Question

Satellites used for telecommunication relay are kept in a geostationary orbit. A satellite is said to be in such an orbit when:
1. The orbit is geosynchronous.
2. The orbit is circular,
3. The orbit lies in the plane of the Earth’s equator.
4. The orbit is at an altitude of 22,236 km.
Select the correct answer using the codes given below:
(a) 1, 2 and 3 only
(b) 1, 3 and 4 only
(c) 2 and 4 only
(d) 1, 2,3 and 4

Answer 1

(a) 1, 2 and 3 only

A geosynchronous Satellite is a satellite whose orbit on the Earth repeats regularly over points on the Earth over time. If such a satellite's orbit lies over the equator, the orbit is circular and its angular velocity is the same as the earth's, then it is called a geostationary satellite. The orbits of the satellites are known as the geosynchronous orbit and geostationary orbit. Another type of geosynchronous orbit is the Tundra elliptical orbit. According to Kepler's Third Law, the orbital period of a satellite in a circular orbit increases with increasing altitude. Space stations and Shuttles in Low Earth orbit (LEO), typically two or four hundred miles above the Earth's surface make between fifteen and sixteen revolutions per day. The Moon, at an altitude of about 238,900 miles (384,400 km), takes about 27 days 7 hours to make a complete revolution [1]. Between those extremes lies the "magic" altitude of 22,236 miles (35,786 km) at which a satellite's orbital period matches, or is an integral part of, the period at which the Earth rotates: once every sidereal day (23 hours 56 minutes 4 seconds). In that case, the satellite is said to be geosynchronous.