Raytheon’s Tomahawk cruise missile Block development provides new challenges to Kongsberg’s increasingly popular Naval Strike Missile.
For a long time in the post-Cold War world, the capability for conducting long-range, precision-targeted conventional strikes from the sea against targets deep inland was the exclusive preserve of the US Navy (USN) and the UK Royal Navy (RN). Their tool for this task was Raytheon’s Tomahawk land-attack sea-launched cruise missile (SLCM).
While Tomahawk was developed originally (in the Block I variant) as a nuclear-capable system, the conventional variant arrived on the world stage in the 1991 Gulf War. High-profile use has followed in combat operations in Kosovo (1998), Afghanistan (2001), and the second Gulf War (2003), alongside use in several expeditionary and regional security operations (most recently, in Syria in 2018). This use can be mapped against the introduction of several different Tomahawk Blocks. Block II versions were used in the 1991 Gulf War. Block III arrived in 1993. Next came Block IV in 2004. The first Block V arrived in 2021. Blocks Va and Vb are planned.
Tomahawk’s development also reflects how combat operations have changed in the post-Cold War world. Block III brought Global Positioning System (GPS) targeting capability, giving Tomahawk 360-degree access onto target (rather than following roadmaps, as Block II had to in 1991). Block IV – as Tactical Tomahawk (TacTom) – brought in-flight re-targeting capability via a two-way datalink, as well as a loiter capacity. According to Raytheon, Block V brings improved communications and navigation within ‘a modernised TacTom’; Block Va will bring anti-ship capability in what is known as Maritime Strike Tomahawk (MST); Block Vb will bring the Joint Multi-Effects Warhead System (JMEWS), delivering capacity to strike more diverse land targets.
The addition of anti-ship missile (ASM) capability for Tomahawk through MST is one of the most striking recent developments, particularly for what it indicates about the emergent operational circumstances that have driven this requirement.
Tomahawk was the epitome of naval land-attack – a deep-strike capability designed to influence events ashore from the sea. In the contemporary operational context, the return of state-based rivalry and the desire to secure spheres of influence ashore and at sea means precision strike capabilities play a key role in constructing – or dismantling – anti-access/area denial ‘bubbles’, for example around key maritime choke points. Building on from this, the return of naval competition – and now combat, as demonstrated in the Ukraine war – has precipitated the need for ships and submarines to target surface ships from stand-off range at sea.
The growing naval threats at sea have also driven many navies to return to conducting task group operations, which in turn generates the requirement to both defend and attack such task groups with stand-off, precision strike conventional capabilities. The driving force here was not so much Western naval capability development as the significant increase in the Russian Federation Navy’s capacity to target Western ships at sea from both surface and sub-surface platforms. The Russian Navy’s tool for such a task would be the Novator 3M14 Kalibr SLCM. Kalibr has been fired from Russian surface ships and submarines against land targets in both the Syria and Ukraine conflicts. However, of equal concern for Western navies is the ability of Russian surface ships and submarines to target Western naval ships with long-range Kalibr ASM capability.
In recent years, these evolving requirements have driven an acceleration in Western navies’ and international partners’ development of SLCM capabilities. For example: France has introduced MBDA’s Missile de Croisiere Naval (MdCN) across its surface and conventional submarine fleet; and the Royal Australian Navy (RAN) and Japan Maritime Self-Defense Force (JMSDF) have expressed renewed interest in acquiring Tomahawk (both having considered it previously). However, perhaps the most interesting development is the increasing export success of Kongsberg’s Naval Strike Missile (NSM).
That Tomahawk is relatively more established and NSM is relatively more emerging reflect the operational circumstances and requirements when each came to the fore. The conventional Tomahawk was developed to provide precision in numbers to offset broader Soviet conventional force mass, Dr Sidharth Kaushal, seapower research fellow at the Royal United Services Institute (RUSI), told Armada International. As nuclear weapons became less relevant in the post-Cold War period, Tomahawk provided for the USN and RN a conventional deep-strike capability that could make a significant contribution to combined, expeditionary operations, Kaushal explained. It also provided a conventional deterrent option.
“By contrast, countries that pursued capabilities like NSM were operating navies built to deny an opponent sea control rather than project expeditionary power,” Kaushal continued. Certainly, the need to re-establish sea control to offset resurgent Russian naval presence points to why NSM has emerged as a primary ASM capability for many NATO navies. The development of an MST capability for Tomahawk may blur the boundary between these two types of requirement and capability going forward, Kaushal added.
Leading Edge
NSM certainly sits at the leading edge of current cruise missile capability and inventory developments. Its launch customer was the Royal Norwegian Navy (RNoN) and is operational onboard the RNoN’s Fridtjof Nansen-class frigates and Skjold-class corvettes, having reached Initial Operating Capability (IoC) onboard these two platform types in 2012.
