French-German institute ISL tests railgun outdoors for first time to advance hypersonic defense.

The French-German Research Institute of Saint-Louis (ISL) conducted the first outdoor free-flight firing of its domestically designed electromagnetic railgun on June 29, 2026, at its proving ground in Baldersheim. This milestone inaugurates the Railgun Free Flight Facility, a specialized testing range established to analyze complete external projectile ballistics, structural stability, and aerodynamic behavior immediately after muzzle exit. The transition from controlled laboratory enclosures to open-range validation marks a critical step toward evaluating electromagnetic weapon technology for future long-range artillery, naval integration, and counter-hypersonic defense.

The open-range test utilized a launcher possibly matching the parameters of the 25 mm RAFIRA system, accelerating projectiles beyond Mach 5 under structural loads exceeding 100,000 g. This inaugural firing successfully validated the tracking, optical, and telemetry instrumentation required to measure external ballistics and aerodynamic stability, feeding ongoing European defense initiatives like the PILUM and THEMA programs.

Related topic: Italy begins development of Herakles railgun demonstrator for hypersonic strikes and orbital launches

Modern railgun experiments generally seek muzzle velocities between 2,000 and 3,500 m/s, equivalent to Mach 6 to Mach 10, with launch energies ranging from less than 1 MJ for small experimental systems to more than 30 MJ for large naval demonstrators. (Picture source: ISL)

On June 29, 2026, the French-German Research Institute of Saint-Louis (ISL) conducted the first outdoor free-flight firing of its electromagnetic railgun at its Baldersheim test site, inaugurating a range designed to measure projectile behaviour after muzzle exit. The Railgun Free Flight Facility programme began in 2024 and combines the launcher, firing controls, optical tracking, velocity measurement, trajectory reconstruction, telemetry and impact instrumentation required to follow a projectile through an external ballistic sequence. Earlier ISL firings primarily established acceleration performance, armature behaviour and projectile survival, but were conducted inside controlled installations.

The new range allows the institute to compare stored electrical energy, current profile and barrel-exit conditions with down-range velocity loss, yaw, pitch, dispersion, structural condition and impact angle. It also creates a controlled route for increasing launch energy and flight distance across successive campaigns, instead of moving directly from indoor trials to a full-energy shot. The June 29 event therefore concerned the commissioning of a new experimental capability, not the qualification of a deployable railgun by France or Germany. Railguns work by sending a very strong electric current through two metal rails and a moving connector between them, which creates a magnetic force that pushes the projectile forward at high speed.

They require a lot of energy: large experimental launchers operate with million-ampere currents, pulse durations measured in milliseconds and stored energies measured in megajoules. A launcher delivering 2 million amperes must therefore manage not only projectile acceleration but also electromagnetic forces that push the rails apart, heating in the conductors, arcing at the sliding contact and plasma formation near damaged rail surfaces. Railgun velocities generally fall between 2,000 and 3,500 m/s, compared with less than 2,000 m/s for most practical chemical-propellant guns, but velocity alone does not determine military relevance. A 100 g projectile at 2,400 m/s carries 288 kJ of kinetic energy, a 300 g projectile at 2,500 m/s carries 937.5 kJ, and the same 300 g body at 3,100 m/s carries 1.44 MJ.

These values remain below the stored energy of the launcher because part of the electrical input is lost through resistance, switching, rail heating, plasma, armature losses and residual magnetic energy. Since the 1980s, the decisive performance measures have consequently shifted from maximum muzzle speed toward conversion efficiency, shot-to-shot consistency, barrel life, firing rate, projectile survival and the volume of the complete pulsed-power installation. To date, no armed force has fielded an operational railgun because existing systems have not combined high launch energy, military barrel life, compact power generation, rapid cooling, accurate guided ammunition and sustained firing in one deployable configuration. 

ISL's high-energy work is centred on the Pegasus, a 6 m-long launcher with a 40 × 40 mm square bore and a 10 MJ Distributed Energy Supply. Operational since 2002, the Pegasus demonstrator uses close to 200 capacitor modules connected at successive points along the barrel rather than relying on a single breech-fed electrical discharge. This arrangement allows current to be injected as the projectile travels down the rails, reduces the mismatch between the current pulse and projectile position, and supports experiments on the relationship between electrical timing, acceleration and conversion efficiency. The launcher produces currents approaching 2 million amperes and has accelerated 300 g-class projectiles beyond 2,500 m/s.

