DESIGN OF LOW THRUST TRAJECTORIES FROM LOW EARTH ORBIT TO DISTANT RETROGRADE ORBITS BY PARTICLE SWARM OPTIMIZATION

The endeavor of human interplanetary missions to Mars could greatly benefit from the employment of a spacecraft fuel depot stationed in a Distant Retrograde Orbit (DRO) around the Moon. In view of this, optimum low thrust trajectories from a low Earth orbit (LEO) to several lunar DROs are designed in this paper using Particle Swarm Optimization (PSO). Lunar DROs of different amplitudes are also generated in the circular restricted three body problem (CR3BP) using PSO. A low thrust Earth-escape spiral is designed using modified equinoctial elements in the Earth-centered inertial frame and later patched with the transfer arc designed using the CR3BP equations in the synodic frame. A fuel efficient trajectory is presented for each case, with each case targeting a different amplitude DRO. Several injection points on the DROs are also studied for their feasibility to allow a minimum-fuel transfer. The final-to-initial mass ratios for all cases and their optimal control policies for the thrust steering angles are studied quantitatively in this paper.