High Power Electric Propulsion System for NEP (systemes propulsifs electriques de forte puissance pour propulsion nucleo-electrique)
SNECMA MOTEURS VERNON (FRANCE) MOTEURS SPATIAUX DIV
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Recent US initiatives in Nuclear Propulsion lend themselves naturally to raising the question of the assessment of various options and particularly to propose the High Power Electric Propulsion Subsystem HPEPS for the Nuclear Electric Propulsion NEP. The purpose of this paper is to present the guidelines for the HPEPS with respect to the mission to Mars, for automatic probes as well as for manned missions. Among the various options, the technological options and the trajectory options are pointed out. The consequences of the increase of the electrical power of a thruster are first an increase of the thrust itself, but also, as a general rule, an increase of the thruster performance due to its higher efficiency. The drawback is the increase of the thrusters size. Due to the large mass of gas needed to perform the foreseen missions, the right selection of the propellant feeding the thruster is of prime importance. The paper presents a discussion on the thruster specific impulse increase that is sometime considered an increase of the main system performances parameter, but that induces for all electric propulsion systems drawbacks in the system power and mass design that are proportional to the thruster specific power increase kWN. The compatibility with NEP systems that implies orbiting a sizeable nuclear reactor and a power generation system capable of converting thermal into electric power, with minimum mass and volumes fitting in with Ariane 5 or the Space Shuttle bay, is assessed.
- Electric and Ion Propulsion
- Unmanned Spacecraft
- Spacecraft Trajectories and Reentry