More Cells, Larger Missiles?

Sit down comfortably people, because it’s time to speculate about VLS-cells. The Pohjanmaa-class is now finally being built, and it will get the new and upgraded ESSM Block 2, both things which you know if you saw my recent piece at Naval News. The Block 2 is a significant boost to an already very capable design, but now a new little clip from the FDF dropped over on YouTube. Nothing revolutionary, but the renders are showing that the design is being finalised, and an interesting detail can be spotted. Maybe.

Between the deck gun – a hand-me-down 57 mm Bofors left over from the Hamina-class which in turn downgraded to a 40 mm gun to balance the weight increase of the MLU – and the superstructure are the Mk 41 VLS. These come in batches of eight launch cells, and will hold the air defence missiles for the vessel. The first few wire frame clips seem to show two batteries of eight. That’s 16 cells, giving 64 missiles if quad-packed, which the ESSM is. A decent load if you don’t plan on using the cells for anything else, which for the time being seems to be the plan -note that the Navy refers to the combination of the ESSM Block 2 and Mk 41 as the ITO20 (Air Defence System 2020). One or two batteries of quad-packed missiles is a quite typical fit for European corvettes and frigates, with e.g. the Norwegian Fridtjof Nansen-class fitted for two modules (though at different times only a single one has been installed). As such, that is to be expected, and I am happy it isn’t a single eight-cell launcher, as I would not have been completely surprised if that was the case.

However, now the intriguing part comes, as just a few seconds later a full render comes up, and that seemingly shows four cells in a 2 x 2 pattern.

Now, renders are somewhat tricky, and YouTube isn’t the world’s greatest way of sharing media. But it does to my eyes look like we are seeing four distinct squares, with each square holding two rows of four lids. A comparison can be made to the aforementioned Fridtjof Nansen-class. While somewhat longer and heavier, they sport the same beam as the Pohjanmaa, meaning that looking at how broad a single cell is on their foredeck should give a sense of proportions.

This does seem to strengthen the idea that the render shows the Pohjanmaa able to take not one, not two, but four eight-cell Mk 41 launchers. This isn’t unheard of in a vessel of this size, but we are at the very edge of the launchers per tonnage-ratio for frigates and corvettes. The current German air defence frigate, the 5,700 ton F124 Sachsen-class as an example sport the same 32 Mk 41 cells, though in addition it also has two 21-shot launchers for short-range RIM-116 RAM-missiles. The British Type 26 (6,900 ton) has 24 Mk 41 cells for larger weapons, and 48 dedicated cells for the Sea Ceptor air defence missiles (roughly similar to the ESSM in capability). The FREMM-class is another design in the 6,000 to 7,000 ton range – depending on exact version – and in the air defence versions sport a relatively limited complement of 32 (French version) or 16 (Italian version) Sylver-cells, which basically is the European system corresponding to the Mk 41.

Now, all of these are significantly larger than the Pohjanmaa, but it should be noted that Finland traditionally hasn’t shied away from fitting a lot of weapons to relatively small hulls. In part this has come down to the concept of operations, where operations close to shore means you can make do with less space reserved for stores, fuel, and crew spaces, as endurance isn’t as critical. However, it isn’t out of the question that it could carry over to the blue-waters, as globally several navies are fitting more launchers to their hulls than is typical in European waters.

The really interesting thing is not necessarily the ability to fit 128 ESSM to each vessel, as that might be a bit of an overkill for most of the envisioned missions and would cost. A lot. However, what it does mean is that larger weapons can be carried, without significantly reducing the number of medium-range missiles kept for air defence. While Finland has so far not ordered any larger weapons, the straightforward nature of the Mk 41 and the powerful sensor suite and combat management system of the Pohjanmaa-class means that they could rapidly unlock even further mission sets if NATO’s capability targets so require. The obvious candidate is to give the vessel’s air defences even longer reach, with the Standard-family of missiles.

The Standard-family was born 70 years ago, when the US Navy wanted to standardise on a single family of missiles following the early developments post-war. Here is a rather nice Raytheon-made YouTube-documentary for those interested in the backstory, but the tl;dr version is that through standardising components, a whole family of air defence missiles was born, which has continued to be updated throughout their career and has seen long and stellar service all over the world, including in combat. The issue for Pohjanmaa is obviously that any member of the family hasn’t been integrated with Saab’s Giraffe-radars, though the fact that a number of European operators sport Thales-made radars give an indication that it likely can be done.

