Kelluu raises €15M from NATO Innovation Fund for a network of surveillance aerostats in Europe

Finnish Kelluu, operator of the world's largest fleet of autonomous aerostats, has raised €15 million in a Series A round. The company is building a permanent layer of aerial surveillance for Europe that can be used both for defense and for monitoring critical infrastructure.

Where the money is going

The Series A round for Kelluu was led by NATO Innovation Fund — a venture fund backed by 24 NATO alliance countries. This is the fund's first investment in a Finnish company. The deal also includes Keen Venture Partners, Gungnir Capital, and Tesi, the Finnish state investment company.

Kelluu will direct the attracted funds toward technology refinement, development of its AI direction, expansion of the fleet and team, and entry into new international markets already in 2026. Investors are entering the project at a moment when demand for continuous reconnaissance and surveillance in border, maritime, and Arctic zones is rapidly growing in Europe. Against this backdrop, Kelluu is trying to occupy a niche between satellites and drones: the former provide broad coverage but not always the necessary detail and update frequency, the latter take more precise images but are too limited in flight time and perform worse in harsh weather conditions.

What makes aerostats strong

Kelluu designs, manufactures, and operates autonomous hydrogen-powered aerostats. They operate almost silently, produce no direct emissions, and are designed for conditions where ordinary drones and satellites begin to lose out: extreme cold, complex airspace, long-duration missions, and satellite navigation jamming. In essence, the company sells not just a platform, but a permanent presence in the air with a set of sensors and a stream of real-time data.

• Five aerostats from a single base can cover up to 30,000 km² The fleet has already flown over 50,000 km The platform can sustain missions lasting over 12 hours The system supports multiple types of sensors and high-resolution video transmission Aerostats are designed to operate at temperatures down to -33 °C > "This is not two separate missions, but one fleet and one layer of data," says Kelluu CEO Janne Hietala.

Military and civilian missions

Kelluu has already completed two phases of the NATO DIANA program and was selected as one of 15 companies from over 2,600 applications. In February 2026, at the Steadfast Dart 26 exercises in Germany, the company integrated its data in real-time with the Maven Smart System and transmitted live video and geolocation to allies. Before that, Kelluu demonstrated compatibility with NATO standards at a demonstration in Finland, and also participated in exercises with forces in Norway and NATO Maritime Command.

But defense is only part of the story. Kelluu was built from the outset as a dual-use company, so the same aerostats can be used for forest monitoring, weather observation, power grid protection, early fire detection, and smart city applications. In parallel, the company is developing Kelluu AI Labs — a direction that should turn flight hours and each sensor pass into a hard-to-replicate array of geospatial data.

Based on this, Kelluu wants to build foundation models for the physical world, that is, models that learn to understand the state of terrain, infrastructure, and changes in them.

What this means

The deal shows how rapidly defence tech and physical AI infrastructure are converging. If Kelluu can scale the fleet and maintain flight economics, Europe will get not just another intelligence startup, but a new layer of permanent data for defense, ecology, and critical infrastructure.