How rocket moves in space without air?

The reaction force comes from the gases that are being thrown out. It's bit difficult to visualise unless you truly understand what Newton was trying to say with his third law of motion.

Thrust is generated by the propulsion system of the rocket.
Here the Newton's third law of motion comes into play.

For every action there is an equal and opposite re-action.

I think that folks over at NASA have done a good job in explaining the thrust.



Read: #-Link-Snipped-#

Newton 3rd Law: Every action has exact and opposite reaction. Recoil theory

Air is not medium but the cause of friction in such cases.
Get a balloon fill the air and leave it, that's exactly happens in rocket movement. In space (no air), balloon would move much faster.

cilin rose babuCan any one tell me how a rocket move in space without air? How will the rocket get the reaction force for its motion?

The satellite may get launched with the help of two rocket boosters. By these rocket boosters the space shuttle may gets lift off , after a certain height when the space shuttle leaves the earth and enters into the space , the rocket boosters gets drop down back into the earth.

In space there is no gravity. So the satellite gets float over.

One more thing, In space there is very little or no atmosphere for the fuel to burn. So SpaceCrafts carry oxygen tanks to ignite the fuel which would produce the thrust. Also since the drag in space is very less, even a small thrust would result in a larg momentum change.

well there are specialized engines for this which is called Cryogenic Engines its fuel are gases which are stored in very low temperature as in liquid forms.
Recently ISRO has developed Indian made Cryogenic Engine.
Read here :

<a href="https://en.wikipedia.org/wiki/Cryogenic_rocket_engine" target="_blank" rel="nofollow noopener noreferrer">Cryogenic Rocket Engine</a>