The basic missile is the SM-2, which gives a seriously increased range compared to the ESSM, and is in operational service with a number of our close friends and allies (it still feels really good to be able to say that), including Denmark, Germany, Poland, the US, and Canada. It also sports a secondary capability as an anti-ship missile, though in that role it is more of a back-up weapon than a first choice. It is often described as ‘medium-range’, which is the same terminology used for the ESSM. However, for the SM-2 we are looking at 150+ km, while the ESSM has a 50+ km range. While these numbers are always given with caveats, it deserves to remember that a tripling of the radius gives a covered area that is nine times greater (due to the area of a circle being based on the radius squared).

A short caveat – we still don’t have official confirmation of the length of the Mk 41 modules of the Pohjanmaa. If they are the shorter ‘Tactical Module’ the choices are limited to ESSM, SM-2, and VL-ASROC. That ‘limitation’ would still allow for one of the more solid air-defence loadouts among European vessels. However, the ‘Strike’-length does open up for more varied weapons, and if the amount of cells fitted really is 32, I wouldn’t be surprised if part of the reasoning is the possibility of carrying a more varied weapons load, which would make me lean towards ‘Strike’-length cells.

Enter the more exotic (and costly) members of the Standard-family, such as the (eye-wateringly expensive) SM-3 designed to intercept short- and intermediate-range ballistic missiles, with a proven capability against satellites and ICBMs as well. A really interesting weapon is also the SM-6 long-range surface-to-air-missile which serve alongside the SM-2 on USN vessels. Exactly how much longer the range is is unclear, and the US Navy keeps testing ever more intricate variants, but it is way above 240 km, perhaps over 350 km in the most recent versions. The SM-6 is also anti-ship capable, has an anti-ballistic missile capability, and apparently feature a nascent capability against hypersonic glide vehicles. But the price tag means that while extremely capable, it won’t replace the SM-2, and any export order by a small- or medium-sized would be for a limited number of ‘silver bullets’, likely to be fired only as part of joint-targeting under a common NATO-plan.

Putting to sea with a mixed load of e.g. 16 SM-2 and 64 ESSM would give a completely different kind of air defence coverage, both for coastal areas and on the open seas (interestingly, while the SM-2 is more expensive than the ESSM, it isn’t four times as expensive, so this loadout would actually be cheaper than an all-ESSM one). Cough up something along the lines of 10-15 millions, and we could even bring an SM-3 along, to shoot down a satellite or intercept an ICBM, likely with another vessel or ground-based radar working as the sensor spotting the target.

It also open up the possibility of non-air defence missiles. The obvious alternative is the Tomahawk cruise missile, which in addition to the US Navy and the Royal Navy is going to arm e.g. the Dutch frigates. The Tomahawk likely needs no further introduction, but lets just give the short version and say that it’s a weapon that has seen thousands of combat launches, has a range well in excess of 1,500 km, and would certainly be a serious contribution to the FDF long-range precision-strike arsenal. As mentioned, a more obscure alternative is the RUM-139 VL-ASROC (or simply VLA), which in essence is a missile that flies out and drops an anti-submarine torpedo on a designated spot, or the boosted LRASM which is the anti-ship version of the JASSM fitted to an ASROC-booster, which provide a heavy anti-ship missile out of a Mk 41 cell (the weapon has been successfully demonstrated, but not ordered into production).

As noted, all of these weapons can be fitted into Mk 41, regardless of whether you have eight, sixteen, or 32 cells, but the quad-packed nature of the ESSM means that you start to quickly lose a large amount of your primary weapon if you want to start mixing in heavier missiles. Eight SM-2 and 32 ESSM simply doesn’t provide for the weapon numbers to be able to fight a prolonged battle either at medium or at closer ranges, in particular as the Pohjanmaa lack a true close-in weapons systems such as the RIM-116 Rolling Airframe Missile. 32 cells offering a combination such as eight Tomahawks, eight SM-2, and 64 ESSM is already a load that wouldn’t look out of place in a NATO North Sea task force, and would provide a land-attack capability, a limited area air defence capability, and a serious medium-range air defence capability any task force commander would be happy to have in his or her force.

If it turns out that the render is just too blurry and the number of cells actually is  the expected sixteen, this post will go down as a somewhat-useful-but-not-really look at what a larger number of VLS-cells would open up when it comes to realistic opportunities. However, in the meantime I will start tying my shoelaces. Just to be on the safe side.