Through a partnership developed between Kongsberg and Raytheon, NSM was introduced into the USN as a medium-range, over-the-horizon, anti-surface warfare (ASuW) and land-attack weapon. It is to be deployed via box-launcher fits on the USN’s Independence-class Littoral Combat Ship (LCS) variant, and is slated for deployment onboard the navy’s future FFG 62 Constellation-class frigate. Under a strategic partnership established in 2018, Germany and Norway are co-operating on development of NSM capability to the German Navy. NSM has also been selected for the Royal Canadian Navy’s Canadian Surface Combatant programme and the Royal Malaysian Navy’s Gowind/Maharaja Lela-class frigates.
These are all well-established plans, but NSM continued to be in the news in 2022.
In late December, Kongsberg announced that the Norwegian Defence Material Agency had ordered – through a $60.1 million (NOK604 million) contract – additional NSMs to support the further development of NSM capability under the Germany-Norway collaboration.
That same month, the Royal Netherlands Navy (RNLN) joined the NSM ‘user group’. The Netherlands Ministry of Defence (MoD) signed a contract with Kongsberg for the supply of NSM onboard the RNLN’s De Zeven Provincien-class air-defence and command frigates. In a statement, Kongsberg said “NSM, at its core, is designed to handle future threats and warfighting environments, making it a fifth-generation, long-range, multi-mission (anti-ship and land attack) precision strike missile designed to ensure efficient strikes under complex conditions.”
For the RNLN, NSM will replace the McDonnell Douglas/Boeing Harpoon Block 1C ASM capability onboard the De Zeven Provincien-class frigates. In its own statement, the Dutch MoD said that NSM brings several capability upgrades compared to Harpoon. “The missile is more precise …. The range is much longer, and the missile uses an advanced infrared search head.” “Furthermore,” the MoD continued, “the missile is difficult to detect by enemy ships due to the use of stealth properties.” The MoD noted that NSM deliveries to the RNLN would start in 2025.
A month previously, in November 2022, the RN had joined the NSM ‘user group’, signing up to introduce NSM as the UK’s surface ship ASM capability, replacing its legacy Harpoon fit. The contract was signed onboard the UK aircraft carrier HMS Queen Elizabeth, when the ship conducted a port call in Oslo during an operational deployment of the Queen Elizabeth carrier strike group in the North Atlantic. Hosting the signing ceremony onboard the carrier alongside in Oslo underlined the growing strategic relationship between the UK and Norway, too.
In a statement, Kongsberg noted that the RN fit will encompass its Type 23 frigates and Type 45 destroyers, with the first NSM-capable RN ship being fitted out with the missile and ready for operations within “a little over 12 months”.
For the RN, NSM adds a land-attack capability from surface ships, complementing the Tomahawk land-attack capability provided by the RN’s nuclear-powered attack submarines (SSNs). In its own statement, the RN confirmed that a total of 11 Type 23s and Type 45s would receive an NSM fit. It added that the first NSM-capable ship is scheduled to be operational by the end of 2023.
For the RN, NSM will plug the gap between Harpoon and a permanent successor, which – under the ‘future offensive surface weapon’ programme concept – will be delivered from 2028 and carried by the future Type 26 frigates, the first three of which (in a class of eight) are in build at BAE Systems’ Govan shipyard on the Clyde.
NATO Capability
The breadth and depth of NSM acquisition – including in September 2022 by the Armada Espanola, and in April 2022 by the RAN – highlights the extent to which NSM is becoming a major capability across NATO and its close partners. This has pan-alliance benefits in both operational and programme terms.
In terms of operations, many NATO navies are rebuilding task group structures at a national level, and are contributing more regularly to multinational task group structures, including the Standing NATO Maritime Groups (SNMGs). NSM is set to become a central anti-ship defensive capability for all such task groups. NSM’s wider availability also creates options for user group members to co-operate in developing concepts of operation (CONOPS) for NSM use.
In terms of programmes, the increasing NSM procurement may enable user group members to achieve economies of scale in missile maintenance (for example, collective purchase of spare parts) and in any future additional procurement of NSM rounds.
The widespread investment in NSM also points to NATO navies recognising the need to rebuild ASM capability, a need made more urgent by the returning Russian threat. “The purchases are a reflection that many NATO navies have under-invested in such capability for some time because attention has been elsewhere, while others (including potential adversaries) have been putting considerable resources into this area. So, it’s a case of playing catch-up – and to help restore some deterrent and operational value,” Nick Childs, senior research fellow for naval forces and maritime security at the International Institute for Strategic Studies (IISS) in London, told Armada. “NSM has found favour because it appears to fit the bill in a number of ways, including being able to carry out targeting in a complex environment, having a land-attack option as well as a few other handy attributes like low observability, and because it’s available (and has been adopted by the USN).”
