Inclination is a fundamental orbital parameter that plays a crucial role in defining the path of a satellite as it orbits a celestial body, such as Earth. It refers to the angle between the satellite’s orbital plane and the equatorial plane of the celestial body it orbits.
The equatorial plane is an imaginary plane that passes through the centre of the celestial body and is perpendicular to its rotational axis. For Earth, the equatorial plane coincides with the plane of the Earth’s equator.
When a satellite’s orbital plane is aligned with the equatorial plane of the celestial body, its inclination is said to be zero degrees. In this case, the satellite’s path traces a circular track around the celestial body’s equator, and it remains fixed relative to the Earth’s surface. However, if a satellite’s orbital plane is tilted with respect to the equatorial plane, its inclination becomes non-zero. The value of the inclination can range from 0 degrees (equatorial orbit) to 180 degrees (polar orbit), with values in between representing inclined orbits.
The inclination of a satellite’s orbit has a significant impact on its coverage area and accessibility to different regions on Earth. Satellites in low inclinations, close to the equator, cover a larger portion of the Earth’s surface between specific latitudinal limits. These orbits are often used for communication and Earth observation satellites that require broad coverage.