Monopropellant thrusters

Hydrazine has been studied extensively for use in monopropellant thrusters for space flights of long duration. Thrusters are used or altitude control of communication satellites. Here the decomposition of hydrazine over a packed bed of alumina-supported iridium catalyst is of interest. " In a proposed study, a 2% hydrazine in 98% helium mixture is to be passed over a packed bed of cylindrical particles 0.25 cm in diameter and 0.5 cm in length at a gas-phase velocity of 15m/s and a temperature of 750 K. The kinematic viscosity of helium at this temperature is 4.5 X 10 nF/s. The hydrazine decomposition reaction is believed to be externally mass transfer-limited under these conditions. If the packed bed is 0.05 m in length, what conversion can be expected Assume isothermal operation. 

Maided, A.E. and Belal, H. (2009) Modeling of hydrazine decomposition for monopropellant thrusters. 13th International Conference on Aerospace Sciences 8c Aviation Technology pp. 22. 

The use of N2H4 as a hypergolic propellant fuel for rocket propulsion is discussed in detail in this Vol under Hypergolic Propellants. It has also been used extensively as a monopropellant fuel or in combination with hydrazine nitrate and/or water as a thruster for maneuvering space vehicles (Ref 31)... 

Thrusters are rockets for maneuvering and controlling the attitude of space vehicles. The usual monopropellant for thrusters is catalytically decomposed Hydrazine. The usual catalysts are iridium, rhodium or ruthenium and their mixts. For a review of Hydrazine thrusters see Refs 33, 34 35. Russi (Ref 34) emphasizes that, in spite of many studies and the general acceptance and apparent success of hydrazine thrusters, new rocket motor design is still largely empirical. A biproplnt consisting of Hydrazine mixed with Hydrazine Nitrate has also been tried in thrusters but is no longer popular... 

A Survey of Monopropellant Hydrazine Thruster Technology , Aerospace Corp, San Bernadino, Calif (1974) 35) R. Meetin ... 

The current state-of-the-art monopropellant systems for the attitude and orbit control of satellites are achieved by using several small thrusters powered by the catalytic decomposition of hydrazine flowing through Ir/AliOs catalysts. ... 

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