted here yet with a plotline that is going to proceed roughly thus:

There are two civilisations; let's call them Race A and Race B for now. Race A is mostly still confined to one planet, with a handful of colonies on its moons and the next planet over and some tentative plans for space habitats. Overall technology level is intended to be about where we would have been by now if NASA's budget had stayed at 1969 levels. The only thing Race A have that we don't at least on paper (yet) are somewhat rudimentary FTL communications and a prototype Alcubierre warp drive. At the time of the events of the story, they have precisely one working FTL spacecraft which is a test-bed and research vessel converted from an asteroid mining tender, but the shipyard did find room for a warship-grade railgun and some missile-defence lasers. Refitting existing warships is probably not all that feasible, but if absolutely necessary they could probably scrounge up a dozen more of the same design as the testbed within a year and a half.

Nope. Railguns and lasers are extremely energy intensive. Depending on what your warship uses as a drive (nuclear thermal for example), it might have to install a power generating station just for the new weapons, driving your mass requirements sky high.
The simplest refit of a civilian craft into a military craft that does not require a complete restructurizing in terms of energy production and management, not to mention adequate aiming and target identification hardware, is to load it with missiles.

Missiles are self-powered, self-propelled and self-aimed if done correctly. For the launcher, it is no different from carrying around a few tons of rocks.

Speaking of warships, the eight or nine major spacefaring nations have about forty proper warships between them as well as roughly two hundred lightly armed patrol boats for search and rescue, anti-smuggling and general law-enforcement out on the edge of inhabited space.

I'm, dubious about the need for 200 patrol boats.
By definition, a smaller spacecraft is not more useful than a larger one in space, except for the cost. It all depends on the mass ratio, and that can be equal for a 1000 ton or 1 ton spacecraft.

Plus... law-enforcement in space? Are you going to tell the smuggler to cut the engines and prepare for docking? This is space. He'll keep on drifting at the initial trajectory, and docking can be prevented indefinitely by simply telling the crew not to wear spacesuits. If the police enter forcefully, they depressurize the hull and kill everyone.

The only real law enforcement is before launch and after entering orbit. There, you can prevent the craft from leaving, and they will be forced to dock with a space-station lest they starve or run out of oxygen. So yeah, there is no need for hundreds of small, lightly armed useless craft. You need 2 and a bunch of orbital weapon platforms.

One craft sits at launch and only comes near the suspicious craft if they obtain a surrender. If they do not, the orbital weapon platform can blast them with power much greater than the patrol craft could ever handle. At destination is the same thing. You allow entry into your orbit only if the airlock is open for you to enter and inspect. If not, boom up to thousands of kilometers away.

A handful of the richer nations have small numbers of SSTO spaceplanes that can carry some armament, and nearly every country can at least put a communications satellite in orbit. A few of the larger and wealthier nations have nuclear weapons, many others could probably acquire some without much trouble if they felt the need, but they haven't known real war in two or three generations so there's not much call for them.

You have spacecraft travelling at dozens of kilometers per second just to get into space. Having nuclear weapons or not doesn't seem so big anymore when each private SSTO shuttle has enough kinetic energy to level a city.

That brings us to Race B. They're somewhat more advanced than Race A in certain areas; they've had FTL comms much longer and have refined it enough that their Internet equivalent is fully interplanetary, their terraforming capabilities have enabled them to put permanent colonies of some kind nearly everywhere in the system and they have artificial gravity. They don't currently have a warp drive, but as soon as they realised someone else did then a whole hell of a lot of R&D money was diverted to rectifying this deficit. Their military is much larger, capital ships numbering in the low hundreds, but it also has its hands rather full with internal security at the moment.
Politically, they're almost completely unified, though not exactly through choice; about fifty years before First Contact, one large power bloc started swallowing up some of its smaller neighbours and things kind of snowballed into forcible annexations and eventually flat-out wars of conquest... which they won. They have elections and a parliament, but actually getting -or more importantly keeping- a seat in it entails all but selling yourself into indentured servitude to your campaign contributors so describing it as a democracy is stretching it a bit. They're not particularly evil but they're repressive, imperialistic and possibly expansionist, with a side order of deeply unethical medical experiments that Race A finds out about accidentally in the course of making contact.

It would be funny if Race A doesn't mention the medical experiments they found to race B because they are making a fuss out of something race B finds completely normal.

I mean, if they are completely different species, applying your own ethical code to the other is straining things a bit. Do I judge octupuses when they eat hundreds of their own young?

To say that diplomatic relations are not terribly convivial is probably putting it mildly. It didn't quite come to an outbreak of open hostilities but there was a nasty stand-off after Race A received and granted a request for political asylum that Race B were keen to contest. As Volume 1 ends, domestic opinion on Race A's homeworld is pressing hard for diplomatic overtures to be made to the remnants of the losing side in the aforementioned wars of conquest and Race B is debating whether or not they have a casus belli that will look convincing in the media. But neither of them have ever actually fought an interstellar war before and in-universe they're not honestly sure how they should go about it if and when it proved necessary.

