Near-rectilinear halo orbit

In orbital mechanics a near-rectilinear halo orbit (NRHO) is a halo orbit that passes close to the smaller of two bodies and has nearly stable behavior.^[1] The CAPSTONE mission, launched in 2022, is the first spacecraft to use such orbit in cislunar space, and this Moon-centric orbit is planned as a staging area for future lunar missions. In contrast with low lunar orbit which NASA characterizes as being deep in the lunar gravity well, NRHO is described as being "balanced on the edge" of the gravity well.^[2]

The NRHOs are a subset of the L₁ and L₂ halo families.^[3] This orbit type could also be used with other bodies in the Solar System and beyond.

^ Whitley, Ryan J.; et al. (2018). "AAS 18-406 EARTH-MOON NEAR RECTILINEAR HALO AND BUTTERFLY ORBITS FOR LUNAR SURFACE EXPLORATION" (PDF).
^ Nujoud Merancy (June 2023). "How: NRHO - The Artemis Orbit" (PDF). NASA.
^ Spreen, Emily; et al. (May 2017). "NEAR RECTILINEAR HALO ORBITS AND THEIR APPLICATION IN CIS-LUNAR SPACE". IAA.

[1] Whitley, Ryan J.; et al. (2018). "AAS 18-406 EARTH-MOON NEAR RECTILINEAR HALO AND BUTTERFLY ORBITS FOR LUNAR SURFACE EXPLORATION" (PDF).

[2] Nujoud Merancy (June 2023). "How: NRHO - The Artemis Orbit" (PDF). NASA.

[3] Spreen, Emily; et al. (May 2017). "NEAR RECTILINEAR HALO ORBITS AND THEIR APPLICATION IN CIS-LUNAR SPACE". IAA.

[1]

[2]

[3]