The path ahead for tube and rocket artillery

The ongoing conflict in Ukraine has very clearly demonstrated the continued importance of artillery – both tube and rocket – on the modern battlefield. It has also supplied real world data on what artillery can achieve today and what it needs to achieve to meet the conditions expected in the conflicts of tomorrow. Developers of artillery systems are already working on key technology areas that will be required to deliver capabilities that could be decisive in future conflicts. However, success in the future will not just be a matter of improving the physical performance of artillery systems, it will be a matter of integrating artillery with other systems and sensors to maximise that performance.

The US Army field manual “Fire Support and Field Artillery Operations (FM3-09)” looks at fire support (FS) and describes it as: “A rapid and continuous integration of surface-to-surface indirect fires, target acquisition, armed aircraft and other lethal/non-lethal attack/delivery systems that converge against targets across all domains in support of the maneuver commander’s concept of operations.” The manual also states that: “FS is inherently joint, conducted in all domains and simultaneously executed at all echelons of command. Lethal FS attack and delivery systems consist of indirect fire systems and armed aircraft to include field artillery (FA), mortars, naval surface fire support and air-delivered munitions from fixed-wing and rotary-wing aircraft.”

While FS might be described as ‘inherently joint’, the realities of the situation could leave a ground forces commander more reliant on organic assets, such as FA, for FS capabilities. The availability of fixed-wing aircraft for ground support is dependent on winning air superiority and on being able to subdue or degrade hostile air defences over the battle area. The availability of rotary-wing support is also dependent on air superiority and reducing the threat of hostile air defences. Naval gunfire support (NGS) is always welcome, but its presence obviously depends on the location of the battle area. All of which means that the primary source of FS that a ground commander can rely upon is FA.

Matters of doctrine

Returning to FM3-09, FA is described as follows: “equipment, supplies, ammunition and personnel involved in the use of cannon, rocket or surface-to-surface missile launchers”. These are supported by non-lethal capabilities such as Cyberspace Electromagnetic Activities (CEMA), information-related activities, space and munitions, such as illumination and smoke. The end result is that: “The commander employs these capabilities to support the scheme of maneuver, to mass firepower and to destroy, neutralize and suppress enemy forces.”

Significantly, this US Army doctrine document does not assume that US and allied forces will have either superiority in numbers or in equipment capability in comparison to the FS capabilities of a peer competitor. US and allied forces have not operated without air superiority and FS superiority in the modern era, meaning that FS superiority will have to be fought for.

It is therefore likely, according to FM3-09, that future operational environments will see a situation where “US and allied forces’ FS assets will be outnumbered and outranged by peer systems. To defeat peer forces in large-scale combat, US forces must first penetrate anti-access/area denial (A2/AD) systems, establish a position of relative advantage, retain the initiative and prevent enemy forces from achieving mass, momentum and continuous land combat A balanced application of both firepower and maneuver is essential for US forces to achieve these goals. This calls for synchronisation and convergence across the FS system to attack high-payoff targets (HPT) across the width and depth of the operational area (OA).”

The definition of an HPT is a target whose loss to the enemy would significantly contribute to the success of friendly forces. Whereas a high-value target (HVT) is a target that the enemy commander requires for successful mission completion. In US FS doctrine, not all HVTs become HPTs. The successful delivery of FS could take place in numerous different environments around the world featuring differing operational requirements. As such, the FS system must be flexible to operate in all of these different circumstances. Added to which, “Threat operations across all domains will attempt to degrade all aspects of FS, from command and control (C2) to target acquisition (TA) to delivery.”

Within all of this, the fundamental mission of artillery still remains the same, being the destruction, neutralisation and suppression of enemy forces, particularly their FS structure, C2 elements, TA capabilities, weapon systems and the supporting structure that sustains these capabilities. The mission remains the same, but achieving the desired effects requires new methodologies to deliver the FS required to prevail against peer or near-peer competitors. To do this will also require significant developments in the means of delivering FS; advances in tube and rocket artillery that will outpace the capabilities of threat systems in terms of range, accuracy and on-target effects. If this can be achieved, then friendly artillery can successfully conduct counter-battery missions, reducing the capability of hostile artillery to influence the fight and delivering a situation where FS superiority is achieved across the desired portion or totality of the OA.

The reality of all of this is that artillery, whether tube or rocket, still remains an arm of decision in ground combat. Napoleon said: “It is with artillery that one makes war.” That was true then, it is still true now and will remain so into the future. The difference comes in the practical application of artillery, the integration of weapons, sensors and command systems to deliver the necessary results. Another important aspect is to think beyond the immediate battlefield, the scope of artillery is far broader than that. Artillery will range deep into enemy positions, its deep fires capabilities will seek to shape the OA, so that enemy forces at the frontline are separated from their supporting infrastructure, denied access to supplies and replacements and consistently degraded leading to loss of effectiveness. Delivering results of this nature once required airpower, now artillery can perform this mission as well and with much less risk.

