Future Point Defense Options

Jonathan_S wrote:I think you're confusing heading with vector.

It's the same acceleration to change heading 90 degrees no matter what your base velocity is (say, relative to the nearest star). Sure if you're going an appreciable fraction of c it'll take many hours to actually alter your vector. But your heading should be changable just as quickly as if you were at rest relative to the local system. There's no medium to "corner" against, so your speed is irrelivant to your heading change ability.


But for some reason SDs have lethargic heading changes; even before they start trying to build up a new, or counteract an old, vector.

Is there any speculation or plausible-sounding excuse for why this is so? As scandals go, this one makes my suspension of disbelief ache more than stealth in space or missile control caps.

--snipping--

Jonathan_S wrote: It's the same acceleration to change heading 90 degrees no matter what your base velocity is (say, relative to the nearest star). Sure if you're going an appreciable fraction of c it'll take many hours to actually alter your vector. But your heading should be changeable just as quickly as if you were at rest relative to the local system. There's no medium to "corner" against, so your speed is irrelevant to your heading change ability.

Acceleration perhaps, but not so, mein Kapitan! in terms of heading change at least so far as I can tell.

"An object in motion... straight line" dynamics plus velocity means that it takes a helluva lot more force to alter that straight line the faster the object going. Figure the force in joules for a kilogram of weight at .3C, then multiply by 8 million times 2000. How much force does it take to get the nose of that ship around vs. how much force for the backend following yada yada yada. Unless the compensator field works 360 degrees at equal strength irrespective of the wedge direction, the shear would tear any ship into pieces. That's often what happens when the inertial compensator fails, no?
That also accounts for why it takes an SD longer to roll than a DD as well. No free energy lunch here.

Now then, compare that to turning the ship, heading and vector at a velocity of few hundred km/sec. It would take the wedge what, 10-12 seconds to alter the direction of the ship's momentum at 500G?

Somewhere between the two, we're assuming that turning the wedge can turn a ship's heading, but how the time required until the full vector change can complete is a lot longer.

Battles and maneuvers in the Honorverse only seem faster because we're reading them, not living them.

1) "Dodging" means "varying acceleration so that your predicted position changes". It can be done without turning at all.


2) A ship doesn't need to know when it needs to dodge. It can simply be dodging all the time during combat. I.e instead of keeping a steady 700 gs acceleration it can have a variable 600-700 gs acceleration. Since a mere 20 gs of difference can change its predicted position by 200 meters between the enemy firing a grazer and that grazer hitting, that's enough to dodge.


3) As a last resort, a ship doesn't need to use the wedge to dodge. As long as its total acceleration doesn't exceed its compensator limit, does it matter where the acceleration comes from? And if it doesn't, then it could use its thrusters, which can provide up to 200 gs in more directions that forward.

Belial666 wrote:3) As a last resort, a ship doesn't need to use the wedge to dodge. As long as its total acceleration doesn't exceed its compensator limit, does it matter where the acceleration comes from? And if it doesn't, then it could use its thrusters, which can provide up to 200 gs in more directions that forward.

Point out the obvious time. A ship is longer than 200m or 400m or even 600m...

Changing accelerations is not instantaneous. How quick the change is, we do not know.

Relax wrote:

Belial666 wrote:3) As a last resort, a ship doesn't need to use the wedge to dodge. As long as its total acceleration doesn't exceed its compensator limit, does it matter where the acceleration comes from? And if it doesn't, then it could use its thrusters, which can provide up to 200 gs in more directions that forward.

Point out the obvious time. A ship is longer than 200m or 400m or even 600m...

Changing accelerations is not instantaneous. How quick the change is, we do not know.

Um, RFC has already thoroughly covered this: He does not have 100% Graser hits at extended range. Why ships close closer. We all know ships can "dodge" within a 1km? box around the ship while keeping its wedge at same orientation.

Was reading another thread dealing with time dilation, and a somewhat obvious problem occurred to me in terms of long range missile interception without FTL, I think...

Let's say you have an attack missile coming at your ships at a high percentage of C. Your CM goes out at high G's to intercept, but... the combined closing speed at some point becomes faster than C. That seems to preclude "seeing" an oncoming attack missile at all, unless the CM's seekers can also pick up gravitic "wave energy" off of the shipkiller's wedge, correct? and I think the CM's available telemetry size is too small for that.

Am I missing something, or does this preclude extended range missile interceptions without an ACM or Mycroft/KHII based solution?

SharkHunter wrote:Was reading another thread dealing with time dilation, and a somewhat obvious problem occurred to me in terms of long range missile interception without FTL, I think...

