An Engineering Oriented Rendezvous Phasing Strategy
- Paper number
IAC-08.E2.1.5
- Author
Mr. Jin Zhang, National University of Defence Technology, China
- Year
2008
- Abstract
The Rendezvous and docking (RVD) mission can be divided into a number of major phases: launch, phasing, far range rendezvous, close range rendezvous and mating. In the phasing segment, the chaser performs several maneuvers to reduce the angle between the chaser and the target, and reach the initial aim-point where the chaser has a definite relative position and velocity to the target. It is difficult to reach a precise terminal due to orbit perturbations, orbit determination errors, maneuver control errors, and the long duration to rendezvous (about two days). The main goal of this paper is to provide a new engineering oriented rendezvous phasing strategy which has a good performance in terminal precision considering orbit perturbations, orbit determination errors and maneuver control errors. The strategy includes a nominal programming problem and several real time programming problems. There are five maneuvers in the strategy including four tangential impulses and one normal impulse. A nonlinear programming model is introduced to get nominal maneuver data. The objective function combines the fuel with the deviations at the rendezvous terminal using weighting factors, the design variables are maneuver positions and impulses, and the terminal relative position and velocity are used as equality constraints. Based on sensitivity analysis, the variables are divided into three groups in simple iteration to get initial reference solution, and the accurate solution can be obtained by employing sequential quadratic programming algorithm. Before every maneuver is performed, the real time programming is made with the updated orbit data and new objective weighting factors, and the nominal solution is used as the initial guess. The errors can be compensated by adjusting the latter maneuvers in the next programming. The Monte-Carlo method is introduced to make an analysis for the terminal precision under this phasing strategy. The result shows that the proposed strategy is robust and makes a great improvement in terminal precision. Compared with the nominal programming, the real time programming has only a little fuel increase.- Abstract document
- Manuscript document
IAC-08.E2.1.5.pdf (🔒 authorized access only).
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