Railgun Advancements: Powering the Future of Naval Warfare

Introduction:

In the realm of naval warfare, the US Navy faces mounting concerns over the vulnerability of its surface ships in potential combat scenarios against technologically advanced adversaries like China. To counter this threat, the Navy has embarked on a revolutionary initiative known as distributed lethality, aiming to enhance the offensive capabilities of its surface fleet. Central to this strategy are railguns – electromagnetic projectile launchers poised to redefine the dynamics of modern warfare. This article delves into the transformative potential of railgun technology, from its origins to the latest advancements and the challenges it seeks to overcome.

The Evolution of Distributed Lethality:

As adversaries bolster their arsenals with advanced missiles and unmanned aerial vehicles (UAVs), the US Navy recognizes the need for a paradigm shift in its surface fleet strategy. Distributed lethality emerges as a strategic response, aiming to disperse offensive capabilities across a wider array of naval assets. By equipping Navy surface ships with anti-ship cruise missiles (ASCMs) and implementing new operational concepts, the goal is to mitigate the risk of adversaries targeting high-value assets like aircraft carriers, thus bolstering the fleet’s overall combat effectiveness.

This strategy involves distributing offensive weapons like anti-ship cruise missiles across a wider range of Navy surface ships, aiming to mitigate the risk of adversaries crippling high-value targets such as aircraft carriers. The development of three new ship-based weapons—solid-state lasers, electromagnetic railguns, and gun-launched guided projectiles—offers significant potential to bolster Navy surface ships’ self-defense capabilities against surface craft, unmanned aerial vehicles (UAVs), and anti-ship cruise missiles (ASCMs).

Among these new weapons, the electromagnetic railgun (EMRG) stands out as a revolutionary technology that employs magnetic force instead of chemical propellants to launch projectiles at speeds exceeding Mach 5. Unlike conventional guns limited by gas expansion, EMRGs have no maximum acceleration, theoretically enabling limitless velocity. The railgun platform offers advantages such as large firepower input, extensive bomb storage, and flexible combat applications, making it a crucial component of future weapon systems with capabilities for long-range artillery, anti-surface naval operations, and anti-aircraft and anti-missile defense. Various countries, including the US, India, the UK, Japan, Russia, and China, are actively pursuing electromagnetic railgun research, with China reportedly conducting at-sea tests of its prototype. Despite ongoing development, no railgun systems have been fielded yet, reflecting the complexity and challenges associated with this advanced technology.

Railguns: A Game-Changing Technology:

At the forefront of the Navy’s arsenal are railguns – cutting-edge electromagnetic launchers with unparalleled speed and precision. Developed as part of the Navy’s quest for enhanced defensive capabilities, railguns promise to revolutionize naval warfare. By utilizing electromagnetic force instead of traditional propellants, railguns can launch projectiles at speeds exceeding Mach 7, with ranges surpassing 100 nautical miles. This extraordinary firepower not only enhances ship-to-ship combat but also enables effective defense against UAVs and surface craft.

Railgun System

A railgun is a device that uses electromagnetic force to launch high velocity projectiles, by means of a sliding armature that is accelerated along a pair of conductive rails. A railgun consists of two parallel metal rails (hence the name).

The railgun mainly consists of one power source, two parallel long straight conductive rails, and a small mass armature which places between the rails as a conductive projectile, which completes the circuit. When the two rails are connected to the power supply, a strong current is injected from one rail and flow back from the other rail through the armature to generate a strong magnetic field, as shown in Fig.. Meanwhile, the armature is accelerated by Ampere’s force generated by electromagnetic fields

EMRGs are made up of a few subsystems: an electrical subsystem, an injector, a pair of supported conductive rails, and a projectile. The two industry-built prototypes are designed to fire projectiles at energy levels of 20 to 32 megajoules, which is enough to propel a projectile 50 to 100 nautical miles. (Such ranges might refer to using the EMRG for NSFS missions. Intercepts of missiles and UAVs might take place at much shorter ranges.)

1. Electrical Subsystem
The EMRG electrical subsystem is composed of three subsystems that output a pulse of current: a power source, a storage system; and a delivery system. The power source provides the storage system with electricity that is then stored. When the EMRG is fully charged and ready to fire the storage system sends the electricity as quickly as possible through a delivery system, a system of electrical cabling, and to the conductive rails.

