ESSM for the Pohjanmaa-class

Yesterday the Finnish MoD announced that the RIM-162 Evolved SeaSparrow Missile (ESSM) has been chosen as the main air defence weapon for the upcoming Pohjanmaa-class corvettes.

The weapon systems already acquired for the Pohjanmaa-class include Torped 47 ASW-torpedoes (Sweden), Gabriel anti-ship missiles (Israel), and ESSM surface-to-air missiles (USA). Source: Finnish MoD

The DSCA cleared the ESSM for export already a year ago, and crucially this was for the quad-packed Mk 25 launcher. This is fitted into the Mk 41 VLS launch system, which is a module of eight box-shaped shafts in which the missiles are stored until launch. The Pohjanmaa-class will be the smallest operational vessel fitted with the system by some margin (Taiwanese test bed LCC-1 Kao Hsiung is roughly same size), and interestingly enough it seems the full strike-length cells will be fitted.

This will give the corvettes a total of 32 ESSM per vessel (the astute observer will notice that the DSCA request only cover 68 missiles, meaning that further orders are to be expected), a significant upgrade in both range and numbers compared to the Hamina-class. While the Hamina’s Umkhonto have an IR-seeker, the ESSM have a passive radar seeker, which gives better performance in bad weather. When it comes to active versus passive radar seekers, unlike the situation in air-to-air combat where requiring the launching platform to keep it’s radar on target conflicts with the need to evade incoming fire, on a surface ship it isn’t necessarily as much of a problem as the radar stays active in a 360° search sector throughout the engagement.

Range is another major factor. The increase in range from 12 to 50 km gives a 17 times greater theoretical area covered. It has also been announced that the vessels, both as sensors and as shooters, will be integrated as part of the joint air defence network of the Finnish Defence Forces. This will give a significant boost to the air defences around the southern coastline, a key area for the country due to its concentration of population centres, ports, and heavy industry. This would be of particular importance in the early stages of a conflict, where the ground based systems of the Army might not have had time to deploy in the field.

The Mk 41 also allows for significantly larger missiles to be used, including the Standard-family of the US Navy and land-attack weapons such as the TLAM. However, with only eight available cells per corvette, swapping out a quad-pack of ESSM for a single longer-ranged SAM has serious effects on the ability of the vessel to fend off prolonged attacks. The Mk 41 could be used as a platform for missile defences to target systems such as the Iskander. E.g. Denmark is planning on doing this, but this would effectively tie up our limited number of corvettes in point defence missions along the southern shore.

An important factor in the choice was likely the widespread use of the Mk 41 and ESSM-combination, which ensure the ability to quickly fill up stocks if the need arises (i.e. we can hopefully get more missiles from US or even Norwegian stocks if we get dragged into a war).

The choice of ESSM will also have indirect effects on the Army’s GBAD program for a medium-range SAM-system. The inability of MBDA to secure a naval CAMM-order from Finland will likely impact the chances for the same missile on land as well. The NASAMS-compatible AMRAAM-ER in turn got a further boost, as it share some parts commonality with the ESSM (the ESSM can also be fired from the NASAMS launcher, though it is dubious if the Army wants a passive seeker head). Overall, MBDA has had a surprisingly hard time in securing any kind of orders in Finland. Time will tell if HX changes this.

On a final note, it is nice to finally see the MoD and Navy fully switch to referring to the vessels as the Pohjanmaa-class. The name has been known for quite some time, and in building a connection between the general public and the project it certainly has a nicer ring to it than the formal Squadron 2020.

Ballistic Missile Defence for Pohjanmaa?

As was noted earlier Finland has requested the export of quad-packed ESSM surface-to-air missiles for fitting in the Mk 41 vertical launch system (VLS). In itself the request was rather unsurprising, but I did find it odd that the Navy was asking about the canister designed for the Mk 41 and not the dedicated Mk 56 ESSM VLS.

