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Relativity

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Re: Relativity
Post by ThinksMarkedly   » Tue Oct 13, 2020 5:44 pm

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cthia wrote:Are you sure about that? You seem to be attributing superhuman abilities to humans and technology. You are telling me that a fleet or ship that is completely oblivious to an attack in a total time of peace, a fleet that is sharing birthday cake of one of the officers, can suddenly shake off their shock, launch LACs and the LACs can get into position, and the XO can give orders to the helmsman (because the Captain is in her quarters) and the helmsman can react and the ship can respond all in three minutes? The human brain needs time to process the impossible, the improbable and the unlikely. See Chin in At All Costs. Assuming!...the wedges are magically even up anticipating a sucker punch! On top of that, are you absolutely certain software can cope with these, insane, acceleration rates???


Yes. That's why they drill, so they can go from Condition 4 to Action Stations in the least amount of time. How low that number is, I can't tell (I don't think it was said in the text at all). 60 seconds may be too little, but 3 minutes sounds plenty. It is, after all, the time it took single-stage missiles to burn out their impellers.

More importantly, a ship not in friendly territory would maintain some level of readiness, from which it can get to full battle stations in less time.

At least not onscreen, so thanks for adding the qualifier, "as far as we know." Cataphracts would not represent the state of the art MAlign design. No Navy wants to serve any wine before it's time.


I understand. My argument is that they knew the SLN was losing the war. They rushed Cataphracts A, B and C and did anything they could to make the SLN survive. If they had more hidden up their sleeves that wasn't a Top Secret state secret (like the spider or streak drives), they would have. If they had 10x improved impellers, they might have given the SLN / TIY a 1.5x improvement.

RFC is fond of saying that you have to think through the implications of technology. If you have it, how does it transform your warfighting techniques?

Uh huh, after they can bring the wedge up. As I understand it a three minutes sucker punch ain't gonna given sitting ducks enough time. Byng would be proud.


Any ship not at a dock or in orbit of a planet, or instead repairing the impellers, should keep its wedges up. There's no reason to shut it down, even in the Manticore system. Especially lone ships -- and capital ships are never alone. A squadron should also not keep all its wedge aspects oriented in the same way, which makes stealth ambushes quite difficult. The GA knows the MAlign is out there and has good stealth. Rule #1 of Space Warfare: don't make it easy for the enemy to kill you.

You've pointed out before that over a decade, the SOPs may relax. I agree. But we know there won't be a decade jump in the books, so the pressure will continue up. I don't see the GA relaxing procedures any time soon.

ThinksMarkedly wrote:You have to posit a plausible scenario by which the technology breakthrough happened. RFC has been very careful in extending the technology in such a way it is believable and builds upon previous hints. The spider drive and the MDM are so far the only that aren't Black Swans (i.e., you can't simply say it's a logical extension of where the state of the art was). The streak drive was explained as pure brute force and we know hyperspace bands had been cracked 7 times before in the past.


Note: I meant the spider and MDM are Black Swans.

cthia wrote:True, I can't say it is a logical extension of RMN tech. I can say it would be a consistent habit of the MA to think outside the box. And, having their location classified, not operating on a time schedule while fighting for its life, able to work on tech sporadically for centuries allows them to accomplish what the average Navy doesn't have time to do. Even if that other Navy hasbthe motivation or insight. We're talking Alphas, baby.


On the other hand, not having to fight for its life never produced the type of encouragement that Samuel Johnson talked about ("when a man knows he is to be hanged in a fortnight, it concentrates his mind wonderfully."). We know, for better or for worse, that conflict and war are moments in history that spur innovation. And we know RFC believes that because it's the underpinning of the entire Honorverse and he explicitly wrote so in The Valkyrie Protocol.

The MAlign was never under existential threat, but the MA and later the RoH were. They are now, though.

