US mortar systems keep pace with modernization efforts

While much attention has focused on the U.S. Army’s ability to achieve greater distances with artillery and missiles, mortar systems are also keeping pace with technology advances. Ed Lopez, Picatinny Arsenal Public Affairs, reports.
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Sgt. Trevor Cacciatore, assigned to the 3rd Cavalry Regiment, braces himself as a Coalition partner from Australia prepares to drop a mortar during a live fire exercise. Mortar systems are a familiar fixture in warfare and continue to keep pace with evolving technology at the Mortars Division of the U.S. Army Combat Capabilities Development Command (DEVCOM) Armaments Center at Picatinny Arsenal. (Picture source: U.S. Army/Spc. Eric Cerami)

When it comes to a relatively close fight with the enemy, mortars have a variety of advantages that over the years have made them a warhorse of warfare, with capabilities that have inspired the name "infantryman's artillery." Typically, mortar systems provide close-range, quick-response, indirect fire in tactical combat. This is achieved by launching high explosive, smoke and illumination mortar shells in high-arcing trajectories.

“Mortars have historically been a cheap and effective form of indirect fire to provide suppression of enemies,” said Matthew Terreault, Chief, Mortar Systems Branch, Mortars Division, located at Picatinny Arsenal. The Division is part of the Combat Capabilities Development Command (DEVCOM) Armaments Center, which is under the Army Futures Command.

Mortars are considered an “organic” system because the level of control is assigned to the echelon that uses them. For example, the 60 millimeter mortar is the lightweight company mortar system, responsive to the direction of the company commander. Similarly, the 120mm is a battalion mortar system, so battalion leaders can use it as they see fit. “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 said. “That's also assisted by the fact that they're relatively short range when you compare it to other forms of modern artillery,” he continued. “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.”

Improvements in technology and manufacturing have played a role in shifting mortars away from their historic role of bulk suppression of troop movements in favor of very precise fires.

Over time, mortar capabilities have been expanding, along with the increasing demand on the field 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,” Terreault said. “And you'll see that across the mortar system portfolio as a whole.”

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.

Patria Nemo 120mm mortar on 8x8 armored vehicle (Picture source: Patria)

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 U.S. systems. The Patria NEMO is a turreted, breech-loaded, 120mm smooth-bore mortar system with both direct and indirect fire capability. In addition to being highly protected, Patria Nemo is light, compact and easily installable on a light, tracked chassis, wheeled armored vehicles or navy vessels.

Under the agreement, the Army will assess the Patria NEMO’s compatibility with U.S. mortar fire control systems, as well as evaluate the use of, and potential range increase, of the current U.S. 120mm mortar ammunition in the longer, breech-loaded NEMO barrel.

The assessment continues the Army’s effort to provide 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 U.S. 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,” said Jussi Järvinen, President of Patria’s Land Business Unit. “It is also logical continuation to the cooperation between Patria and the U.S. government that began with Patria NEMO sales to a third country through a Foreign Military Sales program.”

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, which is part of Project Manager Combat Ammunition Systems. Those organizations are under the Joint Program Executive Office Armaments and Ammunition, which is located at Picatinny Arsenal.

The Army’s emerging Armored Multi-Purpose Vehicle, or AMPV, program has a turreted mortar variant, which provided part of the impetus to closely 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,” Terreault said. “We don't look at the NEMO project, or the turreted mortar systems projects, as being specific to the Armored Multi-Purpose Vehicle because we would like to get a modular solution that would also work on the Stryker platform as well.”

A breech-loaded mortar system has several advantages compared to traditional, muzzle-loaded systems. “There's a crew safety factor, where by the system being breech-loaded, the crew doesn't need to be near the muzzle of the weapon, where all the blast-over pressure from the firing event occurs,” Terreault said.

Another safety factor related to breech-loading is that loading the weapon occurs from within the vehicle. In contrast, with muzzle-loading, the muzzle needs to be outside the vehicle or outside of protection. That’s because there can't be anything between the mortar barrel and the open sky when it fires its ammunition.

Breech-loading also offered more flexibility in firing that is related to how the system is automated, maneuvered and controlled. “Once you're breech-loaded, you no longer have to shoot directly up into the sky,” Terreault said. “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.”

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,” Terreault said. “If we weren't able to fire below 45 degrees, we'd be very limited in the amount of firing engagements we could use in order to achieve multi-round, simultaneous impact events,” Terreault added. “And typically, we consider anything above 45 degrees as indirect fire and below 45 degrees as direct fire.”

As the march of technology moves ahead, the “infantryman’s artillery” will be part of the impetus of enhancement and capability.