Question

Which type of satellite is generally used for communication purposes?

• A. Polar-orbiting
• B. Sun-synchronous
• C. Geostationary
• D. Experimental

Hint:

A geostationary satellite can "see" about one-third of the Earth's surface. Only three such satellites are needed for near-global coverage.

Answer 1

The Correct Option is C

Step 1: Understanding the Concept:
Satellites are placed in different orbits depending on their mission. Communication satellites require a stable link with ground stations.

Step 2: Detailed Explanation:
A Geostationary orbit (Statement 3) is a circular orbit approximately 35,786 kilometers above the Earth's equator.
In this orbit, the satellite's orbital period matches the Earth's rotation period (23 hours, 56 minutes, 4 seconds).
As a result, the satellite appears to remain fixed at a specific point in the sky relative to an observer on the ground.
This is ideal for communication purposes because ground-based antennas can be permanently pointed at a single spot in the sky without needing a complex tracking system.
Polar-orbiting (Statement 1) and Sun-synchronous (Statement 2) satellites are much closer to Earth (Low Earth Orbit - LEO) and move rapidly across the sky. They are used primarily for Earth observation and meteorology, not for continuous broad-area communication.
Communication for television, internet, and telephony relies heavily on geostationary satellites.

Step 3: Final Answer:
Geostationary satellites are the standard for communication because they remain stationary relative to the Earth's surface.