And I've said before and will say it again: RFC must be holding something about MAlign tech that he hasn't told us about. The little we know about the Lenny Dets makes no sense as a warship. It's too slow and too vulnerable, depending exclusively on stealth. So I do think they must have some technological breakthrough we haven't heard about yet, which makes this ship useful in combat. Maybe it is a 2-million-gravity missile, but I don't think so. A 5-million-km graser is more likely and grasers are an area we've been told they've researched.

For purely stealth surprise attacks, I'd go smaller, not bigger. A Shark can do the job as well as an LD, but having a smaller profile it's less susceptible to detection. And if destroyed, the loss in investment is smaller.

Agreed, but those limitations were reached long ago. See my sentiments of missiles operating in a veritable minefield of debris on the aptly named thread. But somehow matter has never seemed to...matter.


It hasn't happened often that the ships being attacked stay with their debris. Almost every single engagement involves ships accelerating somewhere, which means the debris is always left behind (or ahead, as the case may be). Shaping a course around a cloud of debris that you know is there is trivial.

The one exception I can think of is the Battle of Hypatia, where SLN TF 1030 stayed put close to the planet, and this only because they were caught with their pants down and didn't have time to accelerate away from the planet anyway. But in this battle, RMN TG 110.2 was firing 4-minute ERMs at 46000 gravities, which only gave them 110 Mm/s more than the launching ships' base velocity. TG 110.2 had accelerated for the attack, though, but that means the missiles' terminal velocity must have been around 0.4c to 0.45c.
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Re: Relativity
Post by ThinksMarkedly   » Tue Oct 13, 2020 5:45 pm

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kzt wrote:Comparing a 911 to a sedan is not the right comparison. Compare the 0 to mach 1.5 of your 911 and an f18 off a carrier catapult.


Can the 911 use the same catapult?

I had written but erased that a better comparison was a sedan to a bullet.
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Re: Relativity
Post by Jonathan_S   » Tue Oct 13, 2020 5:47 pm

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cthia wrote:What's ignoring relativistic effects a bit more and coming even closer to c? The difference is what Navy gets an allocation of handwavium?

Well RFC doesn't come out and say in the books that the missiles ignore relativist effects. This is snarky way of referencing that for those of us who took a slipstick (okay, actually a spreadsheet) to the novels it was obvious that the missile performance data given - acceleration, duration, range, and burnout velocity - was all calculated with Newtonian formulas; not relativistic ones.

Which means that the missile accelerates from 0 to .1c no faster than it accelerates from 0.7 to 0.8c -- which would be impossible under constant thrust. (But one possible loophole / handwave would be for the magic of the wedge to somehow provide ever increasing thrust - that perfectly counterbalances the relativistic "drag" - so the acceleration is constant at any speed; despite that requiring exponentially more thrust to achieve at relativistic velocities)


I did have one conversation here with RFC about how that Newtonian calculation would work on the new 4-drive system defense MDMs - as Newton would erroneously state they could exceed 1c. As I recall I asked if they'd just have an arbitrary top speed applied and he indicated that likely how it would go.
Last edited by Jonathan_S on Tue Oct 13, 2020 6:31 pm, edited 1 time in total.
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Re: Relativity
Post by Jonathan_S   » Tue Oct 13, 2020 5:54 pm

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Theemile wrote:What do you mean "no one had the motivation" - such a technology would be advantageous to anyone. Everyone has been trying to push their missiles, faster, and longer, and the technology tree has been a slow, linear climb.

I agree everyone has wanted that combination.
But as I understand it Cthia is looking for missiles with very short (maybe a couple million mile) range but covering that range very quickly. And nobody has been willing to trade off the majority of their antiship missile's range for extreme acceleration at short range. They know they'd be battered to a wreck before reaching their own range. But a stealthy enough ambush ship could conceivably sneak into suicidally close range where a low range very quick antiship missile would be useful. So only someone with that level of stealth and interested in unconventional combat would be motivated to develop an antiship missile with that flight profile.

However that's flight profile is almost exactly what CMs do; so navies have been motivated to build short range high acceleration drives yetthe best CMs we've seen are still under 150,000g. A long way from the near-instant missile weapons Cthia is looking for.

