MULTIPLE REVOLUTION LAMBERT ́ S TARGETING PROBLEM : AN ANALYTICAL APPROXIMATION

Solving a Lambert’s Targeting Problem (LTP) consists of obtaining the minimum required single-impulse delta-V to modify the trajectory of a spacecraft in order to transfer it to a selected orbital position in a fixed time of flight. We present an approximate analytical method for rapidly solving a generic LTP with limited loss of accuracy. The solution is built on an optimum single-impulse time-free transfer with a D-matrix phasing correction. Because it exhibits good accuracy (both in terms of delta-V and time of flight) near locally optimum transfer conditions the method is useful for rapidly obtaining low delta-V solutions for interplanetary trajectory optimization. In addition, the method can be employed to provide a first guess solution for enhancing the convergence speed of an accurate numerical Lambert solver.