Combined System-Trajectory Design for Geostationary Orbit Platforms on Hybrid Transfer

A novel methodology for a combined systems–trajectory optimization for a geostationary equatorial orbit (GEO) platform is proposed to obtain comprehensive design solutions. A combined chemical–electric propulsion system is used to execute hybrid high-thrust/low-thrust trajectory transfer to GEO, thereby balancing the overall system mass and transfer time. A systematic and payload-centric mission design provides a new set of design options to deliver tailored solutions to customized payloads. The hybrid trajectory characterization and spacecraft systems design find the required platform launch mass to deliver a GEO platform with a defined final mass and operational power. Elements of the system design are combined with those of multispiral low-thrust trajectory optimization as well as radiation absorption and solar array degradation to provide a comprehensive design solution. The result is a wide set of solutions to reach GEO, where fully chemical and fully electric transfers represent the boundaries of the hybrid transfer trade space. A payload throughput power of 20 kW entails a spacecraft mass in GEO between 4000 and 4550 kg, an initial thrust-to-mass ratio range of 1.7−2.3×10−4  m/s2, and a cover-glass thickness between 4 and 24 mils to guarantee a minimum end-of-life/beginning-of-life power ratio of 85%. In addition, all-electric solutions from different injection orbits yield transfers to GEO with a time of flight of 60–150 days and an initial mass for the platform of 4400–5500 kg.