But if someone came up with a new drive that let a CM accelerate 200 times faster, at the expense of only a 5 second drive endurance, designers would snap it up in a heartbeat. Who cares if the drive lasts only 5 seconds if you can cover nearly the same distance in that reduced time.



Now a weapon with basically the characteristics he wants does exist - a few million km range, 0.9c over its entire range, and as a bonus no FTL grav signature reducing the target's warning time still further. Too bad that weapon is the energy torpedo; and thus utterly worthless against an intact sidewall.
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Re: Relativity
Post by cthia   » Tue Oct 13, 2020 6:03 pm

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ThinksMarkedly wrote:
kzt wrote:Comparing a 911 to a sedan is not the right comparison. Compare the 0 to mach 1.5 of your 911 and an f18 off a carrier catapult.


Can the 911 use the same catapult?

I had written but erased that a better comparison was a sedan to a bullet.

Have you ever been insane enough to floor a 911 Turbo, after you engage the ATC so you won't simply burn out the tires?

Well, FYI. It IS an F-18!!! :o :o :o LOL

It even has wings.

Son, your mother says I have to hang you. Personally I don't think this is a capital offense. But if I don't hang you, she's gonna hang me and frankly, I'm not the one in trouble. —cthia's father. Incident in ? Axiom of Common Sense
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Re: Relativity
Post by Jonathan_S   » Tue Oct 13, 2020 6:27 pm

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cthia wrote:
ThinksMarkedly wrote:To do the same in 60 seconds, it needs to go to 458,000 gravities. If current burn-out rates are linear (1/3rd the time is 2x the acceleration), the MAlign would need a 1.5x improvement in impellers over current state of the art. Doable, but starts to become unlike. And 60 seconds is still plenty of time for sidewalls, full action stations, and a partial rotation to interpose the wedge.

Are you sure about that? You seem to be attributing superhuman abilities to humans and technology. You are telling me that a fleet or ship that is completely oblivious to an attack in a total time of peace, a fleet that is sharing birthday cake of one of the officers, can suddenly shake off their shock, launch LACs and the LACs can get into position, and the XO can give orders to the helmsman (because the Captain is in her quarters) and the helmsman can react and the ship can respond all in three minutes? The human brain needs time to process the impossible, the improbable and the unlikely. See Chin in At All Costs. Assuming!...the wedges are magically even up anticipating a sucker punch!
Well if the LD catches the target with wedge down, in orbit, then that's not enough reaction time. But as for whether a ship can react quickly enough I'd refer you back to HMS Bellerophon [SVW]- jumped in energy range, during peacetime, with a junior watchstander in command. Despite everything against them the junior officers still reacted quickly enough to raise sidewalls and interpose them before 4 BCs could overcome their surprise and fire their energy mounts. That's got to be under 30 seconds! And her offensive mounts were ready just moments later to return fire and blow the BCs out of space.

These ships are designed to bring up their defenses really quickly and the defenses are initially mostly under computer control - so you really just need a couple crew to hit the "defenses activate" buttons and the tac computers will get busy firing them. It may take several minutes to get everything to full effectiveness (hard to pick the optimal ECM or counter-ECM if you aren't sure who's shooting at you or given several salvos to analyze their response. But the basic sidewalls up, PDLCs and CM active and firing, can be done by normal watch crew in seconds.
This isn't WWII where people have to run to physically man the AA guns before they can begin firing back.


cthia wrote:On top of that, are you absolutely certain software can cope with these, insane, acceleration rates???

ThinksMarkedly wrote:Anything above 450,000 gravities is stretching the imagination. The MAlign has not been researching impeller improvements that deeply, as far as we know. We'd have seen some bigger breakthrough in the Cataphracts than we've seen so far, for example.

