SF-warship plausibility question. (Some Phlebotinum)

[ShadowOfMadness]

If you introduce magic armor (besides reactive one) to deal with fast rocks,

The rocks aren't moving. Its the ships that are (hence, the switching to a % PD to remove them from the path).

Technically, relative to the ship, the rocks are moving .

Har har

... Also, why doesn't everyone just heavily mine and focus fire on the few jump points in every relevant system, thus stopping any invasion force that doesn't spend hundreds of years in transit?

Mining 5 light minutes (in diameter) of space is likely to be highly resource intensive. Also, nothing stops the other guy from simply jumping in large rocks with engines (essentially) to soak up said mines. That doesn't consider the impact of mines on trade.

You could however mine an area with bomb-pumped X-ray lasers (and big ones, as they won't need to be fired via missile). Enemy fleet exiting the jump point? Press the button. Enemy asteroids with engines on them? Let 'em pass the mines, we have FTL sensors / comms so we can track them easily, and mop them up later.

Ya...until you realize you still have to rely on light speed sensors for both sides...which is likely to be a big missile volley (vs. null field mines) which can be stopped with PD, etc. to an extent since non-mines lack that first strike capability.

e.g.
Ships jump in.
Ships detect Drones & Missiles 'instantly' due to information already 'traveling' which may be up to 5 minutes out of date depending on the exact location.
Ships open fire on enemy fixed defences.
Sensor Drone detects Ships.
Sensor Drone informs Fixed Defences.
Fixed Defences fire back (probably after suffering 1-2 rounds of anti-fixed defences fire).

Which is why I was bringing in null-field mines (essentially invisible rocks) to serve as mines.

I suppose the most obvious response to this would be to spam the jump point you're about to attack with something designed to either destroy or disable the mines. Depending on distance between mines, big but otherwise regular nukes might do it (or at least punch a hole in the minefield). Defenders of course could respond with multiple layers of mines at the most likely exit routes, or minelayers designed to rapidly deploy new mines to plug any breaches.

That's the other option.

No matter how I see 'fixed defences' going, they need to be either:
1) Essentially limited mobility ships
2) Invisible (Null Field)

Anyway, like I said, I still need to do a new OPish style post simply because my assumptions are incorrect due to torpedo-style defenses vs. this style of missile.

[Teleros]

Ya...until you realize you still have to rely on light speed sensors for both sides...

You have FTL comms though, so... why can't the same technology be adapted for sensors ?

[ShadowOfMadness]

Ya...until you realize you still have to rely on light speed sensors for both sides...

You have FTL comms though, so... why can't the same technology be adapted for sensors ?

You can't have 'FTL sensors' that are prescient which is what it would take to detect a ship in jump (its basically skipping over the intervening space).

[Teleros]

Sorry, I thought you were on about FTL sensors detecting things in normal space. They should exist given that you have FTL comms, so you should be able to take out anything launched at significant fractions of c, because you can actually see where it is.

[ShadowOfMadness]

Sorry, I thought you were on about FTL sensors detecting things in normal space. They should exist given that you have FTL comms, so you should be able to take out anything launched at significant fractions of c, because you can actually see where it is.

Na, I was illustrating the communications/events loop right after a ship 'skips'. Sorry for the confusion.

Yes, the detection would be FTL ... but FTL is still slower than instantaneous.

[Sea Skimmer]

Its perfectly reasonable to have FLT communications but not any real FTL sensors aside from direction finding on the FTL comm. signals, which might not accomplish might if the FTL comms are using highly directional antennas.

In real life a whole lot of the frequency spectrum works fine for communications but is totally worthless as a sensor because it would have less resolution then the background clutter. VLF and ELF radio come to mind, and HF radio which is used very heavily for communications can make a radar set, but only a very crappy one.

[ShadowOfMadness]

Its perfectly reasonable to have FLT communications but not any real FTL sensors aside from direction finding on the FTL comm. signals, which might not accomplish might if the FTL comms are using highly directional antennas.

In real life a whole lot of the frequency spectrum works fine for communications but is totally worthless as a sensor because it would have less resolution then the background clutter. VLF and ELF radio come to mind, and HF radio which is used very heavily for communications can make a radar set, but only a very crappy one.

I'm figuring 'FTL sensor capability' comes in two varieties:
Sensor Drones (basically, hard to hit sensor arrays that move close to the enemy and relay data via FTL comm)
FTL Communication detection, at the same speed as FTL.

[Sarevok]

FTL sensors would require said FTL magic to interact with physical matter. That opens a huge can of worms as to how does tachyons or whatever effect normal matter. Just FTL comms are simpler. You can handwave away FTL comms by doing what stargate does. The stargate allows radio communications through the wormhole. So you could communicate at interstellar range using radio in real time. You dont have to rationalize how your stargates/wormholes work. But tachyon beams or whatever that allows FTL sensors require greater degree of magical explanations.

[ShadowOfMadness]

FTL sensors would require said FTL magic to interact with physical matter. That opens a huge can of worms as to how does tachyons or whatever effect normal matter. Just FTL comms are simpler. You can handwave away FTL comms by doing what stargate does. The stargate allows radio communications through the wormhole. So you could communicate at interstellar range using radio in real time. You dont have to rationalize how your stargates/wormholes work. But tachyon beams or whatever that allows FTL sensors require greater degree of magical explanations.

You mean FTL comm detecting 'sensors' are a bad idea?

Alright.

[Sarevok]

The thing is the moment you gain FTL communications you might as well adding plasma cannons and energy shields. Operating under light speed lag limitation is paramount to realistic space combat.

[ShadowOfMadness]

The thing is the moment you gain FTL communications you might as well adding plasma cannons and energy shields. Operating under light speed lag limitation is paramount to realistic space combat.

In other words, you think I should make it up and make it internally consistent?

[Sarevok]

Yeah. We have no idea about what actual hypothetical future space combat is going to look like. We dont even have true interplanetary ranged spaceships, only orbital capsules and probes and an expensive spaceplane attempt. Given the circumstances even the greatest minds today could not predict space combat anymore than best and brighest of 19th century forseeing modern air warfare.

Better to write a story with an internally consistent set of inuniverse rules.

[ShadowOfMadness]

Yeah. We have no idea about what actual hypothetical future space combat is going to look like. We dont even have true interplanetary ranged spaceships, only orbital capsules and probes and an expensive spaceplane attempt. Given the circumstances even the greatest minds today could not predict space combat anymore than best and brighest of 19th century forseeing modern air warfare.

Better to write a story with an internally consistent set of inuniverse rules.

Ya, then I think I might just go back to the original plan or some variant of it.

Thanks.

[Teleros]

FTL sensors would require said FTL magic to interact with physical matter. That opens a huge can of worms as to how does tachyons or whatever effect normal matter. Just FTL comms are simpler. You can handwave away FTL comms by doing what stargate does. The stargate allows radio communications through the wormhole. So you could communicate at interstellar range using radio in real time. You dont have to rationalize how your stargates/wormholes work. But tachyon beams or whatever that allows FTL sensors require greater degree of magical explanations.

Could you not open a comms wormhole to a point in space and simply use that as a sort of FTL sensor? Light from ships emerging from a jump point would enter the wormhole, exit at your end, and you could then respond. Radio waves work both ways via Stargates after all, and although visible light doesn't, why not bounce your radar pulses through said wormhole(s)?

Better to write a story with an internally consistent set of inuniverse rules.

This. If you can keep it internally consistent, your readers will be able to suspend their disbelief better, and that makes it much easier to handwave away little details (like anything FTL in nature for starters ).