  We develop a framework based on energy kicks for the evolution of
high-eccentricity long-period orbits with Jacobi constant close to 3 in the
restricted circular planar three-body problem where the secondary and primary
masses have mass ratio mu << 1. We use this framework to explore mean-motion
resonances between the test particle and the secondary mass. This approach
leads to (i) a redefinition of resonance orders to reflect the importance of
interactions at periapse; (ii) a pendulum-like equation describing the
librations of resonance orbits; (iii) an analogy between these new fixed points
and the Lagrangian points as well as between librations around the fixed points
and the well known tadpole and horseshoe orbits; (iv) a condition a ~ mu^(-2/5)
for the onset of chaos at large semimajor axis a; (v) the existence of a range
mu < ~5 x 10^(-6) in secondary mass for which a test particle initially close
to the secondary cannot escape from the system, at least in the planar problem;
(vi) a simple explanation for the presence of asymmetric librations in exterior
1:N resonances.