Interstellar war? Unless you are going to duke it out in the emptiness between the stars, then it's pretty much going to be identical to interplanetary war with the added step of switching on the warp drive for a bit.

Out of universe, I'm trying really hard to keep this as hard-SF as possible and haven't really got a plan for Volume 2 yet, so I'm hoping the collective knowledge and wisdom of this forum can help me work out something that will make sense and still be interesting.

Oh, and the Alcubierre Drive's top speed is about one lightyear a month, and it turned out that the theory about a massive and deadly energy release whenever you turn it off is absolutely true, as Race A found out when they accidentally blew up a dwarf planet. Weaponising this is off the table in-story by way of an unspoken mutual consensus along the lines of, "if you don't try and do it to our noncombatants, we won't try and do it to yours". Race B is slightly more likely to be the first one to break said agreement, having a previous history of breaking out the salted nukes to make examples of their enemies, but have never previously been in a position where they might have to take it as well as dish it out.

So... Is it possible to write a thrilling tale of interstellar space warfare and still be a harder SF writer than David Weber, or do I need to think of something else?

Oh, and I'm not naming the story, but it's online elsewhere on t'internet and if anyone guesses right I'll say so.

Alcubierre drives that explode violently when you switch them OFF? Heck, you've got your FTL missiles ready and prepped. All they need is a drive and energy source. Switch them on, travel to target, return to normal space and boom! Entire fleet dead in port.

[Zaune]

Guess I'd better do the same.

Nope. Railguns and lasers are extremely energy intensive. Depending on what your warship uses as a drive (nuclear thermal for example), it might have to install a power generating station just for the new weapons, driving your mass requirements sky high.
The simplest refit of a civilian craft into a military craft that does not require a complete restructurizing in terms of energy production and management, not to mention adequate aiming and target identification hardware, is to load it with missiles.

Missiles are self-powered, self-propelled and self-aimed if done correctly. For the launcher, it is no different from carrying around a few tons of rocks.

The justification for railguns vs missiles is that railgun ammunition is a) significantly cheaper and b) can be made in the field out of readily obtainable materials. The first FTL mission was designed in the expectation that they'd be spending two years away from home and couldn't expect resupply flights. The lasers also aren't that big a deal as the ship was originally designed for turning chunks of asteroid into refined metal.

I'm, dubious about the need for 200 patrol boats.
By definition, a smaller spacecraft is not more useful than a larger one in space, except for the cost. It all depends on the mass ratio, and that can be equal for a 1000 ton or 1 ton spacecraft.

Plus... law-enforcement in space? Are you going to tell the smuggler to cut the engines and prepare for docking? This is space. He'll keep on drifting at the initial trajectory, and docking can be prevented indefinitely by simply telling the crew not to wear spacesuits. If the police enter forcefully, they depressurize the hull and kill everyone.

The only real law enforcement is before launch and after entering orbit. There, you can prevent the craft from leaving, and they will be forced to dock with a space-station lest they starve or run out of oxygen. So yeah, there is no need for hundreds of small, lightly armed useless craft. You need 2 and a bunch of orbital weapon platforms.

One craft sits at launch and only comes near the suspicious craft if they obtain a surrender. If they do not, the orbital weapon platform can blast them with power much greater than the patrol craft could ever handle. At destination is the same thing. You allow entry into your orbit only if the airlock is open for you to enter and inspect. If not, boom up to thousands of kilometers away.

Hmmm. You could be right there. I'll have to rethink that one.

You have spacecraft travelling at dozens of kilometers per second just to get into space. Having nuclear weapons or not doesn't seem so big anymore when each private SSTO shuttle has enough kinetic energy to level a city.

Perhaps, but they're quite difficult and expensive to manufacture and the chances of actually needing one are fairly remote, so not many nations bother. If they needed that sort of capability in a hurry they'd more likely go the Project Thor route.

It would be funny if Race A doesn't mention the medical experiments they found to race B because they are making a fuss out of something race B finds completely normal.

I mean, if they are completely different species, applying your own ethical code to the other is straining things a bit. Do I judge octupuses when they eat hundreds of their own young?

They aren't. The medical experiments in question are controversial enough that even Race B's government is subjecting them to public inquiry, and the two species actually have similar ethical codes overall. Which is maybe not all that original or realistic, but such are the constraints of crossover fanfiction.

Interstellar war? Unless you are going to duke it out in the emptiness between the stars, then it's pretty much going to be identical to interplanetary war with the added step of switching on the warp drive for a bit.

Come to think of it, Race A have only ever considered that as a purely theoretical possibility, but good point.

Alcubierre drives that explode violently when you switch them OFF? Heck, you've got your FTL missiles ready and prepped. All they need is a drive and energy source. Switch them on, travel to target, return to normal space and boom! Entire fleet dead in port.

It's not quite that simple, unfortunately. It's not really possible to steer the ship when under warp because it's impossible to see out of the warp bubble, so they'd need to know exactly where the enemy installation was to within a fairly small area -a few seconds of such a missile's flight time- in order to achieve a good effect on target. That would require extremely good intelligence, better than either side currently has on the other. Also, "in port" usually means in a parking orbit or docked with orbital facilities above a planet or moon, usually (but not always) one with a civilian population.

