The frequently asked questions on the Science of Cryogenic Rockets are mentioned below:
The ISRO crossed another milestone with the successful test of the indigenously developed Cryogenic Stage, to be employed as the upper stage of the Geosynchronous Satellite Launch Vehicle. With this test, the indigenous Cryogenic Upper Stage has been fully qualified on the ground.
1. What is a cryogenic rocket engine?
Cryogenic rocket engines are those that use liquefied gases (like liquid hydrogen, liquid oxygen) for rocket propulsion. In gaseous form, oxygen and hydrogen have such low densities that huge tanks would be required to store them aboard a rocket. But compressing them into liquids vastly increases their density, making it possible to store them in large quantities in smaller tanks.
2. How does it work?
Sir Isaac Newton’s Third Law of Motion says “every action is accompanied by an equal and opposite reaction”. A rocket operates on this principle. The continuous ejection of a stream of hot gases in one direction causes a steady motion of the rocket in the opposite direction.
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Cryogenic material is held at very low temperatures (the word cryogens comes from the Greek “kyros”, which means icy cold). A cryogenic liquid with which many are familiar is liquid nitrogen but other materials are also widely used in science as cryogenic liquids. It is used as a rocket fuel as well as for other industrial purposes.
3. How is a cryogenic engine different from a conventional rocket engine?
The solid-propellant engine is the oldest and simplest form of rocketry, dating back to the ancient Chinese. It is simply a casing, usually steel, filled with a mixture of solid-form chemicals (fuel and oxidizer) that burn at a rapid rate, expelling hot gases from a nozzle to achieve thrust. Unlike liquid-propellant engines, though, a solid-propellant motor cannot be shut down. Once ignited, it will burn until all the propellant is exhausted.
4. How are rocket engines different from jet engines?
A jet aircraft operates on the same principle, using oxygen in the atmosphere to support combustion for its fuel. But a rocket engine has to operate outside the atmosphere, and so must carry its own oxidizer. The gauge of efficiency for rocket propellants is specific impulse, stated in seconds. The higher the number, the “hotter” the propellant.