The Characteristics of Critical Inclination of Satellite Orbit

The orbit characteristics and perturbation effects of an artificial satellite with critical inclination have been studied. The critical inclination problem in artificial satellite theory is treated as Ideal Resonance Problem(IRP). The KITSAT-1 satellite launched by Arian 42P at Guiana in August 11, 1992 has orbital inclination close to the critical value cos^-1(1/5^(1/2)). In that case, there is a singularity in some perturbation terms and perigee of the orbit is fixed because d¥ø/dt is theoretically equal to zero. But actually the long periodic behaviour in argument of pergee, ¥ø shows a small oscillation. The causes of the oscillation and the relativistic effect in IRP have been studied and applied to the KITSAT-1. The geo-potential perturbation terms which are seperated inclination terms have been obtained using Algebraic manipulation. Also luni-solar disturbing function based on the relative position of the sun, moon, and satellite has been obtained. Phase portraits are used to depict the change of eccentricity and argument of perigee. The variations of each orbital elements have been obtained in case of the KITSAT-1.