UPSC Prelims 2011 question on Geostationary Orbit Conditions

Statement by statement

1. The orbit is geosynchronous — Correct
A geostationary orbit is geosynchronous because the satellite’s orbital period matches the Earth’s rotation period, approximately 24 hours.

2. The orbit is circular — Correct
The orbit must be circular so that the satellite maintains a constant speed and remains fixed relative to the same point on Earth.

3. The orbit lies in the plane of the Earth’s equator — Correct
A geostationary satellite must orbit above the equator with zero inclination. If the orbit were inclined, the satellite would appear to move north and south in the sky.

4. The orbit is at an altitude of 22,236 km — Incorrect
A geostationary orbit is located at an altitude of about 35,786 km above Earth’s surface. The figure 22,236 refers approximately to miles, not kilometres.

Extra UPSC Info
Geostationary satellites are mainly used for telecommunication, TV broadcasting, weather monitoring and navigation support.
Ground antennas can remain fixed because the satellite appears stationary.
Three geostationary satellites placed at suitable intervals can cover most of the Earth, except polar regions.
India’s INSAT and GSAT series include communication satellites placed in geostationary orbits.
Geostationary orbit is also associated with the Clarke Belt, named after Arthur C. Clarke.
Final Takeaway

For a satellite to be geostationary, its orbit must be geosynchronous, circular and equatorial. The altitude is about 35,786 km, not 22,236 km. Therefore, statements 1, 2 and 3 only are correct.