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 Post subject: RFC
PostPosted: Fri Jul 14, 2017 7:48 am 
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As I've mentioned before, I'm writing on battleships for a blog I follow. However, I've decided to branch out into other naval matters, and I'm starting with 'why the carriers are not doomed'. I'm posting my draft here for comment before it goes up there:
(Note that I'm using this as my working copy, and I'll be editing it, as I find changes I want to make or I receive feedback)

A question that has come up several times recently is the controversy over the future of the US carrier force in the face of new threats, and it deserves an answer at some length. As such, I’m going to talk about carriers instead of battleships today.

The basic theory is that improved Chinese missiles, particularly the DF-21D anti-ship ballistic missile (ASBM) mean that the US cannot bring carriers within 1000-2000 km of the Chinese coast without them being killed. Some go even farther, and claim that soon, any country (we’ll call it Enemyistan) with some cash will be able to stand off the USN, and the carriers will be totally obsolete.

Fortunately for the US, this is not true. Today, we’ll start with the threat from conventional missiles. ASBMs can wait for later, because I have more than enough for this week.

So, what does a US carrier group (CVBG) look like when trying to defend itself? Well, a typical CVBG is composed of a carrier, a Ticonderoga-class cruiser (CG), and 3-4 Arleigh Burke-class destroyers (DDGs). The CG normally carries the burden of long-range air defense, while the DDGs are configured to protect themselves and execute land-attack missions. If they were going up against China, or some other high-threat area, the DDGs are perfectly capable of carrying more SAMs, and a second CG might well be assigned to the group.

The outer ring of defenses is going to consist of proactive measures. The USN learned at Pearl Harbor that it is better to give than to receive. As such, the various US commanders will be trying to eliminate as many enemy missile launchers as possible before they can be used. This could mean a submarine or destroyer launching Tomahawks at an airfield, naval base, or coastal-defense position, or it could be the carrier’s airplanes attacking missile boats or airplanes before they get within range. This is very hard to quantify, so I’ll ignore it in my numerical analysis (which I’m going to try to keep conservative), but it will be very important in an actual war.

The second layer is to keep the enemy from getting targeting data good enough to launch a strike. Getting targeting-quality data on a naval force is surprisingly hard, although I’m not going to go into much detail this week. (That will be in an installment quite soon.) For this week, I’m just going to say that no, whatever wonder device you’re thinking of won’t solve it completely for China, and Enemyistan has next to no chance provided that the CVBG’s commander is competent. However, this is also hard to quantify, and I’m trying to give a reasonable worst-case scenario, so I’ll ignore the problems here and assume that the CVBG has been located.

Now we come to the missiles. The outer layer is going to be Standard Missiles, the USN’s long-range air defense missile dating back to the 60s (although it’s the ship of Theseus by now). There are two subvariants, Extended-range and Medium-range. The ER variant has a range of 200 nm, while the MR version is around 90 nm. For a normal, peacetime carrier group, you have the CG with 96 of these (not sure of the exact mix of MRs and ERs) providing the outer layer of fleet air defense. In an air-defense configuration, a DDG will carry 72.

The middle layer is the Enhanced Sea Sparrow Missile (ESSM). This is a shorter-range missile (at least 30 nm), and a normal peacetime loadout is 24 on each DDG and 16 on the carrier. It is fantastically maneuverable, and I was told that they basically come out of the Vertical Launch System (VLS) sideways. Because 4 can fit in each VLS cell (as opposed to a single Standard) a CVBG can in theory carry upward of a thousand, although the US doesn’t have enough missiles in inventory to support this kind of loadout. (But we’ll come back to that problem later.)

The inner layer is point-defense systems, designed to protect only the ship mounting them. There are two, the Rolling-Airframe Missile (RAM) and the Phalanx Close-In Weapons System (CIWS). Almost all of the escorts mount one or more CIWS, which is a 20mm gatling gun hooked up to a radar system that automatically shoots down anything it thinks is a missile. Unfortunately, it’s not that effective against high-speed missiles because the debris from even a shot-down missile can still strike the ship. The RAM was designed to solve this, shooting down missiles at greater range. A carrier carries 2 21-round RAM launchers.

