Geo – Stationary Satellite:

Geo – Stationary Satellite: if a satellite revolves in equatorial plane in the direction of earth ‘s rotation i.e. from west to east with a period of revolution equal to time period of rotation of earth on its own axis i.e. 24 hours , then the satellite will appear stationary relative to earth. Such a satellite is called Geo-stationary satellite. Such a satellite revolves around the earth at a height of 36000 km. the orbit of Geo-stationary satellite is called parking orbit. Arthur C. Clarck was first to predict that a communication satellite can be stationed in the geosynchronous orbit.

Escape velocity: Escape velocity is that minimum velocity with which a body should be protected from the surface of earth so as it goes out of gravitational field of earth and never return to earth.

Escape velocity is independent of the mass, shape and size of the body and its direction of projection. Escape velocity is also called second cosmic velocity.

For earth , escape velocity = 11.2 km/s.

For moon, escape velocity  = 2.4 km/s.

Orbital velocity of a satellite V₀∫g  R and escape velocity Vₑ = ∫2gR

Where R= Radious of earth i.e. Vₑ =∫2  V₀  i.e. escape velocity is ∫2  times the orbital velocity.

Therefore if the orbital velocity of a satellite is increased to ∫2 times (increased by 41 % the satellites will leave the orbit and escape.