Field Emission Electric Propulsion (FEEP),which has undergone extensive research in Europe over the past eighteen years, now represents one of the most interesting alternatives to the traditional propulsion technologies for low-thrust applications. Its characteristics of high specific impulse, accurate thrust control both in stationary and pulsed mode, and intrinsic structural simplicity make the FEEP system a very attractive concept, even taking into account problems arising from the utilization of caesium as a propellant and the high specific power levels required. The present paper describes the experimental facility presently available at Centrospazio and outlines the programmes being carried out in the FEEP area. The results of a first series of tests, aimed at the investigation of the quality of emission as a function of background pressure, are presented and dicussed. The complete electrical characterization of the emitter has been made for three different pressure levels, together with a one-hour duration test. The analysis of the data collected enables to evaluate the variation of the beam current during the initial phase, showing a strong dependence upon the evolution of the degree of wetting of the emitter blades by the propellant. The concept of emitter ageing is introduced, as a fundamental phase of the pre-light preparation procedure. Further experimental test activities are envisaged.
File in questo prodotto:
Non ci sono file associati a questo prodotto.