LIBRATION POINT SPACECRAFT FORMATION TRAJECTORY DESIGN USING GENETIC ALGORITHMS

Utilizing distributed spacecraft technologies in combination with small satellites offer the benefits of quicker manufacturing, simpler designs, and mission redundancy over traditional monolithic spacecraft. Identifying natural (i.e., ballistic) relative nominal trajectories at libration points decreases stationkeeping costs and expands the range of realizable mission concepts. In this study the authors extend their previous use of genetic algorithms to identify natural formation geometries in the vicinity of the collinear libration points when using the circular restricted three-body problem nonlinear equations of motion. The current work includes modifying the fitness function to include relative proximity of the deputy spacecraft as a function of time, trajectory periodicity, and collision avoidance. A case study compares the results when using the modified fitness function to previous versions. In addition, two case studies are presented simulating the separation of two mated spacecraft using different constraints. The genetic algorithm incorporates the modified fitness function and identifies separation velocities that place the deputy spacecraft into a bounded relative orbit. This study indicates that using a genetic algorithm can be an effective relative trajectory design tool, and in particular when constraints are placed on the initial state vector.