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Apogee Motors

Apogee Motor Introduction
400 N Apogee Motor
500 N Apogee Motor (EAM)

500 N Bipropellant European Apogee Motor (EAM)

An advanced high performance, light weight apogee motor with all-in-one combustion chamber and nozzle.

The Lampoldshausen team Airbus Space Systems is developing an all European 500 N apogee motor for large GEO-platforms.


The motor's development is in conjunction with the European Space Agency and supported by the German National Space Agency DLR. The advanced, high performance apogee motor will be produced from all European components and will thus be an all European product and has therefore been dubbed the European Apogee Motor (EAM).


The EAM operates with MMH (Monomethyl Hydrazine) and MON (Mixed Oxides of Nitrogen) propellants.


The motor is designed with complete interface versatility for use in the propulsion systems of the existing platforms, SpaceBus and Eurostar, as well as of the future large European platform AlphaBus.


The engine is being developed with the objective of providing the best performance in its class world-wide, with an Isp greater than 325 seconds.

Major Assemblies

The EAM consists of the following major assemblies:

  • Injector assembly with engine mounting interface.
  • Combustion chamber with expansion Nozzle.
  • Propellant flow control valve (Fuel and Oxidizer).
  • Trim Orifices


The propellant valves are mounted perpendicular to the axial direction to achieve minimum possible motor length and small injector dribble volumes. The interface from the motor to the spacecraft is realised by three attachment points with alignment capabilities.


Propellant atomisation is achieved through a special injector delivering the appropriate droplet size for effective and stable combustion over a wide motor operation range.


All parts in contact with the propellants are manufactured from stainless steel, titanium and a special material for the chamber and expansion nozzle. Combustion chamber and expansion nozzle are designed to withstand very high temperatures; this is the key for achieving the envisaged high motor performance, i.e. high specific impulse.


The combustion chamber is protected against oxidation and erosion. The chamber-nozzle unit is welded to the injector housing using a special joining technology.

  • Technology

Two new technologies enable the high motor performance:

  • A special injector system to achieve excellent propellant atomisation and mixing.
  • A new material for the chamber and nozzle capable of withstanding high thermal and mechanical loads.



500 N European Apogee Motor Characteristics
Propellant: MMH, NTO, MON-1, MON-3
Nominal thrust vac: 500 +/- 20N
Nominal Isp vac: >/= 325 sec
Nominal mixture ratio: 1.65
Operating Range: 11 to 18 bar
Nominal chamber pressure: 10 bar
Total impulse 11.85 x 10-6 Ns
Maximum burn time: 10.5 h
Thermal Cycles 55
Operating Voltage 50 VDC
EAM Overall length: 803 mm
Nozzle dia: 382 mm
Mass: < 5 kg
Mission design Life: 15 years