[krakonfour]

The justification for railguns vs missiles is that railgun ammunition is a) significantly cheaper and b) can be made in the field out of readily obtainable materials. The first FTL mission was designed in the expectation that they'd be spending two years away from home and couldn't expect resupply flights. The lasers also aren't that big a deal as the ship was originally designed for turning chunks of asteroid into refined metal.

Actually... umm, unless you want to discuss Railguns vs Missiles in your setting, I won't answer this, okay?

Perhaps, but they're quite difficult and expensive to manufacture and the chances of actually needing one are fairly remote, so not many nations bother. If they needed that sort of capability in a hurry they'd more likely go the Project Thor route.

What I meant was that if you have drives with nuclear-weapon-levels of energy density, then there is no need for a nuclear warhead on top of the weapon. If you have a nuclear missile with a fusion drive, drop the warhead and just ram the drive into the enemy.

They aren't. The medical experiments in question are controversial enough that even Race B's government is subjecting them to public inquiry, and the two species actually have similar ethical codes overall. Which is maybe not all that original or realistic, but such are the constraints of crossover fanfiction.

Maybe they've established a common rule of conduct beforehand? For example, no torturing prisoners to get information out of them. Then they see Race B doing that very thing on their own citizens, leading to legitimate outrage. Meaning, if race B thinks it is wrong enough to agree that it is so with another species, then it is wrong for their own population too.

It's not quite that simple, unfortunately. It's not really possible to steer the ship when under warp because it's impossible to see out of the warp bubble, so they'd need to know exactly where the enemy installation was to within a fairly small area -a few seconds of such a missile's flight time- in order to achieve a good effect on target. That would require extremely good intelligence, better than either side currently has on the other. Also, "in port" usually means in a parking orbit or docked with orbital facilities above a planet or moon, usually (but not always) one with a civilian population.

Humm. If they can't see out, and the enemy can't see them coming (faster than light... what are going to detect them with? Light?) then what you need is a form of 'hyperspace skipping' where they periodically enter and leave the warp bubble. Getting detected is not a problem because by the time the enemy sees your after-image, you've already arrived.

Also, when you're dealing with an interstellar war between species, with their survival at stake, then civilian casualties are at the bottom of the list of important problems. At the very least, they'd think: Ok, it's bad to kill civilians, but of their warships are destroyed, then they have no way to reach us and retaliate!

It's one of the can of worms opened by FTL travel.

[Simon_Jester]

I'm, dubious about the need for 200 patrol boats.
By definition, a smaller spacecraft is not more useful than a larger one in space, except for the cost. It all depends on the mass ratio, and that can be equal for a 1000 ton or 1 ton spacecraft.

The main reason for smaller craft is size- hm.

The main reason to need a lot of hulls is to police a lot of traffic. If the traffic is orbital, "patrol craft" would be shuttles with very minimal delta-v, just enough to change orbits and refuel automatically from orbital fuel dumps. They might not be armed, as you speculate, since they are designed to operate in a volume of space that is entirely under the guns of heavier orbital weapon platforms.

On the other hand, the "patrol craft" might be long-duration vessels designed to keep up a steady, circulating presence among remote outposts (i.e. asteroid colonies), which are spatially far apart. If there are hundreds of things to police, and moving from one to the next takes several days, then you need a lot of hulls to keep up a significant police presence.

Such craft would probably be quite bulky to provide room for all the stores they'd need, and the relatively bulky living quarters it takes to keep people from going crazy on three or six-month long patrol cruises.

Plus... law-enforcement in space? Are you going to tell the smuggler to cut the engines and prepare for docking? This is space. He'll keep on drifting at the initial trajectory, and docking can be prevented indefinitely by simply telling the crew not to wear spacesuits. If the police enter forcefully, they depressurize the hull and kill everyone.

Given the consequences of rogue spacecraft (i.e., being hazards comparable to large, fast-moving meteors), the patrol might well be empowered to do exactly that- and the smugglers would quickly learn that the patrol will kill you if you resist, even passively.

A handful of the richer nations have small numbers of SSTO spaceplanes that can carry some armament, and nearly every country can at least put a communications satellite in orbit. A few of the larger and wealthier nations have nuclear weapons, many others could probably acquire some without much trouble if they felt the need, but they haven't known real war in two or three generations so there's not much call for them.

You have spacecraft travelling at dozens of kilometers per second just to get into space. Having nuclear weapons or not doesn't seem so big anymore when each private SSTO shuttle has enough kinetic energy to level a city.

The main difference is that a nation with its own nuclear missiles can, for example, build nuclear-tipped ABMs that will very reliably shoot down an incoming private SSTO shuttle that threatens to crash into them- or, heck, conventional weapons capable of doing the same, though that's a little harder.

Nuclear weapons can be used for defense as well as offense.

Alcubierre drives that explode violently when you switch them OFF? Heck, you've got your FTL missiles ready and prepped. All they need is a drive and energy source. Switch them on, travel to target, return to normal space and boom! Entire fleet dead in port.

