Gateway's invisible traffic choreography in NRHO: a 'string of pearls' plan for lunar arrivals

NASA researchers detail a traffic-management approach for Gateway in its near-rectilinear halo orbit, proposing a 'string of pearls' strategy that keeps loitering spacecraft safely phased with Gateway. The study compares independent reference trajectories with a relative-motion method, testing 60-, 30-, and 10-minute phase offsets; 60 minutes keeps large separations but costs more propellant, 30 minutes offers a balance, and 10 minutes can lead to dangerous close approaches in the simulations. The plan is a theoretical starting point for operational rules and must be refined with vehicle-specific models and contingencies, given the realities of three-body gravity and docking margins.