Full Lunar Surface Coverage Orbit

Author: CislunarSpace

Website: https://cislunarspace.cn

Definition

Full lunar surface coverage orbit refers to orbit designs capable of providing complete visibility of the lunar surface, which is a key requirement for future lunar exploration and communication relay architectures. While invariant manifolds derived from libration point orbits enable ballistic landing access to various lunar regions, natural manifolds from any single orbit typically cover only a limited area of the lunar surface.

Different orbit amplitudes provide different coverage characteristics. Small-amplitude libration point orbits offer relatively uniform global coverage but with limited access to polar regions. Large-amplitude orbits and Near-Rectilinear Halo Orbits (NRHO) provide significantly better polar coverage, which is critical for missions targeting the lunar south pole.

NASA's Lunar Gateway program plans to use a Near-Rectilinear Halo Orbit (NRHO) as its reference orbit, in part because of its favorable coverage properties for the lunar south pole region where sustained sunlight and water ice deposits have been identified.

Key Properties

  • Coverage tradeoff: Orbit amplitude determines the balance between global and polar coverage
  • Manifold access: Invariant manifolds provide ballistic transfer paths to multiple landing sites
  • Continuous visibility: Certain orbit families maintain near-continuous line-of-sight to large portions of the lunar surface
  • Communication relay: These orbits are essential for maintaining contact with surface assets on the far side and in polar craters

References

  • Lo, M. W. & Chung, M. J. (2001). "Lunar Sample Return via the Interplanetary Superhighway." AIAA/AAS Astrodynamics Specialist Conference.