An energy approach for orbital transfers

Evaluating the energy change in an orbital transfer vehicle due to its propulsion system provides an approach for solving a variety of transfer problems and expressing results in common propulsion terms. A high thrust Centaur G geosynchronous mission is given as an example to demonstrate one application. Exact solutions to low thrust ion engine transfers are developed by equating work performed to total energy change. Low thrust plane changes are also analyzed. With the energy approach an analogy is made between orbital transfers and certain classical problems in mechanics.