Yeah, the alpha strike potential of this weapon is terrifying. The only effective counter is to have a deterrent force parked somewhere the enemy's first strike can't reach, which would do the same thing to their home system that they just did to YOU.

[Simon_Jester]

If ammunition constraints are an issue, you should just stick with the lasers- they have longer effective range by orders of magnitude, and you can't run out of (precisely shaped, heat-resistant) coilgun slugs.

Also, magnetic mass drivers are highly subject to barrel wear- they burn out, and the components for the guns are probably not replaceable in the field. The main reason to bother with them is if for some reason it matters that you use a physical projectile as your attack- say, because you're firing a guided shell, or because you're firing a shrapnel shell that bursts into pieces and saturates a small volume of space with fragments to increase hit probability against a soft target. A laser cannot do either of those things.

[krakonfour]

The main reason for smaller craft is size- hm.

The main reason to need a lot of hulls is to police a lot of traffic. If the traffic is orbital, "patrol craft" would be shuttles with very minimal delta-v, just enough to change orbits and refuel automatically from orbital fuel dumps. They might not be armed, as you speculate, since they are designed to operate in a volume of space that is entirely under the guns of heavier orbital weapon platforms.

On the other hand, the "patrol craft" might be long-duration vessels designed to keep up a steady, circulating presence among remote outposts (i.e. asteroid colonies), which are spatially far apart. If there are hundreds of things to police, and moving from one to the next takes several days, then you need a lot of hulls to keep up a significant police presence.

Such craft would probably be quite bulky to provide room for all the stores they'd need, and the relatively bulky living quarters it takes to keep people from going crazy on three or six-month long patrol cruises.

I see your point.
In a setting with relatively slow travel, having a large number of craft designed to deal with a large number of distant areas is logical.

I wrote on the assumption that there are points A and B with nothing between them. The best solution was therefore to control the departure and arrival points, preferably holding incoming craft at a high orbit before they are inspected and cleared to descend to low orbit.

In the case of asteroid colonies and multiple points of departure/arrival, having more then just a few craft becomes sensible.

However, I have no idea how long it takes to travel in the setting, nor how prevalent asteroid colonies and moon bases are.

Given the consequences of rogue spacecraft (i.e., being hazards comparable to large, fast-moving meteors), the patrol might well be empowered to do exactly that- and the smugglers would quickly learn that the patrol will kill you if you resist, even passively.

Not in all cases though... maintaining your parking orbit or heading in a trajectory which takes you away from a settlement won't make you a threat.

The main difference is that a nation with its own nuclear missiles can, for example, build nuclear-tipped ABMs that will very reliably shoot down an incoming private SSTO shuttle that threatens to crash into them- or, heck, conventional weapons capable of doing the same, though that's a little harder.

Nuclear weapons can be used for defense as well as offense.

It's just that the OP mentioned them as a weapon with a level of power requiring a distinction between the haves and have-nots. Conceivably, a railgun is a more effective anti-ballistic system, at least because it won't create nuclear fallout and a huge thermal shockwave when it is used.

Yeah, the alpha strike potential of this weapon is terrifying. The only effective counter is to have a deterrent force parked somewhere the enemy's first strike can't reach, which would do the same thing to their home system that they just did to YOU.

And then we've got a very fun story involving Mutually-Assured Destruction and twiddling thumbs during a political debate.

More:

If ammunition constraints are an issue, you should just stick with the lasers- they have longer effective range by orders of magnitude, and you can't run out of (precisely shaped, heat-resistant) coilgun slugs.

Also, magnetic mass drivers are highly subject to barrel wear- they burn out, and the components for the guns are probably not replaceable in the field. The main reason to bother with them is if for some reason it matters that you use a physical projectile as your attack- say, because you're firing a guided shell, or because you're firing a shrapnel shell that bursts into pieces and saturates a small volume of space with fragments to increase hit probability against a soft target. A laser cannot do either of those things.

Lasers need more power, a continuous waste heat management system and a large vulnerable lense. Plus, shooting things from drive-limited power levels of distance is basically the most boring slugfest ever.

In fact, if lasers are powerful enough that they can damage enemies from lightseconds away, then equal-powered railguns will never get a hit on target, and equal-massed missiles will be shot down by lasers unless you shoot a megaton worth of material at the enemy.

On the side, coilguns solve all the problems of railguns. Plus, you can shoot pretty much anything from a coilgun by using a recoverable bucket to hold the projectile.

[Borgholio]

Yeah, the alpha strike potential of this weapon is terrifying. The only effective counter is to have a deterrent force parked somewhere the enemy's first strike can't reach, which would do the same thing to their home system that they just did to YOU.

Reminds me of that thread a couple months ago about RKV combat. The only sure-fire way to survive an RKV attack is to be so spread out that they can't get you all, then launch your counterattack with assets that are similarly spread out.

[krakonfour]

Yeah, the alpha strike potential of this weapon is terrifying. The only effective counter is to have a deterrent force parked somewhere the enemy's first strike can't reach, which would do the same thing to their home system that they just did to YOU.

