Question

The geostationary satellite revolves ____
A. From south to north in the polar plane
B. From north to south in the polar plane
C. From east to west in the equatorial plane
D. From west to east in the equatorial plane

Answer 1

You may know that the geostationary satellite is a special type of geosynchronous satellite. The very name of the satellite may make you wonder whether this satellite is stationary for real (they do appear stationary for a ground based observer). You may also know that their time period of revolution around Earth is one sidereal day (time period of rotation of earth). Putting the above two facts together will lead you to the answer.

Complete step-by-step answer:
Before knowing about geostationary satellites, we should know about geosynchronous satellites. Geosynchronous satellites revolve in geosynchronous orbit and these orbits have an orbital period which is the same as that of earth. Hence, these satellites return back to the same position in the sky after 23.9344696 hours (that is, a sidereal day). Geostationary satellite is a special case of a geosynchronous satellite.
Geostationary satellite is an earth-orbiting satellite that revolves in geostationary orbit. These orbits are the circular geosynchronous orbit located directly above the Earth’s equator. They get their name from the fact that they appear stationary in the sky when viewed from any point on the Earth. They are placed at 22.3kmiles over the equator. Geostationary satellites revolve in the same direction as the Earth’s rotation. As we all know, Earth rotates from west to east. Therefore, the geostationary satellite revolves from west to east in the equatorial plane.

So, the correct answer is “Option D”.

Additional Information: Geostationary satellite has a major advantage that an earthbound directional antenna can be aimed and then left in position without doing any further adjustment. They also have another advantage (because of the possibility of using highly directional antennas) of minimization of interference from surface-based sources and from other satellites.

Note: Among the small drawbacks of geostationary satellites, there are two major drawbacks. First is that, there is a limitation in the number of satellites that can be accommodated in geostationary orbits without mutual conflict or collision. Another drawback is that there is a delay of about 240 milliseconds for the EM signal while making the round trip from the Earth’s surface to the satellite and back.