BASIC CONCEPTS (Rocket Motor)

2.

Basic Rocket Function

Most rocket motors are powered by the chemical reaction between a fuel which is burned and an oxidizer that supplies the oxygen needed for burning. In a solid fuel rocket motor the fuel and the oxidizer are premixed. This blend of chemicals is called a propellant. and when molded into a solid shape inside of a rocket motor, it is called a propellant grain. From room temperature to a safe temperature above, the propellants chemicals peacefully coexist, allowing the rocket motor to be handled, transported, and safely stored. When raised to the proper ignition temperature, those same chemicals begin a violent but predictable combustion reaction that spreads through the propellant at a controlled and predetermined rate.
As the atoms of fuel and oxygen combine, some of their electrons drop into lower energy states, and the lost energy is released as light (the bright and impressive-looking flame) and a great amount of heat. The heat is. in fact, so intense that it raises the temperature of the reaction products by several thousand degrees, causing most of them to expand into a gas. Because these hot gases occupy a much larger volume than the original propellant. a tremendous pressure develops that forces them out the motor’s exhaust nozzle at supersonic speed. The motor is placed in the rocket so that its nozzle points backward, and since Newton’s Third Law of Motion states that for every action, there is an equal and opposite reaction, a pushing force called thrust occurs that drives the rocket forward.

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