As the US Army focuses attention on achieving extended ranges with artillery and missile systems, mortar systems are also keeping pace with advances in technology.
Typically, mortar systems – which have become the ‘infantryman’s artillery’ over decades – provide close-range, quick-response, indirect fire in tactical combat. “Mortars have historically been a cheap and effective form of indirect fire to provide suppression of enemies,” commented Matthew Terreault, Chief, Mortar Systems Branch, Mortars Division, at Picatinny Arsenal, part of the Combat Capabilities Development Command (DEVCOM) Armaments Center, under Army Futures Command.
Considered as ‘organic’ due to direct control being assigned to the operating unit, mortars provide flexible response for unit commanders. “When a maneuvering unit calls for fire support from their mortar section, they don't need approval from any intermediary commands in order to get effective fires. This allows them to be very fast,” Terreault stated. “That's also assisted by the fact that they're relatively short range when you compare it to other forms of modern artillery […] And because of their shorter range, they tend to be closer to the fight. With artillery projectiles, the time of flight alone in the artillery firing can be upwards of five minutes, where the flight time for a typical mortar mission is around 50 seconds.”
Advances in technology and manufacturing have helped to shift mortars away from their historic role of bulk suppression of troop movements in favour of very precise fires. Over time, mortar capabilities have been expanding, along with increasing demand for greater responsiveness. “That's caused us to take a look at our mortar systems and try and get them to be more accurate to fit that new role of providing precise fires […] And you'll see that across the mortar system portfolio as a whole,” Terreault explained. Improving mortars involves several areas: greater responsiveness, survivability, range and accuracy. This is accomplished through increased automation of fires and adding soldier protection when possible. The use of digital fire control helps to both reduce human error and increase accuracy.
As part of the Army’s ongoing drive to improve mortar systems, the Armaments Center has signed a Cooperative Research and Development Agreement, or CRADA, with Finnish company Patria Land Oy to determine the feasibility of incorporating its new mortar (NEMO) technology into US systems. The system is a turreted, breech-loaded, 120mm smooth-bore mortar with both direct and indirect fire capability. In addition to being highly protected, NEMO is light, compact and easily installable on a light, tracked chassis, wheeled armoured vehicles or even naval vessels.
Under the agreement, the Army will assess NEMO’s compatibility with US mortar fire control systems, and will evaluate the use and potential benefits of current ammunition in the longer, breech-loaded NEMO barrel. The assessment continues the Army’s effort to provide both Armored and STRYKER Brigade Combat Teams with rapid, precise indirect and direct fire capability, along with protecting the operating crew and greatly reducing its physical burdens. “The agreement between the US Army and Patria exemplifies the capability leap that modern turreted mortar systems can introduce to armed forces and illustrates Patria’s leading role in this technology area,” commented Jussi Järvinen, President of Patria’s Land Business Unit. “It is also [a] logical continuation to the cooperation between Patria and the US government that began with Patria NEMO sales to a third country through a Foreign Military Sales programme.”
The agreement with Patria stemmed from an Army initiative to produce a 120mm Mortar Future Indirect Fire Turret by 2021, and a 120mm Extended Range Mortar system by 2026. That initiative was undertaken by Product Manager Precision Fires and Mortars, part of Project Manager Combat Ammunition Systems.
The Army’s emerging Armored Multi-Purpose Vehicle (AMPV) programme has a turreted mortar variant, which provided part of the impetus to examine the current state of turreted mortar technology. “Given the early age of the AMPV program, we felt like it was an opportune time to pursue and look at opportunities to meet requirements that include the incorporation of a turreted mortar system […] We don't look at the NEMO project, or the turreted mortar systems projects, as being specific to the [AMPV] because we would like to get a modular solution that would also work on the STRYKER platform as well,” stated Terreault.
A breech-loaded mortar system has several advantages compared to traditional, muzzle-loaded systems. “There's a crew safety factor, whereby the system being breech-loaded, the crew doesn't need to be near the muzzle of the weapon, where all the blast overpressure from the firing event occurs,” Terreault explained. Another safety factor related to breech-loading is that loading the weapon occurs from within the vehicle. By contrast, with muzzle-loading, the muzzle needs to be outside the vehicle or outside of protection, because there can't be anything between the mortar barrel and the open sky when it fires.
Breech-loading also offers more flexibility in firing, related to how the system is automated, manoeuvred and controlled. “Once you're breech-loaded, you no longer have to shoot directly up into the sky […] You can shoot at lower angles, because you no longer are relying on the rounds that drop down the barrel in order to have enough kinetic energy to strike a firing pin, initiate the primer, and then come back out the muzzle,” observed Terreault. With a combination of breech-loading and an electronic firing mechanism, the weapon can be positioned in a near-horizontal angle and engage targets directly, similar to a tank cannon. “Now, that's not an optimal mission role for a mortar system, but it does provide the system a certain level of self-defense that it didn't have previously, which helps make the platform overall more survivable […] If we weren't able to fire below 45°, we'd be very limited in the amount of firing engagements we could use in order to achieve multi-round, simultaneous impact events[…] And typically, we consider anything above 45° as indirect fire and below 45° as direct fire.”
As the march of technology moves ahead, the “infantryman’s artillery” will be part of the impetus of enhancement and capability.