The Zurich-based startup is developing compact rotating detonation rocket engines (RDRE's) to make movement between orbits faster, smaller, and more efficient. Just 82 days after incorporation, Stellar Alpina completed Europe's first known commercial RDRE hotfire campaign, turning a deep-tech concept into tested hardware at exceptional speed. The CHF 3.5 million, approximately USD 4.5 million pre-seed round is led by Founderful, Switzerland's leading pre-seed venture fund, with participation from LP&E.
From left to right: Rick Röthlisberger, Simi Y. Wespi, Victor Elliesen, and Patrick Egli, Founders of Stellar Alpina.
Photo: Daniel Kunz, www.danielkunzphoto.com, Adliswil, Switzerland.
ZURICH, May 28, 2026 (GLOBE NEWSWIRE) -- Stellar Alpina, a Swiss space startup headquartered at Innovation Park Zurich, has secured CHF 3.5 million, in pre-seed funding led by Founderful. The round includes participation from LP&E, a deep-tech venture capital firm whose portfolio includes investments in Isar Aerospace, Quantum Systems, and Impulse Space, alongside selected strategic investors from the deep-tech ecosystem. Stellar Alpina built and commissioned its test infrastructure and completed a full engine test campaign with Engine 0, its first rotating detonation rocket engine, 82 days after incorporation. The campaign included eight detonative hotfires and produced footage showing up to five stable detonation waves, marking the first known commercial RDRE hotfire milestones in Europe. The funding will now help Stellar Alpina turn that momentum into engines designed for the next era of in-space mobility.
THE SPACE ECONOMY IS ENTERING A NEW PHASE
Over the past decade, the cost of reaching orbit has fallen dramatically. Launch is becoming more frequent, more reliable, and more accessible. But as is often the case when one constraint begins to ease, another becomes visible.
Today, a satellite operator that needs to move a payload from low Earth orbit to geostationary orbit depends on propulsion architectures that have changed little in decades. Operators planning for in-space servicing, assembly, or repositioning find few systems designed for the cadence and flexibility their missions demand.
Stellar Alpina's Engine 0, Europe's first commercially developed Rotating Detonation Rocket Engine.
SPEED AS A FOUNDING PRINCIPLE
Stellar Alpina reflects the kind of grit frontier technologies demand. The founding team has its roots in ARIS, the Academic Spaceflight Initiative Switzerland, where they worked on interdisciplinary rocketry projects and developed the world's first student-built rotating detonation rocket engine in 2024. For years, co-founder Simi Wespi pushed the idea of RDREs in Switzerland despite repeated rejection. Instead of accepting that resistance as the end of the road, he helped build a team within ARIS and proved the concept.
Stellar Alpina's engineering culture is built on destructive, iterative testing: build hardware, fire it, break it, learn, improve. In a field where development cycles are often measured in decades, Stellar Alpina's speed of execution is its defining advantage.
This approach enabled the small founding team to reach the present milestone at an unprecedented speed and will shape what comes next: extensive hotfire campaigns across many engine configurations, build-out of larger test infrastructure and development of the flight engine.
Engine 0 during hot-fire testing.
Quotes
"The space economy is moving beyond the question of access to orbit. The next challenge is movement after launch: transferring, repositioning, and operating assets across higher-energy orbits, cislunar space, and more complex mission architectures. We believe detonation-based propulsion can provide the step change this requires by making rocket engines smaller, more efficient, and more capable. Stellar Alpina is building the foundation for mobility in the space between worlds."
Victor Elliesen, Co-Founder, Stellar Alpina AG
"My dream is to see Swiss technology enabling and enlarging space exploration. To do that, we need true entrepreneurial drive and action. We must back the builders who work hard and take personal risks to turn these ambitious goals into reality, and Stellar Alpina is exactly that kind of team!"
Thomas H. Zurbuchen, Prof and Director ETH Zurich | Space, NASA Head of Science 2016-2022.
"Founding to hotfire in under three months. That tells you how this team operates. The in-space mobility market is large, underserved, and growing fast. We believe the founders of Stellar Alpina are the team to build a category-defining company from Switzerland."
Alex Stöckl, Founding Partner, Founderful
Notes to the editor
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About Stellar Alpina
Stellar Alpina AG is a Swiss space startup founded in 2026 and headquartered at Switzerland Innovation Park Zurich in Dübendorf. The company develops rotating detonation rocket engines and in-space vehicle architectures for orbital mobility, high-energy transfers, and future deep-space infrastructure. Founded by four alumni of ARIS, the Academic Spaceflight Initiative Switzerland, Stellar Alpina is harnessing detonations to build the infrastructure for mobility in the space between worlds.
Photos accompanying this announcement are available at: https://www.globenewswire.com/NewsRoom/AttachmentNg/b6c0b70b-ebb6-45da-aec0-867b82e6cd21
https://www.globenewswire.com/NewsRoom/AttachmentNg/4ed6e022-964a-43ea-83e0-785304ad4be5
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For further information please contact the Stellar Alpina Spokesperson: Victor Elliesen, victor.elliesen@stellar-alpina.ch
