What is the propellant ?

The Space Shuttle,
one of the most famous rocket.

Like I promised, here is my second post.

I think it is important to explain all the parts you will be building before attempting anything.

So, a rocket is mainly 4 components : the engine, the propellant that comes inside, the body and the payload.

I will explain all the components, how to make them, one at a time.

So let's begin with the propellant.

What is it ? It's simply the fuel that propel (hence his name) your beautiful rocket up to sky.

The propellant consist mainly of 2 different chemicals that act together.

The first is the fuel, it is the chemicals that will burn (like wood or gasoline).

The second chemical is the oxidant, it's purpose is to burn the fuel (like oxygen).

You all know, thanks to your chemistry classes, that for something to burn, it requires oxygen.

But in space or in your engine there is not enough or simply no oxygen.

Simply put the oxidant is the chemical that bring the oxygen on it and allow the fuel to burn.

There is also a third component, the catalyst, but I will describe it in the next post because it is not in all propellants.

You also know that matter has 3 states : solid, liquid and gaseous.

So it's the same for the fuel and the oxidant : they can be either solid, liquid or gaseous.

Having said this, there is different kind of rocket, the solid-fueled, the liquid-fueled and the hybrid rocket.

First, the solid-fueled is like its name means, a rocket with the fuel and the oxidant being solid. They are the cheapest and the easiest to build.

That is the reason why I will concentrate in next coming post I will only give you recipes for solid propellant.

One major drawback is that it cannot be stopped.

After there is the liquid-fueled rocket. It is far more complicated and expensive that the two others.

It requires pumps, tubing and the fuel and oxidant, being liquids, are difficult to handle if you don't have the required tools. But can be stopped.

To finish, there is the hybrid rocket. It is between the solid and liquid-fueled rocket in term of complexity and cost.

Its fuel is solid and the oxidant is either liquid or gaseous.

In the following post, I will describe you what make a propellant a good one or a bad one in terms of characteristics.

The two little rocket next to the External Tank are the Shuttle's Boosters, they are solid-fueled.

The 3 thrusters behind the Space Shuttle are 3 liquid-fueled rocket. The fuel is liquid hydrogen and the oxidant is liquid oxygen.

The External Tank contains just the oxidant and the fuel for the 3 thrusters in separate parts but in the same container.