Now it’s time to look at how many missiles we’d need to overwhelm a carrier’s defenses. A typical group in peacetime conditions (which we’d expect if we were going up against Enemyistan) would have 96 Standards, 88 ESSMs, and 42 RAMs, a total of 226 missiles (actually more, because I’m not counting ESSMs on the CG, which is another 24). Based on recent experience off of Yemen, I think it’s very conservative to assume that you’ll have a 50% kill probability against a typical missile with one of these weapons. (I believe the actual number is more like 70%.) Under this assumption, the CVBG can shoot down 113 incoming ASMs. In a war with China, that number might well top 200.

But the defenses don’t stop there. There’s also electronic warfare to consider. This is a fantastically complicated topic, and we can’t know the answer without an actual war, but I think it’s reasonable to assume that EW will draw off another 50% of missiles. This decoy work will probably take place at some point in the ESSM engagement zone, and well before the RAMs come into play. So for our fight with Enemyistan, we have 48 missiles shot down by Standards, 22 shot down by ESSMs before the EW takes effect. To saturate the rest of the defenses will require 43 missiles to not be drawn off, taking the number of missiles the CVBG can handle to 156. If the missiles in question are subsonic (the vast majority of ASMs worldwide are, and I’d expect higher-speed missiles to be preferentially targeted), then the Phalanx on a targeted ship will probably take out another 2-3, maybe more, depending on how spread out the salvo is. So we now have a round number for Enemyistan, 160 missiles to make one possible hit on a carrier. (One hit is not going to kill the carrier outright, and I’ve systematically erred in favor of the attacker. The CVBG will have to go home to reload, but it’s still alive, and the next carrier coming up behind it doesn’t have to face those missiles.)

But what does that number mean in context? In the grand scheme of things, how many missiles is Enemyistan likely to be able to put into the air?

Unfortunately for Enemyistan, they are going to have a very difficult time of it. A typical surface warship carries 4-8 ASMs, and for most second-rate navies, there are no missiles kept ashore as replacements. (As a side note, I’ve assumed perfect reliability on the part of the attacker’s missiles. This is a very bad assumption for Enemyistan, who has probably been skimping on maintenance.) The Iranian navy has a total of ~200 missile tubes on its surface combatants, including the ones currently under construction. Obviously air-launched and shore-based missiles could be added to this, but it is also necessary to subtract the missiles lost to US counterattacks before launch, and the missiles that are not fired due to the ship having a broken engine that day, or because they couldn’t get targeting data due to US jamming. A best case for Enemyistan is that they sink one US carrier, then get smashed by the next two CVBGs behind it, which they have no missiles left to engage. A more likely case is that they sink a couple of merchant ships that were where they thought the US carrier was, then get destroyed by all three CVBGs.

China is going to be a tougher nut to crack. Obviously, they have more missiles, enough so that launching a couple of 200+-missile salvoes is not out of the question. And they’re going to have better surveillance equipment, so that we can’t just trick them into wasting their ASMs on empty ocean (probably). China has approximately 224 naval strike aircraft, each of which can probably carry 2 missiles. That’s almost certainly enough to overwhelm a single CVBG, even in wartime, but a lot of the attacking aircraft would be destroyed in the attack and they would probably be unable to take out a second CVBG the same way. And the US has 9. (Note that we're ignoring strike aircraft destroyed on the ground, down for maintenance, or simply assigned to a different region, as well as the fact that carriers usually operate in groups in a serious war, driving up the number of escorts available.) Much the same math applies to shore-based and shipboard ASM launchers, although I’m not going to go into detail here because counting platforms is boring, and there’s surprisingly little data available on Chinese coastal missile strength. The ultimate balance between US naval forces and the Chinese is pretty close right now, and I don’t see improved technology skewing the balance too much one way or the other.

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Last edited by ByronC on Fri Jul 14, 2017 12:11 pm, edited 1 time in total.

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 Post subject: Re: RFC
PostPosted: Fri Jul 14, 2017 12:08 pm 
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Another issue that people forget: carriers come in packs.

Consider wartime carrier operations since 1945. Falklands War saw two carriers operating together. Gulf War saw two groups of three carriers operating together. Yankee Station saw four or five carriers operating together. Korean War saw lots of carriers operating together. Same with invasion of Afghanistan. Same with invasion of Iraq in 2003. It's also not just one battlegroup's worth of escorts in that situation either.


