From the early 70s onward, the Sea Sparrow was the primary point-defense missile used by the USN. But it had always suffered from a fundamental handicap. It was a derivative of the AIM-7 Sparrow air-to-air missile, and the Navy's desire to maintain commonality between the two had limited what they could do with the Sea Sparrow. But by the mid-80s, it was obvious that the air-launched Sparrow would soon be superseded by the new AIM-120 AMRAAM, opening the way for a version of the missile entirely dedicated to the naval point-defense role.
A Japanese destroyer launches an ESSM
The result was the RIM-162 Evolved Sea Sparrow Missile, generally known as ESSM. It was designed to be more or less a drop-in replacement within the various environments where the existing Sea Sparrow missile was used, although the designers, freed from the form factor of the existing missiles, chose to completely redesign the aerodynamics, replacing the big fins, useful at altitude, with small fins and strakes optimized to work near sea level. The result resembled a miniature version of the SM-2MR, and the reduction in the size of the fins allowed the missile to be packed much more densely, with four fitting into one cell on the Mk 41 VLS. Even with this, the 8" motor previously used could be replaced with a 10" model optimized for the task, which not only gave the missile far more energy, doubling range, but was also optimized to burn quickly. This got the missile up to maximum speed (around Mach 4) early on, helping performance, and reduced how much the smoke from the motor interfered with optical tracking of incoming targets. To enable VLS launch and improve close-in maneuverability, a thrust vector control system is fitted. The design goal for the missile is to be able to maneuver at 50G, giving it the capability to take out a supersonic missile maneuvering at 4G.1 Most of the guidance system was taken from the late-model Sea Sparrow, easing integration with Aegis, NATO Sea Sparrow systems, and other fire-control systems designed for the earlier missile, although the autopilot was upgraded and the warhead was fitted with insensitive explosives, less likely to go off in case it was caught in a fire.
RIM-162 in flight
The result of all of this work was an excellent close-in anti-missile weapon, swiftly adopted not only by the USN, but also by 17 allied navies, ranging from Germany and Norway to Japan and Mexico. The small size of the missile was a significant advantage, as it could not only be quad-packed into the Mk 41 VLS used aboard the USN's Burkes and Ticos, but also dual-packed into the smaller Mk 48 VLS that had originally been designed to carry single Sea Sparrows. The Mk 48 proved popular with a number of NATO navies, as the two-cell module was small and light enough to fit to almost any frigate, virtually all of which have switched over to ESSM. Norway even felt confident enough in the missile to equip their Fridtjof Nansen class air-defense frigates only with ESSM in place of Standard, with a single 8-round Mk 41 as their sole armament. While this was probably not a great decision, it demonstrated the ability of the new missile to provide very substantial air-defense capabilities in a small package. The actual range of the missile is obviously classified, but most estimates put it at somewhere over 50 km (27 nm). To put this into context, that gives it a similar range to the RIM-2D Terrier or RIM-66B Standard MR, both weapons that were at one point considered mainstays of the USN's fleet air defenses.
Fridtjof Nansen fires an ESSM during an exercise
ESSM was originally slated to replace most other close-in defense systems, particularly aboard ships which had VLS capability. Delays to the missile, which finally entered service in 2004, and the growing threat of small boats, saw most of the Burkes retain one Phalanx in addition to the new missile. This isn't to say that the ESSM didn't have anti-ship capability. It did, as do virtually all SAMs, but it wasn't particularly suited for dealing with the kind of small-boat threat exemplified by the suicide boat attack on Cole in 2000.
ESSM has performed well in tests, shooting down a number of high-speed maneuvering targets. It also saw action in 2016, when USS Mason engaged cruise missiles fired by Houthi rebels in Yemen. Unfortunately, few details of this engagement have been revealed to the public, but a single ESSM and two SM-2s were fired at a pair of incoming missiles, most likely Chinese-built YJ-83 missiles. Neither cruise missile hit, although it's not clear if they were intercepted, decoyed, jammed or just crashed on their own. More recently, it has likely been used in the engagements in late 2023 off Yemen, but no details have been released.
