MGALT-STOpS is a software suite which allows for optimization of low-thrust spacecraft trajectories between multiple planets. The Spacecraft Trajectory Optimization Suite (STOpS) uses Multiple Gravity-Assist Low-Thrust (MGALT) trajectories paired with the island model paradigm to accomplish this goal. The island model utilizes four different global search algorithms: a Genetic Algorithm, Differential Evolution, Particle Swarm Optimization, and Monotonic Basin Hopping. Each island runs either a direct or indirect optimization method to solve for the most optimal trajectory between multiple planets.

Included in this download is a demo program, titled "MGALT_STOpS_DEMO", which provides a step by step walkthrough of MGALT-STOpS and explains everything along the way. It is recommended to become familiar with the demo script before venturing into customization with the main script.

All of the files were built and tested with MATLAB 2019b MATLAB. Future versions of MATLAB may not be supported, and there are no plans for continued development of MGALT-STOpS on future versions of MATLAB.

No toolboxes are necessary to run MGALT-STOpS; however, the "Parallel Computing in Optimization Toolbox" can be used to greatly speed up execution time of MGALT-STOpS. There is an option to enable/disable parallel computing at the beginning of the scripts.

Version 1.2 fixes a bug with the implementation of parallel computing in the MBH secondary search, updates default weighting parameters, and makes the arrows on the direct method plot more consistent.

This code was inherited/developed/updated by Malloy to support his thesis, "Spacecraft Trajectory Optimization Suite (STOpS): Design and Optimization of Multiple Gravity-Assist Low-Thrust (MGALT) Trajectories Using Modern Optimization Techniques"; a requirement for a MS in Aerospace Engineering at California Polytechnic State University, San Luis Obispo.

The development of MGALT-STOpS was a continuation of prior work on STOpS by Shane P. Sheehan and Timothy J. Fitzgerald. The supporting thesis for MGALT-STOpS, Low-Thrust STOpS, and STOpS can be found below:

• "Spacecraft Trajectory Optimization Suite (STOpS): Design and Optimization of Multiple Gravity-Assist Low-Thrust (MGALT) Trajectories Using Modern Optimization Techniques" by MALLOY (2020)
• "Spacecraft Trajectory Optimization Suite (STOPS): Optimization of Low-Thrust Interplanetary Spacecraft Trajectories Using Modern Optimization Techniques" by SHEEHAN (2017)
• "Spacecraft Trajectory Optimization Suite (STOpS): Optimization of Multiple Gravity Assist Spacecraft Trajectories Using Modern Optimization Techniques" by FITZGERALD (2015)

The author can be contacted on Discord at "HuntrTrakr#8835" if there are any questions.