Let's say you have an attack missile coming at your ships at a high percentage of C. Your CM goes out at high G's to intercept, but... the combined closing speed at some point becomes faster than C. That seems to preclude "seeing" an oncoming attack missile at all, unless the CM's seekers can also pick up gravitic "wave energy" off of the shipkiller's wedge, correct? and I think the CM's available telemetry size is too small for that.

Am I missing something, or does this preclude extended range missile interceptions without an ACM or Mycroft/KHII based solution?

Gravitic detection of impeller wedges is FTL - either the 64c of FTL comms or instantaneous, someone else will know better than me there. The CM has gravitic sensors, and at the end, it's on its own for bringing its wedge into contact with that wedge.

SharkHunter wrote:Was reading another thread dealing with time dilation, and a somewhat obvious problem occurred to me in terms of long range missile interception without FTL, I think...

Let's say you have an attack missile coming at your ships at a high percentage of C. Your CM goes out at high G's to intercept, but... the combined closing speed at some point becomes faster than C. That seems to preclude "seeing" an oncoming attack missile at all, unless the CM's seekers can also pick up gravitic "wave energy" off of the shipkiller's wedge, correct? and I think the CM's available telemetry size is too small for that.

Am I missing something, or does this preclude extended range missile interceptions without an ACM or Mycroft/KHII based solution?

Unless my (admittedly very basic) understanding of relativity is wrong, the whole point of it is that the velocity of two objects can never exceed c, regardless of their velocities relative to other things. For example, Ship A and Ship B are firing at each other. Ship A's missile closes on Ship B at 200,000 kps, and Ship B's missile closes on Ship A at 200,000 kps. On the simple maths, the missiles should have a closing velocity on each other of 400,000 kps (200,000 + 200,000), or 1.33c, but because of relativity their closing velocity relative to each other is <300,000 kps, regardless of their motion relative to the two ships.

JeffEngel wrote:Gravitic detection of impeller wedges is FTL - either the 64c of FTL comms or instantaneous, someone else will know better than me there. The CM has gravitic sensors, and at the end, it's on its own for bringing its wedge into contact with that wedge.

Should be the 64c since it's all ripples on the alpha wall.

Although, I think there's likely an error with that number, or more specifically an error in Storm from the Shadow which gave it to us. "Footprints, like gravitic pulses, were detectable by the fluctuations they imposed on the alpha wall interface with normal-space, which meant they propagated at roughly sixty-four times the speed of light." [SftS]

At All Costs where Apollo was introduced was more vague "all [Apollo] really does, if you want to come right down to it, is to extend our effective control loop by about a factor of sixty." [AAC]

But the Speed by Hyper Band table from the infodumps shows that the velocity multiplier for the Alpha band is 62c.
And the infodump on FTL fire control information lag used 62c (or rather 1/62nd of the lightspeed time) for the calculations.

So I'm reasonably sure SftS should have said 'roughly sixty-two times'.



But in any case, that doesn't change the fact that all gravitic pulses or signals travel the same way, so should travel at the same speed. (At least in n-space. If you go up to the Alpha bands I believe the velocity multiplier ratio between Alpha and Beta means that an FTL signal would only do a touch over 12c)

SharkHunter wrote:Was reading another thread dealing with time dilation, and a somewhat obvious problem occurred to me in terms of long range missile interception without FTL, I think...

Let's say you have an attack missile coming at your ships at a high percentage of C. Your CM goes out at high G's to intercept, but... the combined closing speed at some point becomes faster than C. That seems to preclude "seeing" an oncoming attack missile at all, unless the CM's seekers can also pick up gravitic "wave energy" off of the shipkiller's wedge, correct? and I think the CM's available telemetry size is too small for that.

Am I missing something, or does this preclude extended range missile interceptions without an ACM or Mycroft/KHII based solution?

This is a common question about Relativity. It turns out that if you apply all of the Lorentz equations correctly, you never get the situation you are worried about. From the perspective of the counter-missile, the velocity of the oncoming attack missile is less than the speed of light. The Lorentz equations can be combined together to create an equation for this: if Frame A measures the velocity of Frames B and C, the equation will tell you the velocity of Frame B from the perspective of Frame C. It is called the Relativistic velocity addition formula, or composition law for velocities:
s = (v + u)/(1 + (vu/c^2))
where v and u are the velocities of Frame B and C as seen in Frame A, and s is the velocity of Frame B as seen in Frame C (or the velocity of Frame C as seen by Frame B).