Reminds me of that thread a couple months ago about RKV combat. The only sure-fire way to survive an RKV attack is to be so spread out that they can't get you all, then launch your counterattack with assets that are similarly spread out.

The Fermi Paradox?

[Zaune]

Actually... umm, unless you want to discuss Railguns vs Missiles in your setting, I won't answer this, okay?

We can, but it's not really important at this point; warships in the setting are equipped with both, though Race A uses them rather more extensively while Race B treats them as a secondary weapon only, and both have their pros and cons.

Simon already covered the kinetic bombardment versus nukes angle.

Maybe they've established a common rule of conduct beforehand? For example, no torturing prisoners to get information out of them. Then they see Race B doing that very thing on their own citizens, leading to legitimate outrage. Meaning, if race B thinks it is wrong enough to agree that it is so with another species, then it is wrong for their own population too.

Pretty much; they both independently came up with laws and customs of war that broadly overlap, and neither civilisation has a totally spotless record when it comes to adhering to them.

Humm. If they can't see out, and the enemy can't see them coming (faster than light... what are going to detect them with? Light?) then what you need is a form of 'hyperspace skipping' where they periodically enter and leave the warp bubble. Getting detected is not a problem because by the time the enemy sees your after-image, you've already arrived.

Creating a warp bubble is a lot less energy-intensive than sustaining it afterwards, but that could work. In principle it's not much different to what they do in the normal course of an interstellar transit, making two or three jumps of one or two light-years at a time with short stops to take position fixes and course adjustments.

Also, when you're dealing with an interstellar war between species, with their survival at stake, then civilian casualties are at the bottom of the list of important problems. At the very least, they'd think: Ok, it's bad to kill civilians, but of their warships are destroyed, then they have no way to reach us and retaliate!

It's one of the can of worms opened by FTL travel.

But if you miss a few warships, or they had a couple of extra installations you didn't know about, the survivors will be pissed. Additional complicating factors, at least in Race A's case, include the likelihood of the military refusing to carry out an unlawful order and/or the civilian population reacting very badly indeed to mass murder being committed in their name.

By definition, a smaller spacecraft is not more useful than a larger one in space, except for the cost. It all depends on the mass ratio, and that can be equal for a 1000 ton or 1 ton spacecraft.

The main reason for smaller craft is size- hm.

The main reason to need a lot of hulls is to police a lot of traffic. If the traffic is orbital, "patrol craft" would be shuttles with very minimal delta-v, just enough to change orbits and refuel automatically from orbital fuel dumps. They might not be armed, as you speculate, since they are designed to operate in a volume of space that is entirely under the guns of heavier orbital weapon platforms.

On the other hand, the "patrol craft" might be long-duration vessels designed to keep up a steady, circulating presence among remote outposts (i.e. asteroid colonies), which are spatially far apart. If there are hundreds of things to police, and moving from one to the next takes several days, then you need a lot of hulls to keep up a significant police presence.

Such craft would probably be quite bulky to provide room for all the stores they'd need, and the relatively bulky living quarters it takes to keep people from going crazy on three or six-month long patrol cruises.[/quote]

Little of column A, little of column B. There aren't any asteroid colonies as yet but there's a lot of 'factory ships' that turn chunks of asteroid into refined materials for return to the populated regions. (They used to use the asteroid capture method advocated by Planetary Resources until someone got their sums wrong and nearly clobbered their homeworld with a rock the size of Luton, after which some payload restrictions were imposed.) Some of these ships have quite large crews, bored and sexually frustrated crews with access to moonshine, and it's rare but not unheard of for two or more of them to get into an argument over a particularly valuable claim. There have also been a handful of hijackings and one or two acts of genuine space piracy on the heavily-trafficked orbits between the homeworld and the larger colonies.

Given the consequences of rogue spacecraft (i.e., being hazards comparable to large, fast-moving meteors), the patrol might well be empowered to do exactly that- and the smugglers would quickly learn that the patrol will kill you if you resist, even passively.

Sort of. Passive resistance just means the patrol boat will forcibly attach itself to the docking collar and its crew will take an acetylene torch to the airlock before sending in the heavy mob with flashbangs and automatic weapons. Actively resisting, ie by standing in an airlock taking potshots with a rifle, is grounds for immediate escalation to "disabling fire"... Which is a polite euphemism for "aiming for a part of your ship where there's a small chance you won't immediately suffer explosive decompression and/or rapid inflight disassembly if you are very very lucky". Not many people are dumb enough to try.

If ammunition constraints are an issue, you should just stick with the lasers- they have longer effective range by orders of magnitude, and you can't run out of (precisely shaped, heat-resistant) coilgun slugs.

Also, magnetic mass drivers are highly subject to barrel wear- they burn out, and the components for the guns are probably not replaceable in the field. The main reason to bother with them is if for some reason it matters that you use a physical projectile as your attack- say, because you're firing a guided shell, or because you're firing a shrapnel shell that bursts into pieces and saturates a small volume of space with fragments to increase hit probability against a soft target. A laser cannot do either of those things.

