Ir/Al2O3 catalysts with an approximate metal content of 30% in weight were prepared by incipient wetness methodology. Three alumina with different textural properties were chosen due to their different macro and mesoporosity. Catalysts were prepared through three consecutive impregnations and H2IrCl6 was used as a metallic precursor. They were characterized before and after the tests in a 2N satellite thruster, according to specific surface area, volume and pore size distribution, and specific metallic area. Thrust performance stability, temperature and stagnation pressure in the chamber, and mass loss were analyzed. Catalyst's performance was then compared with that of the Shell 405 commercial catalyst. © 2011 Elsevier B.V.1731220225Armstrong, W.E., Ryland, L.B., Voge, H.H., (1978), Iridium or iridium-ruthenium catalyst for hydrazine decomposition, US Patent 4,124,538Armstrong, W.E., Ryland, L.B., Voge, H.H., Catalyst for hydrazine decomposition and method for preparing such catalyst (1980), UK Patent Application GB 2,027,357Armstrong, W.E., Ryland, L.B., Voge, H.H., Catalyseur pour la decomposition de l'Hydrazine (1980), Brevet D'Invention FR 2,433,371Hartung, W., Evaluation tests of new german catalysts for the spontaneous decomposition of hydrazine (1974) International Conference on the Properties of Hydrazine and its Potential Applications as an Energy Source, p. 109Hartung, W., Weidenbach, G., Tiedtke, P., A new catalyst for monopropellant hydrazine thrusters (1977) Proceedings of AOCS ConferencePfeffer, H.A., ESA activities in the field of hydrazine monopropellant technology for satellite auxiliary propulsion (1976) ESA Scientific & Technical Review, 2, p. 43Valentini, R., Hydrazine thrusters for space applications, ESA attitude and orbit control systems (1977) ESA-SP-128, p. 435Schmidt, E.W., (1984) Hydrazine and Its Derivatives - Preparation, Properties, Applications, , John Wiley & Sons Inc., New YorkNewton, N.C., Rice, P.R., Nuxtable, D.D., Shell 405 Catalyst Improvement Substrate Evaluation (1971), pp. 71-81. , Technical Report Air Force Rocket Propulsion Laboratory (AFRPL - TR)Huguier, P., (1971), Introduction Générale à la Stabilisation et Propulsion, La Technologie Spatiale Française, IFP ÉditeurMarteney, P.J., Kesten, S.A., Catalyst particle wetting and breakup in hydrazine systems (1976) Journal of Spacecraft, 13 (7), p. 430Cruz, G.M., Cunha, D.S., Rodrigues, J.A.J., Freitas, A.G., (1989) Catalysis Today, 5, p. 473Rodrigues, J.A.J., Cruz, G.M., Djegá-Mariadassou, G., Carbetos e Nitretos de elementos de Transição Aplicados à decomposição Catalítica de Hidrazina. (1995), Br n° PI 9501616, INPI, São Paulo, BrasilRodrigues, J.A.J., Cruz, G.M., Bugli, G., Boudart, M., Djéga-Mariadassou, G., Nitride and carbide of molybdenum and tungsten as substitutes of iridium for the catalysts used for space communication (1997) Catalysis Letters, 45, pp. 1-3Soares Neto, T.G., Cobo, A.J.G., Cruz, G.M., Evolution of morphologic properties on the preparation of Ir/Al2O3 catalysts with high metallic contents (2005) Applied Surface Science, 240, pp. 355-365Soares Neto, T.G., Cobo, A.J.G., Cruz, G.M., Textural properties evolution of Ir and Ru supported on alumina catalysts during hydrazine decomposition in satellite thruster (2003) Applied Catalysis A: General, 250, pp. 331-340Greer, H., King, S.M., Marx, P.C., Taylor, D., Experimental evaluation of catalysts for monopropellant hydrazine propulsion (1971) Journal of Spacecraft, 8 (2), pp. 105-110Balcon, S., Mary, S., Kappenstein, C., Gengembre, E., Monopropellant decomposition catalysts ii sintering studies on Ir/Al2O3 catalysts, influence of chloride anions (2000) Applied Catalysis A, 196, p. 179Soares Neto, T.G., Gobbo-Ferreira, J., Cobo, A.J.G., Cruz, G.M., Ir-Ru/Al2O3 catalysts used in satellite propulsion (2003) Brazilian Journal of Chemical Engineering, 20 (3)