The Effect of the Spherical Harmonic Gravitational Potential on Satellite Orbits
The Effect of the Spherical Harmonic Gravitational Potential on Satellite Orbits
The Earth is not a perfect sphere, as its rotation causes it to be slightly flattened at the poles. This oblateness can be modeled as a extra band of material encircling the equator. The extra material exerts torque on an orbiting satellite, causing the orbital planes to slowly precess in space rather than being fixed in an inertial frame. The oblateness torque will also cause the line of the apsides to rotate slowly in the orbital plane itself. This Demonstration shows the effect of the Earth's asphericity on the mean orbit elements.