Tube evolution

In an ideal world, tube artillery, whether towed or self-propelled, would be able to achieve extremely long ranges, while minimising dispersion, and achieving high levels of accuracy with standard projectiles. In addition, there would be the option of using guided-rounds to achieve even higher levels of accuracy, although this would come at a substantially increased procurement cost per round. Over the years, the growth in range exhibited by conventional 155 mm rounds has conclusively demonstrated that more performance can be extracted by weapons in this calibre.

The evolutionary possibilities in 155 mm guns and ammunition have not been exhausted, on the other hand there is still the challenge of defeating dispersion. One possible solution to meet the requirements for future long-range fires, while offering maximum accuracy and minimised dispersion, would be to look beyond the 155 mm calibre and consider something larger. At one stage, the US had the M107 self-propelled gun with 175 mm gun and the M110 203 mm howitzer. The M107 did not stand the test of time, with many being converted to the M110A2 configuration. The M110 could achieve – considered respectable for the time – a range of 25 km, but was replaced in the 1990s by the M270 Multiple Launch Rocket System (MLRS).

Assuming that there was a user prepared to look beyond the standard NATO 155 mm artillery system and who decided that 203 mm was the optimum calibre – and could pay for the privilege of having a new gun, accompanied by new ammunition, fuzing and a new charge system developed – then you could have the possibility of a rather special tube artillery system. Larger-calibre projectiles are thought to be less prone to dispersion at extended range and being larger, they can have a larger explosive filling or a more substantial submunition payload. There are potentially numerous possibilities with a larger calibre artillery system, but before embarking on such a programme, one would have to ask if this was a valid use of resources? The answer is probably not. The performance evolution of artillery rockets for MLRS and HIMARS really removes the need for a larger calibre tube artillery system, as rockets already fill that niche.

In fact, there is a body of opinion that believes that investing resources in major range extensions for 155 mm artillery systems has no merit. For example, while the British Army currently has 29 M270 MLRS launchers, its long-term objective is to have a force of 61 M270 launchers to provide it with its desired ‘deep fires’ capability. Various types of long-range rocket will be developed/deployed. The British Army also has the 155 mm self-propelled artillery system, the Mobile Fires Platform (MFP) and, at least initially, the outline MFP requirement was in ‘deep fires’ territory.

The original outline MFP requirement provides an insight into what was thought possible with future tube artillery systems. The British Army wanted the MFP artillery system to be air transportable in an A400M, and were looking at a range of out to 80 km with a rate of fire of 20 rounds per minute that could be sustained for 10 minutes. This new system was to be compliant with the NATO Joint Ballistic Memorandum of Understanding (JBMOU), which standardised 155 mm artillery, for example via a 23 litre chamber volume, and 155 mm artillery ammunition, with numerous STANAG requirements also forming part of the overall artillery design structure for NATO. The MFP started with a very ambitious set of requirements, many of which were difficult to achieve, and many were deemed unnecessary. As MFP was to be acquired under the Close Support Fires heading, there was therefore no need for a maximum range of 80 km, as that was a deep fires requirement that would be met by future MLRS developments. It was felt that there was no need to duplicate capability, hence the performance requirement for MFP started to be dialled down.

Germany also has a future 155 mm requirement which was described as a ‘future medium-range indirect fire system’. The objective was to equip German ground forces with what eventually became a wheeled 155 mm artillery system. There were a number of factors that were considered to be important in the system selection process; these included reduced crew numbers meaning a high degree of automation was required, range and accuracy were key criteria, but achieving long-ranges with expensive guided rounds was not a metric for success. Long-range engagements were thought to be more suitable for rocket artillery systems and more cost-effective as well.

In 2022, the German government ordered 18 RCH 155 artillery systems from KMW (KNDS) for Ukraine, due to be delivered in 2024. German media reports from 2023 suggest that the RCH 155 has been selected for the German medium-range artillery requirement and that a first official order will be placed in 2024, and that eventually some 168 systems will be acquired, with first deliveries from 2026. This is a 155 mm L52 system mounted in an artillery gun module that also holds 30 projectiles and 144 modular charges, with full automatic loading. The artillery module is mounted on a Boxer armoured vehicle platform with a crew of two.

The RCH 155 was chosen over a proposal from Rheinmetall that was the product of cooperation between the German company and Elbit Systems in Israel. Elbit had been selected by the Israeli military to develop a fully automatic 155 mm artillery system installed in a turret that can be mounted on a 10×10 truck chassis, allegedly due to be named ‘Ro’em’. Rheinmetall looked to build a European solution based on the foundations of the Elbit design, with the turret mounting the 155 mm L52 gun of the PzH 2000 (the same Rheinmetall gun is used in the RCH 155) based on an HX 10×10 truck chassis. While their gun system might not have prevailed, Rheinmetall will still be the primary source of ammunition and charges for German artillery.