At least not onscreen, so thanks for adding the qualifier, "as far as we know." Cataphracts would not represent the state of the art MAlign design. No Navy wants to serve any wine before it's time.
You may have a point about the accel rates - OTOH the harder thing to handle is the closing speed and Manticoran missile defense is already built around stopping inbounds moving a 0.8c or above. It's unlikely that crazy accel alone will cause them to miss.


But to the drive design point, let's be fair to the MAlign. They have very quickly released several generations of Cataphract with steadily climbing performance. They were either holding back a lot of researched improvement or their drive researchers have been on a hell of a hot streak over the last couple years. With the same drive endurance their powered range has roughly doubled between the Cataphracts they used in Oyster Bay and the most recent observed during Uncompromising Honor!
The latest ones we saw fired had a first stage half-power setting of 841.8 KPS^2 (85,898g). Compare that to Manticore's current missiles with their half-power setting of 46,000g; or even with the first gen Cataphract with their 47,600g half-power first stage. That's a hell of an improvement!

However a top accel of 171,796g for 60 seconds (for 3 million km range) is a long way from the kind of million+ g accel you're looking for. But it's some evidence that the MAlign has been looking at missile drive tech and been making breakthroughs we've seen from nobody else.
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Re: Relativity
Post by cthia   » Tue Oct 13, 2020 9:28 pm

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Jonathan_S wrote:I agree everyone has wanted that combination.
But as I understand it Cthia is looking for missiles with very short (maybe a couple million mile) range but covering that range very quickly. And nobody has been willing to trade off the majority of their antiship missile's range for extreme acceleration at short range. They know they'd be battered to a wreck before reaching their own range. But a stealthy enough ambush ship could conceivably sneak into suicidally close range where a low range very quick antiship missile would be useful. So only someone with that level of stealth and interested in unconventional combat would be motivated to develop an antiship missile with that flight profile.

Yes! I couldn't have said it any better. Really, I literally couldn't have said it any better. Thanks.


Jonathan'S wrote:But to the drive design point, let's be fair to the MAlign. They have very quickly released several generations of Cataphract with steadily climbing performance. They were either holding back a lot of researched improvement or their drive researchers have been on a hell of a hot streak over the last couple years. With the same drive endurance their powered range has roughly doubled between the Cataphracts they used in Oyster Bay and the most recent observed during Uncompromising Honor!
The latest ones we saw fired had a first stage half-power setting of 841.8 KPS^2 (85,898g). Compare that to Manticore's current missiles with their half-power setting of 46,000g; or even with the first gen Cataphract with their 47,600g half-power first stage. That's a hell of an improvement!

However a top accel of 171,796g for 60 seconds (for 3 million km range) is a long way from the kind of million+ g accel you're looking for. But it's some evidence that the MAlign has been looking at missile drive tech and been making breakthroughs we've seen from nobody else.

But also consider that the MA's advances are possibly without access to GA tech. Over in the ? thread, the possibility of stolen GA tech may inject a shot in the arm of MA tech.

Jonathan_S wrote:You may have a point about the accel rates - OTOH the harder thing to handle is the closing speed and Manticoran missile defense is already built around stopping inbounds moving a 0.8c or above.

It's unlikely that crazy accel alone will cause them to miss.

Agreed, but remember, there's also a bit of room available near top speed. While the GA is wrestling with these missiles during battle, a more stealthy but deadly graser torp is enroute.

I'm simply trying to cover all bases. An LD can get extremely close. It needs a new breed of weapon to fit it's capabilities.

BTW, foreign sports cars have traditionally measured their accell in 0-100 mph times. American cars used 0-60, because they didn't want to seem like they were recommending testing 0-100 mph rates on 60 mph limited US highways. As I was told. This was yesteryear.

