Question

Due to third law of motion a Rocket go to space because it pushes the ground but if a Rocket is to be come back to the earth then what should be done because in space their is no air?

Answer 1

According to NASA this principle is easy to observe on Earth. If you stand on a skateboard and throw a bowling ball forward, that force will push you and the skateboard back. However, because your weight on the skateboard is heavier than that of the bowling ball, you won't move as far.

That's the challenge engineers face when designing space engines. Yes, a small amount of thrust does push the spacecraft forward, but it often takes a great deal of fuel to get going anywhere quickly. More fuel means more weight, which adds to the cost of a mission.