That's part of it, but Race A's state of the art in laser weaponry just isn't very good; it creates much more waste heat and takes up much more space than a mass driver for comparable energy delivered to a target. And part of the reason their prototype FTL ship even has it in the first place was that it already had a cargo mass driver fitted from its previous career; all the yard had to do was neck down the calibre a bit and amp up the muzzle velocity.

[krakonfour]

The caliber of a railgun has absolutely no effect, and increasing the muzzle velocity mostly means that you have to increase the switch rate and capacitor size of the assembly. There is a point where the magnets just cannot scale up their power output anymore, and when you are half-melting through your barrel with every shot anyway, the limit is quickly reached.

Laser weaponry is effective in that it will always hit, and it can deal the same damage from a much farther point. Plus, you can scale the attack (useful for neutralizing enemy craft) or render the spacecraft useless without damaging it (blind the sensors or cut off the radiators).

[Simon_Jester]

I see your point.
In a setting with relatively slow travel, having a large number of craft designed to deal with a large number of distant areas is logical.

On top of that, in a setting with faster travel (and, logically, more powerful engines), the total number of bases, installations, and settlements will tend to proliferate. So the police cars are faster, but there's more places to patrol and cover, so you still need a lot of them.

Plus, you need to remember that the total size of a fleet is defined not just by the number on duty, but by serviceability. In a real navy, very few of the warships are at sea at any one time under peacetime conditions. In a space fleet, the spacecraft might need several months of refurbishing and maintenance between cruises; the Space Shuttle did.

Given the consequences of rogue spacecraft (i.e., being hazards comparable to large, fast-moving meteors), the patrol might well be empowered to do exactly that- and the smugglers would quickly learn that the patrol will kill you if you resist, even passively.

Not in all cases though... maintaining your parking orbit or heading in a trajectory which takes you away from a settlement won't make you a threat.

But being a spacecraft which feels free to ignore traffic control instructions makes you a threat by default- if not today, then some time next week.

It's just that the OP mentioned them as a weapon with a level of power requiring a distinction between the haves and have-nots. Conceivably, a railgun is a more effective anti-ballistic system, at least because it won't create nuclear fallout and a huge thermal shockwave when it is used.

A typical nuclear-tipped ABM (or light surface-to-space missile, which amounts to the same thing) would have a warhead in the single-digit kiloton range. Since it's going off in the high upper atmosphere, it's not much of a threat to anyone on the ground unless the EMP is frying satellites, which might be an issue if you're not careful.

Meanwhile, a railgun is essentially a glorified version of a WWII AA gun and runs into some of the same problems. Even if its muzzle velocity is much higher than the orbital velocity of a re-entering target, it's still a hard ballistics problem to solve with an unguided projectile. Guided missiles are far more likely to actually hit the target. Plus, unless the railgun shells themselves mount very large warheads (which makes them extremely heavy), they lack the 'blast' capability of a surface to air missile, which becomes even more obvious when you're thinking about nuclear-tipped ABMs.

More:

If ammunition constraints are an issue, you should just stick with the lasers- they have longer effective range by orders of magnitude, and you can't run out of (precisely shaped, heat-resistant) coilgun slugs.

Also, magnetic mass drivers are highly subject to barrel wear- they burn out, and the components for the guns are probably not replaceable in the field. The main reason to bother with them is if for some reason it matters that you use a physical projectile as your attack- say, because you're firing a guided shell, or because you're firing a shrapnel shell that bursts into pieces and saturates a small volume of space with fragments to increase hit probability against a soft target. A laser cannot do either of those things.

Lasers need more power, a continuous waste heat management system and a large vulnerable lense. Plus, shooting things from drive-limited power levels of distance is basically the most boring slugfest ever.

1) It is not a foregone conclusion that a laser will require more power to cause a given amount of harm to a target than a railgun would. See below.

2) The heat management system is a problem, but is it more of a problem than dispersing the high instantaneous heat load from a railgun? Sure, you can space out the firings, but that limits your ability to inflict harm on the enemy even more than before... see below.

3) The lens (there is ONE 'e' in lens) is potentially vulnerable, but it has a very small target profile, and I cannot easily imagine an effective weapon that would target it from long range. Moreover, a given laser could easily consist of a single beamline that can use mirrors to send its beam to several 'emitter heads' on the ship's hull surface, in which case losing one lens is not a problem, and spares can be kept under armored hatches until needed.

4) If you think ship duels at long range with continuous beam energy weapons are dull, you've never read Doc Smith. Even I can make those interesting, for certain values of interesting.

5) The main range issue for lasers is that they cannot be dodged except at improbable combat range. Even at very high muzzle velocities (say, 100 km/s or so) for hard SF, a railgun round will be very unlikely to hit a target at ranges of over a few thousand kilometers. By the time the shell arrives, the target will have long since accelerated out of the way. Even if they don't see the bullets coming, they can still random-walk their way out of the path of the incoming fire.

By contrast, a laser or particle beam is almost certain to hit a target a few thousand kilometers away.

On the side, coilguns solve all the problems of railguns. Plus, you can shoot pretty much anything from a coilgun by using a recoverable bucket to hold the projectile.

