<h2>AAS 99-131</h2>
<h2>A Direct Trajectory Optimization Method for Constrained Interplanetary Missions                                                                  </h2>
<h4>C. Kluever*, M. Cupples**, R. Kirchmyer***                                                                                                                                          </h4>
*U. of Missouri, ** DESE Research, Inc., ***NASA MSFC                                                                                                                     
<h2> Abstract </h2>
A direct optimization method (DTOM) for computing optimal interplanetary missions that involve a variety of specific mission constraints is presented. The DTOM can easily accommodate a variety of very specific mission constraints and includes several for the performance index. The method can accommodate finite continuous burns, staging, hyperbolic approach velocity constraints, and nonlinear relation for vehicle sizing considerations. The DTOM is a useful tool for mission designers who need to consider mission-specific constraints. Several Earth-Mars mission designs are presented in order to demonstrate the method.