Optimal guidance of spacecraft rendezvous via free initial velocity vector

Abstract

In this research, we focus on an optimal trajectory of a spacecraft rendezvous operation. This optimal trajectory, which is studied in rendezvous problem consists of a controlling distribution, parametric and permitted forms of performance index of minimum fuel-time free; this method will guide the chaser spacecraft toward the target spacecraft in optimal trajectory by using multiple-subarc sequential gradient–restoration algorithm. During trajectory analysis, we will define two problems, P1 and P2. In P1, initial position vector and initial velocity vector are given and fixed and in P2, initial position vector is given and fixed, while initial velocity vector varies and will be free. Previous studies show that the condition of optimal fuel in a solution will be obtained with four subarcs and it shows that for distribution of optimal thrust, the amount of maximum thrust or zero during each subarc will be needed. The main result is that, the new method proposed by this study leads to reduction in performance index and also fuel consumption will be in an appropriate amount. This event takes place in proportion of initial free velocity (problem P2) to initial fixed velocity (problem P1). Another result is that the reduction in fuel consumption and performance index is associated with a remarkable reduction in central processing unit time up to 1650 order. The result of this investigation for rendezvous mission between target spacecraft and chaser spacecraft named OCAT1.1 was extracted and examined on SuperCluster computer.