Range extension

Rheinmetall already has a road map covering the development of 155 mm projectiles, fuzes, charges and guns over the long-term. Rheinmetall states that the 155 mm L52 gun of the PzH 2000, using the DM92 Modular Charge System, can reach 30 km with an HE-BT round, 40 km with an HE-BB round and 54 km with a Velocity Enhanced Long-Range Artillery Projectile (V-LAP) round. Rheinmetall has developed an Extended Range Charge (ERC) system using P6 propellant, that will increase the range of conventional, rocket-assisted projectiles (RAP) and guided rounds. They note that muzzle velocity is greater than JBMOU norms, but that the maximum pressure remains within STANAG 4110 artillery safety limits.

With ERC charges, 155 mm L52 gun can reach 36 km with an HE-BT round, 46 km with an HE-BB round and 63 km with a V-LAP round. In the medium term, with the introduction of the improved L52A1 gun, range will be 39 km with HE-BT, 52 km with HE-BB and 68 km with V-LAP. Rheinmetall believes that the long-term artillery solution will be new 155 mm L60 gun. The weapon remains JBMOU compliant, but can support higher pressure levels opening the way to longer range. The L60 gun reaches a range of 48 km with an HE-BT round, 64 km with a HE-BB round and 82 km with a V-LAP round.

The Republic of Korea (ROK) also has an artillery development programme, which involves generation-by-generation upgrades to the Hanwha K9 self-propelled artillery system that will see K9 variants in service through the 2040s and beyond. The first upgrade to the K9A1 configuration was fielded from 2018. By the end of this decade, the K9A2 configuration will be standardised, featuring a reduced crew of three instead of five, automatic loader, higher rate of fire (up to nine or 10 rounds from six), with the 155 mm L52 gun retained.

The next evolutionary stage, likely to have the K9A3 designation, is due to enter service later in the 2030s and will have significantly increased capabilities. The vehicle will be optionally manned or remotely operated, with an automatic loader to support a rate of fire of 10 rounds per minute. The difference comes is with the gun as the K9A3 will have a new 155 mm L58 gun capable of reaching ranges of between 70 and 100 km, depending on ammunition natures. The ROK is funding development programmes into indigenous precision-guided munitions for artillery, most likely to be fielded with the K9A3.

As currently planned, the final K9 evolutionary stage will be the K9A4, which will have no embarked crew and autonomous mobility. It will also have a hybrid propulsion system, rather than the previous diesel. The K9A4 system is envisaged to arrive in the 2040s and by this point it is believed that ammunition will have developed beyond the capabilities of the K9A3, therefore maximum range will be in excess of 100 km. There will be an automatic loader and rate of fire should be in excess of 10 rounds per minute. Interestingly, there is no information on the gun selected for the K9A4, whether it is an evolution of the K9A3 gun or perhaps even a non-traditional high-technology solution.

As mentioned above, smoke rounds are an important part of FA non-lethal capabilities with smoke playing a role in both defensive and offensive fires and, more broadly, in shaping the battlefield. Smoke rounds do – at least on the surface – seem to just be another obscurant. However, in the US, the Defense Advanced Research Projects Agency (DARPA) has a programme known as Coded Visibility (CV) which is intended to develop the next generation of battlefield obscurants. CV is intended to develop tailorable, tunable, safe obscurants that will enhance friendly forces’ visibility while suppressing hostile vision and detection systems.

The idea is to investigate two approaches in the shape of passive and active asymmetry. The passive option will have multiple obscurant materials deployed in specific ways that will allow one-way vision through a smoke plume. The active option will have a single obscurant material that can be tuned in real time to potentially enable dynamic control of its properties after being deployed and in cooperation with sensors. The CV programme is in the research phase, but if it can deliver either passive and/or active solutions, then this will represent a transformational capability for FA.

One theme in the discussion of tube artillery is the obvious desire to achieve extended ranges. Norwegian/Finnish company Nammo has been working on integrating Ramjet propulsion with artillery rounds to achieve extended ranges, out of standard 155 mm L39 and L52 guns. Boeing has teamed with Nammo to propose a Ramjet 155 mm round in connection with the US Army Long Range Precision Fires activity, specifically the XM1155 advanced projectile requirement for which two teams, Boeing-Nammo and BAE Systems, are competing. In 2023, tests with the Ramjet round were successfully conducted at Yuma Proving Ground with a 155 mm round fired from a 155 mm L58 Extended Range Cannon Artillery (ERCA) system. A precision guidance system, derived from the JDAM mission computer is being integrated with the Ramjet round.