Sailors load an ESSM
But despite its capabilities, ESSM still had the drawback of all previous versions of Sea Sparrow. It relied on semi-active guidance, requiring illumination from the firing ship. It did have an autopilot and uplink from the firing ship, allowing illumination only in the last moments of its flight, but this was still a potential problem when facing saturation attack. The obvious way to solve this was to fit the missile with an active seeker head, and discussions of doing so were happening as far back as 2002, but it wasn't until relatively recently that serious work began on what is known as ESSM Block II. Block II kept the motor and fins, and replaced the forward 8" section with a new 10" guidance section, with a new dual-mode active/passive radar seeker. This removed the need for firing-ship illumination entirely, allowing Block II to be used against swarm attacks or targets that the firing ship couldn't see, although reports don't seem to indicate that it's fully integrated into the Collective Engagement Capability (CEC) system. In any case, the Block II ESSM entered service in 2021, paving the way for the Sea Sparrow lineage to continue protecting America's ships for decades to come.
1 The difference in these values is likely because 50G maneuvers bleed off a lot of energy very quickly, while it seems unlikely that a missile could maneuver for any length of time at more than 4G without slowing way down and leaving itself a sitting duck. ⇑
Comments
This should be either "This was probably not a great decision but it demonstrates" or "While this was probably not a great decision, it demonstrate."
Yeah, bad editing on my part. Fixed now.
Couldn't the discrepancy between interceptor and threat maneuverability also be due to the disproportionate effect on the intercept point that threat maneuvers have at long range?
E.g. the Sparrow launches vs a target 50km out and calculates an intercept point 10km out and starts going there, but then the target, while still far away, changes course and the new intercept point is far from the initial one, requiring the Sparrow to chase it across the sky. The cruise missile could even switch targets, eg between different ships in a task force, so you can't even count on knowing its final destination.
@alexT That was my assumption as well.
Not really, because physics doesn't work that way. Yes, a small change in course at long range moves the intercept point quite a bit, but it also gives you lots of time to respond. In practical terms, it pretty much cancels out, and the interceptor just has to match the maneuver 1 for 1. It's when you get close that you start needing to be able to maneuver more than the target.
Protecting America's ships for decades to come, and now Ukraine's cities.
https://www.politico.com/news/2023/01/05/biden-ukraine-bradley-vehicles-tanks-00076549
Apparently the Ukrainians have figured out how to integrate Sea Sparrow with their Soviet-era 9K37 "Buk" (aka SA-11) surface-to-air missile system. Not clear what version, but I don't think the pre-Evolved models with the big delta wings will fit on a Buk launcher. Both systems use semi-active (unless we're giving them the very latest) radar guidance with X-band CW illumination, so it's not too surprising they can be kludged together.
Not that there was anything wrong with the Buk, against the sort of targets Russia is giving it, but after almost a year of war the Ukrainians have probably run through most of their inventory. NATO's got lots of Sea Sparrows it's not using, and if we're upgrading to the Block 2 version, no sense letting the old Block 1s go to waste.
Actually, I wouldn't be surprised if it was the RIM-7. Looking at the numbers, the Buk has a wingspan of 2'10", while the deployed wingspan of the RIM-7 was 3'4". I am very sure that all of the non-folding-fin RIM-7s are long gone, but there's going to be quite a few of the later models sitting around in Western arsenals.
I don't think the folding fins would clear the support cradle a Buk launcher uses to hold the missile center body. See e.g. https://upload.wikimedia.org/wikipedia/commons/thumb/e/e8/9M317surface-to-airmissileofBuk-M2E.jpg/1280px-9M317surface-to-airmissileofBuk-M2E.jpg
But we'll see.
I'm going to stick to my guns on this one. The Buk is 15" diameter, as opposed to 8" for RIM-7. If anything, I'd expect the solution to be unfolding the fins manually and fitting only two missiles to the launcher. Or you could get a welder and fabricate some new structure out there.
