Orbit of the Moon the Moon varies as it orbits Earth and hence is not always equal to the Moon's rotational velocity. When the Moon is at its perigee, its rotation is slower than its orbital motion, and this allows us to see up to eight degrees of longitude of its eastern (right) far side. Conversely, when the Moon reaches its apogee, its rotation is faster than its orbital motion and this reveals eight degrees of longitude of its western (left) far side. This is referred to as "longitudinal libration". Because the lunar orbit is also inclined to Earth's ecliptic plane by 5.1°, the
Earth orbit rendezvous EDS and Altair would be met by the separately launched Orion (CEV). Once joined in low Earth orbit, the three would then travel out to the Moon and the Orion/Altair combination would fly a lunar orbit rendezvous flight pattern. Earth orbit rendezvous Earth orbit rendezvous (EOR) is a potential methodology for conducting round trip human flights to the Moon, involving the use of space rendezvous to assemble, and possibly fuel, components of a translunar vehicle in low Earth orbit. It was considered and ultimately rejected in favor of lunar orbit rendezvous (LOR) for NASA's Apollo Program of the 1960s and