The Navigation and Mission Design Branch is currently investigating a wide range of optimization techniques for applications to many trajectory design problems we face. Both direct and indirect methods are being applied to problems including minimum fuel transfers, minimum time transfers, and optimal science mission performance.

We have implemented and tested several numerical approaches in a Matlab/COTS environment. The optimization routines we are focusing on are generally industry standard. For nonlinear constraint optimization we are investigating three SQP algorithms including SNOPT, NPSOL, and Matlab's fmincon function. For unconstrained optmization we have tested Matlabs Quasi-Newton and Nelder-Meade simplex algorighms. The test cases have included science performance for LISA, MagIC, and Leonardo as well as mimimum fuel rendezvous for GOES-N and MMS.

We are also investigating Primer Vector Theory as an alternative solution to the minimum fuel orbit maneuver problem. Currently, a tool is being developed to allow an analyst to apply Primer Vector Theory to an orbit rendezvous problem for a minimum fuel, multiple impulse transfer, between arbitrary initial and final orbits.