NHRO to PCO System Check

Near-rectilinear halo orbit

PE 3,000 AP 7,000

Prograde Circular Orbit

PE 3,000 AP 7,000

Orbit Period 11 hrs
Lunar (or L-point) Amplitude Range
3,000 to 5,000 km
E-M Orientation
∼ 75 ◦ inclination

Prograde Circular Orbits (PCOs) are defined in this paper as circular orbits of various sizes that rotate in the prograde

direction and are highly stable, requiring few to 0 corrections to be maintained. Frozen orbits are similar but need not be circular and have orbital parameters that oscillate around fixed values. Highly stable and/or frozen orbits have been discovered for both the Earth [13] [14] and Moon [15] [16]. Frozen orbits are generally discovered by analyzing unique aspects of the gravitational potential and finding regions of behavior that lend themselves to canceling the effects of shape irregularities.