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How does a Rocket Work? A Fundamental Explanation of Rocket Science

Jagatheesh is a Mechanical Engineer and interested in writing on science and technology in our life.

This article will simplify rocket science and the technology involved in rocketry

This article will simplify rocket science and the technology involved in rocketry

Rocket science is the science of designing and building rockets. It is the system of using rocket propulsion to lift anything. Have you ever watched a rocket launch? A cloud of smoke covers the entire area, and a huge noise unbearable to the ears. It is the rocket launch, and Newton's laws of motion are the basic principle behind rocketry.

Rocket science is a combination of various branches of Engineering with Physics and Chemistry. It made a huge revolution in the modern world of science, and this article will explain the fundamentals of rocket science.

History of Rocket Science

A historical record of rocketry was found in the 4th century B.C. The Greeks devised wooden birds, a concept similar to modern-day rockets. 300 years later, the Greeks proposed the idea of Aeolipile, which was used as power toys. Chinese were the first people to use gun powder-propelled rockets in their war against the Mongols in the 13th century. Later, Mongols spread the science of rockets to Europe.

The discovery of Gun powder was an accident in a Chinese lab. The first rockets made of iron were used by the kingdom of Mysore against the British forces. Later, Colonel William Congreve developed the next stage of Mysorean rockets.

Konstantin Tsiolkovsky, the father of modern astronautics, proposed the idea of space exploration by rockets. In the early 20th century, Robert Goddard conducted various experiments and made a successful test flight of the first-ever liquid-propelled rocket. Germany's V5 is another milestone in the history of rocket science.

The cold war benefitted the scientific community to bring rocket science to new heights. The advent of NASA and various space organizations across many nations made a remarkable change in rocket science for space research. In the 21st century, the entry of various corporations is taking rocket science to the next level.

“We can build rockets to explore outer space and enhance the quality of life on Earth, or we can use them to destroy other nations.”

— Jacque Fresco, The Best That Money Can't Buy: Beyond Politics, Poverty & War

Newton's Laws and Rocketry

Newton's laws of motion are the basic working principle behind rockets. The third law is the main governing law, and the other two laws also have their role in successful rocketry.

First Law

If a body is at rest or moving at a constant speed in a straight line, it will remain at rest or keep moving in a straight line at constant speed unless it is acted upon by force.

In rocket science, forces will be balanced and unbalanced all the time. This law helps to maintain the balance during launching and direction change.

Second Law

The acceleration of an object depends on the mass of the object and the amount of force applied. The force will be equal to the mass times the acceleration.

The greater the mass of rocket fuel burned, the faster the gas produced can escape the engine, the greater the thrust of the rocket. It is useful in building efficient rockets.

Third Law

For every action, there is always an equal and opposite reaction. This is the primary law for rocketry.

A rocket can lift off from the launchpad only when it expels the gas out of its engine. The rocket pushes on the gas, and the gas, in turn, pushes on the rocket.

It was a single Apple from this tree that changed the direction of the world. Newton laid the foundation for modern science.

It was a single Apple from this tree that changed the direction of the world. Newton laid the foundation for modern science.

The Four Major Systems of a Rocket

A rocket is a complex assembly of various parts. The parts are grouped into four major systems based on their functions.

1. The Structural System

The structural system is the basic frame of a rocket. It involves complex engineering with accurate math. Strong and lightweight materials like Aluminium and Titanium are used for the frame structure. Numerous stringers are connected with hoops and assembled to form a stable rocket structure. The skin is coated with a thermal coating to protect the rockets from the heat produced by air friction.

Thermal coating maintains the temperature of the liquid fuel and oxidizer. Fins are a vital part of the structure it maintains the stability of the rockets.

2. The Payload System

The payload system defines the mission of a rocket. It defines the carrying capacity of a rocket in terms of weight. The payload may be a satellite, space probe, or a spacecraft carrying astronauts. Launching the payload without any impairment determines the success of a rocket.

The fireworks carry black powder, and a ballistic missile will carry nuclear warheads. The working principle is the same for all the rockets.

3. The Guidance System

It is a combination of various devices to control the rocket. A guidance system includes sophisticated sensors, radars, onboard computers, and communication equipment to control the rocket.

The guidance system maintains the stability of the rocket and controls the maneuvers. It continuously calculates the direction of the flight.

4. The Propulsion System

The propulsion system includes the rocket engines, tank pumps, powerhead, and rocket nozzle. Their major function is to produce thrust. The system accelerates a working fluid, and the reaction will produce a force on the system.