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 Post subject: Re: RFC
PostPosted: Fri Jul 14, 2017 12:10 pm 
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David Newton wrote:
Another issue that people forget: carriers come in packs.

Consider wartime carrier operations since 1945. Falklands War saw two carriers operating together. Gulf War saw two groups of three carriers operating together. Yankee Station saw four or five carriers operating together. Korean War saw lots of carriers operating together. Same with invasion of Afghanistan. Same with invasion of Iraq in 2003. It's also not just one battlegroup's worth of escorts in that situation either.

Good point. Edited to include a brief mention of that.

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 Post subject: Re: RFC
PostPosted: Fri Jul 14, 2017 1:43 pm 
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Keep in mind that there are limits to the rate at which you can fire SAM's and on how many birds you can have in the air at the same time. That probably counts for the AShM's as well, but I don't know that for a fact. The end result is that it's easier to shoot at the ships than to shoot at the vampires.

There are also co-operative methods to keep in mind. We liked to lurk upwind of CVBG's and call in air strikes. When the CV launched interceptors it would run into us.

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 Post subject: Re: RFC
PostPosted: Fri Jul 14, 2017 2:07 pm 
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drunknsubmrnr wrote:
Keep in mind that there are limits to the rate at which you can fire SAM's and on how many birds you can have in the air at the same time. That probably counts for the AShM's as well, but I don't know that for a fact. The end result is that it's easier to shoot at the ships than to shoot at the vampires.

Yes, but those limits are fairly high, something like 24 SAMs for AEGIS, IIRC. I don't have hard numbers on launch rate, but it's no more than a couple of seconds per missile for VLS. Unless the attacker is really good at coordinating their salvo, this isn't going to be that relevant.

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There are also co-operative methods to keep in mind. We liked to lurk upwind of CVBG's and call in air strikes. When the CV launched interceptors it would run into us.

Yes, but you're a bubblehead, and thus not to be trusted on this.

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 Post subject: Re: RFC
PostPosted: Fri Jul 14, 2017 2:16 pm 
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I would probably reverse your posts.

The first one would be how the carrier group is targeted1, how the different missiles try to intercept the target2, and the final guidance phase3. This is really important to even start to understand what you've posted here. The dismissal of the DF-21D would make a whole lot more sense with that information, rather than just saying you'll talk about it later.

1) radar vs plane activity, communication delays between search and strike, ship movement, confusion between Navy and commercial traffic
2) cruise missile, subsonic vs supersonic, hi-lo-hi, lo-lo, ballistic trajectories, difference between Tomahawk and AS-6 problems
3) size of the target basket, time of flight between getting in the area, finding the ship, and hitting it, and how far the ship moves between launch and final attack.

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 Post subject: Re: RFC
PostPosted: Fri Jul 14, 2017 2:45 pm 
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I'll have to think that over. This is due Sunday, and that's going to mean a whole new post. But yes, I do see your point.

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 Post subject: Re: RFC
PostPosted: Fri Jul 14, 2017 3:04 pm 
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ByronC wrote:
Yes, but those limits are fairly high, something like 24 SAMs for AEGIS, IIRC. I don't have hard numbers on launch rate, but it's no more than a couple of seconds per missile for VLS. Unless the attacker is really good at coordinating their salvo, this isn't going to be that relevant.


Its actually a missile limitation more than Aegis. They can only listen on so many frequencies at the same time. The French may have been on to something with that IIR head for Mica.

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Yes, but you're a bubblehead, and thus not to be trusted on this.


I was on an AAW destroyer first. My rate was sorta like the Senior Chiefs but I done got edumacated first. I was an FC tech, while he was a JAFO. :D

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 Post subject: Re: RFC
PostPosted: Fri Jul 14, 2017 3:25 pm 
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ByronC wrote:
I'll have to think that over. This is due Sunday, and that's going to mean a whole new post. But yes, I do see your point.

In that case, add a paragraph about the DF-21D, and the problems with making sure the carrier stays in the same position in the half hour between spotting and launch, and the further half hour of flight time. Because of course carriers drift around at steerage pace all the time, especially during flight ops.

Otherwise, some wise guy will start the discussion by stating that the DF-21D is an Überweapon, meaning sure death to anything within 1500 miles, and is as unstoppable as a kitten seeing a food bowl.

