Three methods for mitigating the secular and long-period eccentricity vector drift. The panels on the left ((a) e-drift compensation) show the approach for compensating for the eccentricity vector drift of the chief using continuous control. The center panels ((b) e-error compensation) show the method that accepts the small eccentricity error and compensates for the relative perturbing acceleration of the deputy via continuous control. The panels on the right ((c) e-drift and e-error compensation) show the hybrid approach. The top and bottom panels for each approach show the time histories of the eccentricity and control accelerations, respectively.