INCLINED ORBIT

Inclined Satellite

A satellite is said to occupy an inclined orbit around the Earth if the orbit exhibits an angle other than zero degrees with the equatorial plane. The angle of inclination vary between 0 degree and 90 degree. This angle is called the orbit's inclination. A satellite in an inclined orbit has certain known characteristics (to a close approximation). The inclination of the satellite's orbital plane relative to the earth's equatorial plane increases at a rate of between 0.6 and 0.9 degrees per year. The rate varies from year to year.

The apparent motion of the satellite is periodic with time, the period is approximately 23 hours, 56 minutes, 4 seconds. The apparent motion of the satellite about a nominal position as viewed from the center of the earth is a figure eight pattern, as described by the following equations. Height of the figure eight (North-South): 2 * i degrees. Width of the figure eight (East-West): (i2) / 115 degrees, where it is the inclination of the satellite's orbital plane to the earth's equatorial plane in degrees.

The figure above shows three satellites in inclined orbit. One has only a small inclination, the other two much larger. The scale here is exaggerated for clarity.