93-146
An Indirect Method For Fixed-Time Finite-Thrust Optimal Orbit Transfer
Guido Colasurdo* and Dario Pastrone**
Abstract
The optimization of fixed-time finite-thrust orbital manoeuvres is carried out according to the theory of optimal control. The formulation of the problem strictly corresponds to the classical indirect approach, but the time is substituted by a new time-like variable, in order to fix, from the numerical point of view, the position of the discontinues in the control variables. This formulation matches the capabilities of an available efficient solver of boundary value problems, which uses the Newton method. The technique, which is fairly general and extendible to a wide variety of similar problems, seems to reduce the sensitivity of the indirect methods to the initial value of the adjoint variable. The procedure is extremely accurate. while the computation time results to be sufficiently low. A personal computer has been used in order to solve test problems, which deal with low-thrust escape trajectories and multi-burn rendezvous manoeuvres.
*Associate Professor, Dipartimento di Energetica, Politecnico di Torino, c.so Duca degli Abruzzi 24, 1-10129 Torino, Italy.
**Researcher, Dipartimento di Energetica, Politecnico di Torino, c.so Duca degli Abruzzi 24,1-10129 Torino, Italy