ABSTRACT

We undertake a comparison of the latest developments in propulsion technologies, for a manned mission to Mars. The main objective is to assess the possibility of reducing travel time keeping the mass at departure within bounds. For the sake of comparison we used representative systems of different state of the art or proposed technologies, from the chemical engine to the "Pure Electro-Magnetic Thrust" (PEMT) concept, using a nuclear engine proposed by Rubbia. A mission architecture is suggested, based on existing mission proposals to Mars, to estimate the mass budget that influences the performance of the propulsion system. The trajectory of the spacecraft is determined by a numerical integration of the equations of motion and a partial optimization procedure, for the interplanetary phase with continuous thrust, and by conics and instant manoeuvres in the regions of influence of the departure and arrival planets. Pareto curves of the duration of the mission and time of flight versus mass of mission are drawn. We conclude that the ion engine technology, combined with the classical chemical engine, is the one which yields the shortest mission times with the lowest mass, and that chemical propulsion alone is the best to minimise travel time. The results obtained using the PEMT suggest that it is a more suitable solution for farther destinations than Mars.

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