<h2>AAS 99-138</h2>
<h2>Gravity-Assist Trajectory Design with MATLAB                                                                                                     </h2>
<h4>C.D. Eagle                                                                                                                                                                          </h4>
Lockheed Martin Astronautics, Denver, CO                                                                                                                                  
<h2> Abstract </h2>
This technical paper describes a MATLAB script that can be used to design patch-conic, gravity-assist interplanetary trajectories.  The use specifies the departure, flyby and arrival planets, a departure calendar date and flyby altitude. The numerical method in this script performs a flyby and arrival date grid search looking for a trajectory which satisfies two mission constraints defined by a v-infinity match and flyby altitude. This application includes a graphical display of the planetary orbits and interplanetary transfer trajectory. The use can also elect to create an orthographic view of the flyby hyperbola. This  script can also be used to design free-return interplanetary trajectories.