Stellar Alpina Raises $4.1M for Space Propulsion Tech

Jan de Vries · 2026-05-28

### A New Engine for a New Space Era Space is getting crowded. And not just with satellites. We're talking about a whole new economy up there -- from servicing old spacecraft to building new ones in orbit. But here's the problem: moving stuff around once it's in space is still surprisingly clunky. That's where Stellar Alpina comes in. This Zurich-based SpaceTech startup just raised $4.1 million (that's CHF 3.5 million, or about 3.8 million euros) in a pre-Seed round led by Founderful. LP&E and a few strategic DeepTech investors also joined in. The company is building compact rotating detonation rocket engines, or RDREs. Think of them as a smarter way to get from point A to point B in space. Instead of the old-school slow burn, these engines use controlled explosions to squeeze more energy out of the same amount of fuel. ### Why Detonation Matters Here's the thing: every rocket engine in space today works by deflagration. That's just a fancy word for burning fuel at subsonic speeds. It's been the standard since the 1950s. But Stellar Alpina is betting on detonation -- where the flame front moves faster than sound. "Detonative propulsion has far-reaching implications," says Victor Elliesen, co-founder of Stellar Alpina. "For a given thrust level, these systems can be smaller and lighter, require fewer mechanical components, and deliver higher performance." In plain English: you get more power from a smaller package. That could mean cheaper missions, more payload room, and entirely new types of space operations.  ### From Student Project to Startup The team behind Stellar Alpina isn't your typical Silicon Valley crew. They all met at ARIS, the Academic Spaceflight Initiative Switzerland, where they built the world's first student-designed rotating detonation rocket engine back in 2024. Co-founder Simi Wespi spent years pushing for RDRE research in Switzerland, getting rejected more times than he'd like to admit. Instead of giving up, he rallied a team inside ARIS and proved the concept worked. Then in 2026, they founded Stellar Alpina. And they wasted no time. Just 82 days after incorporation, they had their test infrastructure up and running. Their first engine, Engine 0, completed a full test campaign with eight detonative hotfires. The footage showed up to five stable detonation waves -- a first for a commercial RDRE in Europe. ### The Gap in Space Mobility Here's the problem Stellar Alpina is solving. Right now, if you're a satellite operator and you need to move a payload from low Earth orbit to geostationary orbit, you're stuck with propulsion systems that haven't changed much in decades. Same goes for anyone planning in-space servicing, assembly, or repositioning. - Thousands of satellites need orbit management and repositioning. - Lunar programs like NASA's Artemis and ESA's exploration roadmap depend on reliable transfer and landing. - In-space servicing and manufacturing are moving from concept to real procurement. - Governments are investing in more maneuverable space architectures. But the infrastructure to support all this doesn't exist at scale yet. That's the gap Stellar Alpina wants to fill. ### What's Next With the new funding, Stellar Alpina plans to move from Engine 0 to production-ready engines. They're targeting orbital mobility, high-energy transfers, and eventually deep-space infrastructure. The idea is that detonative propulsion could reshape which missions are even possible -- and at what cost. "We believe detonation-based propulsion can provide the step change this requires," says Elliesen. "Stellar Alpina is building the foundation for mobility in the space between worlds." It's a bold vision. But if they can pull it off, we might look back at this $4.1 million round as the moment space travel got a whole lot more interesting.