2. Injector
The injector subsystem is required to accelerate the projectile before it reaches the electric rails. If the projectile enters the electric rails with no or a low initial velocity, the projectile will weld to the rails. To combat this, an injector system must be used to give the projectile an initial velocity. The more initial velocity obtained using the injector is also energy that the electric rails do not have to impart onto the projectile; ideally an injector that provides as much velocity as possible should be used.

3. Supported Conductive Rails
The conductive rails are the most important subsystem in the EMRG. They are the system responsible for converting electrical energy into kinetic energy using Lorentz force. Based on the size and distance between the rails the rate of conversion between electrical and kinetic energy is controlled. This conversion creates a large amount of force on the projectile but also on the rails themselves. To ensure that the rails do not fail due to the induced force, they are supported by a rigid structure.

4. Projectile
The projectile itself must be conductive. This allows the current to pass through the projectile and convert the electric energy into a force on the projectile. High melting points will maintain their shape better under firing conditions, but will also tend to do more damage to the barrel when they fragment.

Overcoming Technical Challenges:

Despite their immense potential, railguns face significant technological hurdles. Challenges include erosion protection of rails, miniaturization of energy storage systems, and the development of precision-guided projectiles. To address these obstacles, industry and defense agencies are collaborating on research and development initiatives.

Additionally, railguns require immense power, with a 25-megawatt power plant needed for firing, posing challenges for integration onto naval vessels and sustaining long-range impacts against air resistance. Guiding systems based on GPS and the need for durable electronics add further complexity.

Advances in materials science, pulse power storage, and thermal management are critical for optimizing railgun performance and durability. Moreover, efforts are underway to enhance the weapon’s integration with naval platforms, ensuring seamless deployment in diverse operational environments.

Efforts to overcome these challenges include research into advanced rail materials, miniaturized energy storage systems, and precision-guided projectiles. Innovations in pulse power systems, such as smaller capacitors capable of supplying high energy per shot, have been developed, enabling multiple successive shots and improved firing rates. General Atomics has made strides in reducing railgun size and weight, although enhancing capabilities while maintaining size constraints remains a key engineering challenge. The Office of Naval Research (ONR) is actively working on improving railgun durability, energy storage, and thermal management, aiming to achieve higher firing rates and energy levels for naval applications. Despite these advancements, significant research and development efforts are ongoing to realize the full potential of electromagnetic railgun technology.

In a bid to fortify its naval capabilities amidst evolving threats, the US Navy has turned to cutting-edge technologies, with railguns at the forefront of its innovation agenda. Spearheading this initiative is Raytheon, delivering pulse power containers (PPCs) to support the Navy’s railgun program. This article explores the transformative potential of railgun technology, examining recent developments, global research efforts, and the path forward in revolutionizing naval warfare.

Raytheon’s Pulse Power Containers:

Raytheon has commenced the delivery of pulse power containers (PPCs) to bolster the US Navy’s railgun program, a project initiated with an initial $10 million contract from the US Naval Sea Systems Command in January 2012. These PPCs, developed by Raytheon, are housed within standard ISO containers and contain large banks of capacitors or rechargeable batteries. Each container is capable of discharging 18 kilowatts for every shot, with the aim of supporting the railgun to fire ten shots per minute. Critical to their function is the ability to rapidly recharge from the host ship, manage thermal loads, and efficiently store and discharge energy within short timeframes.

Raytheon’s PPCs, integral to the US Navy’s railgun endeavors, encapsulate immense energy within standard ISO containers. These containers house banks of capacitors or rechargeable batteries, capable of discharging 18 kilowatts per shot. Designed to facilitate rapid recharging from host ships and manage thermal loads efficiently, PPCs play a pivotal role in powering the electromagnetic launch of railgun projectiles.

