Speaker
Mr
MIn Thein
(Moscow Aviation Institute)
Description
The problems of joint optimization of the main design parameters of electric propulsion, power supply systems and trajectory of the spacecraft is considered in two formulations: minimum-thrust problem and maximum payload mass problem under the optimal parameters of the electric propulsion system (thrust, exhaust velocity, power).
The first problem allows solving one of the fundamental problems in optimization of trajectories for the spacecraft with finite thrust related with the existence of the solution which is one of the reasons for the complexity of the constructing robust and efficient numerical optimization technique. Indeed, if the numerical scheme does not converge to a solution then the real reason is unknown since it can be either the absence of a solution or the numerical scheme failure. Therefore, identification of the boundary of the solution region is an actual problem. In this way, solving the minimum thrust problem gives necessary assessment. The minimum thrust problem is formulated similar to any other low thrust trajectory optimization problem but the functional to minimize is the thrust. It is supposed that the thrust can be either maximal or zero, the maximal thrust magnitude is constant along the trajectory and its direction is unconstrained. The transfer time is fixed.
The second problem is directly related to the optimization of the parameters of the propulsion system in the region of the existence of solutions. It is well known that for every space transportation operation there is an optimal value of specific impulse corresponding to the minimum total mass of electric propulsion system, power supply system providing electric propulsion operation and propellant. It is easy to show that there is also an optimal value of electric power of the electric propulsion system that being associated with the growth of the required characteristic velocity while reducing the thrust. It is obvious that the optimal values of specific impulse and electric power of the main electric propulsion system can be found by joint optimization of the trajectory and design parameters.
An approximated design model of the spacecraft equipped with main electric propulsion system and the Pontryagin’s maximum principle are used for optimization. The necessary conditions for the optimality of specific impulse and electric power of the electric propulsion system are derived. Numerical examples of the joint optimization for the interplanetary spacecraft trajectory are presented.
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Primary authors
Mr
MIn Thein
(Moscow Aviation Institute)
Mr
Viacheslav Petukhov
(Research Institute of Applied Mechanics and Electrodynamics of the Moscow Aviation Institute (RIAME MAI))
