Polish researchers have successfully completed the second phase of testing for a new variable-thrust rocket engine. The Throttleable Liquid Propulsion Demonstrator (TLPD), developed by the Łukasiewicz Research Network – Institute of Aviation, completed 14 hot-fire tests in November 2024.
The engine demonstrates significant thrust flexibility, operating between 10% and 110% of its standard thrust levels. It uses non-toxic, easily-storable propellants and features restart capability, making it suitable for various space applications including upper stages on small rockets, spacecraft, kick-stages, and planetary exploration missions.
The latest test series incorporated a new 3D-printed, water-cooled combustion chamber that enabled longer test durations of up to one minute. This design improvement allowed engineers to evaluate the engine’s performance while varying thrust levels during operation, a technically challenging requirement for rocket engines.
The TLPD project operates under ESA’s Future Launchers Preparatory Programme (FLPP), with the Łukasiewicz Research Network – Institute of Aviation serving as the prime contractor. Project partners include Astronika and Jakusz SpaceTech, with Thaliana Space, a Łukasiewicz spin-off company, joining the second phase to work with potential customers on engine design requirements.
The engine maintained stable combustion throughout all operating points during testing, successfully managing the complex transient phases that occur during thrust adjustment. These phases, which involve dynamic operating conditions, represent one of the more challenging aspects of variable-thrust engine development.
Source: esa.int
