The system dynamics are modeled as a simplified circular-restricted three-body problem (CRTBP). Additional modeling assumptions are (1)the massless third body is subject only to the point-mass gravity of the earth and moon (2) the moon is subject only to the point mass gravity of the earth (3) the moon’s orbit is circular and all motion lies in the moon’s orbital plane (4) departure from the earth park orbit is the counterclockwise direction (5) trans-lunar injection (TLI) occurs impulsively from a circular earth park orbit (6) the TLI departure maneuver is applied tangential to the earth park orbit (7) the earth orbit insertion (EOI) impulsive maneuver is applied tangential to the return trajectory (8) the lunar flyby is a no maneuver, ballistic trajectory.
David Eagle (2020). Lunar Free-Return Trajectory Analysis with MATLAB (https://www.mathworks.com/matlabcentral/fileexchange/45710-lunar-free-return-trajectory-analysis-with-matlab), MATLAB Central File Exchange. Retrieved .
Added main script (free_return_64bit.m) that uses the March 17, 2014 version of SNOPT.