How do rockets work in space? The secret behind thrust in a vacuum

DNVN - When it comes to rockets, many people wonder: "In space, there is no air to push, so how can a rocket move?" The answer lies in the classical physics principle that you may have learned in high school - Newton's third law.

Airless Propulsion

Unlike airplanes that need air to create lift and thrust, rockets work by ejecting extremely powerful combustion gases in the opposite direction of the desired direction of travel. When the rocket engine burns fuel, it releases a stream of hot gases at very high speed backward. According to Newton's third law: "For every action there is an opposite reaction of equal magnitude", the gas pushed backward will create thrust to push the rocket forward.

Frictionless space – the advantage of rockets

Once the rocket leaves the atmosphere, it flies into a near-absolute vacuum – no air, no drag. That means that with just a little push, the rocket can keep flying forever until something else comes into play, like gravity or a change in direction from the boosters.

Illustration photo.

Rockets carry their own “oxygen” to burn

On Earth, engines burn fuel using oxygen in the air. But in space, there is no air, so rockets must carry both fuel and oxidizer. This is why rockets are so big: most of their mass is fuel and oxidizer.

Smart navigation system

In space, to change direction or adjust speed, rockets use small auxiliary engines, called thrust control systems (RCS). These engines shoot gas in different directions to rotate, tilt, or change the trajectory of the rocket or spacecraft.

Space does not make rockets "powerless"

Rockets work without air thanks to the principle of jet propulsion and the fact that they carry enough fuel and oxidizer. Rockets don’t need an environment to “push” them into – they just need a strong enough force from within themselves.

Conclusion: Flight in a vacuum

In a seemingly powerless environment like space, rockets demonstrate their maximum power thanks to the basic laws of physics and intelligent technological design. This is how humans conquer the universe, from the Moon to Mars – with the propulsion coming from within.

Bao Ngoc (t/h)

Source: https://doanhnghiepvn.vn/cong-nghe/trong-khong-giant-ten-lua-hoat-dong-nhu-the-nao-bi-mat-dang-sau-luc-day-giua-moi-truong-vac-khong/20250419020336809