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Mk 41 Strike length launchers in action, as the destroyer USS Donald Cook (DDG 75) fires a TLAM cruise missile against Iraqi targets in 2003. Source: US Navy via Wikimedia Commons

This week a key part of the answer was revealed, as the DCSA report for the Mk 41’s themselves was released. The Finnish request is for four 8-cell Mk 41, of the full-long ‘Strike length’ version. This is the same as carried by US Navy (and Japanese) destroyers and cruisers, as well as by a number of NATO frigates. The options for the strike length launcher include a large variety of US-built surface-to-air missiles, as well as the TLAM (Tomahawk) long-range cruise missile and the VL-ASROC anti-submarine weapon (a rocket which carries a parachute-retarded anti-submarine torpedo out to a considerable range). The downside is the size. To fit the large missiles, the cells are 7.6 m long. The logical choice if one want to fit Mk 41 solely for use with ESSM’s into a corvette is the 5.2 m Self-defense module. In between the two is the 6.7 m Tactical length cells, which add the SM-2 long-range SAM and the ASROC, but is unable to fit the TLAM or the SM-6/SM-3/SM-2 Blk IV (SM-2 with a booster). The SM-2 Blk IV and SM-3 are able to target ballistic missiles, while the SM-6 is a longer-range missile against airborne targets.

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Concept render showing the key combat systems of the vessel. Note the placement of the surface-to-air missiles. Source: Finnish MoD

Now, as late as last week I said in a discussion that it is not possible to fit the Strike length cells on the Pohjanmaa-class, as they are too long for a corvette. In all renders so far the VLS cells have been fitted in front of the superstructure, on deck level. Considering the low draft of the Pohjanmaa-class corvettes, just over 3 meters, it is doubtful whether the cells can be fitted within the confines of the bow. However, if the single cell is mounted along the centreline as opposed to across it, and if it gets a stepped platform a’la Type 26, it just might be doable (or a reshuffle with the Mk 41’s moving into the superstructure and the SSM’s moving to the foredeck/mission bay/further forward/aft/somewhere else).

So why would the Navy be interested in a cell that is two sizes larger than the missile they are planning on pairing it with? The answer is likely that they want to keep all options open. While I very much doubt that the ASROC would fit Finnish doctrine, the TLAM could open up new possibilities. However, if the Defence Forces want more cruise missiles, buying more of whatever will replace the JASSM on the winner of the HX-program is likely the better option (or alternatively buying a long-range weapon for the M270 MLRS). However, the possibility to provide some measure of protection against ballistic missiles might be of interest. While it certainly would be a major undertaking, the vessels will be in service for a long time and “fitted for but not with” is a time-honored tradition when it comes to naval shipbuilding. It should be noted that all kinds of ballistic missile defences are politically highly sensitive. Analysts have noted the similarities to the acquisition of the multirole F/A-18 Hornet back in the day, where even if the fighters were capable of flying ground attack missions, political considerations meant that the capability was only taken into use at a later stage, with the MLU2 mid-life upgrade.

The strike length cells also open up the possibility to fit some interesting anti-ship missiles in the future, as both the LRASM and the JSM are currently being tested in configurations suitable for launch from the Mk 41. Being able to swap out a number of SAM’s for more anti-ship missiles might be an interesting option at some point down the road (or at least interesting enough that the Navy doesn’t want to close the door just yet).

I will admit that the latest development have taken me by surprise. However, it does seem like the Navy is serious about fitting the vessels with systems that will allow them to field firepower to rival some significantly larger vessels. The question is whether the budget will live up to the ambitions?

No Finnish Harpoon/ESSM-order (at least for now)

As the headline says, yesterday’s big news from the naval sector is not that Finland has ordered the Harpoon and/or the Evolved Sea Sparrow Missile (ESSM). In fact, what has happened is that the US offers for two major Finnish naval programs have become open knowledge. This happened as the US Defense Security Cooperation Agency has requested clearance for the sale of 112 RGM-84Q-4 Harpoon Block II+ ER anti-ship missiles (of which twelve are of the older RGM-84L-4 Harpoon Block II version which will be upgraded) and 68 ESSM missiles. These kinds of pre-clearances are not uncommon, and allow for a rapid deal following a (potential) procurement decision by a foreign customer (thanks to Aaron Mehta for providing insights about US export).

