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I liked the Sci Fi battles in The Culture book series- no armies, no heroics. Just one AI spending milliseconds blasting another AI at extreme distance in space

I liked the Sci Fi battles in The Culture book series- no armies, no heroics. Just one AI spending milliseconds blasting another AI at extreme distance in space. Victory or defeat comes down solely to tech-tree development and physics, nothing else.

grues-dinner 2y ago
We may not have gridfire or CAM dustings but I'm pretty sure that's how space combat will end up really going. No cinematic Expanse-style Gatling gun vs inexplicably slow missile dogfights, just getting vapourised by something going 50km/s that was fired from hundreds of thousands of km away by something you never even saw. The good news is at least those engines don't use physics we have access to - Inaros didn't need the whole rocks thing, he could have just fuelled up a freighter and brought it in at some fraction of c from outside the ecliptic. I don't care how good your railguns are, they won't hit something that has its own blueshift.
- jltsiren 2y ago
  Space combat in The Expanse kind of makes sense, assuming that you have magic engines that can accelerate you to something like 5% or 10% of light speed before running out of propellant. The thing is that space is big. Hundreds of thousands of kilometers is a short range, and 50 km/s is a low speed. Missiles appear slow, because they use the same engine technology as ships, which limits the acceleration they can achieve. Reaching 50 km/s at 50g takes over 100 seconds and is obvious to everyone in the general area. Railgun speeds are inconsistent in the setting, but firing them is also obvious, and random course corrections are an effective defense against them. Your freighter trick would not have worked. The acceleration would have taken days or even weeks, depending on what kind of acceleration the ship can handle. And it would have been obvious to everyone in the solar system. That would have been plenty of time to send a fleet (that can accelerate faster) to intercept it.
  - grues-dinner 2y ago
    I dunno, surely you would coast out of the system for a year or two. Once out in the Oort cloud, you can drift and turn quietly with your engines away from the solar system and vanish. Then point your engines away (add a glare shield maybe) and nail it inwards. Even if you get so spotted coming from some angle out of the ecliptic no one is going to be able to catch up considering you're coming straight at them rather than a nice stern chase. Accelerating out to meet you head on only makes it worse (though at 50,000km per second, say, you won't be in range for long no matter how far they go). And even in the books the missiles that killed the Canterbury closed 200,000km in eight minutes. That's nearly 200g and the closing speed would have been 800km/s. They'd go 20 miles in a single frame of the 24fps video of the event. Even 50km/s is not a low speed if your defensive strategy is a machine gun. You have 1 second to go from a dinner plate sized cross section object at 50km to being dead, and if even if you did hit it with a bullet going say 2km/s the other way, which is a very fast bullet, if it was on target before, the bits will still hit you nearly as effectively. In fact, a better missile would disperse into a spray of fine metal pieces a few 10s of km away and be uninterceptible and cover a wider area in car you can try a dodge. Seems to me like combat in the universe would be a lot less close-in dogfights and a lot more long range stealth kills by tiny relativistic bullets. And a lot more plausibly deniable "disappearances" in deep space. And I get it, don't get me wrong, rule of cool and all that. And while we don't have those engines, the approximate same techniques probably apply to any spaceship combat we'll see in the next 100 years. Months of nothing slogging across nothingness then dead in a second out of nowhere. Unless radar really improves and stealth doesn't, I guess. And surface impacts from deep space will make current ICBM concerns seem quaintly sedate, even if we can't get to relativistic speeds.
    - jltsiren 2y ago
      The exact numbers in the books are often inconsistent. In Persepolis Rising, the forces that surround the Tempest form a bubble almost three light seconds across. And railgun rounds take less than a minute to reach the center. My overall impression from the books was that the typical engagement distance is from seconds to tens of seconds at railgun speed (relative to the target), whatever that speed is. Anything beyond that, and random course corrections would make hitting anything with an unguided round effectively impossible, no matter how accurate your weapons are. And if you hit a missile at that distance, the random corrections will probably also get you out of harm's way.
shawn_w 2y ago
Not all battles in Culture books are like that. Hydrogen Sonata has close range equiv-tech fights on a planetary surface, for example. Still AIs running the show while the (armored) human hopes they survive, of course.

