Mumbai University > EXTC > Sem 8 > Satellite Communication and Networks

Marks: 5M

A sun-synchronous orbit, also known as a helio-synchronous orbit, is one thatlies in a plane that maintains a fixed angle with respect to the Earth–sun direction. Thus, the orbital plane has a fixed orientation with respect to the Earth–sun direction and the angle between the orbital plane and the Earth–sun line remains constant throughout the year, as shown in Figure.

As a result of this property, sun-synchronous orbits ensure that:

1. The satellite passes over a given location on Earth every time at the same local solar time,thereby guaranteeing almost the same illumination conditions, varying only with seasons.
2. The satellite ensures coverage of the whole surface of the Earth, being quasi-polar in nature.

Satellites in sun-synchronous orbits are particularly suited to applicationslike passive remote sensing, meteorological, military reconnaissance and atmosphericstudies