This 300 N cryogenic propellant engine has a vacuum Isp of 415 seconds - the highest value ever achieved in Europe for an engine of such small size. Being pressure-fed, the engine assembly is relatively simple and avoids the need for a turbo-pump. The thrust chamber and throat region of the engine are regeneratively cooled using hydrogen propellant. The nozzle extension is radiation cooled. The engine incorporates a splash-plate injector having a star shaped configuration. Ignition and subsequent re-ignition is achieved using Triethylaluminium (TEA) - which is hypergolic with the oxygen propellant. The number of re-ignitions is a function of the volume of Triethylaluminium accommodated. The engine nominally provides for 1 ignition and 3 re-ignitions using just 1.5 cc of Triethylaluminium. The use of a chemical ignition system enables a very compact design. The engine needs no pre-cooling prior to ignition. Only the propellant feed lines to the engine propellant valves need be pre-cooled. Engine construction materials are mainly stainless steel, Nimonic 75 (Chromium-Nickel Alloy) and copper. The engine has the status of a flight prototype and is available for flight qualification. Currently, 5 prototype engines have been manufactured.
The 300 N cryogenic engine enables the simplicity of a pressure fed propulsion system whilst offering the performance of a turbo-pump propulsion system. Being pressure fed, the engine does not require an additional turbo-pump, with its associated complexity. The 300 N cryogenic engine may be used as a main engine in dedicated stages for orbital insertion, orbital transfer, orbital, and interplanetary applications, including: Upper stages