Resoloon is a European defense-tech startup building a high-altitude imaging platform that sits between drones and satellites. The company is developing a balloon-based system that operates at around 30 km altitude and captures high-resolution imagery over very large areas, aiming to combine the coverage advantages of satellites with the sharper imaging and deployment flexibility of lower-altitude systems.

The startup is still early, but it has already reached a point that many deep-tech companies struggle to get to: the prototype was working before the company was formally set up. Since then, the main challenge has been turning a functional technical concept into a legal, operational business capable of running pilots, raising capital, and beginning commercial deployment.

In this conversation, founder Domokos Kertész shares how his background in hardware and prototyping led to the idea, why the team is deliberately avoiding premature deployment in Ukraine, and why the company’s next milestone is not technology alone but revenue. He also explains how the startup raised €550K at an early stage and why founder networks around Project Europe and 20VC have already become strategically valuable.

Who are You and What Problem Are You Solving?

I started working on technical projects very young, building things at 14, and from around 16 onward, I worked on larger projects. Since then, I have built many of my own projects and have also worked with startups and companies building very different systems.

For example, I built a robotic submarine and worked with companies on hardware problems across diverse domains, including agricultural and industrial systems. A lot of my background is in prototyping — building things quickly, testing them, and improving them.

The current project is built around a simple idea: there is a gap between drones and satellites.

Our system works like a balloon. It flies at an altitude of around 30 km, and we have an onboard optical imaging system that can capture high-resolution images over roughly 800 square kilometers.

Because we are much higher than drones, we can achieve much wider coverage. But because we are much closer than satellites, we can achieve much higher physical resolution. So in a way, we are trying to sit in the middle of those two categories.

A big part of the challenge is achieving that with a very lightweight system. We want the full navigation and high-resolution imaging package to stay within roughly 4 kilos, so it can be moved easily, deployed from almost anywhere, and connected through systems like Starlink.

What Does That Look Like in Practice?

The value proposition is really about coverage, portability, and image quality.

If you use drones, you can get excellent detail, but coverage is limited, and the operational footprint can be relatively high. If you use satellites, you get scale but lose flexibility and resolution due to the physical distance.

Our approach is to create something that is lightweight and deployable, but can still observe a much larger area than a drone while staying close enough to the ground to capture sharper imagery than a satellite can.

The ambition is to make that system easy to transport and operate. If the total system remains small and lightweight, then it becomes much more practical to deploy in different environments and for different missions.

Have You Already Tested It in Ukraine?

No, not yet.

One of my concerns is that we are not yet ready enough from a technology perspective. I do not want to go to Ukraine — especially Ukraine — with something that is only half working.

If you are doing a commercial pilot and the system is imperfect, that is one thing. But for military use cases, especially in an active war environment, that is different. There, the standard has to be much higher.

So at this stage, we are deliberately cautious. We do not want to show up with something immature just to say we are “in defense.” That would not be useful for the end user, and it would not be the right way to build trust.

How Did You Come Up With the Idea for the Company?

A lot of it came from my background.

I have spent years building unusual hardware systems and prototypes, and over time, you start seeing where the technical gaps are. In this case, the gap between drones and satellites felt especially interesting.

There is a real tradeoff in existing systems: either you are close to the ground and constrained in coverage, or you are far away and constrained in resolution. That middle layer seemed underexplored.

The prototype itself actually existed before the company did. That is a bit of the cheat code here. The hard technical idea was already working before the company was fully established.

What took longer was the legal and company-building side: setting up the structure properly, getting everything ready to operate formally, and building the business around the technology.

The legal HQ is in London, while the company has also been developed in Hungary. That setup took time, but now it is in a much better place, and we are finally ready to operate more cleanly as a company.

How Far Along Is the Product Today?

We recently did a test flight and tested many new elements of the system.

We have already corrected some of the weaker parts, and there has been a lot of progress in the last two or three weeks. In one sense, it still feels like we are only at the beginning. But if you zoom out, there has actually been a lot of movement.

That is often the strange thing with deep-tech companies. Day to day, it can feel like you are constantly still starting. But if you take a bigger-picture view, you realize you have built a prototype, set up the company, tested the system, improved the hardware, and laid the groundwork for the next step.

How Are You Thinking About the Defense Market at This Stage?

For us, defense is interesting but also risky.

The timelines can be long, and in some cases, there is also the question of whether customers are buying for real peacetime adoption or mainly because of wartime urgency. That can make the market hard to read for a very early-stage company.

So our near-term thinking is pragmatic. We need to drive one pilot project. That is the key milestone.

It can be in defense, but it does not have to be exclusively defense. If another adjacent market presents a strong opportunity, we will take it too. The important thing right now is revenue and validation.

In that sense, the next step is less about choosing an ideological market identity and more about proving that the system solves a real customer problem and someone will pay for it.

What Are the Next Steps for the Company?

For us, the main thing and next milestone is revenue.

The technology is important, of course, but the company now needs proof that it can convert that technology into a real pilot and then into commercial traction. That is especially true in defense and adjacent markets, where development cycles can otherwise stretch for too long.

So the focus now is to push from prototype and testing into a real deployment opportunity.

What Feels Most Important Right Now?

At this stage, I would say the company is moving from “interesting prototype” to “real business.”

That transition is harder than it sounds. The technology was already functioning before the company itself was fully formed, so in some sense, the product started ahead of the organization. Now the task is to catch the company up with the prototype: legal structure, fundraising, pilots, and go-to-market.