I suspect that the easier method is to have some sort of crate to hold the fins closed during launch and attach those to the Buk's attachment points. Might raise the CG a bit doing that, but it makes it really simple to field. If it can also be the shipping container, it might be even easier to load then, assuming you have something to act as a crane.
The official list is out, and Ukraine is getting RIM-7s.
And that's because it seems that the Ukrainians are able to adapt the BUK launchers to use the RIM-7.
https://i.redd.it/lntyy776odaa1.jpg
What do you think the minimum (cheapest) ship sensor suite for ESSM blk2? Would it work ok on a ship without something on the level of Aegis, or are RAMs the only option for low cost ships?
Good question. To some extent, you can make the sensors as cheap as you like, but you're going to get worse performance. For instance, I've heard that the SM-1s on the Perrys were no better than Sea Sparrow (original flavor, I think) in terms of general performance because the electronics weren't very good. At some point, if the sensors are bad enough, then ESSM isn't that much better than RAM, and RAM is cheaper. Not sure exactly where that line is. I'd guess it's somewhere below the radar on the Constellation (can't remember the designation offhand) but I am not familiar enough with the world's naval radars to point offhand to the minimum system needed to get good results with ESSM.
I lost a "would be" in that first sentence, whoops.
Glad you saw where I was going with the frigate thing. I've been fascinated with the "actually effective low-end warship" concept, and have been trying to figure out if it's worth putting a VLS on anything with less than top-tier radar.
Or if the only stable equilibrium is a high-low mix of "Aegis+SM+ESSM" and "a gun and some SeaRAM" a la LCS.
The idea of a cheap warship with basic self-protection that could also be a missile slinger in high intensity conflicts as part of a CEC network seems very appealing.
But I'm not a naval strategist and "hey, it works in Aurora 4x" is even worse than "hey, it works in Kerbal Space Program."
With active guidance missiles you could probably have a bunch of cheap ships with just VLS cells and a small handful of expensive sensor ships to guide the weapons using network centric but whether that actually makes any sense is another matter.
Specifically those sensor ships are going to make very inviting targets, only way I could see it working is if the enemy can't tell them apart from those that can only sling missiles which does not seem likely.
Cheaping out with active guidance missiles that don't need illuminators may well mean less larger ships so you can maximize missiles per radar set at which point destroyers start having prefixes starting with B.
What sort of capability does a radar need to get the most out of ESSM?
Aegis is overkill. That system was designed to deal with Tu-22Ms firing Kh-22/AS-4 missiles en masse from 300+ km; a threat that is rapidly losing relevance as the remaining supply of Kh-22s are used to destroy Ukrainian shopping malls.
You'd need target detection for sea-skimming missiles out to roughly the radar horizon, and large aircraft out to maybe 100 km. You'd want to be able to track 16+ targets simultaneously with high precision, and unless you're planning Block 2 only, you'll want to be able to illuminate 2-4 targets simultaneously (depending on how fast you can switch between targets). And it has to integrate well with some sort of battle management system that will be e.g. passing midcourse updates to the missiles.
So, the big S-band surveillance radar is unnecessary. Any decent X-band AESA should do, or a PESA with a few dedicated illuminators. The Dutch "APAR" looks very good in this context, but it's still a bit on the large/expensive side. Sweden's "Sea Giraffe" series might have something in the sweet spot.
That's basically the model behind the arsenal ship and CEC, although in different ways. My issue with it has always been that I don't think VLS cells are the major bottleneck, and even if they are, it's not that difficult to make an existing ship bigger and give it more VLS cells. There's a limit on that, obviously, but we're not close to it, and it just seems more efficient.
I should have been more explicit in the "VLS is mostly steel and air" part. I figured the main value was being able to tell Congress they're getting a Great Deal on dollars per missile launcher, to justify buying a cheap, lightly-armed, and very unsexy ship for essential grunt work. Without, you know, making it a trimaran that's 10kts too fast and not cheap at all.
(Plus now you can say "our VLS cells at sea are only x% filled, down 30%! We need more missile production!")
