Stellar Alpina, a Zurich-based SpaceTech startup developing compact rotating detonation rocket engines (RDREs) to make movement between orbits faster, smaller, and more efficient, has secured €3.8 million (CHF 3.5 million) in a pre-Seed funding round.
The round was led by Founderful, with participation from LP&E and selected strategic investors from the DeepTech ecosystem.
“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,” said Victor Elliesen, co-founder, Stellar Alpina.
Stellar Alpina was founded in 2026 by Rick Röthlisberger, Simi Y. Wespi, Victor Elliesen, and Patrick Egli, all of whom are alumni of 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 continued advocating for RDREs in Switzerland despite repeated rejections. Instead of giving up, he assembled a team within ARIS and proved the concept.
The company develops rotating detonation rocket engines and in-space vehicle architectures for orbital mobility, high-energy transfers, and future deep-space infrastructure.
According to the company, 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.
The startup highlights a widening gap between the requirements of the space economy and the capabilities of existing in-space mobility systems. It states that thousands of satellites require repositioning and orbit management. Lunar programmes from NASA’s Artemis to ESA’s exploration roadmap depend on reliable transfer and landing capabilities. In-space servicing and manufacturing are moving from concept to procurement. Governments and institutions are investing in resilient, manoeuvrable space architectures. The infrastructure to support all of this does not yet exist at scale, the company mentions.
Stellar Alpina believes detonative propulsion can help tackle this challenge. Every chemical rocket engine operating in space today burns propellant through deflagration, a subsonic combustion process that has defined rocket engineering since the beginning of the space age.
The company claims that detonation, a process in which a flame front moves at supersonic speeds, can extract even more energy from the same amount of propellant
Stellar Alpina is harnessing these detonation waves. “Detonative propulsion has far-reaching implications: for a given thrust level, these systems can be smaller and lighter, require fewer mechanical components, and deliver higher performance. Far beyond incremental engine improvement, Stellar Alpina is advancing a paradigm shift in how rocket engines look and operate. At a system level, RDRE technology has the potential to reshape which missions are viable and what costs operators face when moving between orbits,” the Swiss startup explained.
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.
“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,” said Alex Stöckl, founding partner, Founderful.
Read the orginal article: https://www.eu-startups.com/2026/05/zurichs-stellar-alpina-raises-e3-8-million-to-build-detonation-based-propulsion-for-in-space-mobility/
