An uncrewed hydrogen-powered autonomous surveillance airship the size of a small bus has been floating over Portuguese waters, collecting imagery of ships and other objects. The goal of these test flights is to see if this airship can provide NATO with situational awareness of the maritime domain.

The flights are part of the alliance’s annual demonstration seeking new robotic technology to boost its defenses. The airship is one of several systems that NATO is evaluating during this exercise, which is called Robotic Experimentation and Prototyping using Maritime Unmanned Systems (REPMUS) 25 and Dynamic Messenger (DYMS) 25. NATO is also trialing unmanned surface and underwater vehicles, as well as other aerial ones, as part of the exercise.

The airship being tested is made by the Finnish Kelluu company, which also operates the aircraft. It is one of about 10 that are providing imagery and other sensing capabilities for commercial and scientific purposes. With NATO already conducting maritime security missions, the company sees a potential military role for its airships to provide persistent, low-level surveillance. 

The Kelluu LTA is relatively small as far as airships go, clocking-in at about 12 meters long. It can fly for up to about 12 hours at low level, the company states. They are designed to carry an assortment of sensors, including electro-optical/infrared cameras and passive systems that can detect electromagnetic emissions. Able to launch from austere locations with no runways, these airships operate “very quietly and without emissions, providing real-time connectivity without being limited by radio-link ranges (BRLOS),” company CEO Janne Hietala told us on Wednesday.

NATO officials did not want to elaborate on any particular system taking part in REPMUS25. However, they did discuss the overall goals for this demonstration.

“All of these systems require experimentation and integration into the operational environment,” Cmdr. Arlo Abrahamson, spokesperson for NATO’s Allied Maritime Command, told TWZ on Wednesday. “We want to place these systems in the hands of our operators and ensure those systems meet the operational requirements of Allied forces.”

Dynamic Messenger/REPMUS is working to bring new unmanned systems into the operational environment by gaining user feedback to spur development, Abrahamson told us. With the tests still being conducted, it is too early to say if or how an airship would be useful for NATO operations, Abrahamson noted.

Earlier this year, the alliance stood up Operation Baltic Sentry in response to several instances of underwater cable sabotage believed to have been carried out by China and Russia. In one such incident, Finnish authorities say the Russian-linked Eagle S purposely dragged its anchor across the sea floor to break undersea cables. The ship was later found to be full of spy equipment. Finnish authorities detained the ship and its crew, which you can see in the following video.

One of the main goals of Baltic Sentry is to provide additional persistent surveillance to better track vessels. That in turn is meant to ensure a quicker response to ships acting in a suspicious manner. 

The case could be made that airships in general could potentially benefit such a mission because of their long loitering and diverse sensing capabilities, as well as their efficiency. It doesn’t take much imagination to see the potential that deploying larger numbers of these uncrewed airships over a wide area can provide a drastic increase in situational awareness. This distributed approach to persistent sea surveillance using extended-endurance uncrewed systems has garnered major interest from militaries around the globe.

Overall, the U.S. and other nations are either developing or increasingly using lighter-than-air-craft for just those reasons. The Chinese spy balloon incident brought this reality to the headlines.

Additionally, China, in particular, as we have frequently noted, appears to be investing heavily in lighter-than-air technologies. A huge hangar in a remote area in the country’s northwest is a key example of this. The War Zone has been following activities at the facility, which is tied to the country’s development of high-altitude airships that could potentially gather intelligence, facilitate long-range communications, provide early warning capabilities for missile defense, or even possibly serve as launch platforms for drones and other payloads.

Balloons, airships and aerostats have a long history as surveillance and maritime patrol platforms, and transportation aircraft.

Kelluu’s uncrewed concept is a revamping of sorts of the maritime patrol role of lighter-than-air craft dating back to the First World War and widely used during the Second World War.

However, several fatal accidents and mishaps in the past have created headwind for the development and fielding of these systems.

There appears to be growing interest in the Kelluu airship.

The Finnish Air Force tested the Kelluu LTA in June. It was the first time an airship took part in Atlantic Trident 25, a two-week tactical and operational training exercise held across multiple locations in Finland.

“The airships complement high-level intelligence with low-altitude precision data and multi-sensor capabilities that support real-time situational awareness,” the Finnish Air Force stated on X at the time.

The Finnish Air Force did not provide details about what, if any, plans it has to further test or use the Kelluu airships. We’ve reached out for comment. Kelluu declined comment.