TITLE: Dynamical aspects of multi-round horseshoe-shaped homoclinic orbits in the RTBP Celestial Mechanics and Dynamical Astronomy (to appear) AUTHORS: Esther Barrabes, Josep M. Mondelo, Merce Olle E-mails: barrabes@ima.udg.edu, jmm@mat.uab.cat, merce.olle@upc.edu ABSTRACT: We consider the planar Restricted Three-Body problem and the collinear equilibrium point $L_3$, as an example of a center$\times$saddle equilibrium point in a Hamiltonian with two degrees of freedom. We explore the existence of symmetric and non-symmetric homoclinic orbits to $L_3$, when varying the mass parameter $\mu$. Concerning the symmetric homoclinic orbits (SHO), we study the multi-round, $m$-round, SHO for $m\ge 2$. More precisely, given a transversal value of $\mu$ for which there is a 1-round SHO, say $\mu _1$, we show that for any $m\ge 2$, there are countable sets of values of $\mu$, tending to $\mu _1$, corresponding to m-round SHO. Some comments on related analytical results are also made.