Question

Which of the following conditions is/are essential for geostationary satellite orbits?

• A. Eccentricity is zero
• B. Inclination is close to zero
• C. Prograde
• D. Retrograde

Hint:

A geostationary satellite must have a {circular}, {equatorial}, and {prograde} orbit with a period of 24 hours to stay fixed over a single point on the equator.

Answer 1

The Correct Option is A, B, C

A geostationary satellite must satisfy several orbital conditions to remain fixed above a point on the Earth's equator:

(A) Eccentricity is zero: Correct. A geostationary orbit must be circular, so the eccentricity must be zero.
Any non-zero eccentricity would cause the satellite to appear to move in the sky.

(B) Inclination is close to zero: Correct. The orbit must lie on the Earth's equatorial plane.
An inclination of 0° ensures that the satellite remains directly above the equator.

(C) Prograde: Correct. A prograde orbit (i.e., in the same direction as Earth's rotation, with an inclination < 90°)
is necessary for the satellite to match the Earth's rotational direction.

(D) Retrograde: Incorrect. A retrograde orbit (i.e., opposite to Earth's rotation, inclination > 90°)
would not allow the satellite to maintain a fixed position relative to the Earth's surface.