Son, your mother says I have to hang you. Personally I don't think this is a capital offense. But if I don't hang you, she's gonna hang me and frankly, I'm not the one in trouble. —cthia's father. Incident in ? Axiom of Common Sense
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Re: Relativity
Post by ThinksMarkedly   » Tue Oct 13, 2020 11:04 pm

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Jonathan_S wrote:These ships are designed to bring up their defenses really quickly and the defenses are initially mostly under computer control - so you really just need a couple crew to hit the "defenses activate" buttons and the tac computers will get busy firing them. It may take several minutes to get everything to full effectiveness (hard to pick the optimal ECM or counter-ECM if you aren't sure who's shooting at you or given several salvos to analyze their response. But the basic sidewalls up, PDLCs and CM active and firing, can be done by normal watch crew in seconds.
This isn't WWII where people have to run to physically man the AA guns before they can begin firing back.


When I briefly worked on Safety Critical software development, I was told that the US Navy warships' point defence reaction time is 15 milliseconds. I understood that to be the time between radar confirming incoming bogey to commanding the PD weapons to move to aim. I don't know if the actual firing needs a human to press a button and don't know how long the guns take to physically move.

Identifying isn't difficult. What else could there be moving at high speed (or high accel) on an intercept course except a hostile missile or projectile? The problem is mis-identifying due to faulty sensors or data processing. A false positive means you identify something innocent as a hostile and shoot some poor people or property down. A false negative means you fail to identify a threat -- this is usually the province of ECM.

Here's another possible HH weapon: a gravitic rail gun that fires a massive projectile (1 tonne of depleted uranium, for example) at 0.5c. At light-seconds away, that's just 6 seconds from launch to impact. The projectile itself radiates no energy; depending on its shape it can also have a very small radar/lidar profile. Because of those two factors, it might confuse the crews and computers long enough to make the impact inevitable. By that I mean that there's not enough time to fire a CM which rotates to present its wedge to the projectile; and the sidewalls may not rise up fully in time to make it go "fzzt."

Of course, the physics of such a rail gun would require quite a bit of handwavium. If it is a spinal mount on a 10-km long ship, the projectile would need to accelerate for 266.85 ms, at a whopping 57.2 billion gravities. If you think that's a big number, consider this: ignoring relativity, a projectile of 1 tonne would have a kinetic energy of 11.2 billion gigajoules. And since this was all discharged over 266.85 ms, that's a power generation of at least 84 billion gigawatts. Or 0.02% of the power output of the Sun.

With this amount of energy dumped into it, the projectile might come out of the rail gun as a blob of plasma. Which would make it an energy torpedo.
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Re: Relativity
Post by kzt   » Tue Oct 13, 2020 11:27 pm

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The NATO standard for air defense statuses is:
Weapons Hold, where you don’t engage a target even if hostile without further orders
Weapons Tight, where you can engage targets positively ID as hostile without further orders
Weapons Free, where anything not identified as friendly may be engaged without further orders
So at weapons free anything inbound that isn’t ID as friendly will get shot at as soon as the system prioritizes it in the queue and it’s reaches the right range.
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Re: Relativity
Post by tlb   » Wed Oct 14, 2020 9:38 am

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kzt wrote:The NATO standard for air defense statuses is:
Weapons Hold, where you don’t engage a target even if hostile without further orders
Weapons Tight, where you can engage targets positively ID as hostile without further orders
Weapons Free, where anything not identified as friendly may be engaged without further orders
So at weapons free anything inbound that isn’t ID as friendly will get shot at as soon as the system prioritizes it in the queue and it’s reaches the right range.

That is how you can get the incident in 3 July 1988. Under orders issued after the USS Stark was hit by missiles a year earlier, essentially designed to err on the side of protecting US lives -- and with just minutes to decide if his vessel was within range of missiles carried by an Iranian warplane -- the captain of the guided-missile cruiser USS Vincennes gave the order to fire.

Seven minutes after takeoff, the Iran Air Airbus A300 was struck by surface-to-air missiles fired from the US cruiser. The US military later called it "a tragic and regrettable accident after "US Navy investigations of the incident showed the Iranian airliner was in an approved commercial airway and was identifying itself on air traffic control frequencies as a civilian flight.

Without fighters in the sky to intercept and identify the plane as a passenger jet, there was no alternative.
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