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 Post subject: Re: RFC
PostPosted: Fri Jul 14, 2017 4:51 pm 
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drunknsubmrnr wrote:
Its actually a missile limitation more than Aegis. They can only listen on so many frequencies at the same time. The French may have been on to something with that IIR head for Mica.


Most certainly not an expert on these things (nor do I play one on TV) but wasn't one of the drivers for Type 45 (and PAAMS / Sea Viper) increasing the ability of a vessel to engage saturation attacks vs a SARH missile system. Ie a system only reliant on a datalink vs illumination for the intercept phase and active radar for the terminal phase?

Thus the move by the USN towards SM6 with the ability to be directed to the target area by anything with a datalink (the published stuff I've read on this isn't entirely clear on whether it requires the actual firing vessel or just anything with CEC probably for good reason) and the move towards active terminal radar seekers on SM6 and ESSM Block II.


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 Post subject: Re: RFC
PostPosted: Fri Jul 14, 2017 5:01 pm 
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KDahm wrote:
Otherwise, some wise guy will start the discussion by stating that the DF-21D is an Überweapon, meaning sure death to anything within 1500 miles, and is as unstoppable as a kitten seeing a food bowl.

I actually have enough credibility in the forum I'm posting in to be able to say 'next week, I'll explain the problems with that' and have people believe me.
(I have enough credibility that they believed me about mail buoys, and those that knew better didn't blow the whistle. I confessed after 24 hours, although one person did have to retract on facebook.)

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 Post subject: Re: RFC
PostPosted: Fri Jul 14, 2017 7:03 pm 
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ByronC wrote:
I have enough credibility that they believed me about mail buoys


All buoys are male.

(Two scoops, two genders, two terms, deal with it.)

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 Post subject: Re: RFC
PostPosted: Fri Jul 14, 2017 9:01 pm 
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Straker wrote:
drunknsubmrnr wrote:
Its actually a missile limitation more than Aegis. They can only listen on so many frequencies at the same time. The French may have been on to something with that IIR head for Mica.


Most certainly not an expert on these things (nor do I play one on TV) but wasn't one of the drivers for Type 45 (and PAAMS / Sea Viper) increasing the ability of a vessel to engage saturation attacks vs a SARH missile system. Ie a system only reliant on a datalink vs illumination for the intercept phase and active radar for the terminal phase?

Thus the move by the USN towards SM6 with the ability to be directed to the target area by anything with a datalink (the published stuff I've read on this isn't entirely clear on whether it requires the actual firing vessel or just anything with CEC probably for good reason) and the move towards active terminal radar seekers on SM6 and ESSM Block II.


Different issues. The idea behind using active radar homing is to avoid the issue with overloading the ships directors using semi-active radar homing. You still have the limitation with the missile seeker only being able to use x numbers of frequencies, it doesn't really matter whether the transmitter is on the ship or the missile.

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 Post subject: Re: RFC
PostPosted: Sun Jul 16, 2017 11:00 pm 
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Bean? I have to say, I have enjoyed your essays.


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 Post subject: Re: RFC
PostPosted: Sun Jul 16, 2017 11:43 pm 
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Beowulf wrote:
Bean? I have to say, I have enjoyed your essays.

Indeed I am. And thank you.

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 Post subject: Re: RFC
PostPosted: Thu Jul 20, 2017 1:05 pm 
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I've gotten this upcoming week's done in rough-draft form. This time, it's on detection/location:

