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Space Missions

Space Research in India

You must have seen the firework rockets in the sky. Also you must have seen the launching of rockets for the space programmes in the movies or documentaries. Have you ever thought is there any resemblance between the two? Yes of course, as both of them work on the same principle i.e. the conservation of momentum, you can say the firework rocket as the demo model of space programme rocket.

Principle of rockets

The basic principle of the working of rocket is the conservation of momentum. The principle of conservation of momentum states that the total momentum of the system remains conserved if the external force acting on the system is zero. This principle can be elaborated by the following example:


Let us take the bullet-gun system. Before the firing of the gun, the velocity of the bullet and the gun is zero. Thus the momentum of the system is zero. Now when the bullet of mass ‘m’ is fired with velocity v from the gun of mass M, the bullet leaves the muzzle with the momentum ‘mv’ and the gun moves backward (recoil) with a momentum MV. From the principle of conservation of momentum, the initial momentum will be equal to the final momentum. Thus the final momentum of the system will also be zero.


mv + MV = 0

V= –(mv)/M

The rocket also works on the same principle and on firing it the gases at higher pressure escapes out from exhaust nozzle with high velocity which provide momentum to the rocket in the opposite direction.

Features of rocket


• The combustion takes place in the chamber called engine and the exhaust comes out from the exit towards the earth.

• The payload ratio i.e. the ratio of the payload mass to the mass of fuel is taken into account while designing the rocket.

• The propellant constituting the fuel and the oxidants are kept in separate chambers.

• The propellant is supplied to the engine in controlled quantities with the help of the valves.

• The scientific instrument or the satellite known as payload is placed in the front portion of the rocket.

Working of rocket

• As the rocket carry its own oxidants so it can operate even in the vacuum. The oxidants provide o…

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