Q1. What do you understand by term ‘space’. How can we classify ‘space’?
Ans.: Space is defined as a place free from obstacles. Space is a region above an altitude at which an aircraft cannot fly due to lack of aerodynamic force. Space may be classified as (i) Air space (ii) Outer space and (iii) Deep space.
Q2. Define (i) Air Space, (ii) Outer space (iii) Deep space.
Ans.: (i) Air space is the region of space below 100 Km from the surface of the earth.
(ii) The region of space between 100 Km and 42,000 Km is called outer space or cosmic space.
(iii) Deep space is the region of space beyond 42,000 Km.
Q3. What is a Geo-synchronous Earth Orbit (GEO) Satellite?
Ans.: Any satellite at a height of about 36,000 Km from the earth’s surface orbiting at an angular velocity equal to the angular velocity of rotation of the earth around its axis is called a geo-synchronous earth orbit (GEO) satellite.
Q4. What is a Geo-stationary Satellite? Why is called so?
Ans.: If a satellite moves around the earth in an equatorial circular orbit at a height of about 36,000 Km from the earth’s surface such that its orbit period is exactly equal to the rotational period of the earth its own axis; the satellite is called a geo-stationary satellite.
Q5. “All geo-stationary satellites are geo-synchronous but all geo-synchronous satellites are not geo- stationary”. Explain.
Ans.: A particular case of geo-synchronous satellite is a geo-stationary satellite. A geo-stationary satellite is a category of geo-synchronous satellite which moves in a circular and equatorial orbit round the earth. The orbit of a geo-synchronous satellite may be circular or elliptical and it may move in an equatorial plane or in an inclined plane. When the orbit is circular and equatorial a geo-synchronous satellite may be termed as geo-stationary satellite. However, both of them have one common feature i.e. the satellite move at an angular velocity equal to the angular velocity of rotation of earth around its own axis. Thus their orbit period is always 23 hrs. 56. Minute 4.1 sec.