Citation needed on both the first sentence, and on the practicality of using recoverable buckets at useful muzzle velocities.

But if you miss a few warships, or they had a couple of extra installations you didn't know about, the survivors will be pissed. Additional complicating factors, at least in Race A's case, include the likelihood of the military refusing to carry out an unlawful order and/or the civilian population reacting very badly indeed to mass murder being committed in their name.

If they are remotely human-like, and they think they are in serious danger of being exterminated themselves, they'll do it. That's the real issue.

Little of column A, little of column B. There aren't any asteroid colonies as yet but there's a lot of 'factory ships' that turn chunks of asteroid into refined materials for return to the populated regions. (They used to use the asteroid capture method advocated by Planetary Resources until someone got their sums wrong and nearly clobbered their homeworld with a rock the size of Luton, after which some payload restrictions were imposed.) Some of these ships have quite large crews, bored and sexually frustrated crews with access to moonshine, and it's rare but not unheard of for two or more of them to get into an argument over a particularly valuable claim. There have also been a handful of hijackings and one or two acts of genuine space piracy on the heavily-trafficked orbits between the homeworld and the larger colonies.

Right. Thus the desirability of keeping up a space patrol. Note that space patrol craft would probably NOT be heavily armed; the most likely weapon mount would be something like a 20mm cannon, which would be more than enough to see off any probable hard-SF civilian spacecraft. Also a rack of missiles just in case you need something that can reach and destroy a target that has an advantage of a few km/s of velocity on you in a hurry.

http://www.designation-systems.net/dusr ... hibex.html
http://en.wikipedia.org/wiki/Sprint_%28missile%29

Something like this maybe. It'd make one hell of a kinetic impactor; the main drawback is that the stick of solid rocket fuel burns out in a few seconds.

Sort of. Passive resistance just means the patrol boat will forcibly attach itself to the docking collar and its crew will take an acetylene torch to the airlock before sending in the heavy mob with flashbangs and automatic weapons. Actively resisting, ie by standing in an airlock taking potshots with a rifle, is grounds for immediate escalation to "disabling fire"... Which is a polite euphemism for "aiming for a part of your ship where there's a small chance you won't immediately suffer explosive decompression and/or rapid inflight disassembly if you are very very lucky". Not many people are dumb enough to try.

Well, my main point is that if you are a criminal wanted by the Space Patrol, you would be foolish to gamble on them being willing to let you go to spare your life.

That's part of it, but Race A's state of the art in laser weaponry just isn't very good; it creates much more waste heat and takes up much more space than a mass driver for comparable energy delivered to a target. And part of the reason their prototype FTL ship even has it in the first place was that it already had a cargo mass driver fitted from its previous career; all the yard had to do was neck down the calibre a bit and amp up the muzzle velocity.

This would... probably actually require an extensive refit of the driver, but at least the power trunking and spinal reinforcement would be there.

[Borgholio]

Yeah, the alpha strike potential of this weapon is terrifying. The only effective counter is to have a deterrent force parked somewhere the enemy's first strike can't reach, which would do the same thing to their home system that they just did to YOU.

Reminds me of that thread a couple months ago about RKV combat. The only sure-fire way to survive an RKV attack is to be so spread out that they can't get you all, then launch your counterattack with assets that are similarly spread out.

The Fermi Paradox?

Think that was it. The general idea was that we don't detect any alien civilizations because they're hiding out of fear of being bombed by RKVs from a hostile civilization that they don't know about. Anybody who broadcasts their location gets nuked.

[Zaune]

If they are remotely human-like, and they think they are in serious danger of being exterminated themselves, they'll do it. That's the real issue.

The second point is the big "if". Excessive orbital bombardment reduces the economic value of the newly-conquered territory, and total planetary annihilation would make the whole exercise completely pointless by wiping out the lebensraum and technology and other valuable loot.

At any rate, both races are human-like enough (one of them actually is human) that the losing side would probably cut their losses and sue for peace before their position became desperate enough that the Samson option looked attractive. I should probably emphasise that the pro-war factions on both sides are a minority.

The Fermi Paradox?

Think that was it. The general idea was that we don't detect any alien civilizations because they're hiding out of fear of being bombed by RKVs from a hostile civilization that they don't know about. Anybody who broadcasts their location gets nuked.

Actually, the reason Race A picked Race B's home system was that they picked up something not entirely unlike the "Wow!" signal from its general direction. I haven't yet made a final decision on what that was, but I'm thinking of making it somewhat important to the plot.

[Zaune]

By the way, is anyone interested enough to warrant my posting this story on here as well as SB and the official forums of one half of the crossover?

[krakonfour]

By the way, is anyone interested enough to warrant my posting this story on here as well as SB and the official forums of one half of the crossover?

Sure! I'd read it.
In return... anyone want to check out my setting? Link below.

[Zaune]

Well, here it is.

Bet you didn't see that crossover coming.

[Simon_Jester]

HOLY SHIT YOU WROTE A KERBAL SPACE PROGRAM/FIREFLY CROSSOVER

[Zaune]

I think I broke Simon.

