European Rocket Engine Greta Completes Successful Test Campaign Paving Way for Future Space Missions

A new European rocket engine, named Greta, has successfully wrapped up a comprehensive series of hot-fire tests at ArianeGroup’s facility in Trauen, Germany. This testing, conducted for the European Space Agency, confirmed the engine’s capability for stable operations, controlled shutdowns, and multiple restarts.

Greta, designed to operate in the 5 kN thrust category, utilizes a blend of hydrogen peroxide and ethanol as propellants, making it more environmentally friendly than the conventional monomethyl hydrazine typically used in engines of similar power. The engine’s design positions it for potential applications in lunar landers and on advanced stages such as the Astris, which is intended to enhance the performance of Europe’s forthcoming Ariane 6 rocket.

The hot-fire tests for Greta took place across several months, from July to November 2025, during which the engine demonstrated its reliability by igniting multiple times and achieving sustained burn durations exceeding 40 seconds. These trials were conducted on a newly developed, cost-effective mobile test platform, equipped with sensors to monitor critical data such as pressure and temperature, which will aid future optimization efforts.

In a move toward advancing its manufacturing techniques, Greta’s combustion chamber, measuring 30 centimeters in height, is produced using laser melting technology. This method enables the creation of intricate designs and cooling channels that enhance the engine’s performance by allowing fluid to circulate closely along the walls of the combustion chamber, where temperatures soar above 2000°C.

ArianeGroup, which oversees the Greta project as part of a €3 million contract, aims to deepen its understanding of hydrogen peroxide propulsion systems. This endeavor reflects the European commitment to innovation in space exploration technologies. Following the successful test campaign, a new phase for the Greta project commenced on February 6, 2026, focusing on the development of a flight-ready version of the engine. Collaboration with subcontractors from Belgium, Poland, and the Czech Republic will contribute to this next iteration, which is set for testing on the same mobile platform in late 2027.