Was thinking about the benefits of being able to rotate in missile frigates without taking a Burke off station to reload (or having to learn underway rearming again), but couldn't even come up with a contrived scenario where it'd be particularly useful.
Anyway, I'm getting us way off topic from the missile itself.
Strategic argument for a bunch of smaller ships with Cooperative Engagement Capability, CEC, is that the oceans are very big and a nation with global interests like the USA has interests almost everywhere. One ship with 128 VLS can only be in 1 place at a time, or 0 when it's in dock for maintenance. If, and it's a big if, most hotspots / crises can be responded to with a smaller ship, then four x 32 VLS ships can be in 4 places at a time, or more likely 3 given maintenance schedules.
Tactically, the 4 ships are more resilient to someone hitting a mine or something. If, again a big if, the networked radar and other sensors really work, against a more serious threat one ship with really good radar and sensors can use the VLS cells of the four smaller ships as if they were its own, effectively becoming a 128 VLS ship.
Given how expensive radars are, I'm not actually sure that the 4 smaller ships would be cheaper than the one big, even before adding in the 5th ship with really good radar.
I am very sympathetic to the view that we need to look hard at how we buy lower-tier ships (cough Type 31 cough) but that's a different thing from distributing VLS cells around. The basic problem is that in any sort of high-threat area, you're going to need the ship with the good radar, and if it goes, all of the other ships are pretty vulnerable. So all having the other ships really gives you is more chances for one of those ships to get sunk, and less available firepower if the enemy manages to jam the CEC link.
I can even see the case for fitting the US Type 31 equivalent with a 32-cell VLS on the grounds that it would be nice to have Tomahawk available, and we can use the cells with CEC in an emergency. I just don't think we're anywhere near the point where VLS cells are our biggest bottleneck, which makes some of the USV stuff of dubious value.
The value of small, cheap ships is that they let you put a ship in a place where you otherwise wouldn't have any ship, not that they let you have bigger fleets of punier ships in the major naval battles. It's been pretty clear for most of the past four centuries that if you're trying to win a major naval battle, you want to be using the largest, toughest ships you can reasonably build in modest quantity, whether that means "ship of the line" or "armored frigate" or "dreadnought battleship". We can argue about whether it now means "CVN" or "DDG" or "SSN", but a swarm of low-grade FFGs probably isn't the answer for winning a big naval battle.
That being the case, you really want your small, cheap ships to be ships that can actually fight a battle without mommy DDG holding their hand. A Type 31 can win a broad range of battles (against forces of comparable scale) all by itself. So can a Constellation, or an Absalon. An LCS, or an "arsenal ship", not so much.
The 31 having Sea Ceptor and a "for but not with" VLS seems like a more extreme version of my proposal. Imaginary missile launchers are even cheaper than empty ones!
Seems like a nice way to stop people going "can't you make it smaller to cut costs?"
That's a really good point about Tomahawk, now that they're being used in ones and twos to knock some guy's tent over, rather than just in massive pre-invasion strikes. And they don't need an entire office complex for targeting plans now.
Btw, seaceptor is much lighter and less capable than ESSM, but more than RAM, right?
It's interesting that we have anti air missiles of all sizes rather than evolving towards a few similar types (like artillery did)
A VLS cell that you only imagine having built, is indeed cheaper than one you paid real money for but can only imagine using if there's an imaginary DDG right next to it with a proper fire control system. And if the DDG isn't imaginary, you should probably just put your extra VLS cells on that - a hull stretch is going to be cheaper than a whole new ship.
Sea Ceptor, at least in the ER version, doesn't seem to give up much capability to ESSM as a surface-to-air missile. But the warhead is substantially smaller, which mill make it less capable against surface targets. That's troublesome for a warship that doesn't carry dedicated antiship missiles; we know Sea Sparrow can mission-kill a frigate or destroyer escort but Sea Ceptor would be marginal at best.
Yes. I suspect that RAM is a bit light for general use (as opposed to as a better CIWS) while ESSM is maybe heavier than you really need because it was sized by existing equipment. Or Sea Ceptor is small because of the land version.