The pulse forming network (PFN) housed within the PPCs serves as the key component providing electromagnetic energy for the railgun projectile’s propulsion, eliminating the need for explosive charges or rocket motors. These containers, integrated into the navy’s railgun test range, are poised to advance the development and testing of the railgun system. Colin Whelan, Vice President of Advanced Technology at Raytheon Integrated Defense Systems Business, emphasized the transformative potential of directed energy technologies like railguns, highlighting the role of pulse power modules in enabling applications such as the navy’s railgun. Powered by electromagnetic forces like the Lorenz Force, the navy’s railgun propels projectiles at speeds exceeding Mach 6, promising a paradigm shift in military technology. Additionally, the Navy is concurrently developing a hypervelocity projectile (HVP) to complement both the railgun and conventional 5-inch guns, aimed at achieving hypersonic speeds. However, efforts to integrate the fire control loop between the gun and the projectile are still ongoing in collaboration with the Pentagon’s Strategic Capabilities Office.

Requirements of the rail materials

Rail materials for electromagnetic railguns must meet specific requirements to withstand the harsh operational environment characterized by large electrical currents, high temperatures, electromagnetic loads, and sliding velocities. The selection of rail material must prioritize two key objectives: maximizing magnetic efficiency and maximizing durability. To achieve maximum magnetic efficiency, rail materials should minimize electrical resistivity, while durability relies on factors such as high electrical conductivity, hardness, thermal conductivity, and resistance to abrasion and arc ablation. Researchers have identified these performance requirements based on the analysis of rail failure mechanisms and environmental conditions.

Over the past 50 years of electromagnetic gun research, various materials, including single and composite materials, have been explored as potential rail materials. Historically, copper-based conducting rails, such as electrolytic tough pitch copper and oxygen-free high-conductivity copper, have been widely used due to their relative purity and conductivity. However, pure copper exhibits softness and coarse grains, necessitating methods like high-pressure torsion and nano-twinning for grain refinement and strengthening. Alloys like Cu-Cr, Cu-Cr-Zr, Cu–Mo, and Cu–W, as well as composite materials like Cu/Al2O3, have been investigated to enhance performance, along with the application of suitable coatings to mitigate wear and improve longevity in the challenging railgun environment.

The Promise of Railgun Technology:

Central to the Navy’s arsenal, railguns harness electromagnetic force to propel projectiles at speeds surpassing Mach 6, enabling precise and swift engagement of targets. As the Navy explores the integration of railguns with hypervelocity projectiles (HVPs) for both railguns and conventional guns, the potential for enhanced lethality and versatility becomes evident. Collaborative efforts with the Pentagon’s Strategic Capabilities Office underscore the Navy’s commitment to closing the fire control loop, further enhancing the efficacy of railgun systems in diverse operational scenarios.

Global Research Initiatives:

Beyond US borders, the European Defense Agency (EDA) and the French-German Research Institute of Saint-Louis (ISL) have embarked on a pioneering research study, dubbed PILUM, focusing on electromagnetic railguns. With participation from five European countries, the PILUM project aims to demonstrate the feasibility of constructing electromagnetic railguns for artillery applications, with standoff distances exceeding 200 km. Leveraging experimental, simulation, and modeling approaches, PILUM sets the stage for a paradigm shift in long-range precision munitions.

In May 2020, the European Defense Agency (EDA) and the French-German Research Institute of Saint-Louis (ISL) initiated a research study on electromagnetic railguns involving five European countries, termed ‘PILUM.’ The project spans two years and aims to demonstrate the feasibility of constructing electromagnetic railguns for artillery applications capable of achieving standoff distances of up to 200 km. The study will also explore potential integration into ships and other military platforms, employing experimental, simulation, and modeling techniques to validate the feasibility of these railguns. Ultimately, these investigations will inform the development of a demonstrator within an eight-year timeframe, laying the groundwork for a transformative advancement in military technology.

Dubbed ‘PILUM’ (Projectiles for Increased Long-range effects Using Electro-Magnetic railgun), the research endeavor aims to harness electromagnetic acceleration as a disruptive technology for launching projectiles over unprecedented distances exceeding 200 km. By leveraging electromagnetic forces instead of conventional chemical propellants, the electromagnetic railgun holds the promise of enhancing precision and range while maintaining affordability. The project’s objective is to realize a full-scale demonstrator by 2028, marking a potential paradigm shift in artillery capabilities.