In rocket engines, the fuel and oxidizer mix is exploded in the combustion chamber. The combustion produces hot exhaust, which is directed through the nozzle. The hot exhaust is the working fluid of the rocket. As there is no air in space, the rocket always carries an oxidizer for combustion.

There are two kinds of propulsion systems, Solid propellants, and liquid propellants. Fuel and oxidizer are mixed in the solid propulsion rockets. Whereas in liquid propellant systems, fuel and oxidizer are stored in separate chambers in liquid form.


How Does a Rocket Work?

The rockets work on the thrust produced in the combustion chamber. The exhaust gas from the combustion is directed to the nozzle at high speed, giving a lot of momentum. By newton's third law, the exhaust will lift the rocket.

Modern rockets use Convergent Divergent nozzles. The mass flow rate through the engine, exit velocity of the flow, and the pressure of the exit are determined by the nozzle design. The CD nozzles will increase the thrust.

Imagine if you are standing on a skating board with a basketball in your hand. When you throw the basketball in one direction, you and the skateboard will move in the opposite direction, rockets works on the same principle.

Modern rockets use multiple stages. It uses two or more stages with its own engines and propellants. Once the first stage has done its job, the rocket drops that portion and ignites the second stage. From 1980 the parts that fall back are repaired and reused.

How does a Rocket Maintain its stability?

The stability of a rocket is the ability to fly in the right direction without any tumbling. Precision engineering is required to achieve a stable flight. The structural part of the rocket determines the stability of the rocket. For a stable rocket, the following four concepts are vital.

Center of Mass: It is the point at which the entire mass of the rocket acts. A rocket will be perfectly balanced at this point.

Center of Pressure: The aerodynamic pressure of the rocket is concentrated at this point. The surface area on both sides of this point will be the same.

The Nose cone and Fins shape: The nose cone and the fins are specially designed to minimize drag and increase stability and control. The shape of the nose cone determines the air resistance faced by the rocket during its flight. The fins are specially designed to control the air resistance and the center of pressure.

The distance between the center of mass and the center of pressure determines the stability of a rocket. The fins are designed to maintain the center of pressure below the center of mass.

Gimbaled thrust: The exhaust nozzle of the rocket will be swiveled from side to side. It produces a torque that changes the direction of thrust relative to the center of gravity. The navigation of modern rockets follows this mechanism.

Gimbaled Thrust Mechanism

Gimbaled Thrust Mechanism

Why Rocket Science is Hard?

Rocket Science is often considered the toughest subject around the world. It combines so many engineering disciples along with Physics. The truth is rocket science is an easy concept, but rocket engineering makes it complicated. The design and construction of a rocket must be of the highest standards. A small glitch can destroy the millions spend in a minute.

The simple fact is we cannot go and fix any minor mistakes after the launch. So you have to be very accurate with your checklist. A rocket is launched against the forces of nature. It has to overcome gravity, atmospheric resistance and match with the motion of the earth. It involves huge math, and a small mistake will collapse the entire mission.

The cost of failure makes rocket science most complicated. Understanding the basics of rocket science is not so hard. But to become a rocket scientist, you have to study physics, material science, astrodynamics, aerodynamics. So it is up to an individual and his interest to conclude the complexity of rocket science.

The Importance of Rocket science

Our daily life is connected with rocketry. Everyone in the world has used mobile phones or watched television. Thanks to the communication satellites orbiting around the earth. Every news channel broadcasts everyday weather reports that help millions of people, especially farmers. Rocket science made it possible to launch artificial satellites for numerous purposes.

Fireworks play a major role in our celebrations, and rocket science is responsible for the bright sky crackers. Various space scientists are exploring the options to colonize other planets to find an alternative to our planet earth. Rocket science is essential for space exploration.

Citizens of various countries all over the world are living their life peacefully. Every individual nation is responsible for defending its people against invaders. The rocketry in modern weapons is vital in ensuring a sound defense. So without our knowledge, rocket science has a considerable role in our daily life. Let's cheer for the turmoil and the hard work of rocket scientists to make our life more comfortable.


This content is accurate and true to the best of the author’s knowledge and is not meant to substitute for formal and individualized advice from a qualified professional.

© 2021 Jagatheesh Aruchami


Jagatheesh Aruchami (author) from Coimbatore, India on June 26, 2021:

Liz Westwood

Thanks for the read and the comment. I'm glad that the article conveys the information in a user-friendly format.

Liz Westwood from UK on June 26, 2021:

This is a well-structured article that gives an interesting explanation and useful information in a user-friendly format.

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