The closest approach during a spacecraft's encounter with a target, especially a planet. It follows the far encounter phase (FE) and is marked by intense high-priority, data-gathering operations for which the mission is intended. For example, NASA's Voyager 2 probe began its NE with the planet Neptune on 24 August 1989 when it passed 4 827 km above the surface. This phase presents the best opportunity for the highest resolution possible. NE is followed by a post encounter phase (PE) when a spacecraft recedes from a planet, and PE is completed when the spacecraft's observations end.
Subjects: Astronomy and Astrophysics.