Robust NRHO Station-Keeping under Operational Uncertainties

Orbits around the equilibrium points in the Circular Restricted Three Body Problem are attractive locations for future space missions. Spacecraft on these orbits are subject to various disturbances such as solar radiation pressure modeling error, maneuver execution errors, and orbit determination error. Thus, we model such errors with stochastic variables. To enable robust station-keeping under such uncertainties, chance-constrained optimal control theory is applied to find optimal feedback policies that minimize the control efforts while satisfying constraints on the position deviations. This new approach to NRHO station-keeping will allow to quantify the maintenance costs under uncertainties, guarantee operation safety, and provide a more systematic method of modeling the station-keeping problem.