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
Orbit insertion Orbit insertion Orbit insertion is the spaceflight operation of adjusting a spacecraft’s momentum, in particular to allow for entry into a stable orbit around a planet, moon, or other celestial body. This maneuver involves either deceleration from a speed in excess of the respective body’s escape velocity, or acceleration to it from a lower speed. The result may also be a transfer orbit. There is e.g., the term "descent orbit insertion". Often this is called orbit injection. The first kind of orbit insertion is used when capturing into orbit around a celestial body other than Earth, owing to the excess