With the financial support of the European Space Agency, Alta S.p.A. in Italy and DELTACAT Ltd. in the United Kingdom are conducting a joint study on the development of two hydrogen peroxide monopropellant thruster prototypes (5 and 25 N vacuum thrust) using advanced catalytic beds. The present article illustrates the results of recent tests on the developed catalysts and the main aspects of the thruster design as well as of the technique used for quantitative determination of the observed decomposition rates. Preliminary results indicate that platinum deposited on a γ−alumina substrate yields the best performance with respect to the other solutions under consideration.