Experiments using optimized C-shaped armatures exceeded 3,100 m/s, increasing kinetic energy from less than 1 MJ at 2,500 m/s to more than 1.4 MJ at 3,100 m/s for a 300 g projectile. ISL has achieved electrical-to-kinetic conversion efficiency above 35%, with dedicated firings reaching 41%, meaning that a 10 MJ stored-energy installation can theoretically transfer more than 4 MJ into the complete moving projectile and its supporting components under the most efficient test conditions. However, the Pegasus is not a full-scale artillery weapon. It is a research launcher used to study distributed power delivery, armature design, rail-armature contact, projectile survival, sabot or booster separation and the scaling problems associated with heavier hypervelocity projectiles.

ISL's second experimental railgun, the RAFIRA (for RApid FIre RAilgun), addresses the different requirement of repeated firing against fast incoming threats. The 25 mm railgun accelerates projectiles in the 100 g class beyond 2,400 m/s and subjects them to more than 100,000 g, corresponding to acceleration above 981,000 m/s². Reaching 2,400 m/s under that acceleration requires an acceleration interval measured in milliseconds and a bore distance of only a few metres, leaving little time for current control or correction of an unstable sliding contact. The RAFIRA, consequently, uses a multiple-metal-fibre brush armature intended to maintain electrical contact while reducing local current concentration and rail damage during consecutive shots.

The launcher has been tested with a 3.4 MJ power supply and can fire salvos of up to five rounds. Its research requirement exceeds 50 Hz, which corresponds to less than 20 milliseconds between successive shots, because ISL engagement studies concluded that lower rates would provide insufficient projectile density against manoeuvring hypersonic anti-ship missiles. At 50 Hz, a five-round salvo would leave the launcher in less than 0.1 second, placing severe demands on switching, energy distribution, rail cooling, ammunition feed and shot-to-shot alignment. The RAFIRA therefore examines whether an electromagnetic gun can deliver a short burst with consistent velocity and trajectory, while the Pegasus examines how to transfer greater energy into heavier projectiles. ISL has not publicly named the launcher used at Baldersheim, but the available firing parameters correspond more closely to the RAFIRA.

The reported projectile calibre was 25 mm, velocity exceeded Mach 5, acceleration exceeded 100,000 g and launch energy was in the 1 MJ class. Those characteristics logically do not match the 40 × 40 mm bore and 10 MJ stored-energy architecture of the Pegasus. A RAFIRA-based first shot would also be consistent with a staged commissioning process because it reduces down-range energy, instrumentation exposure, rail loads and the consequences of unstable armature separation. The facility must first establish whether optical systems can acquire the projectile immediately after muzzle exit, whether radar can maintain a track on a small hypersonic body, whether timing systems remain synchronized during the current pulse, and whether the projectile remains inside the designated safety corridor.

Only after those functions are verified does it become practical to increase energy, projectile mass and free-flight distance. The Railgun Free Flight Facility nevertheless serves objectives associated with the Pegasus, particularly the transition from in-bore acceleration to complete launch-package validation. A later 10 MJ-class campaign would require verification that the armature, sabot, projectile body, instrumentation and impact zone can absorb a several-fold increase in electrical input and kinetic energy without compromising measurement quality or range safety. The most important new measurements concern the first milliseconds after muzzle exit. During acceleration, the projectile, or launch package, experiences loads above 100,000 g, megaampere current flow, magnetic fields, rail vibration and possible plasma contact.

At the muzzle, the conductive armature or sabot must separate without striking the projectile, disturbing its centre of gravity or introducing angular motion. A projectile leaving the bore with only a small yaw angle can develop higher drag, asymmetric heating and increasing dispersion at Mach 5 to Mach 8. Optical tracking can determine whether separation is symmetrical and measure pitch, yaw and roll during the first metres of flight. Doppler radar can calculate velocity decay and compare measured drag with aerodynamic predictions. Telemetry can record acceleration, vibration, internal temperature and electronic survival when a sufficiently hardened package is installed. Down-range sensors can then determine residual velocity, impact angle, structural fragmentation and dispersion. These measurements are required before ISL can assess finned projectiles, control surfaces, inertial units, data links or hit-to-kill guidance.

A future electromagnetic interceptor would have to preserve sensor alignment after launch, receive target updates, generate aerodynamic control forces at hypersonic speed and correct a trajectory within a flight lasting only seconds. The ISL range therefore addresses the part of railgun development that cannot be resolved by measuring muzzle velocity alone: whether the launched body remains aerodynamically stable, structurally intact and predictable after leaving the rails. Rail erosion remains the principal obstacle to operational use. The armature must carry a very high current while moving along the rails at typically around 2–3 km/s, creating friction, Joule heating, arcing and local melting. If contact degrades, current can transfer through plasma, accelerating rail ablation and changing the electrical force acting on the projectile.