Hugh Fisher:
As long as no one sinks the radar ship, expect any adversary where you'd need it to be able to tell which one carries the radar so the other ships won't even be able to function as decoys.
It looks like the correct way to use smaller cheaper ships in a high intensity war is in peripheral theaters so as to free up the real warships for the main battles, not to provide a few extra VLS cells for the battle fleet.
If you had unlimited resources you wouldn't even talk about smaller ships, you'd just have everything be top end.
And w/re mines, the real warship with the radar is just as likely to hit one of those whether it's got four little friends sailing with it or not.
The other role for low-end warships in a high-intensity conflict is as ASW escorts. Against a submarine, anything with a helicopter and a towed array sonar is roughly equal to anything else with a helicopter and a towed array sonar. But the enemy's submarines could be anywhere, so you want to put your escorts everywhere there's anything worth escorting.
Given that you've paid for the hull, the helicopter, and the sonar, you might as well give it the capability to e.g. defend itself against a maritime patrol aircraft firing a handful of ASMs, that sort of thing, but don't go so far overboard on that that you end up spending three or four times what you need for the capabilities that really matter. And we know we can get the hull, the helo, the towed array, ESSM and a decent radar, and the rest of the basics for $250 million or so.
"anything with a helicopter and a towed array sonar is roughly equal to anything else with a helicopter and a towed array sonar"
How much does the acoustic signature of the warship matter here? I have heard that making ASW escorts quieter is a factor in making the Type 26/Glasgow class more expensive than the "general purpose" (i.e. ffbnw) escorts like the Type 31/Venturer class. If a Venturer with a towed array and a Mk41 (and a 5" gun?) would be essentially equivalent to a Type 26, the decision not to equip them that way (and the extra cost of the ASW Type 26) seems like a bad decision.
For clarity, I'm not suggesting that the small ships be just barges with VLS cells. My suggestion is something with the minimum fire control radar discussed earlier, such as the Swedish Sea Giraffe. So on its own it can defend itself against most threats, out to maybe 20km ? or so. And I happily agree that the four smaller ships won't be cheaper than one big one.
The CEC capability comes in when the fleet needs defence against ballistic missiles, or over the horizon, or something else that only the latest and greatest AEGIS can detect and respond to.
I've read that the USAF is testing something similar in exercises, an F-22 or F-35 leads a handful of F-15s. In this case the F-15s are acting as missile trucks, but they're still capable if not top of the line on their own.
John Schilling:
Which counts as a peripheral theater.
Hugh Fisher:
Maybe not, but in any fight in which Aegis is necessary they may as well be barges with VLS cells.
Hugh Fisher:
They've already got a whole heap of older aircraft that still have some life left in them so may as well figure out how to get more use out of them.
But buying new F-15s for it that role is very unlikely to make sense.
The types 26 and 31 are definitely not equal as ASW platforms. Some of it is silencing, but more of it is sonar and combat systems, bit of which the type 31 is far inferior in.
The stealth is obviously intrinsic to the hull, and it's associated power & propulsion systems, so you couldn't realistically improve that. A towed sonar seems like something that could be added, but tying it in to the combat systems is presumably harder. Even if you containerised whatever you needed to add and stuck it in the mission bay, I assume that not having the CIC set up with it in mind would cause problems.
It isn't easy to understand what makes one frigate several times the cost of another (to buy, I assume operating it would be more similar). Mind you, as you've pointed out before, you can't easily compare the quoted figures for defence procurement.
I guess my big question is how much more safety/capability ESSM gives over, say, seaRAM.
Imagining likely scenarios for a budget frigate is pretty easy:
Say you're inspecting ships in the Persian gulf because the environment is now a little too risky for the coast guard to help with. Someone lobs some ASMs from the coast like off Yemen. Does ESSM give you a better chance of surviving? Better enough to be worth the extra money?