[Simon_Jester]

I haven't actually read it yet, but seriously, good on you.

Anyway, is my depiction of the "space patrol" craft reasonable to you? I'd expect an effective, hardish-SF patrol craft to be mostly living quarters and fuel by volume, but which contains:

-Room for a few armed men in addition to the pilot.
-At least one stores compartment which can be used as a (very cramped) brig if necessary.
-Long endurance from onboard stores, if you don't mind drinking recycled pee-water.
-Relatively high maximum thrust for emergency maneuvers, and considerable reserve delta-v.
-Facilities to dock with an automated fuel tug.

Armament
-Something like a 20mm recoilless cannon, which would be adequate for shooting up something you've (more or less) matched trajectories with.
-A small number of launch racks (say, 2 or 4) for some sort of missile, which would probably be a solid fuel rocket with delta-v of somewhere between 1 and 10 km/s, all of it expended in a single rapid burn. Detailed performance parameters, I do not have.

These things would not be very effective against a competently designed warship, because the missiles in question might well NOT have a terminal guidance stage or anything like that, so their effective range is limited to, oh...

Suppose 50g acceleration and 5 km/s velocity at burnout, indicating a 10s engine burn, which in turn indicates an effective range of only 100-200 kilometers or so before enemy spacecraft will be able to dodge the (burned out and ballistic) missile.

Hm. Not good. Alternatively, suppose 10g acceleration and similar velocity at burnout- longer engine burn translates to much longer effective range; 50s engine burn is quite achievable for a solid fuel rocket stage. With a 50s engine burn, off the top of my head, 1250 km powered range from rest, add maybe 50-100 kilometers for the time it'd take the enemy to sidestep the missile once it goes ballistic.

Much better, more like 1300 km effective range.

[Eternal_Freedom]

It's certainly unexpected. And yes, I think Simon is now broken.

[Simon_Jester]

I just appreciate it because of my involvement in our KSP/BARIS crossover.

[Eternal_Freedom]

Oh I certainly sympathise. Now you've mentioned it I'm going to have to go and read BARIS again. Always good for a laugh or twenty

[Simon_Jester]

Indeed. I'm even enthused enough to read it despite having to scroll left and right for every line of text because Zaune put a million-pixel-wide image in the first chapter!

[Side note, the slide rule of Syrgy Pavylyvych is on display in the Air and Space Museum. My (then girlfriend, now fiancee) was good enough to photograph me with it; I should dig that up some time.]

Anyhow.

It would be helpful, Zaune, to think about how developed the Kerbals are here. If, as you imply, they're still at roughly the same stage of space infrastructure development as might be achieved by a dedicated KSP player... that would imply, say, a moon base or two, maybe a Mars base, a few space stations, and that's about it.

Under no circumstances would there be much demand for numerous armed spacecraft in that case. There'd be more pilots flying the patrol boats than there would be doing everything else in space. My ideas were predicated on the idea of a society where there are many thousands, perhaps even millions, of people living in space, distributed widely throughout the inner solar system, particularly the asteroid belt which is the main thing that might cause proliferation of lightly armed patrol craft.

[Zaune]

I haven't actually read it yet, but seriously, good on you.

Anyway, is my depiction of the "space patrol" craft reasonable to you?

Well, it's pretty much exactly what I'd envisioned them as, albeit with a larger main gun; some of the ships they have to board for an inspection could shrug off 20mm cannon rounds just by sheer mass. They can incidentally carry a rack of missiles that will reliably mission-kill a capital ship if they get past the chaff and flares, point-defence lasers or autocannon and railguns loaded with cannister shot. Space combat doctrine on Kerbin boils down to "launch as many missiles as possible at the enemy at once in hopes of overwhelming their countermeasures, then close and engage with guns when the survivors on both sides have run out."

It would be helpful, Zaune, to think about how developed the Kerbals are here. If, as you imply, they're still at roughly the same stage of space infrastructure development as might be achieved by a dedicated KSP player... that would imply, say, a moon base or two, maybe a Mars base, a few space stations, and that's about it.

Under no circumstances would there be much demand for numerous armed spacecraft in that case. There'd be more pilots flying the patrol boats than there would be doing everything else in space. My ideas were predicated on the idea of a society where there are many thousands, perhaps even millions, of people living in space, distributed widely throughout the inner solar system, particularly the asteroid belt which is the main thing that might cause proliferation of lightly armed patrol craft.

Somewhere in between the two, actually. They've got a decent-sized colony on Duna that's almost met their prearranged criteria for a plebiscite on independence, with a fair amount of trade and passengers going between it and Kerbin, an assortment of orbital factories and industrial facilities with a proper O'Neill cylinder on the way and a few scattered scientific outposts on the other planets and moons. Laythe is soon to be the site of the first 100% privately funded extraplanetary colony, and there's a couple of hundred asteroid mining ships in service.

Oh, and sorry about that damn picture. It looked fine everywhere else I posted the story to, when I posted it last night I was on my netbook; I thought it was just my screen.

EDIT: Okay, fixed.