TITLE: 
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PRELIMINARY STUDY ON THE TRANSLUNAR HALO ORBITS OF THE REAL EARTH-MOON SYSTEM

AUTHOR:
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M.A. ANDREU
Dept. Matematica Aplicada i Analisi, Univ. Barcelona, 
Gran Via 585, 08007 Barcelona, Spain.
e-mail: mangel@maia.ub.es

ABSTRACT:
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The computation of translunar Halo orbits of the real Earth-Moon system (REMS)
has been an open problem for a long time, but now, it is possible to compute 
Halo orbits of the REMS in a systematic way. In this paper, we describe the
method used for the numerical computation of Halo orbits for a time span 
longer than 41 years. Halo orbits of the REMS are computed from quasi-periodic
Halo orbits of the Quasi-bicircular Problem (QBCP). The QBCP is a model for
the dynamics of a spacecraft in the Earth-Moon-Sun system. It is a 
Hamiltonian system with three degrees of freedom and depending periodically on
time. In this model, Earth, Moon and Sun are moving in a self-consistent motion
close to bicircular. The computed Halo orbits of the REMS are compared 
with the family of Halo orbits of the QBCP. The results show that the QBCP is
a good model to understand the main features of the Halo family of
the REMS.

KEYWORDS:
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Halo orbits, Earth-Moon system, quasi-bicircular problem, invariant tori.

