It is well known that the restricted three-body problem has triangular equilibrium points. These points are linearly stable for values of the mass parameter, <i>μ</i>, below Routh's critical value, <i>μ</i>1. It is also known that in the spatial case they are nonlinearly stable, not for all the initial conditions in a neighborhood of the equilibrium points <i>L</i>4, <i>L</i>5 but for a set of relatively large measures. This follows from the celebrated Kolmogorov-Arnold-Moser theorem. In fact there are neighborhoods of computable size for which one obtains "practical stability" in the sense t |