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One of the latest renders, showing the refined corvette concept. Source: Finnish Defence Forces / Insinööriupseeriliitto

The background is two ongoing Finnish projects: the Pohjanmaa-class multirole corvettes and the PTO 2020 heavy surface-to-surface missile. The PTO 2020 will be found aboard the Pohjanmaa-class as well as replacing the current MTO 85M (roughly a RBS 15 Mk II) on the Hamina-class as part of their MLU as well as in truck-mounted batteries. As the MLU for the Hamina is very much underway already, the winner of the PTO 2020 will be announced during the first half of this year. I am still standing by my opinion that the RBS 15 Mk 3+ and the NSM are the two frontrunners, and would be somewhat surprised if Harpoon won the trophy (and even more so if the Exocet MM40 Block 3 did, though everything is possible).

The Pohjanmaa-class is still in the design stage, with the main contract(s) to be signed this year, and the building phase to start next year. The armament shown on renders include two quadruple mounts of PTO 2020 amidships, the new lightweight torpedo from Saab, the BAE/Bofors 57 mm Mk II deck-gun, and a battery of vertical launch system-cells (VLS). The two main VLS-systems on the market are the French Sylver and the US Mk 41 (a modernized version called Mk 57 is also available, and mounted on the Zumwalt-class). Both are available in different lengths, with the shortest Sylver, the A43 (an earlier A35 concept seems to have been dropped), being around 4.3 m long (or rather, high), and the shortest Mk 41 being 5.2 m long. The 8-cell module of the Sylver is also smaller and lighter than the corresponding 8-cell Mk 41 module, in part because the silos themselves are a few centimeters smaller. For a full run-through of the differences, see this post by the UK Armed Forces Commentary-blog, where the differences are discussed with a keen eye to the pros and cons for the British Type 26 Frigate.

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An ESSM leaving a Mk 41 cell. Source: US Navy via Wikimedia Commons

Now, while some vessels, such as the current Finnish Hamina-class and the upcoming British Type 26, feature dedicated cells to their main air-defence assets, the VLS on the Pohjanmaa will likely be home to the ships main air defence weapons. This becomes evident as the ESSM offer is for the weapon quad-packed in Mk 25 modules, designed to fit the Mk 41-system. If the ESSM would be chosen, the Pohjanmaa-class would be by far the smallest vessel to feature the system. The decision to offer the Mk 41 is interesting, as there is a dedicated Mk 56 ESSM VLS-system if the sole use would be for the ESSM.

The ESSM is certainly a competent weapon, and shows what the Navy is aiming for. 8-16 cells with quad packs would provide for 32-64 medium-ranged missiles, a huge boost compared to the current 8 short-range Umkhontos found on the Hamina. While the Mk 41 is too big for the Hamina, the Mk 56 mean that half a dozen ESSM’s could potentially be fitted as part of the MLU if the Navy choose to go down that (unlikely) route. More interesting is that the ESSM could be fired from the Army’s NASAMS surface-to-air batteries, letting the Navy and Army use the same missile stock. The upcoming ESSM Block 2 will feature an active seeker based on that of the AMRAAM, and is potentially the version offered to the Pohjanmaa.

Interestingly, the AMRAAM-ER is a AMRAAM married to the engine of the ESSM, and no, I don’t know what exactly is the difference between an AMRAAM seeker married to an ESSM engine and an ESSM engine married to an AMRAAM seeker.

I am still inclined to believe that the Sylver might be the Navy’s preferred VLS due to the smaller footprint. However, as with the PTO 2020, we will just have to wait and see.