A Novel Variable Specific Impulse Optimization Methodology for Modulable Electric Propulsion Systems

Abstract

The problem of optimizing variable-specific impulse electric propulsion maneuvers is presented, proposing a novel methodology for the computation of near-optimal planetocentric solutions. The methodology is based on relating the thrust effectivity of the Q-law algorithm with the specific impulse through an arbitrary parametric function, whose parameters are chosen by a multi-objective genetic algorithm, concurrently with the Q-law parameters, minimizing propellant and duration of a given maneuver. A set of numerical cases is analyzed and the results are presented. The analysis shows that the methodology can be successfully employed in the context of space mobility of small satellites in LEO: variable-specific impulse maneuvers can lead to improvements of more than 17% both in propellant mass and maneuver duration against a constant-specific impulse case, demonstrating the interest of this methodology for electric propulsion technologies with throttling capabilities.