Rockets fly in the sky using Newton's Third Law of Motion. When hot gas is expelled downward from the rocket engine at high speed, it creates an equal and opposite reaction force that pushes the rocket upward. This upward force is called thrust, and it must be greater than the rocket's weight to achieve liftoff.
A rocket engine has several key components. The fuel tank stores rocket fuel, while the oxidizer tank contains oxygen or another oxidizing agent. These are mixed in the combustion chamber where they burn at extremely high temperatures. The hot gas then passes through a specially shaped nozzle that accelerates it to very high speeds, creating the thrust needed for flight.
The rocket launch sequence involves several critical steps. After pre-flight checks and fuel loading, the engines ignite creating massive thrust. At liftoff, the rocket must generate enough force to overcome both its weight and air resistance. As it climbs through the atmosphere, it gradually accelerates until it reaches the speed needed for space insertion.
Four main forces act on a rocket during flight. Thrust pushes the rocket upward, while weight pulls it down due to gravity. Air resistance creates drag that opposes forward motion. For successful flight, thrust must be greater than the combined forces of weight and drag. As the rocket climbs higher, air becomes thinner, reducing drag and making flight more efficient.
To reach space, rockets must travel through Earth's atmospheric layers. They pass through the troposphere where weather occurs, then the stratosphere with the ozone layer, followed by the mesosphere and thermosphere. The Kármán line at 100 kilometers altitude marks the official boundary of space. Once in space, rockets experience no air resistance and must use orbital mechanics to maintain their trajectory in the weightless environment.