The first modern rocket engines were designed for military use in the 1930′s by Wernher von Braun and Hellmuth Walter. However, rocket engines have been seen in history as far back as 400 BC. A Greek man named Archytas was able to propel a wooden bird along wires using steam propulsion. However, this type of rocket engine was nothing compared to the technology that is used today.
A rocket engine, also called a jet engine, is able to use a propellant to form an extremely high-speed propulsion jet stream and is applicable to both spacecraft and atmospheric use. Missiles use rocket engines to create thrust and typically are internal combustion engines. Rockets are able to create high exhaust velocities and are also energy efficient at high speeds. Propellant used by rocket engines have a tendency to burn out quickly. Large amounts of propellant are needed to keep sustained flight. In the case of space shuttles, rocket engines are able to use a reserve of propellant that allows the shuttle to blast out of our high-gravity atmosphere.
All rockets work on the same principles. They consist of a nozzle, combustion chamber, and an injector of some sort. For propulsion to occur, the combustion chamber must be resilient enough to handle the pressure of the combustion process. The gases released from combustion are then passed through the chamber and nozzle. These components must be cooled due to the high temperatures from combustion. The gases are directed downwards to create an upwards lift.
The solid fuel rocket engine can only be ignited once but has a stupendous amount of power. There are fewer parts and the fuel in the engine is mixed with an oxidizer to become a solid. The solid case will cover the inside of the rocket casing causing all the fuel to burn and be expelled in one direction. The force of this explosion is directed towards the bottom of the rocket.
The liquid mono-propellant rocket engine uses a single liquid, such as hydrogen, to provide lifting power. Hydrogen, for example, is decomposed into oxygen and steam to help lift the aircraft. Since it only uses one liquid, a mono-propellant rocket engine has fewer moving parts and is easier to guide.
The liquid bi-propellant rocket engine is a more complex engine that can is used a various applications. These engines are able to also be restarted and is often used to control movement in a smaller scale. This type of rocket engine has two separate tanks that hold the fuel and a liquid oxidizer. The tanks are opened into a combustion chamber where they are ignited by electricity. This mixture can be released in gradual amounts to control movement.
The nuclear rocket engine is able to create lift by passing hydrogen by the reactor core. This is able to create a propellant that is can be passed through a nozzle to produce massive amounts of power. This nuclear engine is currently is the test-phase and is being studied to create practical uses in the future.
The modern rocket engine now has practical everyday uses from fireworks to weapons. In fact, they are even used in ejection seats for fighter planes, artificial satellites, spaceflight, and even has a hobbyist activity. These rocket engines are able to produce significant amounts of acceleration and get up to high speeds while efficiently using fuel. This monumental creation has even allowed us to reach places that were never thought possible such as the moon or even beyond that.