<h2>AAS  96-100</h2><h2>Approximate Solutions for Lunar Trajectory and Vehicle Optimization Using Electric PropULsion</h2><h4>C. A. Kluever and K. Chang, University of Missouri - Columbia/Kansas City</h4><h2> Abstract </h2>An approximate method for computing minimum-fuel and maximum-payload lunar trajectories using electric propulsion has been developed.  The planar Earth-moon transfer is obtained by patching together two powered escape and capture spirals with a numerically-integrated translunar coasting trajectory.  Curve-fits of universal low-thrust trajectory solutions are used to replace the powered  escape and capture spirals.  The complete trajectory optimization problem is reduced to a small number of design variables and solutions are readily  obtained by using sequential quadratic programming.  Several minimum-fuel and maximum-payload trajectories are obtained for a wide range of thrust-to-weight ratios and the performance of the approximate method exhibits a very close match with published exact optimal solutions.<br><br>