Satellites used for telecommunication relay are kept in a geostationary orbit. A satellite is said to be in such as orbit when:
- The orbit is geosynchronous.
- The orbit is circular.
- The orbit lies in the plane of the earth’s equator.
- The orbit is at an altitude of 22,236 km.
Select the correct answer using the codes given below:
[UPSC Civil Services Exam – 2011 Prelims]
(a) 1, 2 and 3 only
(b) 1, 3 and 4 only
(c) 2 and 4 only
(d) 1, 2, 3 and 4
Geostationary orbit (GEO):
- Satellites in geostationary orbit (GEO) circle Earth above the equator from west to east following Earth’s rotation – taking 23 hours 56 minutes and 4 seconds – by traveling at exactly the same rate as Earth. Hence, statements 1, 2 and 3 are correct.
- This makes satellites in GEO appear to be ‘stationary’ over a fixed position.
- In order to perfectly match Earth’s rotation, the speed of GEO satellites should be about 3 km per second at an altitude of 35 786 km. Hence, statement 4 is not correct.