An automatic tree search algorithm for the Tisserand graph

doi:10.1016/j.aej.2020.10.028

2021-02-01

David de la Torre Sangrà

Elena Fantino *

Roberto Flores

Oscar Calvente Lozano

Celestino García Estelrich

DOI：10.1016/j.aej.2020.10.028

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摘要

En 中文

The Tisserand graph (TG) is a graphical tool commonly employed in the preliminary design of gravity-assisted trajectories. The TG is a two-dimensional map showing essential orbital information regarding the Keplerian orbits resulting from the close passage by one or more massive bodies, given the magnitude of the hyperbolic excess speed (nu(infinity)) and the minimum allowed pericenter height for each passage. Contours of constant nu(infinity) populate the TG. Intersections between contours allow to link consecutive flybys and build sequences of encounters en route to a selected destination. When the number of perturbing bodies is large and many nu(infinity) levels are considered, the identification of all the possible sequences of encounters through visual inspection of the TG becomes a laborious task. Besides, if the sequences are used as input for a numerical code for trajectory design and optimization, an automated examination of the TG is desirable. This contribution describes an automatic technique to explore the TG and find all the encounter paths. The technique is based on a tree search method, and the intersections between contours are computed using the regula-falsi scheme. The method is validated through comparisons with solutions available in the open literature. Examples are given of application to interplanetary mission scenarios, including the coupling with a trajectory optimizer. (C) 2020 The Authors. Published by Elsevier B.V. on behalf of Fat Lilly of Engineering, Alexandria University.

Keyword:

Spaceflight mechanics

Interplanetary trajectory design

Gravity assist

Tisserand graph