Optimal Low-Thrust Orbit Transfers around a Rotating Non-Spherical Body

2006 to orbit the two giant asteroids Vesta and Ceres. The DAWN space-craft will use solar-electric propulsion for both the inter-planetary cruise and orbital operations at each asteroid. A method is required to design low-thrust orbital transfers between the science orbits given the complex gravity fields of both asteroids. This paper describes a technique for com-puting optimal low-thrust transfers in an arbitrarily complex, gravity field of a rotating body. Optimal transfers involving point mass models are compared to optimal transfers in increasingly complex gravity fields. The method is applied to a transfer between a high orbit and a low orbit with a plane change around the Asteroid Vesta using real mission constraints. Vesta’s gravity is modeled with a harmonic expansion of order twenty. The Static/Dynamic Control algorithm is used to solve the optimal control prob-lem