“Having a modern system like this should augment the effectiveness of both national and multinational task groups because it will add effective distributed offensive capabilities to such formations, thus posing new challenges to potential opponents,” Childs continued. “Equipping platforms with such a system (and there are alternatives to NSM) also adds to the value that individual countries can bring to multinational groupings.”
Missile capability
According to Kongsberg, NSM brings several key attributes to contemporary naval operations. First is flexibility: NSM “can be launched from a variety of platforms against a variety of targets on sea and land.”
Second is manoeuvrability, with NSM’s airframe designed around a high thrust-to-weight ratio.
Third is survivability, which is based around a combination of: passive target search, using an autonomous target recognition (ATR)-based imaging infra-red (IR) seeker capability; a low-profile airframe signature; a low-profile, sea-skimming approach to target; and advanced, ‘high-g’ terminal manoeuvres. Integration of the seeker, manoeuvre, and time-on-target capabilities augments this survivability against contemporary air-defence capabilities.
In its latest missile specifications documentation, updated as of December 2022, the company stated that “NSM has very high survivability against modern air defence systems,” bringing “survivability in a denied environment.”
The intensity of the current operating environment at sea underlines the need to be able to survive in such denied environments, for example around maritime choke points and other littoral access areas. NSM’s combined design capabilities enable it to operate effectively in such an environment, Hans Kongelf – Kongsberg Defence and Aerospace Missile Division’s Vice President for Business Development – told Armada. “NSM can fly aggressively in the terrain/littorals due to its extreme ability to turn quickly, hence surprising the opponent with alternative attack angles. In the last phase of an engagement, the passive IR seeker is used against both sea targets and land targets, giving the operator flexibility and precision, which missiles with radar seekers are unable to give,” said Kongelf.
NSM travels at high sub-sonic speeds at ranges of up to 100 nautical miles (185 kilometres)
Range finder
Individually, NSM and Tomahawk bring various capabilities for tackling targets ashore and, increasingly, at sea. These capabilities offer different ways of tackling different target sets.
One of the primary differentiators between the two is range. According to Raytheon, Tomahawk’s range is 870nm (1,600km).
When deployed on ships and submarines that can, almost by definition, roam across 70 percent of the earth’s surface, Tomahawk can either stand off further from a target ashore or at sea so that the launch platform can stay further out of the reach of defences, or can reach further inland. In the latter context, USN briefings previously have highlighted that Tomahawk can reach almost anywhere ashore in the world, apart from one or two isolated areas in the centres of continents and shielded by high mountain ranges.
Especially when set against NSM’s already significant and growing customer base, building on from becoming operational in the RNoN in 2012, the fact that Tomahawk is only operated currently by two navies despite having been in USN operational service since 1991 is quite striking. A number of navies have enquired, either formally and/or informally, over the years about procuring Tomahawk. So far, the Netherlands probably came closest to joining the Tomahawk club, with a decision confirmed in 2005 to purchase 30 rounds. However, a change of government and a change of mind followed, with the procurement plan shelved in 2007.
However, Tomahawk is now on two navies’ radars.
First, it has been reported that – under the Australia/UK/US (AUKUS) strategic partnership announced in September 2021 – Australia is considering a Tomahawk fit for the RAN’s three Hobart-class guided-missile destroyers (DDGs). Such a fit would continue broadening the DDGs’ capabilities above and beyond their original air defence focus. The RAN’s fit may also include its Collins-class SSKs, according to media reports.
USN submarine-launched Tomahawks are fired from vertical launch systems (VLS), rather than from torpedo tubes. The RN’s Tomahawk capability is carried onboard its Astute-class SSNs, but these rounds are torpedo tube-launched (TTL) as Astute does not have a VLS. Collins does not have a VLS either. Thus, if a Collins fit became a serious option for the RAN, the USN and Raytheon would have to re-open the (currently closed) TTL Tomahawk production line – something that would help the RN sustain its own submarine-launched Tomahawk inventory.
Second, in November 2022, Japan’s Kyodo news agency reported that the JMSDF was considering requesting a significant Tomahawk purchase. Set against a requirement to reinforce conventional counterstrike to deter a growing range of regional threats, Japan was reported to be considering a purchase of up to 500 Tomahawks by the end of fiscal year 2027, the Kyodo report added. It noted that destroyer and submarine fits were both possible options.
One reason why Tomahawk may be appealing to the RAN and the JMSDF is the range it brings. A 870nm (1,600km) stand-off capability would offer much range across the Indo-Pacific’s vast maritime reaches. Some analysts also argue that Tomahawk’s straight-line, ‘tanks dry’ range is greater than 870nm. While other analysts had also questioned Tomahawk’s operational responsiveness in an era of requirements for ‘speed, speed, and speed’, the loiter and re-targeting capability delivered in the Block IV and Block V weapons help offset some of the limitations in any relative lack of speed.
Australia is also purchasing NSM, replacing Harpoon onboard the RAN’s Hobart-class DDGs and ANZAC-class frigates.
by Dr. Lee Willett
