OPTIMIZATION PROCEDURE FOR PRELIMINARY DESIGN OF OPPOSITION-CLASS MARS MISSIONS

A numerical procedure, based on the theory of optimal central, is deve loped and used to find the Right opportunities for a manned mission to Mars. High-thrust (impulsive) missions are considered; burns can occu r either inside or outside the planets' spheres of influence, Venus fl yby opportunities also are exploited, anl time constraints are often p resent. The necessary conditions for optimality, derived to deal with such complex missions, constitute an extension of Lawden's primer vect or theory. in particular, the optimal transfers that occur in a syzygi stic period and that belong to the opposition class are analyzed, taki ng the eccentricity and inclination of the planetary orbits into accou nt; adjustments produced by the addition of time constraints are discu ssed.