The rails simultaneously experience lateral electromagnetic loads that attempt to separate them, while the barrel structure must preserve bore alignment to maintain accuracy. Surface damage from one shot changes resistance and current distribution during the next shot, which can alter acceleration, muzzle velocity and projectile attitude even if the same stored energy is used. Insulators face electrical breakdown, heat and mechanical shock, while capacitors, switches, busbars and cables must repeatedly deliver multi-megajoule pulses without failure. A military gun would need a barrel life measured in hundreds or thousands of useful shots, not a limited sequence of laboratory firings, and would need predictable dispersion throughout that life. It would also require rapid recharge and cooling.

A 32 MJ projectile fired ten times per minute represents 320 MJ of muzzle energy per minute, equal to an average kinetic output of 5.33 MW. At 35% conversion efficiency, the launcher alone would require more than 15 MW of electrical input during sustained firing, before accounting for capacitor charging losses, cooling systems, sensors, ammunition handling and ship services. ISL itself is a binational institute established in 1959 under the French and German Ministries of Defence. The institute employs close to 400 personnel, more than 60% of whom are scientists or engineers, and includes close to 40 doctoral researchers. Its research areas include energetic materials, future gun systems, smart ammunition, guidance, navigation, sensors, robotics, acoustics, survivability, vehicle protection and equipment for dismounted troops.

This structure allows railgun research to be connected with projectile materials, hardened electronics, inertial measurement, optical tracking, radar, control algorithms and impact effects. At the European level, ISL initiated and coordinated PILUM, a France-Germany-Poland-Italy-Belgium effort examining electromagnetic artillery and projectiles for ranges beyond 200 km. Its successor, THEMA, is led by KNDS and is intended to mature components toward a land demonstrator with a range target near 30 km by 2028, while a separate French naval objective has examined a 200 km range. These ranges correspond to different technology stages and should not be treated as a single weapon requirement. A 30 km demonstrator is intended to prove launcher, projectile and fire-control integration at manageable energy, while a 200 km system would require substantially greater muzzle energy, a low-drag projectile, guidance, thermal protection and a power installation compatible with a large ship.

France, Germany and Japan have also expanded cooperation on electromagnetic launcher research, linking European work on ammunition and high-rate firing with Japan's repeated-shot and shipboard test experience. International programmes show the gap between test performance and fielded capability. The U.S. Navy spent close to $500 million over 17 years and reached 33 MJ in December 2010 at the Naval Surface Warfare Center Dahlgren Division, after earlier firings at 8 MJ, 10.64 MJ and 18.4 MJ. Its operational concept required 32 MJ shots at rates approaching ten rounds per minute, but rail wear, power demand, integration volume and changing priorities caused railgun funding to disappear from the fiscal year 2022 programme.

The U.S. effort then concentrated on hyper velocity projectiles fired from conventional guns, preserving part of the ammunition work without requiring a dedicated electromagnetic launcher. Japan's ATLA program uses a 40 mm launcher with a 5 MJ capacitor bank, a barrel close to 6 m long and a mass of 8 tonnes. It has fired 320 g projectiles above 2,000 m/s, conducted 120 repeated shots to assess rail durability and carried out the first publicly acknowledged shipboard railgun firing aboard the JS Asuka in October 2023. For its part, China installed a large experimental launcher on a Type 072III landing ship and conducted naval testing focused on pulsed-power integration and sea-based operation.

India's DRDO progressed from a 12 mm square-bore launcher toward a 30 mm system intended to accelerate a 1 kg projectile beyond 2,000 m/s using a capacitor bank approaching 10 MJ. Italy has also approved the second phase of the Herakles programme in June 2025. None of these programmes has produced an operational railgun, as the physical barriers remain the same: barrel life, muzzle velocity variation, conversion efficiency, projectile survival, firing interval, power-system mass, cooling demand, guided-flight performance and the number of accurate shots that can be delivered before maintenance.

Written by Jérôme Brahy

Jérôme Brahy is a defense analyst and documentalist at Army Recognition. He specializes in naval modernization, aviation, drones, armored vehicles, and artillery, with a focus on strategic developments in the United States, China, Ukraine, Russia, Türkiye, and Belgium. His analyses go beyond the facts, providing context, identifying key actors, and explaining why defense news matters on a global scale.

Explore More Defense News

• Land Defense News
• Naval Defense News
• Defense Aerospace News