The BAE Systems XM1155-SC round uses GPS guidance developed from BAE’s Hypervelocity Projectile programme that has demonstrated a range of 110 km. BAE believes that they can achieve or exceed that range with their XM1155 round, while Nammo has openly discussed Ramjet rounds having a range of 150 km. The aim of this US Army programme is to successfully and accurately engage static and moving targets at extended ranges. Also likely to emerge are further extended-range versions of the M982 Excalibur guided round; in a test with the ERCA gun on max charge, this round reached a range of 70 km.

Rocketry evolves

MLRS systems were originally used as area weapons and were not particularly advanced. Today, they provide a sophisticated artillery option, whose capabilities for area and precision attack have been proven in combat in Ukraine, particularly by the M270 MLRS and M142 HIMARS systems. The ability to attack HPTs and HVTs has been a key feature of the success of these systems. More is to come, however; in the future, the MLRS category of systems will offer fires that accurately cover the totality of the battle area, but also a capability to deliver precision strikes against HPTs and HVTs deep into the enemy’s strategic depth.

When the M270 MLRS first arrived in the 1980s, the system could fire an M26 rocket out to a range of 32 km; this was followed by Guided Multiple Launch Rocket System (GMLRS) with M230/M31 rockets offering ranges out to 84 km, while the GMLRS-ER extended-range variant can reach out to 150 km. The US had also developed the ATACMS rocket with a higher payload, for long-range engagements out to 300 km. However, the ATACMS role will be taken over by the Precision Strike Missile (PrSM). This system will meet US long-range precision strike requirements and started to become operational at the end of 2023, offering a range of 499 km. Work is already in progress on an improved guidance system for the PrSM, indicating a continuing evolutionary development investment. PrSM will certainly offer precision strikes against HPTs and HVTs deep into the strategic depth of the enemy.

Long-range precision engagement is becoming a major area of investment, for example DARPA is working on a programme known as Operational Fires (OpFires). This is a ground-launched hypersonic boost glide weapon that can penetrate A2/AD systems to rapidly and precisely engage critical time-sensitive targets at ranges out to 1,600 km. There is a potential problem with truly extended-range systems, as they move out of the category of battlefield weapons and into the area of strategic. Against a peer or near-peer level opponent, the use of what could be considered as strategic weapons could lead to rapid escalation with the potential for an excessive response. More practically air-launched stand-off weapons could fill or do fill this requirement, and with less investment.

For most though, the capability of PrSM is the limit of the long-range fires options that they would be seeking and for weapons with a 300-km range would be more likely to suit. The ROK Agency for Defense Development (ADD) and Hanwha have developed a ‘tactical surface-to-surface missile’ for launch from the K239 Chunmoo MLRS. The second variant of this 600 mm rocket, designated CTM290, has a range of close to 300 km. Apart from the ROK military, the CTM290 has also been acquired by Poland for its Homar-K MLRS system, which is essentially the K239 launcher mounted on a Polish 8×8 truck, doubtless leading to a third-generation development of the CTM290.

Apart from the ROK, significant MLRS system capabilities also exist in Israel; for example, Elbit’s MLRS systems have been acquired by Denmark and are on order for Germany, The Netherlands and Spain. A wide range of rocket types are available, including an extended-range variant that can reach out to 300 km. Then there is Roketsan in Türkiye with a comprehensive MLRS offering. Very few barriers to entry exist with the development of a simple MLRS system, where the state-of-the-art is located with rocket systems offering long-range predictable performance and, most importantly, accuracy. That is a very difficult task to achieve.

It should not be forgotten that other nations possess MLRS capabilities and that they are continuing to develop them. First and foremost is Russia, the first military to use MLRS systems in the modern era; the country also has extensive development capabilities. The latest system to enter service is the 9K515 Tornado-S, a 300 mm calibre system designed to replace the old BM-30 Smerch. The system uses all standard 300 mm rockets as well as a newer extended-range precision guided rocket. Russian rocketry has also inspired developments in China and North Korea, with Iran building its rocketry capabilities on technology from all three. Iranian MLRS systems and artillery rockets have been widely supplied to Iranian surrogates, with Hezbollah in Lebanon having a vast supply of Iranian supplied rockets.

As to the future of both tube and rocket artillery, the trends are clear – it is a matter of more range and more accuracy. That this is already taking place is clear from the discussion in this article. That begs a question though – how much range is enough for an artillery system? Do ground forces truly need rockets with ranges of 300 or 500 km; surely engagements at these distances are what expensive air forces are for? Furthermore, will C2 and targeting systems be able to acquire targets at extended ranges, identify and then engage them accurately in a timely manner? Is there a danger of C2 and targeting systems being overwhelmed by the amount of potential targets from the forward area of the enemy back into their strategic depth? It would appear that the question for the future is not how much artillery capability is needed, but how much capability is enough?

David Saw