Getting shuttles and satellites up into space is no easy task. Rockets are used to produce enough thrust to launch equipment into space. But what’s powering those rockets? Rocket fuel has been around long before space travel. For the most part, they still work on the same basic principles, albeit much more advanced.
Not Your Average Fuel
There are two different types of rocket fuel used. While they both work to get rockets up into space, they go about the task very differently. The first type of fuel is solid fuel. Typically used for the rocket boosters, solid fuel provides that first initial lift. The great thing about solid fuel is that it’s much easier to handle than traditional liquid fuel. Plus, it’s cheaper to manufacture. In most instances, it’s the solid fuel that’s lifting the rocket off the ground during launch.
Solid fuel is primarily made up of aluminum. Of course, creating thrust in the vacuum of space requires a bit more work. The lack of oxygen in space creates a bit of a problem once the rocket has left our atmosphere. Combustion is not possible without oxygen. So how do rockets solve this problem? Well, they pair the aluminum fuel with an oxidizer.
For the case of solid fuel, ammonium perchlorate is used as the oxidizer. A binder is used to hold the aluminum and ammonium perchlorate together. The final result is a rubbery material. It’s not as solid as a block of aluminum, so the fuel needs to be placed in a casing. The casing helps to make the fuel more manageable before and during the launch.
Emissions But Not Exhaust
It’s a common misconception that rockets produce traditional exhaust. Truth is, that giant cloud of “smoke” that you see around a rocket launch pad is nothing like the exhaust from a power plant. When the aluminum burns, it creates water vapor and gases. Those vapors and gases are strategically pointed downward. When they shoot out of the bottom of the rocket, thrust is created to move it towards the cosmos.
Solid Fuel
As we said earlier, solid fuel is predominantly used for the boosters. This is because the fuel doesn’t last long. It’s powerful enough to help the rocket break through our atmosphere and get into space, but it’s not practical to use it for the entire journey. Thus, you’ll see the boosters being ditched after the rocket has made it into the vacuum of space. Then, the second type of fuel takes over.
Liquid Fuel
The other rocket fuel utilized is liquid fuel. It’s used by the rocket’s engines. The biggest benefit of liquid fuel is that it’s very efficient for long-term travel. It doesn’t produce nearly as much thrust as solid fuel. However, that’s not a necessity in space. Without the forces of gravity, Newton’s laws of motion come into play. The rocket can go great distances without using a ton of fuel, which is great for space exploration.
The primary ingredient in liquid rocket fuel is hydrogen. Sometimes, kerosene is used as well. However, hydrogen is considered to be the most efficient and practical option. Like before, an oxidizer is needed to ensure that the combustion process goes off without a hitch. For liquid fuel, liquid oxygen is used. Both the liquid oxygen and the liquid hydrogen are fed into the engine where they can combust.
Byproducts
The byproduct of this combustion is heated water vapor, also known as steam. Like the exhaust of solid fuel, the steam is what provides thrust.
To sum up, rockets use two different types of fuel. Solid fuel, which is usually made up of aluminum and ammonium perchlorate, is what helps the rocket get out of Earth’s atmosphere. Liquid fuel, typically made of liquid hydrogen and oxygen, is what’s responsible for providing the thrust to the rocket’s main engines in space. The next time you watch a rocket launch, pay attention to the cloud of vapor that’s produced. In most cases, you can see when the rocket switches between solid and liquid fuel.