International collaboration will be necessary for a viable program of exploration beyond the Moon, similar to that for the ISS, and reusable spacecraft will also be needed. High-energy Earth orbits that can be drastically modified with lunar swingbys and small propulsive maneuvers are used, especially near the collinear Sun-Earth and Earth-Moon libration points. The first human missions beyond low-Earth orbit may go to the vicinity of the translunar Earth-Moon libration point. This paper will concentrate on the next possible step, the first one into interplanetary space, that could be a one-year return mission to fly by a Near-Earth Object (NEO). Details are presented of a trajectory that leaves a halo orbit about the Earth-Moon L2 libration point, then uses three lunar swingbys and relatively small propulsive maneuvers to fly by the asteroid 1994 XL1, and return to the Earth-Moon L2 halo orbit for a ΔV of only 432 m/s. Next, rendezvous missions to some other NEO's will be presented. Finally, trajectories to reach Mars, first to Phobos or Deimos, will be outlined. The study uses highly-elliptical Earth orbits (HEOs) whose line of apsides can be rotated using lunar swingbys. The HEO provides a convenient and relatively fast location for rendezvous with crew, or to add propulsion or cargo modules, a technique that we call "Phasing Orbit Rendezvous".