It’s so easy to picture a rocket flying in its max speed, but we don’t ever try to learn what makes it go that high with such power in that short time period.
Rocket design is a major concern because every extra cargo adds extra fuel and indirectly, extra weight. Weight is a factor which every spaceship designer always desires to keep as less as possible. And the designers need to be sure that the rocket can cover the required distance without lacking fuel.
Today we are going to discuss what is rocket propellant and what are its different types.
What Are Rocket Propellants?
So, we all know that every action has an equal and opposite reaction. This is what helps the rocket to lift off. Rocket propellant is the fuel that burns and generates thrust to propel the rocket in the opposite direction.
Rocket propellants are mixed with the oxidants for the efficient burning of the fuel. This leads to a chemical reaction in the combustion chamber which produces required power for thrust.
Types of Rocket Propellants
There are three types of rocket propellants, namely – solid, liquid and gas.
1. Solid Propellants
Solid rocket propellants is a solid composite consisting of a solid oxidiser in a polymer binder mixed with energetic compounds, metallic additives, plasticizers, burn rate modifiers and stabilizers.
These are simple and reliable. These are used in the grain forms. A grain is defined as an individual particle of propellant, independent of its shape or size. Solid propellants don’t require special storage facility. It is economic friendly. Due to their high density, these are compact.
Solid propellants have low exhaust velocities due to low specific impulse which is a major drawback as it makes it less efficient. Also, once ignited, it burns until it runs out which makes real-time throttle impossible.
Commonly, these are used in military operations for missiles and boosters.
2. Liquid Propellants
Liquid propellants are of two types, namely – single chemical/monopropellant and bipropellant. Mostly used monopropellants are hydrazine or hydrogen peroxide. In bipropellant, oxidizer and fuel, each contained separately, are mixed in the combustion chamber for further chemical reaction and ignition.
These are easily controllable, unlike solid propellants. This allows astronauts to change the speed of the rocket. Mostly used in orbital launch vehicles due to their high specific impulse. The combustion can also be controlled by simply turning the propellant valves on or off.
Liquid propellants need special care when it comes to handling and storing them. Also, these are unstable, toxic and require special turbopumps and injectors. This increases the weight of the rockets.
3. Gas Propellants
Gas propellants are the least used ones. It contains compressed gas which is inert in nature and are basically impractical for the space travels.
Research is going on for hybrid and gel propellants. There are many technologies and resources which we haven’t used yet but definitely going to use to make our space industry better.