Last time, I handwaved away the problem of finding the carriers, to look solely at the math of a missile engagement. It’s now time to come back to that problem, and see just how hard it is to generate targeting-grade data.
The basic problem is that the sea is very big, and ships are small and mobile. In WW1, the British used codebreaking and direction-finding to keep track of the German fleet, which allowed them to set up Jutland, while the Germans thought it was a fluke, and that they’d stopped a British sortie into the Baltic. In WW2, the British would listen in to the reports of Italian scout planes, and if their position reports were far enough off, they wouldn’t bother shooting them down.
Obviously, radar and modern navigational systems have made it easier to track ships at sea. Clouds are no longer going to hide the surface, and it’s harder (though not impossible) to mess up your navigation. But there are still problems. A typical radar system will tell you that there is a target there, but it won’t tell you what the target is. The Soviet Radar Ocean Reconnaissance Satellites (RORSAT) could only measure the targets parallel to its orbit, so carriers would turn to face it, shrinking their signature considerably. While the RORSAT cue did help, as did data from passive platforms and other sources, the final localization had to be done by a platform vulnerable to the carrier’s defenses, to make sure that the missiles found the carrier and not one of its escorts, usually an airplane of some sort. In the Mediterranean, the Soviets employed destroyers to fulfill this function. These would shadow US groups, and had rear-facing anti-ship missiles, to be fired as they turned away (to avoid becoming targets themselves.) The turn-away was an important indicator of an impending attack.
The preferred way to solve the identification problem is electronic signal measures, or ESM. At the most basic, if there is a radar that only exists on carriers, and you detect it coming from a ship, then that’s your target. On a more sophisticated level, military radars are usually essentially hand-built, and it is possible to take a ‘fingerprint’ and identify a specific radar remotely. The US, Russia, and China all have sea-surveillance ESM systems. However, these can be defeated by emissions control, or EMCON, a common practice in western navies. Satellite communications allow ships to avoid most of the disadvantages of EMCON, as a satellite can transmit to the surface over a broad area, and a ship can send a tight beam back to the satellite. The ship can rely on data from other sensors (including ESM and IR satellites) to learn of an incoming attack, and only break EMCON after it has been located.
Optical cameras don’t require cooperation from the target, but are stymied by clouds and darkness. IR cameras have issues seeing through the atmosphere. Modern SAR platforms like TerraSAR-X/TanDEM-X are quite capable of identifying ships from space using synthetic aperture radar. However, they do have limited swath width, particularly in the higher-resolution modes that are required to get firm identification. The combined TerraSAR-X/TanDEM-X cost approximately $400 million. Jane’s says that it can image 90% of Earth’s surface within 2 days, although there are several different resolution modes. The best data I have suggests that you can get data between 20 and 45 degrees off-nadir, which translates into a swath between 170 and 460 km off the ground track, on one side. This is probably enough to provide a precise location for a carrier that has already been roughly located, although the finer modes have widths of only 10-30 km. X-band radar, though, is badly affected by rain (something Airbus fails to mention in their marketing literature), and the US used to hide ships from similar Soviet systems in bad weather. I’m not sure how effective electronic warfare is against this kind of system, and sources differ on the matter.
But what about non-space-based options? Can’t we just send out drones to look for the carriers?
The obvious problem we come to again is emissions. A radar can usually be detected at least twice as far away as it can detect anything. The obvious solution for the carrier is to use some form of low-power low probability of intercept (LPI) radio to vector fighters out to kill the snooper. (Or even simply brief them on deck and send them out under full EMCON.) The E-2 Hawkeye has a very good ESM system, and with tankers and cleverness, could manage to at the very least significantly mitigate the ‘flaming datum’ problem. Optical surveillance, besides being flummoxed by clouds, has a very limited range compared to radar. The obvious suggestion is drones, but drones probably have to talk to base to be effective. Automated detection systems could solve that, but you’re still looking at a high false alarm rate, and the system would be quite expensive.
For a wonderful explanation of the methods that a carrier group would use to avoid a firm detection, see <a href=”http://navweaps.com/index_tech/tech-031.htm”>this essay</a>.
(TL DR: There are a lot of things a carrier group can do to not look like a carrier group. They work very well.)

