Question

When we walk we will push soil behind and then go in straight direction similarly when aeroplanes fly they push air behind. But in outer space there is no such medium then how spacecrafts move forward?

Answer 1

Once you are far from a planet, say, while flying between Earth and Jupiter, mid-course corrections are fairly straight-forward. To speed up, you fire a rear-facing thruster. To slow down, you fire a forward-facing thruster. To alter your course, you fire a thruster in a sideward direction. To rotate your spacecraft, you fire a pair of sideward-pointed thrusters located near opposite sides of the spacecraft. To stop rotating, you fire thrusters aimed in the opposite direction