CaliToday (03/9/2025): In a unique fusion of century-old aviation principles and cutting-edge technology, Finnish tech company Kelluu has announced that its autonomous hydrogen-powered airship will participate in NATO's upcoming REPMUS 25 exercise. This marks a significant moment for both the company and the alliance, as the innovative platform will be tested in one of the world's largest and most demanding defense trials focused on unmanned systems.
Kelluu's platform is a 12-meter-long autonomous airship that brings the concept of lighter-than-air flight squarely into the 21st century. By integrating artificial intelligence, state-of-the-art sensors, and a clean hydrogen power source, the company has developed a silent, eco-friendly vehicle designed for a critical modern mission: providing persistent intelligence and surveillance from below the cloud layer.
“In the coming weeks, our airships will take part in one of the most demanding defense exercises in the world,” Kelluu stated, signaling its readiness to prove the platform's capabilities on a global stage.
A High-Stakes Proving Ground: REPMUS 25
The exercise, REPMUS—short for Robotic Experimentation and Prototyping with Maritime Unmanned Systems—is NATO's flagship event for integrating unmanned and autonomous technologies across all domains of warfare. It serves as a real-world laboratory where allied nations and industry partners can test, validate, and innovate with the latest robotic systems.
The scale of the exercise is immense. The 2024 event brought together over 2,000 participants from 30 countries, who operated more than 100 different unmanned systems across 700 mission sets. The 2025 edition is poised to be even larger, pushing these platforms to their operational limits in challenging maritime and aerial environments. For Kelluu, performing successfully here would be a powerful validation of its technology.
Filling a Critical Intelligence Gap
In the complex tapestry of modern surveillance, military commanders often rely on two primary assets: satellites and drones. Satellites provide a strategic, high-altitude view but are often predictable and limited by orbital mechanics and cloud cover. Traditional drones offer tactical, close-range intelligence but are constrained by limited flight times, noise, and fuel requirements.
Kelluu argues its hydrogen airship fills the crucial gap between these two.
"Continuous surveillance under the clouds adds a persistent layer of high-fidelity intelligence," the company explained. This capability extends the reach of sensors, radars, and cameras, providing an unbroken, real-time picture of the operational area. Crucially, the airship is designed to navigate and operate effectively even in GNSS-denied environments, a growing challenge in modern electronic warfare.
Unlike fixed-wing drones that must constantly burn fuel to stay aloft, Kelluu's hydrogen-powered system is engineered for extreme endurance. This allows it to serve as a versatile, long-duration sensor platform for Intelligence, Surveillance, and Reconnaissance (ISR), loitering silently over an area for extended periods and complementing NATO's existing assets.
A Commitment to European Security
Kelluu has framed its participation in REPMUS 25 as part of a larger mission to bolster the continent's security architecture. As a Finnish company, its involvement is particularly poignant, coming after Finland's recent accession to the NATO alliance.
“We are here to support a smart and secure Europe,” Kelluu declared, positioning its technology as a homegrown solution to the alliance's evolving security needs.
The deployment of a hydrogen airship in a modern defense context represents a fascinating convergence of old and new. By harnessing AI, advanced materials, and clean energy, Kelluu is aiming to repurpose a historic aviation concept for a vital role in competitive, high-tech environments.
As unmanned technology becomes increasingly central to NATO operations, platforms like Kelluu's airship could offer allies novel and resilient options for surveillance and situational awareness. The company's participation in REPMUS 25 underscores the vital role that smaller, innovative European firms are playing in shaping the future of the alliance's growing defense ecosystem.