ISL’s railgun facilities, including the notable PEGASUS and RAFIRA systems, are at the forefront of electromagnetic launch technology in Europe. PEGASUS, a 10 MJ installation, is spearheading advancements in launcher and armature technology, with successful launches of hypervelocity projectiles demonstrating efficient energy conversion. Meanwhile, RAFIRA, a railgun with a 25 mm2 caliber, boasts the capability to launch salvoes of up to five shots at exceptionally high fire rates. In single-shot mode, RAFIRA accelerates projectiles to velocities exceeding 2400 m/s, showcasing its potential for anti-ship missile defense scenarios. Through operational research and analysis, RAFIRA’s capabilities are being explored to address the evolving threat landscape, with a particular focus on countering hypersonic missiles requiring fire rates exceeding 50 Hz for effective defense.

Japan Conducts First Successful Ship-Launched Railgun Test

The Japanese Ministry of Defense, in collaboration with the Japan Maritime Self-Defense Force (JMSDF), successfully conducted the world’s first electromagnetic railgun firing test from a ship on Tuesday. This marks a significant milestone in Japan’s development of advanced defense capabilities.

“The Acquisition, Technology & Logistics Agency of Japan (ATLA) has accomplished the world’s first shipboard firing test of a railgun with the cooperation of the JMSDF,” the agency announced on the X platform, formerly known as Twitter.

Significance of the test

This successful test represents a significant advancement in Japan’s development of railgun technology. Railguns offer several potential advantages over traditional weapons, including:

• Higher projectile velocity: Railguns can potentially achieve speeds exceeding Mach 7, significantly exceeding the capabilities of conventional cannons.
• Increased range: The high velocity of railgun projectiles translates to greater potential range compared to traditional weapons.
• Reduced recoil: Railguns experience less recoil compared to traditional cannons, potentially improving accuracy and platform stability.

Advancements in Russia:

Meanwhile, Russia remains at the forefront of electromagnetic railgun research, with notable progress in plasma electromagnetic guns. Vladimir Polishchuk, head of the Shatura affiliate institute, highlights advancements in capacitive storage and pulsed inductive energy systems, underscoring the potential for railguns to achieve speeds exceeding 6 km/s. While the US focuses on non-plasma electromagnetic guns, Russia explores the transformative potential of plasma-based railgun systems, envisioning applications in electromagnetic artillery and satellite defense.

Russia’s research and development efforts on electromagnetic railguns continue to advance, with notable achievements reported by the laboratory head of the Shatura affiliate of the institute, Vladimir Polishchuk. Engineers have successfully designed and constructed a new capacitive storage capable of accelerating objects weighing 100 grams to speeds exceeding 3 km/s. Over the span of two years, the power loading in Shatura has increased six-fold, from 0.8 megajoule to 4.8, signaling significant progress in power enhancement.

Experiments involving a railgun powered by pulsed inductive energy storage have been prepared, offering a promising electric power scheme for rapidly introducing energy into plasma. This approach elevates the temperature of the plasma piston, consequently enhancing speed. The Shatura affiliate favors plasma electromagnetic guns, which propel the accelerated object between two parallel electrodes or rails with electric current. Systems employing hard, non-plasma straps tend to reduce acceleration speeds, with record speeds for such railguns peaking at 3 km/s.

Plasma electromagnetic railguns hold the potential for achieving speeds of 10-12 km/s, albeit current technological limitations hinder surpassing this threshold due to the immense heat and dynamic loads sustained by the channel. While the United States is actively exploring railgun applications in combat, its focus leans toward non-plasma electromagnetic guns, although recent tests have demonstrated speeds of 2.5 km/s for projectiles weighing 10-20 kg. Although research on plasma in the USA has a narrower scope, reports suggest successful tests of railguns firing plasma bunches at speeds of 100 km/s, offering potential capabilities for neutralizing radio-electronic satellite systems. With continued advancements, railguns are poised to emerge as the electromagnetic artillery of the future, with potential applications including long-range targeting up to 300-400 km from warships and even destruction of objects in near-Earth orbit.

Looking Ahead:

As railgun technology continues to mature, its implications for naval warfare are profound. Beyond the traditional confines of warships, railguns are poised to extend their reach to land-based platforms, bolstering strategic flexibility and combat readiness. With ongoing research and development efforts, the Navy remains committed to harnessing the full potential of railguns in safeguarding national security interests. As adversaries strive to maintain technological parity, the US Navy stands poised to maintain its edge on the high seas, propelled by the electromagnetic force of railgun innovation.