Say you need to Tomahawk two airports and a presidential palace to send the message that Uncle Sam is very upset with someone. Is having one of your low-end ships being capable of doing the job cheaper than sending a Burke? (Wouldn't an f15 or b52 be even cheaper? Always wondered about why we use tomahawks for stuff like that)
You're imposing a distant blockade on ships entering the South Sina sea, and Sinese diesel subs are known to be lurking along routes to defend merchant shipping from western imperialist piracy. Does having ASROC and heli cover make low-end ships safe enough to use for the job, to free up your expensive dedicated ASW ships for sub-hunting?
Your nation's fishing fleets are suffering unwarranted aggression from Leaf Confederacy offshore patrol boats. Does being able to engage them from outside 5" gun range matter? Or is a low-end frigate more for playing bumper boats and conspicuously manning the 25mm deck chaingun?
Ok now I'm reaching a bit, but you get the idea.
Hmm, I guess that should have been the Grumpy Cat Gulf to stick with the theme.
Relative to RAM, does ESSM have enough anti-surface capability that a frigate wouldn't need to carry Harpoon/NSM? Alternatively, does having the Mk 41 anyway mean you could carry LRASM or SM6 if you really need something that can hurt an enemy FFG/DDG?
ESSM doesn't have over-the-horizon capability, or at least not far-over-the-horizon capability. That's enough of a disadvantage that it's probably not enough for a ship with ASuW as a primary mission. But it can mission-kill just about anything inside the radar horizon, which should be good enough as a self-defense weapon for an ASW or AAW escort, or for a "minimum viable warship".
You should probably still reserve space and weight for a couple of Harpoon/NSM/whatever quad-packs.
I'm not sure that surface launch LRASM is a thing, or at least it wasn't talked about from about 2017 to last year, when the Australians finally bought it. Which does leave a rather odd gap in Mk 41-capable ASMs. Hopefully that gets filled soon. If that's on the table, then I don't see a particularly strong case for NSM or Harpoon. If it's not, then you're going to want those for OTH work. Or the latest Tomahawk variant, although I have some questions about that in a serious war.
That makes sense. Where I was going is, if you have RAM and not ESSM, then you need something for anti-ship self-defense (with the associated topweight and deck space, since there seems to be a dearth of VLS-launched ASMs unless you count SM6), whereas if you have ESSM maybe you don't. That might be enough to make one versus the other a clearer choice, unless it means needing more expensive combat systems.
OTOH, RAM has an IR seeker too, which might give it enough advantage in a very EW-unfriendly environment that you'd want it anyway. (And certainly the USN doesn't seem to think that ESSM entirely obsoletes RAM, since CVNs and LHDs have both, and now some DDGs are getting SeaRAM too.)
I think the USN sees RAM as competing with Phalanx, not ESSM. You need something to deal with leakers, or with minor attacks that come in when you've turned off your main missile-defense radar.
You also need something to deal with small boats and drones, which Phalanx does cheaply and RAM does at something like a million dollars a shot. I think the sweet spot is something like the Oerlikon 35mm "Millenium" for backstopping ESSM.
The only case I know of ESSM being used as a CIWS alternative was on the DDGs, where it makes some degree of sense given the limitations of Phalanx and the fact that you get Aegis for free in that case. In general, RAM is treated as a super-CIWS system (which is pretty much the original brief) and ESSM is a short-range SAM. I'm not actually sure how much sense it makes to keep ESSM on the CVNs, and I wouldn't be surprised if capability was limited by the combat system, not the missile.
The DDGs getting SeaRAM are the BMD ships in Europe, and it's because their radars can't handle self-defense very well while in BMD mode. At this point, I suspect that most CIWS fits are basically a placeholder for future laser installation.
@John Schilling: "You need something to deal with leakers, or with minor attacks that come in when you’ve turned off your main missile-defense radar."
Like, uhm, the Moskva?
@Emilio: Or Stark, or Hanit, or Sheffield (OK, missile-defense RWR vs radar). Or, as bean notes, any DDG standing guard against ballistic missile attack.
Turning off your main missile-defense system in a war zone because reasons, is a thing that's going to keep happening. So have a backup that you can count on.