Nearlunar

Nearlunar is an adjective used to describe objects, regions, or activities in the vicinity of the Moon, within the Earth–Moon system. The term is not part of formal astronomical nomenclature; rather, it appears in scholarly discussions, mission planning documents, and educational contexts as a descriptive shorthand for things that operate in or pass through the Moon’s near neighborhood.

In practice, nearlunar space refers to the zone around the Moon where its gravity interacts with Earth's gravity, typically extending to tens of thousands of kilometers from the lunar surface. This region encompasses low lunar orbits, near-rectilinear halo orbits around Lagrange points, transient trajectories that approach the Moon, and planned cislunar infrastructure such as communications relays and propellant depots. Work in this domain must account for perturbations from both bodies, radiation, and the complexities of changing dynamic regimes.

Applications include mission design for lunar landers, orbiters, and sample-return endeavors, as well as studies of near-lunar debris and natural satellites. While “nearlunar” has no fixed orbital class or official boundaries, it serves as a useful umbrella term for discussions of near-Moon phenomena and operations.

See also: Cislunar space, Lunar orbit, Near-Earth object.