Monopropellants for

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... 

F.J.M., and Zevenbergen, J. (2004) Technology status of HNF based monopropellants for satellite propulsion. Proc. 2nd Ind Conf. on Green Propellants for Space Propulsion, Cagliari, Sardinia, Italy, June 07-08,... 

The most attractive monopropellants are those whose exothermic reaction or decomposition can be catalytically initiated. The employment of monopropellants requiring thermal ignition results in the undesirable addition of an ignition device to the propulsion system. The recent development of a low temperature catalyst for the decomposition of hydrazine has made hydrazine and hydrazine based compounds among the most attractive monopropellants for propulsion purposes. 

In thermobaric weapons, highly aluminized secondary explosives can be used instead of monopropellants. For example, RDX in combination with a binder and a large quantity of aluminum (fuel rich) can be used. Research is currently being undertaken to investigate energetic polymers which could possibly be metallized for possible applications. 

While rarely used now as a monopropellant for large engines, small hydrogen peroxide attitude control thmsters are still in use on some satellites. They are easy to throttle, and safer to fuel and handle before launch than hydrazine thmsters. However, hydrazine is more often used in spacecraft because of its higher specific impulse and lower rate of... 

Fig. 1. The postulated flame stmcture for an AP composite propellant, showing A, the primary flame, where gases are from AP decomposition and fuel pyrolysis, the temperature is presumably the propellant flame temperature, and heat transfer is three-dimensional followed by B, the final diffusion flame, where gases are O2 from the AP flame reacting with products from fuel pyrolysis, the temperature is the propellant flame temperature, and heat transfer is three-dimensional and C, the AP monopropellant flame where gases are products from the AP surface decomposition, the temperature is the adiabatic flame temperature for pure AP, and heat transfer is approximately one-dimensional. AP = ammonium perchlorate.

Cachia, G. P. und Withebread, E. G. The Initiation of Explosives by Shock, Proc. Roy. Soc. A 246, 268-273 (1958). Card-Gap Test for Shock Sensitivity of Liquid Monopropellant, Test Nr. 1, Recommended by the JANAF Panel on Liquid Monopropellant Test Methods, March 1960 Amster, A. B., Noonan, E. C. und Bryan, G. J. Solid Propellant Detonability, ARS-Journal 30, 960-964 (1960)... 

Propellant chemists have proposed a new high energy liquid oxidizer, penta-oxygen 05, which is also a monopropellant. Calculate the monopropellant decomposition temperature at a chamber pressure of 10 atm if it assumed the only products are O atoms and 02 molecules. The heat of formation of the new oxidizer is estimated to be very high, +1025 kJ/mol. Obviously, the amounts of 02 and O must be calculated for one mole of 05 decomposing. The 05 enters the system at 298 K. Hint The answer will lie somewhere between 4000 and 5000 K. 

The data presented in Table El are for fuel gases and vapors and are taken almost exclusively from Zabetakis. [IJS Bur. Mines Bull. 627 (1965)]. The conditions are for the fuel-air mixture at 25°C and 1 atm unless otherwise specified. As noted in the text, most fuels have a rich limit at approximately = 3.3 and a lean limit at approximately = 0.5. The fuels which vary most from the rich limit are those that are either very tightly bound as ammonia is or which can decompose as hydrazine or any monopropellant does. Additional sources of flammability limit data can be found in the Ignition Handbook by Babrauskas (Fire Science Publishers, Issaquah, WA, 2003) and from Kuchta [1/5 Bur. Mines Bull. 680 (1985)]. 

Uses Laboratory reagent for detecting double bonds in organic compounds oxidizer in rocket propellants monopropellant increase octane rating for diesel fuel. 

The ballistic properties of ADN, HNF, and HNIW as monopropellants and as oxidizers in composite propellants have been extensively studied.P2-351 Since ADN, HNF, and HNIW particles produce excess oxygen among their combustion products, these particles are used as oxidizer crystals in composite propellants. The pressure exponents of crystalline ADN and HNIW particles are both approximately about the same value as those for HMX and RDX when they are burned as pressed pellets. However, the pressure exponent of HNF is 0.85-0.95,135] higher than those of the other energetic crystalline oxidizers. 

M.A. Cook et al, JApplPhys 30, 1579-84(1959) (Instrumented Card-Gap or SPHF-Plate Test) 23) Baum, Stanyukovich Shekhter (1959). 754-71 (Deton by influence thru air) 771-78 (Deton by influence thru condensed media) 778-81 (Safe distances for propagation of deton betw some expl chges used in Rus coal mines) 23a) Liquid Propellants Info Agency, Applied Physics Lab, Johns Hopkins Univ, "Liquid Propellants Test Methods, Test No 1, Card-Gap Test for Shock Sensitivity of Liquid Monopropellants (March i960)... 

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)... 

Monopropellant drops have been shown to be capable of detonating in a manner similar to liquid hydrocarbon fuels (Ref 11). With monopropellant explosives, energy release per unit volume of explosive is not limited by atmospheric oxygen however, energy release per unit weight is smaller than for fuels using atmospheric oxygen... 

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