Optimal low-thrust interplanetary transfer including earth escape spiral trajectory

Computations are presented for a minimum low-thrust orbit transfer from GEO to a heliocentric Mars orbit. A coplanar motion is assumed throughout the escape and interplanetary transfer, as is a two-body problem throughout the flight. A three-dimensional gradient search method is employed for the calculations, which include an earth escape spiral trajectory. The total mission time is shown to be slightly less than the sum of the time to earth escape and the earth-Mars heliocentric transfer orbit.