Overview of Physical and Chemical, Operational Properties of Nitrous Oxide Used as a Propellant for Low-thrust Rocket Engines

The results of a system analysis of the efficiency of nitrous oxide(N_2O) as a propellant component for small space vehicles(SSV) were presented. A criterion for mass efficiency of the SSV propulsion system(PS) is determined. The current global state-of-the-art of SSV PSs is shown. The application field of nitrous oxide in SSV PSs is calculated and mass efficiency of N_2O application is quantitatively determined. An overview of physical and chemical as well as operational properties of nitrous oxide as a promising, non-toxic component of rocket propellant is provided. Main physical and chemical constants of gaseous and liquid nitrous oxide; chemical properties of N_2O, thermal stability of N_2O, catalytic decomposition of N_2O, a mechanism of decomposition of N_2O, catalysts for decomposition of N_2O, ballast additives to N_2O, application of nitrous oxide, nitrous oxide as a rocket propellant, production of nitrous oxide, toxicity of nitrous oxide, fire hazard of N_2O, requirements to equipment when handling N_2O; storage and transportation of N_2O are considered. It is demonstrated that nitrous oxide is a chemical compound meeting the requirements to rocket propellants, including those related to the environmental friendliness of propellants. With 75 references.

Brief Review of N2O Decomposition Catalysts for Engines

A brief review of nitrous oxide decomposition catalysts was presented.The features of catalyst operating conditions in low-thrust engines of space vehicles and requirements to monopropellant(hydrogen peroxide,hydrazine,nitrous oxide)decomposition catalysts were considered.A scientific basis for development of a nitrous oxide decomposition catalyst and general principles for selection of efficient catalysts were formulated.The results of selecting catalyst systems for the development of decomposition catalysts for N2O as a monopropellant were presented.Preliminary selection of catalyst systems for the development of a catalyst designed for low-thrust rocket engines(LTREs)was carried out:supporter—Al2O3 and ZrO2;active substances—Co,Ni,Fe,Pd,Rh,Pt,Ru,Ir,NiO,Fe2O3,RuO2,Rh2O3,PdO,IrO2,PtO2,CoO,Al2O3,La2NiO4,Nd2NiO4,Pr 2NiO4,La2O3,TiO2,NiO,La2O3,TiO2,ZnO.With 71 references.

Search for Effective Catalysts for the Development of Engines Based on the Products of Catalytic Decomposition of N_(2)O

The paper presents requirements for the N_(2)O decomposition catalyst and provides justification for the selection of components to develop its formulation.The methods to study the physical and chemical as well as catalytic properties of catalysts were developed,and the results of experimental studies on the properties of catalysts with different composition in the laboratory conditions were presented.The activity of samples of compact metal catalysts as well as samples of supported metal and oxide catalysts in the nitrous oxide decomposition reaction was studies.The methodology for determining the activity of catalysts in the decomposition reaction of N_(2)O is presented,as well as the design of an experimental reactor for determining the activity of the catalyst by the minimum temperature for the onset of the decomposition reaction of N_(2)O.In the course of the study,the following series of catalyst activity are determined in the N_(2)O decomposition reaction up to a temperature of 600℃:based on platinum group metals applied to the aluminum oxide carrier-Rh>Ru>Ir>Pt>Pd;based on simple oxides applied to the aluminum oxide carrier-CoO>Cr_(2)O_(3),MnO_(2)>CuO>ZrO_(2)>NiO>Fe_(2)O_(3).The following activity series for the most promising carriers are also determined:by the onset temperature of decomposition,ZrO_(2)>Al_(2)O_(3)-CaO>Al_(2)O_(3)-ZrO_(2)>Al_(2)O_(3)-AlN>θ-Al_(2)O_(3)>Al_(2)O_(3)-SiO_(2)>SiO_(2)>α-Al_(2)O_(3);by the rate constants of N_(2)O decomposition,Al_(2)O_(3)-SiO_(2)>Al_(2)O_(3)-AlN>ZrO_(2)>Al_(2)O_(3)>Al_(2)O_(3)-ZrO_(2)>Al_(2)O_(3)-CaO>α-Al_(2)O_(3)>SiO_(2).The paper presents the results of selecting the active component and carriers for the supported catalyst.The author proposes formulations of the nitrous oxide decomposition catalyst for bench testing in simulated engines.

Use of Hydrazine and Its Substitutes as Fuel

Due to the properties and high reactivity of hydrazine,it is mainly used as rocket fuel not only in its pure form but also in combination with 1,1-dimethylhydrazine and oxidizers(nitrogen tetroxide or nitric acid)forming a self-igniting mixture with oxidizers.Aerozine 50 and UH 25(a mixture of 75%UDMH(unsymmetrical dimethylhydrazine)and 25%hydrazine hydrate)are the best-known hydrazine mixtures with different hydrazine concentrations.The review addresses the use of hydrazine and its derivatives as fuel.Hydrazine is employed in fuel cells(with air oxygen as an oxidizer)to generate electrochemical energy for transport vehicles.Hydrazine is widely used as monopropellant to design low-thrust rocket engines for orientation and stabilization systems in space vehicles,as well as in energy units.The review also addresses such hydrazine derivatives as methylhydrazine,1,1-dimethylhydrazine,hydrazine monoperchlorate,hydrazine diperchlorate,hydrazine diammonium tetraperchlorate,hydrazine mononitrate,hydrazine dinitrate,hydrazine nitroformate,hydrazine azides,tetrafluorohydrazine,etc.as well as composite propellants,and gel rocket propellants based on hydrazine.The materials in the review can be used as reference information on hydrazine fuels.