grues-dinner 2y ago

We may not have gridfire or CAM dustings but I'm pretty sure that's how space combat will end up really going. No cinematic Expanse-style Gatling gun vs inexplicably slow missile dogfights, just getting vapourised by something going 50km/s that was fired from hundreds of thousands of km away by something you never even saw. The good news is at least those engines don't use physics we have access to - Inaros didn't need the whole rocks thing, he could have just fuelled up a freighter and brought it in at some fraction of c from outside the ecliptic. I don't care how good your railguns are, they won't hit something that has its own blueshift.

jltsiren 2y ago
Space combat in The Expanse kind of makes sense, assuming that you have magic engines that can accelerate you to something like 5% or 10% of light speed before running out of propellant. The thing is that space is big. Hundreds of thousands of kilometers is a short range, and 50 km/s is a low speed. Missiles appear slow, because they use the same engine technology as ships, which limits the acceleration they can achieve. Reaching 50 km/s at 50g takes over 100 seconds and is obvious to everyone in the general area. Railgun speeds are inconsistent in the setting, but firing them is also obvious, and random course corrections are an effective defense against them. Your freighter trick would not have worked. The acceleration would have taken days or even weeks, depending on what kind of acceleration the ship can handle. And it would have been obvious to everyone in the solar system. That would have been plenty of time to send a fleet (that can accelerate faster) to intercept it.
- grues-dinner 2y ago
  I dunno, surely you would coast out of the system for a year or two. Once out in the Oort cloud, you can drift and turn quietly with your engines away from the solar system and vanish. Then point your engines away (add a glare shield maybe) and nail it inwards. Even if you get so spotted coming from some angle out of the ecliptic no one is going to be able to catch up considering you're coming straight at them rather than a nice stern chase. Accelerating out to meet you head on only makes it worse (though at 50,000km per second, say, you won't be in range for long no matter how far they go). And even in the books the missiles that killed the Canterbury closed 200,000km in eight minutes. That's nearly 200g and the closing speed would have been 800km/s. They'd go 20 miles in a single frame of the 24fps video of the event. Even 50km/s is not a low speed if your defensive strategy is a machine gun. You have 1 second to go from a dinner plate sized cross section object at 50km to being dead, and if even if you did hit it with a bullet going say 2km/s the other way, which is a very fast bullet, if it was on target before, the bits will still hit you nearly as effectively. In fact, a better missile would disperse into a spray of fine metal pieces a few 10s of km away and be uninterceptible and cover a wider area in car you can try a dodge. Seems to me like combat in the universe would be a lot less close-in dogfights and a lot more long range stealth kills by tiny relativistic bullets. And a lot more plausibly deniable "disappearances" in deep space. And I get it, don't get me wrong, rule of cool and all that. And while we don't have those engines, the approximate same techniques probably apply to any spaceship combat we'll see in the next 100 years. Months of nothing slogging across nothingness then dead in a second out of nowhere. Unless radar really improves and stealth doesn't, I guess. And surface impacts from deep space will make current ICBM concerns seem quaintly sedate, even if we can't get to relativistic speeds.
  - jltsiren 2y ago
    The exact numbers in the books are often inconsistent. In Persepolis Rising, the forces that surround the Tempest form a bubble almost three light seconds across. And railgun rounds take less than a minute to reach the center. My overall impression from the books was that the typical engagement distance is from seconds to tens of seconds at railgun speed (relative to the target), whatever that speed is. Anything beyond that, and random course corrections would make hitting anything with an unguided round effectively impossible, no matter how accurate your weapons are. And if you hit a missile at that distance, the random corrections will probably also get you out of harm's way.

shawn_w 2y ago

Not all battles in Culture books are like that. Hydrogen Sonata has close range equiv-tech fights on a planetary surface, for example. Still AIs running the show while the (armored) human hopes they survive, of course.