The Greta project, part of the European Space Agency’s Future Launchers Preparatory Programme (FLPP) is developing a 5 kN thrust class rocket engine that can be restarted reliably several times.
Greta uses hydrogen peroxide and ethanol as propellants, a more sustainable alternative with a lower carbon footprint compared to monomethyl hydrazine propellant used by most traditional rocket engines in this thrust range.
Test success
Greta was ignited multiple times from July to November 2025 and showed stable operations, including controlled shutdowns. During the test campaign the engine fired continuously for over 40 seconds at a time.