We all assume that earth is a uniform spherical mass and the only force acting is the Centrifugal force resulting from all satellite motion balancing the gravitational pull of the earth. But it is not true. The other forces which can be significant are the gravitational force of the sun and the moon and the atmospheric drag. The earth is not perfectly spherical, there being an equatorial bulge and flattening at the poles, a shape known as an Oblate Spheroid. This oblateness of the earth causes two rotations of orbital planes, one is Regression of Nodes (node appears to slide along the equator) and the other is rotation of Line of apsides (a line joining perigee and apogee passing through earth center). This effect is prominent for the satellites in geostationary orbit. The atmospheric drag is significant for the satellites in LEO (Low Earth Orbit) and predominant in perigee position. This reduces the velocity at perigee position, with the result the satellite does not reach the same apogee height on successive revolutions in turn reducing semi-major axis and eccentricity. Is it possible to avoid these effects? Yes, the inclination is adjusted periodically by proper attitude control at space segment and orbital perturbation is eliminated.