TY - JOUR N2 - Most satellites stationed in space use catalytic propulsion systems for attitude control and orbit adjustment. Hydrazine is consumed extensively as liquid monopropellant, in the thrusters. Catalytic reactor is the most important section in the catalytic thruster. Ammonia and nitrogen gases are produced as a result of complete catalytic decomposition of hydrazine in the reactor, causing an increase in temperature and a rise in specific impulse. Ammonia is subsequently decomposed, leading to nitrogen and hydrogen gases. Decomposition of ammonia leads to a decrease in temperature, molecular weight and specific impulse. The latter phenomenon is unavoidable. The effect of ammonia decomposition on the reactor temperature, molecular weight of gaseous products and conclusively on specific impulse was studied in this article. At adiabatic state, thermodynamic analysis revealed that the maximum and minimum temperatures were 1655 K and 773 K, respectively. The highest molecular weight was obtained at ammonia conversion of zero and the lowest when ammonia conversion was 100%. The maximum specific impulse (305.4 S) was obtained at ammonia conversion of zero and completely conversion of ammonia, the minimum specific impulse (about 213.7 s) was obtained. For specific impulse, the result of thermodynamic calculation in this work was validated by the empirical results. L1 - http://www.journals.pan.pl/Content/114810/PDF/08_paper.pdf L2 - http://www.journals.pan.pl/Content/114810 PY - 2019 IS - No 4 EP - 166 DO - 10.24425/ather.2019.131432 KW - Catalytic thruster KW - Hydrazine KW - Ammonia KW - Specific impulse KW - Thermodynamic analysis A1 - Pakdehi, Shahram A1 - Shirvani, Fatemeh A1 - Zolfaghari, Reihaneh PB - The Committee of Thermodynamics and Combustion of the Polish Academy of Sciences and The Institute of Fluid-Flow Machinery Polish Academy of Sciences VL - vol. 40 DA - 2019.12.27 T1 - A thermodynamic study on catalytic decomposition of hydrazine in a space thruster SP - 151 UR - http://www.journals.pan.pl/dlibra/publication/edition/114810 T2 - Archives of Thermodynamics ER -