But eventually, the carrier’s luck will run out, and the bad guys will locate them, and they’ll die, right?
Not so fast. A location, particularly one that is targeting-grade, is inherently perishable, and if your opponent knows you’ve got it, then it’s going to spoil even more quickly. Essentially, you have to get your weapons near the target before the area where the target can be gets bigger than the area the weapons can search, and then make sure that those weapons lock on to the right target. This is true regardless of the nature of the weapons, although different weapons have very different parameters for search and lock-on. One example would be an air strike. Searching for the carrier is a good way to get killed by defending fighters, but the attacking aircraft can still compensate for some degree of imprecision in the fix.
A missile is much less capable of such compensation, and this has been a long-term problem with anti-ship missiles. The US has stopped installing Harpoon missiles (range of ~70 nm) on destroyers, and removed the submarine-launched version from service, out of fear of hitting the wrong target. The original Tomahawk Anti-Ship Missile, which had an effective range of over 200 nm, was going to solve this problem by using ESM, looking for the radars of a hostile ship. However, this was problematic, and in exercises, the hit rate was around 25%.
Ballistic missiles have an even bigger problem. Unlike a cruise missile, they cannot wait and search for a target. The first ASBM, the Soviet SS-NX-13, was designed to home in on radar emissions, but never entered service, as it would have displaced ballistic missiles on submarines, the numbers of which were limited by treaty. The guidance mechanism of the DF-21D is not known, but there are only a few options. Optical guidance is right out, as it doesn’t work at night or in bad weather. IR does work at night, but is still vulnerable to bad weather, a common phenomenon at sea. Radar might work, but is vulnerable to countermeasures and there are limits on what can be done with a platform the size of a missile warhead, particularly in terms of non-cooperative identification. (In plain English, the missile can’t tell the carrier from a destroyer with a blip enhancer or a merchantman.) Home-on-radar is an option, but can be foiled by not using radar or using the wrong kind of radar. (Also, SPY-1 apparently has special modes to fool radar-homing missiles.)
All of this gives a very limited window for the attacker to take a targeting-grade sighting and get the data to the weapons. This is usually ignored in popular articles, but it’s very important. Every minute, the carrier gets another ~900 m away from the initial fix. The internet makes instant, reliable communication seem easy, but the list of disruptions due to various bad actors should be a reminder that this kind of communication is difficult and vulnerable to disruption. Throw in an active and very hostile power, and the network is likely to be seriously disrupted at best, and brought down at worst. China might have made the investment in targeting platforms and communications to be able to effectively target something like the DF-21D, although we can’t be sure how well their efforts will work until it’s tried for real. Enemyistan almost certainly hasn’t. I do know that early US attempts at this kind of networking often saw data delayed by an hour or more, for whatever reason, and they were not facing the full array of countermeasures that a major power can bring to bear. If the delay is too great, then there's nothing in the missile's field of view when it shows up, and it either plunges into the sea or takes out something it thinks is a carrier, but turns out to be a Dutch container ship.
None of this should be taken to mean that the US carriers are completely safe from detection. There are ways to find ships at sea, but they are expensive and difficult, and their effectiveness can’t be absolutely certain. But anyone who ignores those difficulties when discussing the effectiveness of the carriers is either ignorant or dishonest.


The last essay went over pretty well, except for one nutjob who decided I was an idiot because I said 'the US response [to China using nuclear weapons on a carrier] involves ICBMs', when nuclear cruise missiles were more likely. Probably. I'm not sure he had coherent positions. Anyway, I eventually decided to ignore him, and so did everyone else.

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Intelligence can be identified by its rejection of self-deception; by its willingness to admit that it might be wrong; by its insistence upon evidence rather than mere impression; by reasoning that cannot easily be assailed. - Orson Scott Card


Last edited by ByronC on Fri Jul 21, 2017 11:33 am, edited 1 time in total.

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 Post subject: Re: RFC
PostPosted: Thu Jul 20, 2017 6:39 pm 
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Add something about the final targeting problem for missiles and you've got it.

Something like:
You have a good firing solution at the target, and have launched the missiles. It takes them X (30) minutes to get to where they expect the ships to be. When they get in range of their onboard sensors, they try finding the ships and target the best match. The sensor detection cone is much smaller, and it's size depends on the missile speed and size. If the ships aren't within that cone, the missile either falls into the sea or hits a bulk car carrier from Korea instead of the carrier.

Dress that thought up a bit, and add it.

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 Post subject: Re: RFC
PostPosted: Thu Jul 20, 2017 7:05 pm 
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There is also the possibility of corrupting the track data that gets passed from sensor to shooter.

Sensors says to user: "Over here." (Might even be true.)

Sensor says to shooter: "Over here."

Sensor says to ASBM: "Over THERE, not over here."

Very expensive ASBM warshots land in empty ocean. Or worse, on a friendly CV.

COMNAVSECGRU checks in to Bethesda Naval Hospital with his face frozen in a permanent s***-eating grin.

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 Post subject: Re: RFC
PostPosted: Thu Jul 20, 2017 8:10 pm 
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Excellent work

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 Post subject: Re: RFC
PostPosted: Thu Jul 20, 2017 8:19 pm 
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BZ! Dolphin 32.

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