Korean lunar navigation constellation with stability-filtered optimisation

The international lunar navigation baseline—eight satellites in elliptical lunar frozen orbits (ELFOs) with ω =90∘ —provides robust south-polar PNT coverage but leaves near-side mid-latitudes largely unserved. This gap directly affects the Korea Aerospace Administration (KASA) 2032 lander mission, whose candidate sites span latitudes 40∘ – 70∘ . We propose the Korean Lunar Navigation System (KLNS): five augmentation satellites in ω =270∘ ELFOs that concentrate dwell time over the northern hemisphere. A two-stage optimisation is employed. First, every candidate orbit in a 10,368-element search space is propagated for 720 hours under a perturbed model (lunar J₂ + Earth third-body) and screened against four stability criteria, removing 2864 (27.6%) dynamically infeasible candidates. Second, a greedy sequential algorithm with hard S-ROI protection selects five KLNS satellites that raise N40–70 PNT availability from 0.0 to 89.5%, far exceeding the 50% target, while preserving 99.7% south-polar coverage. The stability-filtered greedy solution outperforms a 100× 50 genetic-algorithm benchmark (85.6%), demonstrating that a well-designed pre-filter can obviate more expensive metaheuristics. Site-specific evaluation confirms 92.5–94.2% availability at all three northern KASA candidate landing sites under the augmented constellation.