The 400N monopropellant thruster uses the storable propellant hydrazine N2H4 and is designed for both long term steady state and pulse mode operation. This thruster is primarily used for the attitude and roll control of the Ariane 5 launch vehicle during its ascent. After Ariane 5 upper stage separation, the thruster is used for ACS maneuvers preparatory to the separation of one, or more, spacecraft into their initial orbit.
The thruster is also used for re-entry attitude control applications as successfully demonstrated during the Atmospheric Re-entry Demonstrator (ARD) mission. The thruster operates over a wide pressure range and is thus ideal for blow down propulsion systems. The combustion chamber and nozzle are manufactured from Haynes 25 alloy. The structure is also designed to serve as a heat barrier for protecting both the propellant valve and spacecraft structure. An optional internally redundant catalyst bed heater and thermal insulation guarantees optimum start up conditions. In addition, the thruster is qualified for multiple cold starts.